What is a "hybrid" model?

[Steve Kemp]

On Mon, 1 Apr 1996, Raju Bapi wrote:

 ..snip..
>  On Fri, 29 Mar 1996 Jonathan_Stein at com.comverse.hub1 wrote:
>
> >  Next, it has been demonstrated in psychophysical experiments that there
> >  are two types of learning. The first type is gradual, with slowly
> >  improving performance, while in primates there is also "sudden" learning,
> >  where the subject (EUREKA!) discovers a symbolic representation  
> >  simplifying the task. Thus not only is the basic hardware different for
> >  the two processes, different learning algorithms are used as well. 
 
.snip...

> Could you (or any one on the list) please give references to this 
> "sudden" or "Eureka"  type of learning in animals ?
> 
> Thanks
> 
> Raju Bapi

Happy to oblige.

The sudden learning was demonstrated in studies of human problem solving 
where it was eventually dubbed the "Aha!" effect.  (I believe that there 
is a book by that name, but I don't have that reference.)  In animal 
learning, it is known as one-trial learning.  (I am unaware of the 
"Eureka" nomenclature.)

The earliest reference I have for a study of this effect in humans is 
Maier (1930;1931).  Six classic articles are excerpted in Wason & 
Johnson-Laird (1968).  That should be a good source of background info. 

The mention of the demonstration of this effect in primates almost 
certainly refers to Wolfgang Kohler's (1925) classic study, THE MENTALITY 
OF APES,  (Kegan-Paul, also reprinted by Penguin, 1957).  That is the 
study where Kohler hung a banana from the top of a cage and placed 
several blocks in the cage.  With all the blocks placed on one another, 
the resultant stack was tall enough for the ape to reach the banana.  
After some "contemplation," the ape would stack the blocks, climb to the 
top and retrieve the banana.  Another Penguin book of readings, Riopelle 
(1967) includes a number of later articles on primates that discuss and 
followup on the Kohler work.  That collection also includes the classic 
studies of animal problem-solving by Romanes (1888), Lloyd Morgan (1909), 
and Thorndike (1898).

Single-trial learning is not restricted to apes, nor to cognitive learning
alone.  The Garcia Effect (Garcia, McGowan, & Green, 1972), a type of
Pavlovian conditioning wherein animals as simple as baby chicks learn to
avoid foods that have been associated with nausea, can be demonstrated 
after a single exposure.  Indeed, Skinner (1932) demonstrated 
single-trial learning by reinforcing behavior in a pigeon.  (Obviously, 
learning such simple tasks may not be "sudden" in the same sense of 
learning far more complex tasks in the studies cited above.) 

As to whether one-trial learning or the Aha! effect genuinely constitutes 
a distinct *type* of learning, it is most certainly distinct in that 
different experimental procedures are required to elicit such behavior.  
As to whether different brain processes are involved, brain scan studies, 
such as PET scan, single neuron monitoring, etc. will eventually answer 
such questions.  I would imagine that such studies have already begun in 
the last few years, particularly with Pavlovian conditioning, but I am 
not up to date on that research.  Perhaps someone else on the list is.

I am not sure what Stein means by "psychophysical" in this context, but 
there is a relatively recent study by Metcalfe (1986) that attempts to 
measure the speed of sudden learning.

For those interested in searching for further materials the keyword 
"insight" should get you pointed in the right direction on a computer 
search.  Be warned however, that insight studies of REASONING will not be 
of much interest in this context.  You might try INSIGHT and (PROBLEM 
SOLVING or LEARNING).

steve kemp

references:

Garcia, J., McGowan, B. K., & Green, K. F.  (1972).  Biological 
constraints on conditioning.  In Classical Conditioning, vol. 2.,, ed. by 
A. H. Black & W. H. Prokasy.  New York: Appleton-Century-Crofts.

Kohler, W.  (1925).  The Mentality of Apes.  Kegan Paul.

Lloyd Morgan, C. (1909).  Introduction to Comparative Psychology. 2nd 
edition.  Scribners

Maier, N.R.F.  (1930).  "Reasoning in humans I:  On direction."  Journal
of Comparative Psychology, vol. 10, pp.115-143. 

Maier, N.R.F.  (1931).  "Reasoning in humans II:  The solution of a 
problem and its appearance in consciousness."  Journal of Comparative 
Psychology, vol. 12, pp.181-194.

Metcalfe, J. (1986).  Feeling of knowing in memory and problem solving. 
Journal of Experimental Psychology:  Learning Memory & Cognition, vol. 
12, pp. 288-294.

Riopelle, A. J., ed.  (1967).  Animal Problem Solving.  Harmondsworth: 
Penguin Books.

Romanes, G. J.  (1888).  Animal Intelligence.  New York: D. Appleton.

Skinner, B. F. (1932). On the rate of formation of a conditioned reflex.  
Journal of General Psychology.  vol. 7, pp.274-286.

Thorndike, E. L.  (1898).  Animal intelligence:  An experimental study of 
the associative processes in animals.  Psychological Review Monograph 
Supplements, vol. 2, pp. 1-9.

Thorndike, E. L.  (1911).  Animal Intelligence: Experimental studies.  
New York: MacMillan.

Wason, P. C. & Johnson-Laird, P. N., eds.  (1968).  Thinking and 
Reasoning.  Harmondsworth: Penguin Books.

(Please note that Wason & Johnson-Laird also have another book on reasoning 
with a very similar title.  The book cited here is the Penguin book of 
Readings.  Paperback only, but probably found in your local University 
library.  Accept no substitutes.  smk)


Steven M. Kemp                |
Department of Psychology      | email:  steve_kemp at unc.edu
Davie Hall, CB# 3270          |
University of North Carolina  |
Chapel Hill, NC 27599-3270    |   fax: (919) 962-2537

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