Talk:Lateralization of brain function/Archive 1

Confusion on lateralization
I have seen it asserted that scientific research has found that mathematics is done with the left brain. But I wonder whether those whom brain researchers observed "doing mathematics" were doing For example, suppose one who has a good handle on the standard first-year calculus course is asked to evaluate the integral
 * what brain researchers consider to be "mathematics", or
 * what mathematicians consider to be "mathematics"?
 * $$\int {dx \over (x^2 + 4x + 13)^2}.$$

I have a deep dark suspicion that some of those brain researchers think that's what mathematics is (it would be a bit like mistaking copy-editing for English literature). On the other hand, suppose a 10-year-old wonders why it is that when you add two odd numbers you get an even number and when you multiply two odd numbers you get an odd number, and figures it out (all 10-year-olds do things like this, except perhaps those who will grow up to be non-mathematicians). That would in fact be mathematics. Likewise, figuring out how to evaluate the integral above without having seen it done in textbooks, as opposed to following the textbook routines, would be mathematics.

So which is it (if either)? Michael Hardy 23:05, 27 January 2006 (UTC)

Have a look at
 * These results suggest that enhanced interhemispheric interaction is a unique functional characteristic of the mathematically gifted brain.

a bit of intensive websearching reaveals a few interesting gems on the subject which I can't remember off hand. I seem to remember finding a study somewhere showing high numbers of left handed in mathematically gifted people.

As you point out there are two different processes going on in mathematics at different levels. There can be intesive symbolic work which fits with the left hemisphere language processing areas. But there is also a more conceptual side possibly requiring right brain processing.

Good to see this article created. I did quite a bit of research on the subject last year and found a whole bunch of interesting stuff have a look at. --Salix alba (talk) 23:28, 27 January 2006 (UTC)


 * Thank you. Michael Hardy 23:58, 27 January 2006 (UTC)

I am being taken to task for suggesting that it is disrespectful to brain researchers who (and I do know this) use sophisticated mathematics, to suggest that in their assertions about which parts of the brain are involved in mathematics, they are applying a childishly simple notion of what mathematics is. But this article as it is now written does encourage that impression. If the impression is wrong, the article should be changed accordingly. Michael Hardy 00:00, 28 January 2006 (UTC)
 * No one should take you to task; these are important and pertinent points you raise. You may find it useful to look up acalculia; this is a neurologic finding that can be seen in relative isolation.  In clinical practice it refers to difficulty with simple calculation - addition and subtraction, mainly, at least as I have seen it tested.  Gerstmann claimed it was related to lesions of the left angular gyrus, but this is probably too specific to be applicable in all cases. -Ikkyu2 23:14, 28 January 2006 (UTC)
 * Heh. He's referring to my comment here that I left on his user page. As the self-appointed Esperanza bouncer I don't take too kindly to perceived intentional rudeness; I am a big fan of the Don't be a dick policy. Also, your point on acalculia (an article I've helped write) is dead on, but still not quite the point Mr. Hardy is getting at methinks. S  e  miconscious  •  talk  23:36, 28 January 2006 (UTC)


 * "Perceived intentional rudeness" was only perceived. Nor do I think there was unintentional rudeness; someone just misunderstood what I wrote.  However, I will admit that if I had written less hastily, I might have anticipated some ways in which my words could get misunderstood and taken care to phrase it differently.


 * "Semiconscious" also seems to think I was "talking at" him, but in fact I have paid close attention to his words. Michael Hardy 23:53, 2 February 2006 (UTC)

I'll see if I can add dig up some more references. I'm also concerned about the word Reasoning in
 * Reasoning functions such as language and mathematics are often lateralized to the left hemisphere of the brain

from my understanding its more symbolic processing and temporal processing in the left. Reasoning is a little to broad a claim. --Salix alba (talk) 00:30, 28 January 2006 (UTC)
 * Salix alba: If you would not mind altering this as well, I would appreciate it. I'm trying to simultaneously do too many real life things to really correct this language right now. See my response below for my thoughts on this article. If you don't get to this in the next few days I should have time next week to dig up better references and resources to more clearly express the notion of laterality of "reasoning" in the brain. Cheers! S  e  miconscious  •  talk  19:04, 28 January 2006 (UTC)
 * No problem I'll wait. This seem an article very much in gestation at the moment. --Salix alba (talk) 19:11, 28 January 2006 (UTC)

New Scientist 28 Jan 06
Interesting series of articles in this week New Scientist in particular Glad to be Gullible by Clare Wilson. .

A few relevant quotes:
 * What determins our tendancy to spot patterns and form associations? It turns out that the key factor is the relative dominance of the right and left hemispheres of the brain. ... Most neuroscientists would accept that the left side of the brain is primarily responsable for language and logical analysis, while the right side is more involved in creativity and what might be called lateral thinking - making connections between disprate concepts.
 * Several recient studies suggest that people who beleive in the paranomal have greater right brain dominance (See Psychiatry Research:Neuorimaging, vol 100, p139 and Psychopathology, vol 34, p75).
 * Brugger and other have shown that there is relativly more right brain activity in people with schizophrenia

Peter Bruger a neroscientist at University Hospital, Zurich. Seems a man to watch. --Salix alba (talk) 15:25, 27 January 2006 (UTC)

Long-winded reply
We are treading dangerously close to semantics here based upon hearsay rather than fact, so I am going to preface this by providing a definition of mathematics from dictionary.com to ensure we all begin from the same point: math•e•mat•ics n. (used with a sing. verb) User:Michael_Hardy] provides one of these two definitions and seems to assign one of them more correctness than the other based upon a non-defined, unreferenced claim of a "mathematicians definition". In fact this notion is furthermore brought forth in Wikipedia's own entry on [[Mathematics which suggests (without citing any sources) that Another view, held by many mathematicians, is that mathematics is the body of knowledge justified by deductive reasoning, starting from axioms and definitions. Stating that “many people” hold any particular definition of something is extremely vague and potentially unfounded and inaccurate, but I'll run with it.
 * 1) The study of the measurement, properties, and relationships of quantities and sets, using numbers and symbols.
 * 2) a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement [syn: math, maths]

This article from Science magazine attempts to describe more precise definitions of "mathematics", suggesting it either has linguistic origins or is more visuo-spatial. The crux of the article suggests there are different forms, what they call "exact arithmetic" and "approximate arithmetic". "Exact arithmetic"--"what brain researchers consider to be mathematics'"--is strongly left-lateralized as this article suggests. "Approximate arithmetic"--"what mathematicians consider to be 'mathematics'"--is bilateral.

Again, in deference to civility, I will amend this article to more clearly state these differences despite my intuition that this is a semantic argument that is unnecessarily clouding what is essentially an already poorly-defined notion. S e  miconscious  •  talk  00:29, 28 January 2006 (UTC)


 * Also, thank you both for coming here to edit this page: if nothing else it is enforcing a more precise definition of the terms we are using. If I am coming across as abrasive, I have no intentions other than clarity and I truly appreciate the efforts here. S  e  miconscious  •  talk  00:37, 28 January 2006 (UTC)

I was not suggesting anything about "approximate" versus "exact". I was suggesting that


 * using mathematical methods developed by others in more-or-less mechanical fashion

involves a different kind of thinking from


 * actually developing such methods from scratch, regardless of whether that is done by a mathematician breaking new ground or a fourth-grader figuring out without help why it is that when you multiply two odd numbers you always get an odd number, or figuring out, without having heard it asserted by teachers or textbooks or anyone else, that the sum of the angles of a triangle is always 180 degrees.

