Willard Stanton Small (August 24, 1870 – 1943) was an experimental psychologist. Small was the first person to use the behavior of rats in mazes as a measure of learning. In 1900 and 1901, he published journal two of three in "Experimental Study of the Mental Processes of the Rat" in the American Journal of Psychology. The maze he used in this study was an adaptation of the Hampton Court Maze, as suggested to him by Edmund Sanford at Clark University.
Education and Career
He received a Bachelor's degree from Tufts College in 1897 and pursued graduate study at Clark University, working under Edmund Sanford. While at Clark, Small conducted what most historians believe to be the first studies of rats learning mazes. Upon completing his graduate work, Small took faculty positions at Michigan State Normal College and Los Angeles State Normal School. Later, he assumed more administrative roles as an educational administrator in San Diego, Paterson New Jersey, and Washington D.C. Finally, he became the Dean of the University of Maryland in 1923.
Maze Learning and Rats
Small was inspired by Edward Thorndike's well-publicized work with rats and puzzle boxes. His graduate advisor, Edmund Sanford, suggested that since rats like to tunnel and since they are capable of homing in the dark, mazes would provide an appropriate means for studying rat learning. Small used an illustration of the Hampton Maze from Encyclopedia Britannica to develop three mazes. His investigations ignited a craze and inspired researchers for decades.  In order to describe the rats' behavior, Small recorded observations as they occurred, focusing more on the rats' behaviors rather than objective completion times. 
Small initially explored habituation and concluded that wild rats were more active and appeared more frightened than the lab-bred white rats.  His first studies showed that hungry rats, given repeated opportunities, took more than an hour to find food at the end of the maze on the first trial, but got progressively better and could complete the maze in 30 seconds after several more. Small also noted that the animals habituated to the environment (they appeared less anxious) over time.
In the next set of experiments, Small added a door to the box to test how the rats were able to adapt to the change. Similar results were found, with the rats able to decrease the amount of time they took to find food behind the door. However, in cases of extreme hunger, the rats would dig in front of the door, even though the movement was not useful. This suggested that digging for food was an automatic response for rats. 
Next, Small tested to see if the rats were able to recognize and differentiate between the box with the door and without. What he found was that one of the rats could recognize the box without the door but not discriminate between the two. However, another rat showed evidence of recognizing and discriminating between the two boxes. At the point, Small confirmed a suspicion that rats could have variable levels of intelligence.
To discover how rats are able to habituate to change, Small made it so the door to the food in the box did not spring open. The rats would have to crawl under the door to get to the food. The rat Small deemed to be the most intelligent was able to gradually figure out the way to get the food quicker with less fear, showing evidence ofhabituation. Small then removed the box for 40 days to test the rat's memory. After replacing the box, the rat was able to complete the maze in seconds, demonstrating that the rat was capable of long-term memory.
Next, Small wondered if new rats not exposed to the maze were able to learn it just as quickly. Using four new rats, Small found that there tended to be a "lead rat" that would complete the task of opening the door to find food, while the other rats crowded around the spot, demonstrating that they were imitating the lead rat's behavior. As the lead rat was removed, the next lead rat would form, opening the door quicker with each trial for the other rats to go get food. Small concluded that the rats must have some sort of tendency to imitate each other.
To test this theory of imitation, Small used two rats from previous trials that elected not to complete the maze. After being allowed to run the maze, one rat did show evidence of learning it (judged by reduced completion times). However, Small could not demonstrate that these rats imitated each other, as the other rat did not learn to complete the maze. 
Implications of Maze Learning and Rats
The study is considered one of the most influential studies in psychology. The maze specifically was seen as a useful device, being used by animal psychologists through the 1920s and onward. A notable study is James Porter's work in Indiana University using a modified maze with sparrows. Small was also able to show that studying animals was useful for psychology to compare their behavior to humans. 
- Small, Willard S. (1901). "Experimental Study of the Mental Processes of the Rat. II". The American Journal of Psychology. University of Illinois Press. 12 (2): 206–39. doi:10.2307/1412534. ISSN 0002-9556. JSTOR 1412534 – via JSTOR. (Registration required (help)).
- Street, W. R. (1994). A Chronology of Noteworthy Events in American Psychology - August 24 in Psychology. American Psychological Association. Retrieved on March 26, 2007.
- Street, W. R. (1994). A Chronology of Noteworthy Events in American Psychology - March 11 in Psychology. American Psychological Association. Retrieved on March 26, 2007.
- Wozniak, Robert H. (1997). Experimental and Comparative Roots of Early Behaviorism: An Introduction. Retrieved on March 26, 2007.
- Green, Christopher (March 11–17, 2007). "This Week in The History of Psychology: Mar 11-17". THIS WEEK IN THE HISTORY OF PSYCHOLOGY.
- Small, Willard S. (1900-01). "An Experimental Study of the Mental Processes of the Rat". The American Journal of Psychology. 11 (2): 133. doi:10.2307/1412267. ISSN 0002-9556. Check date values in:
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