User:LukeEarnshaw/sandbox

Introduction
Methodologies of psychological sex research are techniques and experimental procedures that allow scientists to investigate physiological, biological, emotional, and hormonal responses that are associated with sexual attraction and sexual desire. Techniques range from self-report questionnaires, observations, physiological measurements of arousal, and non-human animal models and comparisons.

History
Sexual attraction and desire have been observed, written, and remarked upon since time immemorial by scholars and intellectuals throughout the world featuring in illustrations and literature such as the Kama Sutra as early as 400-300 BC, as well as in ancient Roman in such comedies by the playwright Plautus 184 BC. More recently self-titled sexologist such as Havelock Ellis in his book Psychology of Sex (1933) wrote about the development of sexual impulse through the transition from youth into adulthood, claiming that sexual self-excitement was thought to be experienced at an early age. Ellis’s ideas and published works are thought to have had a large impact upon Sigmund Freud who is one of the most notable writers upon the subject of human sexuality. Freud’s work on psychological was purely observational and culminated in the five psychosexual phases of development, where at each stage the infant fixated on a certain body part

Questionnaires and Interviews
Questionnaires have been administered widely throughout the world over many years encompassing man areas within sexual attraction. The main advantage of this type of research is that they are reported anonymously and therefore participants are able to complete more open and honestly and do not risk public ridicule.

One of the most notable examples of interviews in regard to sex research is the Kinsey Reports, in which over 5,300 males and 6,000 women were interviewed. However, upon publication ' Sexual Behavior in the Human Male' (1948) received great criticism as they called Kinsey's methods into question, as interviews for ' Sexual Behavior in the Human Male' were largely obtained from prison inmates and male prostitutes.

Observational
This method was used regularly in the past especially in the 19th and 20th centuries but has now largely fallen out of popularity, although this technique is still used assessing non-human animals, particularly primates and monkeys.

Eye-tracking
This technique is well established in the study of sexual attraction and desire because it is one of the easiest methods to measure attention and gaze capture towards and away from a given stimuli within a scene. Eye tracking equipment allows various eye movements to be captured and analysed, however, the most frequently movements studied particularly within sex research are saccades and fixations. Saccades are fast and explosive movements of the eye that are spontaneous and voluntary and take approximately 30-80ms. Fixations take a longer amount of time, typically within 200-300ms and consist of comparatively steady and stable orientations fixed upon a stimuli or characteristic within the visual scene which allows for information to be extracted and processed. Fixations that occur over a greater length of time and are observed more often are perceived as an indication of a heightened level of interest in a stimuli or location; it would appear valid that our gaze would be longer and more often viewing an object of interest. Humans are able to consciously control the amount of dwell time on a given object, however, the first fixation and first fixation duration after the viewing of a stimulus is thought to be associated with primary attentional processes that are unable to be controlled consciously.

Dilation of the eye's pupil (enlargement in pupil size) is another response that eye-tracking is able to measure, and is considered to be a sign of arousal and interest in a stimulus and is particularly true regarding sexual interest. Physiological desire and/or pleasure are proportionally related to the size of dilation of the pupil, increased attention and greater sexual arousal indicated by exhibiting an enlarged pupil response. Pupil dilation is controlled by the autonomic nervous system and is hence difficult to control consciously and so is a useful measure of sexual attraction and desire.

EEG
An electroencephalogram is a technique in which electrodes are placed upon various sites on the surface of the scalp which measure electrical activity over a set period of time. Occasionally under special circumstances intracranial electrodes are placed within the brain of epileptic patience to observe signals projected and transmitted across each hemisphere. EEG provides direct information as an electrical response produced by the signalling of a great number of post-synaptic neurons in a dipolar field and which produce a number of waveforms that are graded into specific frequencies .The advantage of this technique when investigating the human sexual response is that it has a very high temporal resolution and so able to observe intricacies of the dynamic changes of the brain.

One of the first studies to use EEG to observe the sexual response was Robert G Heath who utilised surface and deep probes in an epileptic man in the early 1970's who suffered from seizures in the temporal lobe. The experiment consisted of two conditions, this first where the patient masturbated alone and the second consisted of heterosexual intercourse. During orgasm in both conditions, activity was observed to change in the septal region, an area of the brain which has been identified as part of the pleasure and reward circuitry of the brain. R.G.Heath notes "...most striking was the appearance of spike and slow-wave with superimposed fast activity in electroencephalograms from the septal region during sexual orgasm...".

fMRI
Functional magnetic resonance imaging is a technique used to measuring haemodynamic fluctuations after enhanced neural activity. This allows scientist to record high spatiotemporal resolution images of the brain to observe which areas and networks interact with each other whilst performing psychological tasks. Within the field of sex research there have been several attempts to scan people having sex, with the first images taken in 1999 showing male and female genitalia interacting. However, the issues with performing an accurate scan of a complex biological organ such as the human brain brings extreme difficulties, the main issue being that the head cannot be moved during recording of the BOLD response. An example fMRI in sex research is the mapping on sensory cortex of the female clitoris, vagina, cervix and nipple in order to investigate the neural systems that elicit the sexual response. In this study participants were scanned whilst self stimulating these regions whilst being scanned in an fMRI machine, this was in contrast to previous comparative experiments in men whereby the sensory motor cortex was stimulated by electrical means and participants asked to indicate where this was emenating from

Animal Models
Much of our recent understanding of the neurochemical, hormonal mechanisms, and physiological responses to the sexual cycle in both men and women have been based upon animal models. This is mainly due to ethical as well as practical constraints and limitations when testing psychological experiments on humans. Another consideration to use animal models rather than humans in experimental settings is that human behavioural and socialisation is far more complex than that of other non-human animals due to personal beliefs, culture, family influences, etc. Using animal models aids scientists in stripping away some of the complexities of human interactions, and using a variety of different animal species with similar social structures to that of humans aids in the ability of these models to extrapolated to humans

Blood Sampling
This method involves inserting a cannula into the participants forearm vein to draw blood samples while participants remain supine. The blood is then collected at various time intervals depending on the paradigm of the experiment. Samples are then tested with the blood plasma separated to test for various nonapeptide neurohypophyseal hormones such as oxytocin and arginine vasopressin. Advantages of this technique is that it collected direct from the body at the time point of stimulus or instruction during the experimental procedure and so is an accurate representation of the hormones being released into the blood and cannot be manipulated by the participant.

An example of the use of this technique within psychological sex research is a study by Murphy et al. examining the the roles of oxytocin and arginine vasopressin (AV)during sexual arousal in men. In this experiment blood samples were taken 30 minutes after the experiment began with the participant lying flat to establish a baseline. Participants were then requested to sexual fantasise without physically touching themselves whilst another blood sample was taken. Participants then masturbated until ejaculation whereupon another blood sample was taken, as well as at intervals of 10 and 30 minutes after. Analysis revealed that AV blood plasma levels increased at the onset of arousal and declined shortly afterwards near baseline, thus implying that AVP plays a role in sexual arousal but not ejaculation as no rise in blood pressure was observed from body movement.