Those are two different kinds of thinking. The latter is not "approximate". Michael Hardy 00:55, 28 January 2006 (UTC)


 * What I seem to be poorly expressing here is that--while I understand your point—it is too ill-defined for an encyclopedic article. You have pointed out to me a place where the language is poorly defined and thus open to many interpretations. Therefore I have altered the language acordingly and provided a citation in support of my change. You can continue arguing about your feelings as to what "mathematics" truly is but that is no longer relevant to this article or this discussion as the word "mathematics" or any of its variants no longer appears in the article in any form (other than in the title of reference I provided).
 * I further agree with Salix alba that "reasoning" is a poor word choice as well. In my experience, the casual reader on Wikipedia does not like a great deal of technical language. In my attempt at trying to communicate a relatively simple idea to benefit the maximum number of readers, I chose to use simpler terms. This was clearly not an appropriate choice however, as I was unaware at how poorly defined a term such as "mathematics" was. My point being, you may continue arguing this--and I will gladly engage you in an argument of semantics if you would like--however in the context of this article I consider this issue to be resolved. S  e  miconscious  •  talk  19:01, 28 January 2006 (UTC)


 * I don't think imprecision in the definition of "mathematics" is the issue here at all. It is not easy to define "mathematics", and any definition would be subject to endless debate among informed people (and uninformed ones too, I suppose).  But I meant that what actual mathematicians and other actual humans actually do, when doing things that everyone would agree is mathematics, is mostly not algorithmic processing. Michael Hardy 01:03, 30 January 2006 (UTC)

A distinction I've always like is betwene Algebra and Geometry. Mathematics can been seen as a process of expressing Geometry in Algebra. Loosly it could be said algebra happens on the left and geometry in the right. (unverified!) --Salix alba (talk) 00:57, 28 January 2006 (UTC)


 * No -- I don't think so. Algorithmic processing versus creative thinking about mathematics is closer to what I had in mind.  The latter is what mathematicians are trying to do; the former is a means. Michael Hardy 01:00, 30 January 2006 (UTC)

Exact/algorithmic/blah blah
Hardy: Did you read the citation I provided? I was simply using the language they used. You can apply whatever words you'd like to this: it's so nebulously defined that I just really don't care. However I find you use of the phrase "recent discussion tends to confirm my suspicion" in your edit summary amusing, since it was more you talking at me rather than a discussion. :) S  e  miconscious  •  talk  00:11, 1 February 2006 (UTC)


 * I've looked at it enough to know that it provides some context that aids in understanding what they mean by "exact arithmetic" and that context is not (yet, anyway) in the present Wikipedia article. That article and the things you and others have said here do tend to confirm my suspicion.  It's just as if they were confusing that sort of thinking with what mathematics actually is. Michael Hardy 21:26, 1 February 2006 (UTC)

A cap on discussion
Recall that we are editing an assemblage of other people's work here, not conducting original research or trying to form cohesive theories out of disparate publications. Much of the current discussion above would absolutely vanish if the editors would confine themselves to statements developed from and taken directly from source publications, ideally cited by page number and possibly quoted briefly under fair use. -Ikkyu2 19:48, 1 February 2006 (UTC)
 * Ugh I'm so sick of this. Michael Hardy clearly has strong feelings a his definition of math. After looking over at the Mathematics article, there's a huge issue with defining mathematis; I'm not sure why Michael Hardy is coming in here and making changes that go against a cited article in Science inserting his own definition based upon phrases such as "confirm my suspicion" and "what mathematics actually is". These are opinions sir, and not worthy of countering a good citation. I have conceded several times over that my original statement was unclear, so I feel the citation is a good compromise. But you just keep inserting your own personal views on the matter.
 * It's clear you feel strongly on this matter, but others feel differently than you and defining mathematics is problematic, so please quit reverting based upon your suspicions. Suspicion does not trump citation. S  e  miconscious  •  talk  02:15, 2 February 2006 (UTC)
 * I did not propose any particular definition of mathematics. I don't know why Semiconscious thinks I did.  I edited this article for clarity, not to support particular opinions.  The only thing I said about the nature of mathematics consisted of a list of examples, not a definition, and I don't think any of them are controversial.  Also, to say that mechanically executing algorithms is not mathematics is also not contrvoersial. Michael Hardy 00:03, 16 February 2006 (UTC)

Recent Brain Research: Fascinating Implications for Educators
Found a facinating review of litrature on brain research: Recent Brain Research for Teachers & Other Curious Souls By Wenda Sheard, J.D., Ph.D. [www.hoagiesgifted.org/Recent%20Brain%20Research.ppt]

Some of the finding include:
 * O’Boyle, M. W., Alexander, J. E., & Benbow, C. P. (1991). Enhanced right hemisphere activation in the mathematically precocious: a preliminary EEG investigation. Brain and Cognition, 17(2): 138-153. EEG patterns of LH activation differ in mathematically precocious youth from that of average math ability students.  “Enhanced RH involvement during cognitive processing may be a correlate of mathematically precocity.” Three tasks: gaze at blank slide, judge which of two faces was happier, determine if a word is a noun or verb.    (EEG, Six mathematically precocious youth mean age 13.2 SAT-Math mean 670, all right-handed, 10-item questionnaire about which hand used when performing tasks.  Control group of 8 right-handed males not precocious at math. Eight EEG sites with cap.)
 * Raz, N., Torres, I. J., Spencer, W. D., & Millman, D. (1993). Neuroanatomical correlates of age-sensitive and age- invariant cognitive abilities: An in vivo MRI investigation. Intelligence, 17: 407-422. MRI, brain symmetry, 29 subjects ages 18-78.  “The magnitude of leftward hemispheric volume asymmetry significantly and uniquely contributed to explaining the variance in both cognitive measures (non-verbal reasoning and vocabulary).
 * Alexander, J. E., O’Boyle, M. W., & Benbow, C. P. (1996). Developmentally advanced EEG alpha power in gifted male and female adolescents. International Journal of Psychophysiology, 23(1-2): 25-31. EEG study of 30 gifted adolescents (mean age 13.3, SAT averages 1100), 30 average ability adolescents, and 30 college-age subjects.  “(T)here were no significant differences in overall alpha power between college-aged and gifted adolescent subjects. These finding suggest that gifted adolescents may have a developmentally enhanced state of brain activity, one that more closely resembles that of college-age adults to whom they also resemble in terms of cognitive ability.”
 * Jausovec, N. (1997). Differences in EEG alpha activity between gifted and non-identified individuals: Insights into problem solving. Gifted Child Quarterly, 41: 26-32. EEG. Seventeen gifted (IQ over 130 WISC, 3 male & 17 female) and 17 non-identified solved four problems.  Recorded relaxed and problem-solving mental states, and hemispheric symmetry/asymmetry.  Gifted more LH (Left Hemisphere activity) when in relaxed state.  Non-identified more LH when in problem-solving state.

--Salix alba (talk) 18:48, 15 February 2006 (UTC)

Split-brain patients: separate article?
I think the section "Split-brain patients" warrants an article. Thoughts?

Lateralization - help request
I've been given a rough time by someone arguing that some authors say brain lateralization is an old concept. Is that so, or not?

I need to know the current state of belief about brain lateralization, and how sure or accepted it is in neuroscience/cognitive science, with a few more cites or findings.

If there was a controversy or dispute, but it's no longer in question, or it's been clarified, could a section "Controversy" be added to the article to make it clearer?

Last, I've tidied up the references as a way to say thankyou in advance for any help. The footnote from "Goulven" isn't referenced in the article, someone needs to fix it :)

Many thanks!

FT2 (Talk 11:43, 30 June 2006 (UTC)


 * Like most science the answers tend not to be cut and dried. The field it is still very much a work in progress and as functional imaging techniques improve we will begin to learn more about how verious functions are localised in the brian. Its worth reading the rest of this talk page where there are quite a few references which haven't made it into the main article. Alas I have several other projects on the go so I don't have much time to devote to this article. If you can get hold of Goulven it might provide a good summary of recient research. --Salix alba (talk) 14:48, 30 June 2006 (UTC)
 * But is the principle of higher cognitive functions being lateralized, pretty much established, or still disputed, or disproven? FT2 (Talk 16:19, 30 June 2006 (UTC)


 * It depends on the function. I think you are referring to popular ideas of left and right. Sure there is a lot of nonsense spread by marketeers of various products. Early in the 70s it was left and right brain people, then later people talked about getting a balance by various means (certain machines, drugs, activities). Some old psychology techniques used the left right brain research of early neuroscience. They made all sorts of unfounded claims for methods. I think this could be added into a section. I have a book on popular myths. It may be useful to open a section. I will add something provisionally using the information. Please revert it if you think it is wrong. Pacificsun 03:18, 19 July 2006 (UTC)

Lateralization in pop psych and as extended to cultural metaphors?
I came to this article looking for a critical discussion of the left-brain/right-brain concept as it is misapplied by non-academics (as well, perhaps, as by some people with enough training in psychology to know better). It's common to the point of cliche to say, usually without any scientific evidence, that a particular activity, organization, job, or even a whole person or society is "left brain" or "right brain". I think that this article would benefit by a section or perhaps an external supplemental article on this question.

