Wasserman,
Edward A.
Same-different
conceptualization by pigeons and baboons
Edward
A. Wasserman
University
of Iowa, USA
Can
animals learn a same-different concept? This intriguing question has a venerable
history in philosophy and behavioral biology. Until recently, the answer has
been "no". Among the skeptics are Rene Descartes, John Locke, and
Lloyd Morgan. However, my associates and I have conducted several recent
research projects which strongly suggest that animals can indeed form an
abstract concept of same versus different. We have trained both pigeons and
baboons to discriminate visual arrays containing 16 identical items from visual
arrays containing 16 nonidentical items. Then, we have tested the animals with
novel same displays and with novel different displays that were created from
untrained visual items. Strong discrimination transfer has been obtained in both
species. Subsequent research has explored the perceptual and cognitive
substrates of this behavior. That work points to the detection of variability as
essential to same-different conceptualization. Variability detection helps to
explain the fact that same-different discrimination performance is a positive
function of the number of icons that are present in the display as well as the
fact that discrimination performance is a graded function of the amount of
variability that is contained in mixtures of same and different items. Finally,
we have obtained evidence that baboons can learn the relation between relations
in a matching-to-sample task that involves sample stimuli which share no
features with the testing stimuli. This relational matching-to-sample behavior
generalizes to novel sample stimuli and is a positive function of the number of
icons that are present in the sample as well as a graded function of the amount
of variability that is contained in sample stimuli containing mixtures of same
and different items. Overall, these results suggest that abstract
conceptualization builds on animals' ability to detect the amount of variability
that is present in their environment.
Wasserman,
E. A., Hugart, J. A., & Kirkpatrick-Steger, K. (1995). Pigeons show
same-different conceptualization after training with complex visual stimuli. Journal
of Experimental Psychology: Animal Behavior Processes, 21, 248-252.
Wasserman,
E. A. (1997). Animal cognition: Past, present, and future. Journal of
Experimental Psychology: Animal Behavior Processes, 23, 123-135.
Young,
M. E., & Wasserman, E. A. (1997). Entropy detection by pigeons: Response to
mixed visual displays after same-different discrimination training. Journal
of Experimental Psychology: Animal Behavior Processes, 23, 157-170.
Young,
M. E., Wasserman, E. A., & Garner K. L. (1997). Effects of number of items
on the pigeon's discrimination of same from different visual displays. Journal
of Experimental Psychology: Animal Behavior Processes, 23, 491-501.
Wasserman,
Edward A.
Department of Psychology, University of Iowa
Iowa City, IA 52242-1407, USA
ed-wasserman@uiowa.edu