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Karl Lashley's Early Life,Education,and Career
Karl Spencer Lashley was a well known Psychologist and behaviorist remembered for his contributions to the study of learning and memory. He was born on June, 7, 1890 in the town of Davis, West Virginia. He first enrolled in at the University of West Virginia where he had originally decided to become an English major. After taking a course in Zoology however he became very intrigued especially due to his prior strong liking of animals. As a result Lashley switched his major form English to Zoology. After obtaining his A.B. at the University of West Virginia, he was awarded a teaching fellowship at the University of Pittsburgh where he taught biology along with biological laboratories. While here he also carried out research which he used for his Master thesis. Once Karl Lashley completed his Master’s degree, he was once again offered another fellowship at Johns Hopkins where he received his Ph. D degree in genetics, June of 1911. After obtaining his Ph. D he became a professor at University of Minnesota, University of Chicago, and Harvard University. Lashley later died a sudden death on August, 7, 1958.

Influences
There were three people in particular that really influenced Karl Lashley’s life. The first was his mother Maggie Blanche Spencer, with whom he had a great relationship with. Maggie was a strong advocate of schooling and from an early age she encouraged Karl intellectually; as a result he was able to read at the age of four. The second influential person that came into Karl’s life was a professor at the University of West Virginia named John Black Johnston. Mr. Johnston was the teacher of the first zoology course that Lashley took. It was this man that had a profound effect on Lashley and led him to understand what he wanted to do the rest of his life. Lastly we have a well-known popular psychologist named John B. Watson who had the most influence on Karl. Together the two conducted field experiments and studyed the effects of different drugs on maze learning of rats. The influence of Watson helped Lashley to focus on specific problems in learning and experimental investigation, followed by the cerebral location of learning and discrimination.

Lashley’s Work
Karl Lashly’s work covered an array of topics. He first began with research concerning brain mechanisms and how they were related to sense receptors. He also conducted work on instinct as well as color vision. In addition he studied many animals and primates, which had always been an interest of his from the start of his freshmen year at college. Although Lashley studied many things, his most influential research centered around the cortical basis of learning and discrimination. Karl researched this by looking at the measurement of behavior before and after specific, carefully quantified, induced brain damage in rats. He trained rats to perform specific tasks(seeking a food reward),then lesioned specific areas of the rat cortex, either before or after the animals received the training. The cortical lesions had specific effects on acquisition and retention of knowledge, but the location of the removed cortex had no effect on the rats' performance in the maze. This led Lashley to conclude that memories are not localized, but that they were widely distributed across the cortex. Today we know that distribution of engrams does in fact exist, however the distribution is not equal across all cortical areas, as Lashley assumed. His study of V1 (primary visual cortex) led him to believe that it was a site of learning and memory storage (i.e. an engram) in the brain. He reached this erroneous conclusion due to imperfect lesioning methods. By the 1950’s two separate principles had grown out of Lashleys research and they were Mass action and Equipotentiality.

Two Principles
Karl Lashley was originally in search of a single biological locus of memory or “engram” however he ended up disproving his own theory suggesting that memories were not localized in one part of the brain rather they were spread out through the cortex. . As a result of this discovery, Lashley develop two separate theories, Mass action and Equipotentiality. Mass action refers to the idea that the rate, efficacy and accuracy of learning depend on the amount of cortex available. To be specific if cortical tissue is destroyed following the learning of a complex task, deterioration of performance on the task is determined more by the amount of tissue destroyed than by its location. Equipotentiality refers to the idea that one part of the cortex can take over the function of another part; within a functional area of the brain, any tissue within that area can perform its associated function. Therefore, to destroy a function, all the tissue within a functional area must be destroyed. If the area is not destroyed then the cortex can take over another part. These two principles grew out of Lashley’s research on the cortical basis of learning and discrimination.

Honors and Elections
It has been said that Lashley was never big on attending conventions or receiving awards, however despite this he was elected to many scientific and philosophical societies. A few are listed as follows: American Psychological Association (Council member 1926-1928; President, 1929), Eastern Psychological Association (President, 1937), Society of Experimental Psychologists, British Psychological Association (Honorary Fellow), American Society of Zoologists, American Society of Naturalists (President, 1947), British Institute for the Study of Animal Behavior (Honorary Member),American Society of Human Genetics, American Physiological Society, Harvey Society (Honorary Member), National Academy of Sciences (elected in 1930). In 1938, he was elected a Member of the American Philosophical Society, the oldest learned society in the United States, dating to 1743. Since 1957, the Society has awarded the annual Karl Spencer Lashley Award in recognition of work on the integrative neuroscience of behavior. In 1943 Lashley was awarded the Daniel Giraud Elliot Medal from the National Academy of Sciences. The list goes on and on, but in addition to these elections Lashley was also awarded the Doctor of Science degrees from the University of Pittsburgh (1936), the University of Chicago (1941), Western Reserve University (1951), the University of Pennsylvania and in 1953 the Johns Hopkins University honored him with the degree L.L.D..