Here's a citation which gives some examples of what I'm talking about, although it is from the management literature and may be slightly off-target for this article:

Hines, Terence (1987). Left Brain/Right Brain Mythology and Implications for Management and Training. The Academy of Management Review, 12:4, 600-606.


 * Excellent call - yes please! Seconded. Some expert....? :) FT2 (Talk 23:24, 2 July 2006 (UTC)

I looked it up and it is good information. I also have other citations to add to the section. I added also the pseudoscience category. This is a category that helps readers browse any articles with pseudoscience issues. Its not a list of pseudosciences and it doesn't mean that lateralization of brain functioning is pseudoscience. Have a good weekend Matlee 06:36, 25 August 2006 (UTC)

copied section

 * In a test in which split- brain patients had to match a series of household objects, the left brain would match by function while the right would match by appearance. So, when seeing a cake on a plate, the left brain would connect to a picture of a fork and spoon while the right brain would select a picture of a broad-brimmed hat. This evidence appeared to support the idea of a highly modular brain in which, for example, thinking in logical categories was a strictly left hemisphere function while mental imagery and spatial awareness were handled on the right


 * But, says Joseph Hellige, a psychologist at the University of Southern California, this picture changed dramatically as soon as brain-scanning experiments began to show that both sides of the brain played an active role in such processes. Rather, it seemed to be processing styles that distinguished the two halves. Under the scanner, language turned out to be represented on both sides of the brain, in matching areas of the cortex. Areas on the left dealt with the core aspects of speech such as grammar and word production, while aspects such as intonation and emphasis lit up the right side. In the same way, the right brain proved to be good at working with a general sense of space, while equivalent areas in the left brain fired when someone thought about objects at particular locations.

Copied from http://www.rense.com/general2/rb.htm --Tgr 09:09, 10 December 2006 (UTC)

InternetHero's edits
User:InternetHero keeps adding the phrase "science of math" to the list of things allegedly done by the left brain. Simple arithmetical calculations are not science. Mathematics, on the other hand, is by some reasonable definitions, science.

In 3rd grade you're told that 5 &times; 3 is


 * 3 + 3 + 3 + 3 + 3

whereas 3 &times; 5 is


 * 5 + 5 + 5.

You're also told that not only do those yield the same number, but that that holds generally, with any other numbers.

If you figure out why that pattern holds generally, you're doing mathematics. But if you develop calculation skills without understanding such things, you're not doing mathematics, let alone "science of mathematics". Michael Hardy 20:45, 19 February 2007 (UTC)


 * The concept of multiplication. Do you understand the brain or just math? Please answer honestly.


 * Again, I think zinc ions are relevent here. I really don't understand the sloppiness and disregard for basic courtesy in your edits. I will revert from editing untill properly designated, but seriously for almost everyone except overly reformative mathematicians, the ability of arithmetic is in strong relation to math.


 * Also, are you denying Benjamin Peirce's words: "the science that draws necessary conclusions". InternetHero--23:31, 27 March 2007 (UTC)

Please see science. Hi, sorry for not discussing with you 1st, but I didn't know you could.

The broadness of science and it's many sub-catogories derived from it's autonomity/abstractness, were meant to be pertained in respect to the concepts of contrast and/or comparison. As you state, the reasonable/logical properties of mathematics can be attributed to both sides of the corpus.

I've made myself a folly. I got 2 attached and let my perogatives take over my reasoning in respect to putting science in both charts. I got attached to this because of the other edit which entitled: Science of Math - Science of Philosophy.

As Michael pointed out, both sides can bi-laterally comprehend mathematical concepts. I was wrong.

Science can constitute any system of objective knowledge - which in this case, refers to the 'system' of simple-algoritmic proccesses via the system of transducing of stimuli.

1) "simple computations are not "science"; 2) mathematics does not consist of simple algorithmic processing"

i) Wiki - Scientific Method: It is based on gathering observable, empirical, measurable evidence, subject to the principles of reasoning.

ii) Wiki - Mathematics: Is the body of knowledge centered on concepts such as quantity, structure, space, and change, and also the academic discipline that studies them.

When savants draw a picture of a buildings window patterns, they can't process concepts like Base x Height. The can individually count or 'grasp' all the windows as a whole, and draw them in that respect. If this process is not a matter of the concepts bolded above, then I don't know what is. 63.135.9.214/InternetHero 05:01, 19 February (UTC)

Semantic and Episodic memory
They both are used my the temporal lobe also:

"The medial temporal lobes (near the Sagittal plane that divides left and right cerebral hemispheres) are thought to be involved in episodic/declarative memory. Deep inside the medial temporal lobes, the hippocampi seem to be particularly important for memory function - particularly transference from short to long term memory and control of spatial memory and behavior."

You guys make a conclusion for yourselves, but I think theres something here. For instance, it states above that the Sagittal plane involves episodic memory, yet is involved in semantic memory as a pre-requisite of declarative memory (Declarative: Semantic/Episodic).



This can also be related to left-handed people and this article:

''"In 2006, researchers at Lafayette College and Johns Hopkins University in a study found that left-handed men are 15% richer than right-handed men for those who attended college, and 26% richer if they graduated. The wage difference is still unexplainable and does not appear to apply to women.[26]

As well as possible intelligence advantages, being left-handed can also bring about other benefits, including:

Brain hemisphere division of labor: The premise of this theory is that since both speaking and handiwork require fine motor skills, having one hemisphere of the brain do both would be more efficient than having it divided up.[citation needed] Advantage in hand-to-hand combat: Left-handers have a 'surprise' factor in combat, since the majority of the population is right-handed."'' - User:InternetHero 17:33, 16 April, 2007 (UTC)

Pseudoscience category?

 * Hines (1987) states that the research on brain lateralization is valid as a research program, though it has been applied to promote subjects and products far out of the implications of the research. For example, the implications of the research have no bearing on psychological interventions such as EMDR, brain training equipment, or management training. One explanation for being so prone to exaggeration and false application is that the left-right brain dichotomy is an easy-to-understand notion, yet is often grossly oversimplified and misused for promotion in the guise of science. This is often known as right-brain mythology, and is associated with occult notions such as yin/yang, righteous and sinister, and day and night. The research on lateralization of brain functioning is ongoing, and its implications are always tightly delineated, whereas the pseudoscientific applications are exaggerated, and applied to an extremely wide range of situations. Hines, Terence (1987). Left Brain/Right Brain Mythology and Implications for Management and Training. The Academy of Management Review, 12:4, 600–606.


 * I moved the above section here for discussion. I don't think this article should be in the pseudoscience category. I have removed it. But wanted to open a discussion here and past this paragraph that I cut from the article. Is this really necessary? --Comaze 15:12, 26 June 2007 (UTC)


 * I think that it's important that such material be here, given that there is a popular misconception about the "left-brain/right-brain" sort of research. There is clearly a real, and proper scientific research program going on regarding the relative strengths and capacities of the cerbral hemispheres (i.e., left for language production, dating back to Broca, or the preponderance of right sided lesions leading to neglect) which serious cognitive neuroscientists recognize as part of their domain.  However, that research has largely caught the attention of the general public in a watered down, distorted manner, and I think that it is important to mention this not as a piece of congitive neuroscience, but as a piece of sociology of how scientific findings are dissemenated and used by the general public.  I agree, however, that laterlazation of brain function is not pseudoscience, and agree that the cat should be removed.  Edhubbard 00:35, 27 June 2007 (UTC)


 * I think the text needs to be summarised and put in the main body somewhere. We do need to be careful because most functions that are popularly thought of as lateralised are present in both sides of the brain. However, in general the left-hemisphere tends to be dominant for logic, language whereas the right hemishpere tends to be dominant for non-linguistic functions (visualisation, mental rotation, face recognition, etc.)(p.7 Western et al. 2006 "Psychology: Austraian and New Zealand edition" John Wiley). So the popular understanding is not too far off the mark. --Comaze 04:56, 27 June 2007 (UTC)

The reference of Hines definitely says its used in a pseudoscientific way if too broad. I will have a look at the rules for inclusion to the pseudoscience category though. I am working in neuroscience research and there is a big complaint by neuroscientists about people saying pseudoscientific things about hemisphericity. Its big issue and is taught at university level. So neuroscientists and science thinkers like Hines want to say that there is a big pseudoscience problem here in this small area of hemisphericity because of commercial persuasion. But they do not say there is a pseudoscience problem generally in neuroscience. Matlee 05:57, 27 June 2007 (UTC)


 * I can understand why you want to warn people about the mythology in brain sidedness. There are people running around saying that people are more left or right brained, etc. However, I'm not convinced that this article should be in the pseudoscience category. Nor am I convinced of the reliability or authority of Hines as a source for this article. Besides, the main issues are covered in the lead. It now says something like the popular lateralised functions are actually located on both sides of the brain. --Comaze 06:33, 27 June 2007 (UTC) Perhaps we could have paragraph covering the left-right sidedness myths with appropriate evidence. --Comaze 06:41, 27 June 2007 (UTC)


 * Ok I'll look for more sources but I think the Academy Management Review is good enough. I kept some references from a seminar I went to on this problem and will check them. There were also some more commercial examples who use the pseudoscience ideas listed. I might have a look on the web because I am sure its a getting more popular problem. Do you know of any other area that might use myths? I have some idea but not sure about the sort of range. Matlee 06:49, 27 June 2007 (UTC)


 * Thanks. These left/right brain myths pop up in teaching, adult education and management training. Best --Comaze 07:19, 27 June 2007 (UTC)


 * I think there are two seperate issues here. One is the category tag, which I should stay removed (good spot Comaze), since it seems to apply to the whole article, while it is only this one section that is potentially pseudoscientific.  As I noted above, there is some scientific truth to the idea that the hemispheres do slightly different things, but that has been radically oversimplified, to the point of potential misrepresentation in the eyes of the generral public.  I think Matlee is right to emphasize the word dominant, which is exactly what is missing from much of the pop-culture discussions of lateralization of brain function.   As for the actual content, I think that we should probably use more up-to-date and more cognitive neuroscience references, of which I can suggest three good ones here off the top of my head:
 * J. Graham Beaumont (1983). Introduction to Neuropsychology. The Guilford Press. ISBN 0898625157. - This book is a bit dated (he is working on an updated version) but his discussion of the link between lesions of the left or right hemisphere, language and handedness is some of the most detailed and complete in the textbook world.
 * Michael S. Gazzaniga, Richard B. Ivry, George R. Mangun (2002). Cognitive Neuroscience, Second Edition. W. W. Norton & Company ISBN 0393977773. - This is the textbook that we used when I was an undergraduate, and will be one of the two texts that I will use (along with Ramachandran's Phantoms in the Brain) when I teach my own class.  It includes a seperate chapter on lateralization of brain function (Ch. 9), but also treats lateralization in the appropriate places, along with the relevant topics.  They are currently working on a third edition.  Note, also that Ivry and Robertson have a more integrated account of how such differences might arise from low-level differences in the spatial and temporal frequencies preferentially treated by the two hemispheres (The Two Sides of Perception, 1997 MIT Press) although this is probably beyond the scope of the current article.  Also, of course, there is a thorough treatment of split-brain work here, given that Gazzaniga is first author.
 * Jamie Ward (2006). The Student's Guide to Cognitive Neuroscience. Psychology Press. 1841695343. The most recent cognitive neuroscience textbook on the market, and one that is unique in that, it is the only one (so far) to have chapters on topics like the cognitive neuroscience of reading and numerical cognition (Chs. 11 and 12, respectively).  It also tends to place more emphasis on neuropsychological methods than does the Gazzaniga text (which is why I would supplement Gazzaniga with Ramachandran).  Again, there's no separate chapter on lateralizaition of function, but the lateralizations of these functions are treated within the appropriate contexts.
 * The important thing to me is that we, in some way, point out this more subtle point. One hemisphere or the other can be dominant for a given function, this varies by handedness, by sex, etc, but at the same time, there is a lot of this type of stuff that has been radically oversimplified in the public literature, since the earliest discoveries of some of these divisions of labor in the human brain.  Edhubbard 07:28, 27 June 2007 (UTC)

Inferior, terrible, dumb? I don't understand how the evaluative words can be used in the overall category. 72.189.94.109gurbinav

Mathematics
Singular concepts of relativity such as counting (not division where a placeholder is needed) would allow the ions/synaptic plasticity to require certain regions of the brain to be used as a prerequite in the left brain. It all depends on which part of the brain the person uses, but I'm pretty sure the Corpus is the divisor/placeholder so most of the counting/multiplying wouldn't occur there. You might be able to count holistically like savants, but I'm useless in that department as I am not a scientist conducting experiments. InternetHero (talk) 02:01, 30 June 2008 (UTC)

I've reverted certain of InternetHero's revisions, sorry, as Dehaene et al. does not address sidedness of counting, measurement, or perception of shapes or motions. Is there a reason the table lists "perception of counting/measurement" as opposed to simply "counting/measurement"? —Preceding unsigned comment added by Grothmag (talk • contribs) 22:26, 1 July 2008 (UTC)
 * The problem really isn't the citations; as they are perfectly reasonable for discussing lateralization of mathematics, but rather the qualifiers of "perception of counting/measurement". I've reinstated the refernces, and put in more precise qualifiers, since at least certain aspects of mathematics ("direct retrieval" as we do with times tables) do appear to be uniquely left-hemisphere lateralized, while other aspects of mathematics, including approximate calculation, comparison and so on, appear to depend on both the left and the right hemisphere. Incidentally, although Dehaene's research does not directly address "perception of shapes or motions [sic]" there is plenty of evidence that demonstrates that visual processing of these features is indeed bilateral (see for example, MT/V5 for processing of motion and LOC for shape). Edhubbard (talk) 02:17, 2 July 2008 (UTC)

discrepancy - table/text
I just wanted to repeat a remark I made in the Cerebral hemisphere talk page (Talk:Cerebral_hemisphere), because it also applies to this article. There is a discrepancy in the presentation: On the one hand it is claimed that popular psychology overemphasizes the lateralization of broadly defined concepts such as logic and intuition, on the other hand the upper half of the table in the section "Which side?" is doing just the same. --88.72.195.165 (talk) 17:13, 8 July 2008 (UTC)
 * Agreed. And the references are from similar non-reliable sources.  I think an expert opinion is required, perhaps a neurologist.  The table has no place in an article about the verifyable neuroscience anatomy of the brain, it is decidedly outof place.  Perhaps the table should be moved into a separate article about popular neuroscience myths. --- Roidroid (talk) 13:50, 27 August 2009 (UTC)
 * Hang on... The discrepancy between the "pop-science" lateralization story and the peer-reviewed cognitive neuroscience understanding of lateralization is a little more subtle than either of you seem to understand. In short, the problem is not that the hemispheres specialize for certain things, which is supported by a host of evidence, going back over 100 years, but rather that this fact has somehow been translated into the idea that there are "left-hemisphere" people and "right-hemisphere" people.  This radical oversimplification of the real evidence from neurology and cognitive neuroscience is what is at issue in several places throughout wikipedia.  But, the basic information in the table does not fall prey to that oversimplification.  Additionally, Roidroid suggests that the references are non-reliable, but from what I can see, the majority of the references in the article and in the table come from peer-reviewed journals, such as Science (reference 10), Cognitive Neuropsychology (reference 11), Brain (reference 16), and textbooks like Psycholinguistics: Learning and using Language (reference 15) and Principles of Neural Science (reference 16).  I would agree that the first three lines of the table have to go, but not the entire table. I have removed them, and as such, I am removing the pseduoscience tag. Edhubbard (talk) 12:55, 28 August 2009 (UTC)
 * This seems good now Roidroid (talk) 05:25, 21 September 2009 (UTC)


 * I was mainly concerned with the removed parts of the table. As far as I understand it the case for lateralization of verbal processing is strong. Numerical processing possibly but I don't know about that. --88.74.56.40 (talk) 21:04, 30 September 2009 (UTC)

Mathematics
Under "left", we find:
 * mathematics (exact calculation, numerical comparison, estimation)
 * mathematics (exact calculation, numerical comparison, estimation)

and under "right", we find:
 * mathematics (approximate calculation, numerical comparison, estimation).
 * mathematics (approximate calculation, numerical comparison, estimation).

Obviously this excludes most of mathematics. Calculation, estimation, and comparison are only a tiny tiny part of all of mathematics. Can more be said, or is that unknown? Michael Hardy (talk) 01:57, 25 October 2008 (UTC)


 * Maybe "arithmetic" would be better than "mathematics" here. Unfortunately, I'm not familiar with the sources that are cited for that entry in the table. Looie496 (talk) 05:53, 25 October 2008 (UTC)
 * Yes, I agree that arithmetic would be better than mathematics. In fact, the truth of the matter is that there have been very few studies of anything "higher-level" than basic addition, subtraction and multiplication.  The only lab that has taken on even basic algrebra is John Anderson at Carnegie Mellon University. Edhubbard (talk) 04:38, 27 October 2008 (UTC)

OK, a favorite example of mine from "arithmetic":
 * 3 &times; 5 means 5 + 5 + 5;
 * 5 &times; 3 means 3 + 3 + 3 + 3 + 3.
 * Why must these two differently defined things always be the same number, not only with this particular pair of numbers, 3 and 5, but also with any other pair?
 * Why must these two differently defined things always be the same number, not only with this particular pair of numbers, 3 and 5, but also with any other pair?
 * Why must these two differently defined things always be the same number, not only with this particular pair of numbers, 3 and 5, but also with any other pair?

It's not too hard to answer that question. And it's not too hard to ask that question, when, in childhood, one first learns the definitions. Any child who is curious about math is likely to ask that question, and with a bit more effort to answer it. Now when one thinks it through and figures out what the answer is, then what one is doing is mathematics, and by some definitions, is arithmetic. But it is not numerical computation; of either an exact kind or an approximate kind. You don't need to ask about more advanced mathematics than that to see the issue here. The right word for what the article talks about is neither "mathematics" nor "arithmetic"; it is "numerical computation" or "calculation" or the like. Michael Hardy (talk) 03:32, 29 October 2008 (UTC)
 * Are you talking about this Wikipedia article or about the Dehaene papers that are being referenced? Anyway, I sort of see what you are saying, but I don't think it's necessarily safe to assume that the brain makes the same distinctions that seem correct philosophically. Looie496 (talk) 05:01, 29 October 2008 (UTC)
 * I think that Michael is referring to the word choice, by pointing out that even what we would typically include under the heading of "aritmetic" is much more complex than what has been done in most imaging studies, due to the technical limitations of the method. So, perhaps something like "calculation" rather than "mathematics"?
 * On the scientific point, the closest thing to the type of analysis that Michael is thinking of is work that has been done by John Anderson's group at CMU, where they looked at multidigit multiplication and tested so-called "novice" (right-to-left) computation and "expert" (left-to-right) computation (presented as a poster at last year's Cognitive Neurosocience Society meeting in SF, not yet peer-reviewed to my knowledge). This jumps even beyond the level of analysis Michael is thinking of, but I don't think the exact question he is asking has been addressed using any techniques that allow us to infer lateralization.  The general inference is that these simpler tasks, like those used by Dehaene or Brian Butterworth's work in patients, allow us to infer what the substrates of more complex processes may be, but this is an inference. Edhubbard (talk) 14:08, 29 October 2008 (UTC)
 * Actually, going back to Michael's initial point, maybe the best thing would be to call this "numerical cognition"? In that case, we make it clear that we are referring to basic numerical processes, since things like comparison and estimation (that is, estimating the number of objects visually seen, not approximate calculation, which is listed seperately) do not even really rise to the level of "computation". Edhubbard (talk) 14:11, 29 October 2008 (UTC)

mentioned in A Scanner Darkly movie and book
popculture sub heading

(side note: I am reading a lot of left hemisphere shatter and you guys need to chill and enter the world of the right hemisphere.Grays upon grays.) —Preceding unsigned comment added by 137.186.195.16 (talk) 11:16, 1 January 2009 (UTC)

Merge with Cerebral Hemispheric Dominance
It has been suggested that the article Cerebral Hemispheric Dominance be merged with this one. I personally dont agree. Dominance and Lateralization are 2 completely different topics.just-emery (talk) 18:46, 1 June 2009 (UTC)

Definitely maintain the separation. Where to put the dominance article without getting into the pseudoscience/ pop-psych debate further would be hard to establish. —Preceding unsigned comment added by 163.238.46.58 (talk) 18:03, 12 August 2009 (UTC)
 * In fact, just a quick look at the cerebral hemispheric dominance article suggests that it is a collection of the worst pop-psych misinformation about the cerebral hemispheres around (the whole basic idea that there are "left-brained" and "right-brained" people being the biggest one), contributed almost exclusively by one editor in the course of two days. I don't think that article should be merged with this one, and in fact, think that the article, although having some reliable sources should probably be deleted, or massively re-written to get rid of the pop-psych "neuromyths"   . Edhubbard (talk) 19:00, 12 August 2009 (UTC)
 * I don't actually see any valid content in Cerebral Hemispheric Dominance that would be worth merging. I left a message at the creator's talk page (User talk:Julie.summey) saying so, but she never responded, consequently the article never came up on my watchlist again, and I forgot about it.  I would favor turning it into a redirect. Looie496 (talk) 19:22, 12 August 2009 (UTC)
 * I tend to agree... the only way to save that article is to make it clear that this is a sort of pop-psych fallacy. I think that this has already been noted in other places, but it might be worth mentioning explicitly in an article with that title.  Or, it could just be too much hassle and a fight to keep it.  If we have some people that are willing to take it on, then it might be a service the wikipedia using world to make sure that it's clear that this is a popular misconception, but a misconception nonetheless.  Otherwise, just redirect here and include some discussion of the fact that these are popular misconceptions? Edhubbard (talk) 19:28, 12 August 2009 (UTC)


 * I agree with Looie. There's no real science here, just pop-psych, and the content already present at Lateralization of Brain Function is better science, better explained, and better referenced.  I would support deleting this article and turning it into a redirect to both the neuromyths article (if we can do that) and the lateralization article. Mirafra (talk) 20:10, 12 August 2009 (UTC)


 * I think merging (on paper) is better - I doubt an AfD would reach consensus and the result would likely be a merge anyway. I have not looked at the articles in detail - I just woke up and require coffee to get my hemispheres working more..... Casliber (talk · contribs) 20:50, 12 August 2009 (UTC)

I moved the article to the correct title (lower-case initials) and did some copy-editing on it, bringing it closer to the norms of WP:MOS. I looked at the history and found that the person who wrote it hasn't done anything else on Wikipedia. I sent her an email saying two concerns had been expressed in regard to the article: that it should get merged into this one, and that few other articles link to it (just one, actually). Michael Hardy (talk) 21:02, 12 August 2009 (UTC)

Pre Natal Hormone imbalances and Decreased Brain Lateralization
Some recent evidence has emerged to suggest that in-utero hormone imbalances may decrease hemispheric brain specialization.

Of course there is the Geschwin Galaburda hypothesis, but in this study, it is suggested that men who were prenatally exposed to Diethylstilbestrol (a synthetic estrogen based fertility drug), are more likely to be left handed.

This study suggest that men prenatally exposed to diethylstilbesterol experienced a decreased effect on hemispheric laterality and spatial ability.

There is also a lot of prenatal hormone research with the Digit ratio wiki page

Since I'm not a scientist, but everyone in my family has been exposed to diethylstilbesterol, I was wondering if someone here can include a section on the perculiars of prenatal hormone imbalances. I would attempt to do it myself, but I don't have the right terminology to really expand on this type of high brow article. Thanks Witch Hazell (talk) 16:35, 22 October 2011 (UTC)


 * The data concerning DES seem pretty sketchy, but I agree that an account of the role of sex hormones in influencing lateralization would be a useful thing to have in this article. Looie496 (talk) 14:42, 23 October 2011 (UTC)

Dehaene et al, 2003 quotes
http://www.unicog.org/publications/DehaeneEtAl_3parietalCircuits_CogNeuropsy2003.pdf
 * p. 488-489: "Our account predicts that depending on lesion localisation, three different categories of numerical impairments should be observed: genuine semantic impairments of the numerical domain following intraparietal lesions; impairments of verbal fact retrieval following lesions to the left perisylvian cortices, including the left angular gyrus; and impairments of spatial attention on the number line following lesions to the dorsal parietal attention system." (emphasis added)
 * p. 495: "In summary, the contribution of the left angular gyrus in number processing may be related to the linguistic basis of arithmetical computations. Its contribution seems essential for the retrieval of facts stored in verbal memory, but not for other numerical tasks (like subtraction, number comparison, or complex calculation) that call for a genuinely quantitative representation of numbers and relate more to the intraparietal sulcus." (emphasis added) Edhubbard (talk) 00:27, 18 February 2012 (UTC)
 * Thanks--missed that!Jbening (talk) 01:02, 18 February 2012 (UTC)
 * Sure. In fact, there's so little in the table that I'm not sure that keeping it in table format adds anything.  Perhaps this material would be better described in text, paralleling the second Dehaene et al. quote above.  What do you think?  Edhubbard (talk) 01:38, 18 February 2012 (UTC)
 * I was thinking exactly the same thing. It's more your field than mine--care to do it?Jbening (talk) 01:44, 18 February 2012 (UTC)
 * Gave it a shot, but feel free to trim as desired. It's a little too much, but the redundant table is gone...  One of these days, the history section should get referenced.  I looked at it and it looks mostly accurate, but it still needs refs.  This would be a good reference for most of it: Stanley Finger Origins of Neuroscience: A History of Explorations into Brain Function.  978-0195146943 Edhubbard (talk) 02:23, 18 February 2012 (UTC)
 * The stuff you did looks fine to me. Agreed on the history section, but it's really not my area. I just reorganized to put history first and retitled the main sections. Please revise if anything better occurs to you.Jbening (talk) 03:24, 18 February 2012 (UTC)

Gender differences
I've rewritten this part of the page to better reflect recent findings. I'll look over the rest of the page to fix any other issues as well, seeing as this is recent research. Countered (talk) 00:48, 31 August 2013 (UTC)
 * Cool! Looie496 (talk) 03:13, 31 August 2013 (UTC)

lateralization differences between men and women
Copied from my (Lova Falk's) talk page into this page, concerning this edit with the following edit summary "One single study cannot refute accepted knowledge. You need a review of all study results that concludes that these differences don't exist.":

I suppose I understand the bureaucratic nature and necessity of such a system, but how does one fit the facts into these goal posts which could seemly move depending on an individuals personal understanding of each bit of research? At which point is enough research enough to negate past research? The article you linked me was interesting - yet it seemingly supports my addition to the page because not only was the primary source peer-reviewed by experts in the field, but has been talked about in almost 20 or more secondary sources, and has been cited by quite a few papers. Such a subjective system seems quite contradictory to science and the pursuit of knowledge because one can claim that no valid scientific consensus has been reached how ever much they want, moving those posts as wide as they wish. Furthermore, the article linked also states that one should use the most up to date information - which is included in the study I cited.

Secondly, the study itself shows directly that lateralization in both men and women does not bias either hemisphere - and in that it also shows that neither men or women are more lateralized than the other. There was only one study cited that claimed that men are more lateralized than women, which doesn't show any sort of "general consensus" when it comes to brain lateralization. The very fact that a new study has in fact challenged that leads to the conclusion that past ideas about lateralization have been wrong. To claim that it is still "generally accepted" is simply false. Countered (talk) 08:20, 7 October 2013 (UTC)


 * I have reverted your edit. The fact that a study was discussed in the popular press is meaningless; this study has not been cited even once yet in the scientific literature.  You have far more faith in the virtues of peer review than reality warrants -- the criteria listed at WP:MEDRS are there for good reasons.  Further discussion should take place at Talk:Lateralization of brain function. Looie496 (talk) 18:00, 7 October 2013 (UTC)
 * You very clearly need to re-read the criteria for adding new data to a wikipedia page when it contradicts old data. Plos one is a peer reviewed medical journal - and it clearly states in WP:MEDRS that "Peer reviewed medical journals are a natural choice as a source for up-to-date medical information in Wikipedia articles." Secondly the only source you have for "general consensus" is a previous study in another journal. Do I really need to spell this out? In all reality this whole page needs to be rewritten because much of the data is now proven to be false by new methods; that is, whole brain lateralization scans as opposed to the previous localized scans. not only is the study I posted more thorough in it's more advanced methods, but it has been completely unopposed in the medical community. Countered (talk) 20:38, 7 October 2013 (UTC)
 * I don't mean to come off as hostile either - I just don't really understand how wikipedia can maintain quality while claiming things which have seemingly been thoroughly disproved. Plos one is even quoted on WP:MEDRS. I guess I just don't understand what more is necessary to disprove past claims. Countered (talk) 21:17, 7 October 2013 (UTC)

Popular meaning
Can't the article start with the popular meaning, as a way to debunk it, but still be useful. People every day say "left brained" and I came here to see what it meant and was confronted by a wordy pedantic wordy blah blah wordy yadda yadda wordy digression. Or perhaps just have an article called "left brained" and put in the popular meaning and say "but it ain't true, see lateralization". Wikipedia is getting ruined by amateur pedants.


 * Disagree. If you want the "popular" meaning based on usage, consult a dictionary. If you want the currently most popular meaning, consult a web-dictionary. Wikipedia strives to be an encyclopedia that indexes and strives toward organization of the knowledgeable, not the knowledge of the man-in-the-street. In any case, there are an almost infinite number of "popular" conceptions about. Which of those do you propose be used? Yours?


 * The same argument can be turned around. Since no area of knowledge is ever "closed," the question becomes one of "which definitive factual meaning do you report on?" The bottom line is that people come here for answers; if you already know the answer to a question, why consult an encyclopedia? And if you don't know the answer, chances are that you may come here without a well-formed question in mind. The phrases "left-brain" and "right-brain" are common, not just on the street, and they refer to something different than just talking about lateralization of brain function. Though the wording may be inaccurate and misleading, it's no more so than saying "the sun is rising." Also, try to remember to sign your posts (not to be too left-brained about it). rowley (talk) 16:00, 13 September 2011 (UTC)


 * I agree. I think covering popular misconceptions about a specific subject in a specific field is well within the bounds of Wikipedia's goals. of course I just phrase that differently then listing a "popular meaning," but I believe the intent is to cover misconceptions about lateralization. it shouldn't be too hard to create a section called "popular misconceptions." Wulframm (talk) 19:14, 9 November 2015 (UTC)

The Master and His Emissary
The Master and His Emissary: The Divided Brain and the Making of the Western World is a new study of the specialist hemispheric functioning of the brain, and the conflict between their world views, by the psychiatrist and writer Iain McGilchrist. Published 2009.  Esowteric + Talk  16:13, 21 December 2009 (UTC)
 * As The Economist notes in their review, McGilchrist seems to take astonishingly liberties with the scientific literature Edhubbard (talk) 18:00, 22 December 2009 (UTC)
 * But the reader is also treated to some very loose talk and to generalisations of breathtaking sweep. The left’s world is “ultimately narcissistic”; its “prime motivation is power”, and the Industrial Revolution was, in some mysterious sense, the left’s “most audacious assault yet on the world of the right hemisphere”. The sainted right, by contrast, has “ideals” that are in harmony with an “essentially local, agrarian, communitarian, organic” conception of democracy... But he offers no evidence that such differences can be explained in physiological terms... The book ends with a deflating admission that will not surprise those readers who feel the author’s main claims about the cerebral hemispheres have the ring of loose analogies rather than hard explanations. Mr McGilchrist would not be unhappy to learn that what he has to say about the roles of the hemispheres in Western culture is simply a metaphor and is not literally true. In other words, he seems to be in two minds about his own thesis, which is fitting but not encouraging.
 * Have expanded and balanced the article a bit now. Apparently the philosopher Mary Midgley will be reviewing the book in The Guardian in early January 2010. Will see what she has to say.  Esowteric + Talk  19:31, 25 December 2009 (UTC)
 * Comment Mary Midgley's review (Jan 2010) says "McGilchrist's explanation of such oddities in terms of our divided nature is clear, penetrating, lively, thorough and fascinating. Though neurologists may well not welcome it because it asks them new questions, the rest of us will surely find it splendidly thought-provoking." Given that Mary Midgley is acknowledged by Wikipedia as being described by The Guardian as "a fiercely combative philosopher and the UK's 'foremost scourge of 'scientific pretension'", Wikipedia would do well to allow McGilchist's book as a reference. Simplicissimo (talk) 17:46, 21 December 2015 (UTC)


 * The book is published by Yale University Press. That is a significant publisher. Whether we think it is hard science, metaphor or philosophy, a book by them addressing this specific topic is a RS and a bona fide addition. -- JN 466  20:41, 25 December 2009 (UTC)
 * Actually, it does matter. See WP:FRINGE and WP:UNDUE. Edhubbard (talk) 02:49, 27 December 2009 (UTC)
 * To clarify, it does not matter for the entry on the book, itself. We should have an entry on the book.  But, given that this book does not purport to actually provide any factually correct information on the topic of this article, lateralization of brain function, but rather uses it as a "loose analog[y]" or a "metaphor" that is "not literally true", it should not be included on this page due to the wikipedia policies cited above. Edhubbard (talk) 02:53, 27 December 2009 (UTC)
 * Comment What we're talking about here is my attempt to include the book in "further reading", an action that was reverted. I can appreciate your desire to keep what you see as "poppsych" weeded out of the article, so that it is not flagged as "pseudoscience" (whilst remembering that this is not someone's "recommended reading list" but a representative list of "further reading"). However, I think it's a little unfair to base your judgement on the reaction of a reviewer in The Economist. The introduction to the book (pdf) seems to paint a different picture of the book's actual content.
 * I like to run articles past their subjects and the author points out to me that "As to the neuropsychological, neurophysiological and other evidence, there are about 3,000 references to the literature included in the notes", and he himself dismisses what he sees as some popular misconceptions about lateralization, though I am reliant on input from reliable sources and cannot of course use phrases like "meticulously documented" until reliable sources use such phraseology. Further reading could perhaps be split into "mainstream" and " fringe " "popular psychology" (again remembering that heliocentricity was at one time dismissed as "fringe" theory :)), if it can be established that this is fringe theory, in order not to give undue weight to the less popular mainstream. Just a thought,  Esowteric + Talk  11:26, 27 December 2009 (UTC)
 * None of the reviewers appear to have scientific credentials, as far as I can see. A book of this sort is likely to be reviewed by Science or Nature soon, if it hasn't been already, and reviews there would give a much better idea of whether this is a suitable book to direct readers toward for further information. Looie496 (talk) 14:49, 27 December 2009 (UTC)
 * Yes, that seems fair enough.  Esowteric + Talk  15:01, 27 December 2009 (UTC)

Connection between Broca's and Wernicke’s
Moved existing comment from the article to here: 69.62.226.199 (talk) 22:30, 23 May 2010 (UTC)
 * The first sentence Area and Wernicke’s Area are linked by a white matter fiber tract, the arcuate fasciculus.is explicitly negated in this article http://en.wikipedia.org/wiki/Arcuate_fasciculus.

[edit]


 * The article Arcuate fasciculus explicitly states (cited) that, while it was believed to connect Broca's area and Wernicke's area, it is no longer believed to do so. I don't have the time now to figure out what should be incorporated into this article, but I did want to be sure to bring it to the attention of hopefully anyone involved with this page. -- Nataly a  21:35, 12 July 2011 (UTC)


 * I think the truth is that the cellular-level synaptic connections and boundaries of Broca's, Wernicke's, and really any other area of the cortex are poorly understood, and therefore an accurate but still helpful statement might be, e.g., "the arcuate fasciculus connects the lateral prefrontal cortex (including Broca's area) with the posterior parietal and temporal cortex (including Wernicke's area) and has been shown to play a role in language processing." (See, e.g., Catani et al 2007 .) PhineasG (talk) 15:01, 12 September 2011 (UTC)

The Relationship Between Sperry and Gazzaniga is Unclear
The article lists Michael Gazzaniga and Roger Wolcott Sperry in that order as the researchers. Sperry actually was Gazzaniga's professor at the start of this research. Sperry is a full generation older and is considered the pioneer in this research. Gazzaniga's work is outstanding, but he got his start under Sperry's lead. Sperry is no longer alive but Gazzaniga is still leading research efforts in neuroscience. I realize this is not much more than a footnote in the full story of split-brain research, but even footnotes (or their metaphorical equivalent) should not be misleading. Soulfulpsy (talk) 06:47, 25 August 2014 (UTC)
 * So basically you're suggesting to change the order? Looie496 (talk) 13:05, 25 August 2014 (UTC)

Additional images
In both of the additional images, "Corpus callusum" should be spelled "Corpus callosum." Correct spelling is vital for anatomic terms (or any standardized terminology). Even if the spelling were corrected, the two additional images do not seem to add anything useful or specific to the article. Remove both images? --Sveika (talk) 16:11, 23 March 2016 (UTC)
 * I think you're right, Sveika. Pinging, the author of the images in question. — Gamall Wednesday Ida (t · c) 06:35, 16 November 2016 (UTC)

The Divided Brain
Right brain: broadly vigilant attention

Left brain: narrow-focused attention — Preceding unsigned comment added by 84.94.37.27 (talk) 00:00, 3 June 2016 (UTC)

Pop psychology - opposite the truth
"Ironically these ideas held denote LHS as the 'logical brain' and RHS as the 'creative brain' which, even in the most generalized sense, is opposite the truth".

I see no evidence for the above statement anywhere. It has the smell of the halfbacked academics faddish taste for wanton and habitual iconoclasm. Shouldn't it be removed or backed up with actual evidence? It disturbs and contradicts the whole article. Frisenette (talk) 09:48, 24 September 2016 (UTC)


 * @Frisenette. Well, the "LHS = logical, RHS = creative" idea is clearly complete nonsense. That said, I doubt it's even coherent enough to be "opposite the truth". To be opposite the truth and not simply irrelevant noise, you need to have a pretty good hunch where the truth is to begin with, and then dutifully miss the target.


 * There were two sources to that "opposite the truth" statement. I just deep-sixed the first one, on grounds that whoever wrote that "paper" was barely literate -- at least in English. The authors seem to be two students. The other source is a serious paper, and at a glance I find nothing in it directly supporting the quote. It concerns itself with more serious questions like language processing and handedness, and doesn't address or reference the pop-psy notion in any way that I can see.


 * It would be nice to enlist an editor competent in neurosciences to go over this paragraph and either rework the statement or provide a more specific reference. Asking for help on relevant wikiprojects might be the best way forward.  — Gamall Wednesday Ida (t · c) 07:05, 16 November 2016 (UTC)


 * I just restored the reference you removed, albeit blindly. (I don't have handy access to the book.) An editor's opinion of the writing in a textbook by a major publisher does not negate its use. Scrapping it would be a WP:RSN issue. BiologicalMe (talk) 13:55, 16 November 2016 (UTC)

Dang-it all to heck, I just wasted 20 minutes dissecting choice quotes from the paper before realising you're right, I'm dissecting the WRONG paper. I blame the flu, it's making me bilaterally distracted. — Gamall Wednesday Ida (t · c) 15:10, 16 November 2016 (UTC)


 * BiologicalMe: I cannot access that source. I have called for help on wikiproject neuroscience. Since this is not my field, there's not much else I can do. Thanks for catching my mistake in deleting that reference. (Thanks to a botched search and a brain bug, I confused the book with a terrible paper citing the book). — Gamall Wednesday Ida (t · c) 15:31, 16 November 2016 (UTC)


 * I feel for you. I haven't tackled the issue because I couldn't check the specific text. I don't like the phrase "opposite the truth" because it is ambiguous. Does it mean that there is lateralization in the reversed pattern or no lateralization? Get better soon. BiologicalMe (talk) 15:53, 16 November 2016 (UTC)
 * Thanks for the kind words. Combined with the opening "ironically", I 100% interpret the last sentence as "there is lateralization in the reversed pattern", (or, more charitably, "to the extent there is lateralisation, it is in the reversed pattern") which, if anything, is even more wrong than the original view, I think. — Gamall Wednesday Ida (t · c) 16:12, 16 November 2016 (UTC)


 * Textbooks are not considered good sources for controversial statements. The sentence in question was introduced on April 1 in a large edit by  (diff). A lot of material introduced in that edit is poorly written and problematic in meaning.  In my opinion the sentence in question should be deleted unless much better sourcing can be found, and even then the wording of the sentence would need to be clarified.  There are lots of other things in this article that need to be fixed as well. Looie496 (talk) 15:59, 16 November 2016 (UTC)
 * Ok, thanks. I might remove the sentence after a while if nobody more qualified takes that step — but I won't be able to more constructively improve the article. — Gamall Wednesday Ida (t · c) 16:12, 16 November 2016 (UTC)

Interactions and Role
Many of the sources in the Interactions and Role section seem to be unrelated to the topic at hand. I've tagged one that was a study on rats (and not about lateralization), which was used as a source for the claim that many studies have shown brain differences between cultures. — Preceding unsigned comment added by 128.61.126.106 (talk) 21:08, 24 February 2017 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified one external link on Lateralization of brain function. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://web.archive.org/web/20110616080310/http://www.allea.org/Pages/ALL/4/881.bGFuZz1FTkc.pdf to http://www.allea.org/Pages/ALL/4/881.bGFuZz1FTkc.pdf

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

Cheers.— InternetArchiveBot  (Report bug) 21:38, 17 December 2017 (UTC)

A lot of work is needed to improve this article
This is the second paragraph of the article:

"''Lateralization of brain structures is based on general trends expressed in healthy patients; however, there are numerous counterexamples to each generalization. Each human’s brain develops differently leading to unique lateralization in individuals. This is different from specialization as lateralization refers only to the function of one structure divided between two hemispheres. Specialization is much easier to observe as a trend since it has a stronger anthropological history. The best example of an established lateralization is that of Broca's and Wernicke's areas where both are often found exclusively on the left hemisphere. These areas frequently correspond to handedness however, meaning the localization of these areas is regularly found on the hemisphere corresponding to the dominant hand (anatomically on the opposite side). Function lateralization such as semantics, intonation, accentuation, prosody, etc. has since been called into question and largely been found to have a neuronal basis in both hemispheres. Another example is that each hemisphere in the brain tends to represent one side of the body. In the cerebellum this is the same bodyside, but in the forebrain this is predominantly the contralateral side.''"

I find this to be completely impossible to understand.

In the phrase "there are numerous counterexamples to each generalization": Which generalization does this refer to? Nobody knows.

In the sentence "Each human’s brain develops differently leading to unique lateralization in individuals": Is this saying that all lateralizations are idiosyncratic? Really? So there are no generalizations that apply to almost all individuals, or at least almost all right-handed individuals? The article should be clear about what it is saying.

In the sentence "This is different from specialization as lateralization refers only to the function of one structure divided between two hemispheres": And "specialization means what?

In the sentence "Function lateralization such as semantics, intonation, accentuation, prosody, etc. has since been called into question and largely been found to have a neuronal basis in both hemispheres." But the first sentence of the entire article states: "The lateralization of brain function is the tendency for some neural functions or cognitive processes to be more dominant in one hemisphere than the other." This requires only greater dominance in one hemisphere than the other. So the phrase "largely been found to have a neuronal basis in both hemispheres" is irrelevant to refuting lateralization, since nothing is said about dominance one way or the other.

The last two sentences are: "Another example is that each hemisphere in the brain tends to represent one side of the body. In the cerebellum this is the same bodyside, but in the forebrain this is predominantly the contralateral side." The second sentence is an example of where the first sentence is false. Why???


 * Having just read this page for the first time, I agree that a lot of improvement is needed. The very first sentence of the first section (after the lede) starts "For example,...". It's not at all clear what this is an example of - is it following on from the a previous statement made in the lede? I could have a stab at trying to restructure the article, and probably simplify the language for the benefit of lay readers, but I am not a subject matter expert. Is there anyone watching this page who would be prepared to assist and help me if I go wrong?Girth Summit (talk) 16:24, 4 June 2018 (UTC)
 * @ I can keep an eye out. Kudos for volunteering. --Tom (LT) (talk) 09:02, 5 June 2018 (UTC)
 * Thanks for the offer Tom. I'll find some time to start working on it soon I hope...Girth Summit (talk) 08:00, 6 June 2018 (UTC)
 * I see you've already started making some improvements! Looks better already, your reordering makes it flow better. Quick question on the opening sentence - it currently says that the 'neural functions or cognitive processes are specialized to one side of the brain...'. Is this common usage in the field? In normal usage we'd say that a thing is specializing in a particular function, rather than the function specializing 'to' the thing. Also, I can't find any examples of the verb 'specialize' being used like this (with the preposition 'to') - you would normally specialize in, specialize at, or specialize for something. I don't want to change it if this is common usage in the field which I'm unfamiliar with, but I'd probably reword to something like:


 * The lateralization of brain function is the tendency one or other side of the brain to specialize in particular neural functions or cognitive processes.


 * What do you think? (I promise not to consult you about every single sentence in future - but since this is the opening sentence, I thought I'd better test the waters first...)Girth Summit (talk) 17:13, 7 June 2018 (UTC)


 * Yikes - I think I'm getting in over my head. I've just done some work on the 'Language' section, trying to remove unsourced and off-topic material and clear up the language. That section seemed to make it clear that speech production was predominantly left-lateralised. Moving on, I started reading through the 'Hemisphere damage' section, which talks almost exclusively about how damage to the right hemisphere affects speech production. The apparent contradiction will be confusing to the general reader and, assuming it's accurate, really ought to be contextualised; however, the 'Hemisphere damage' is entirely unsourced. I don't want to just cut out an entire section despite the lack of source, but I don't feel qualified to research the discrepancy and reword. What's your background Tom - do you know the subject matter well enough to discuss?Girth Summit (talk) 18:47, 7 June 2018 (UTC)

Learning styles
Hi, I just wanted to touch on the edit you recently made, which Flyer22_Reborn reverted. I noticed that the text you inserted referred to individuals' learning styles several times, and that the sources were fairly old (early 2000s). As described in our article on them, the concept individuals having particular learning styles is somewhat controversial, and my understanding is that the accepted position in up-to-date educational psychology scholarship is that they don't. I have some books on the shelf I could dig out to provide references for this if needs be. As Flyer22 said, I think the language would have to be softened, and more recent sources would shed some light on whether anyone still stands by these theories. Cheers Girth Summit  (blether)  18:56, 25 September 2018 (UTC)

Criticism section

 * "Function lateralization, such as semantics, intonation, accentuation, and prosody, has since been called into question and largely been found to have a neuronal basis in both hemispheres."

It would be useful to have a proper, referenced and thorough criticism section / update of this model. It already states that much pop psychology has run with the idea of over-simipfications of hemispheric functions. Much more is needed. Anna (talk) 20:42, 8 December 2019 (UTC)

Is it possible to add this image by M. Gazzaniga?
https://academic.oup.com/view-large/figure/5559555/b071316.gif Is it possible to use this image by M. Gazzaniga into this article? RIT RAJARSHI (talk) 15:22, 31 May 2021 (UTC)

Right/left brain
Studies agree that as nonverbal cues are sent and received, they are more strongly influenced by modules of the right-side neocortex (esp. in right-handed individuals) than they are by left-sided modules. Anatomically, this is reflected a. in the greater volume of white matter in the right neocortical hemisphere, and b. in the greater volume of grey matter in the left. The right brain's superior fiber linkages enable its neurons to better communicate with feelings, memories, and senses, thus giving this side its deeper-reaching holistic, nonverbal, and "big picture" skills. The left brain's superior neuronal volume, meanwhile, allows for better communication among the neocortical neurons themselves, which gives this side a greater analytic and intellectually narrower "focus". Research by UCLA neuroscientist, Daniel Geschwind and colleagues shows that left-handers have more symmetric brains, due to genetic control. 84.94.37.73 (talk) 10:29, 3 July 2021 (UTC)

Wiki Education Foundation-supported course assignment
This article was the subject of a Wiki Education Foundation-supported course assignment, between 8 January 2020 and 25 April 2020. Further details are available on the course page. Student editor(s): Mrs. Yelnats.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 08:52, 18 January 2022 (UTC)

Inadequate images and captions
I think images being presented as examples of counterfactual information are confusing, especially if the original context of the image is not heavily emphasised. Furthermore, simply presenting an example of an image containing factoids without detailing or even indicating which aspects of the image are correct (e.g. the depiction of the brain as having two hemispheres), which aspects have some merit (e.g. intuitive thought in the right hemisphere), which aspect are straight up wrong (e.g. random sequencing in the right hemisphere) and which aspects are not only wrong but also plain nonsense (e.g. creative writing in the right hemisphere - I'd like to see someone write a novel without using language - and I mean a traditional novel, nothing avant-garde) doesn't actually give any real information to people who do not already have it. Anditres (talk) 04:21, 22 January 2023 (UTC)

Wiki Education assignment: Introduction to Psychology Honors
— Assignment last updated by TheOneCheese (talk) 19:26, 7 November 2023 (UTC)