Transcript Document 7434477

Chapter 11:
Biological Dispositions in Learning
November 21, 2005
Class #38
The General Process View of
Learning…
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Stemmed from Watson’s rejection of the
concept of instincts
Foundation of the general process view
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Only two possible influences on behavior
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Instincts
Learning
Innate behaviors such as instincts viewed as
primitive
The General Process View
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Learning has evolved beyond innate tendencies
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All responses are therefore equally conditionable
All organisms are trainable in the same manner given they are at
comparable levels on the phylogenetic scale
Equipotentiality Premise
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States that the laws of learning should not vary with the use of particular
stimuli, responses, or reinforcements
This premise has recently been challenged by some data originating within
the learning tradition itself, for example, studies on the effects of verbal
stimuli in eye-lid conditioning
More importantly, however, the premise of equipotentiality is incompatible
with data from experiments carried out within a biological framework
The results of such studies indicate that a given species is prepared to
associate certain stimuli, responses, and reinforcers but not others
The General Process View
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A number of phenomena are believed to
challenge the validity of the general process
view
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Preparedness
Taste aversion
Belongingness
Instinctive drift
Adjunctive behavior
Preparedness
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Many species are genetically prepared to
learn certain kinds of association more
readily than others (Seligman, 1971)
For example…
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Remember study by Valentine (1930)…
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Attempted to replicate Watson’s “Albert Study”
Blew a loud whistle whenever his 1 year old
daughter touched certain objects
Found he could condition fear to some objects
like a caterpillar
Could not condition fear to other object such as
opera glasses
Preparedness
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Many associations are virtually unlearnable
or so easily learned that the laws of
conditioning are largely irrelevant
Preparedness related to organism’s innate
propensity to form an association
Preparedness
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Preparedness can be viewed as a continuum
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See next slide…
Preparedness
Prepared
Innate tendency
Forms association
easily
Unprepared
Contra-prepared
No specific predisposition.
Associations form with
moderate number of pairings
Difficulty forming
associations even with
repeated pairings
Preparedness
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Preparedness plays a role in a number of
different learning situations
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Taste Aversion
Species Specific Defense Responses (SSDR)
Belongingness
Phobias & other fear responses
Taste Aversion
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Example of the role of preparedness
Common phenomena in both animals
and humans
Typical experiment
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Rats given preferred drink (saccharin flavored
H2O
Later, drank poison to make nauseous
After recovery, rat will prefer non-sweet H2O
Species Specific Defense Response
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Depends on the animal…
 Three possible SSDR to danger:
 Freezing
 Fleeing
 Fighting
Belongingness
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Certain events are perceived as belonging
together
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Thorndike (1905)
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Tried to have cat scratch post to escape puzzle box
Unsuccessful because scratching belongs to itching
not to escape
Instinctive Drift
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We mentioned this earlier…
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A genetically based fixed action pattern gradually
emerges and displaces an operantly conditioned
behavior
Breland and Breland (1961)
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Operantly conditioned pigs to deposit wooden coins
into piggy bank
Pigs began to root coins on the ground
Instinctive rooting behavior associated with food
began to intrude on conditioned behavior
Adjunctive Behavior
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An excessive pattern of behavior that emerges
as a by-product of an intermittent schedule of
reinforcement for other Bx
Falk (1961)
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Conditioned rats with a FI schedule to press level
for food
During session noticed rats drank up to 3.5x
amount of water they normally drank
Behavior called schedule-induced polydipsia
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Drinking water incessantly
Adjunctive Behavior
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Adjunctive behavior occurs in humans:
 Doyle & Samson (1988)
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Human subjects exposed to FI schedule of monetary reinforcement for
game playing
Subjects showed increase tendency to drink water after each
reinforcement
Cherek (1982); Doyle & Samson (1988)
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Subject received monetary reinforcement for button pushing on an FI
schedule
Subjects showed high rate of smoking and beer sipping following
reinforcement
In both studies, the drug-related behavior occurred immediately
following reinforcement
Conclusions: Adjunctive Behavior may play a role in substance
abuse
Activity Anorexia: Basic Procedure
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Activity Anorexia is generated by exposure to a
restricted schedule of feeding & involves:
 abnormally high level of activity
 low level of food intake
Produce it by:
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Allow rats 1 feeding per day lasting 1.5 hours
Allow access to a running wheel the other 22.5
hours of the day
Anorexia Nervosa
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Psychiatric disorder in humans
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Refusal to eat adequate amounts of food
Extreme weight loss
Over 10% of people with Anorexia Nervosa
eventually die from the disorder or
complications stemming from it
Comparisons
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Activity Anorexia
in Rats
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Precipitated by food
restriction
Accompanied by very
high levels of activity
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Anorexia Nervosa in
Humans
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Often begins with dieting to
lose weight
Accompanied by very high
levels of activity
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Exercise or
Restlessness
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Easier to induce in
adolescent rats
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More common in adolescents
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Subjects remain interested
in food without eating it
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Subjects remain interested in
food without actually eating
it
Activity Anorexia
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Two types of Anorexia Nervosa in Humans:
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Restricting type = food restriction
Binge-eating/purging type = food restriction alternating
with episodes of binging and purging
Activity Anorexia in rats is more like the restrictive
version of Anorexia Nervosa in humans
Underlying Mechanisms
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Possible that Anorexia is maintained by an
addiction to endogenous endorphins
Endorphins are morphine-like
neurotransmitters that are involved in pain
reduction
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Runner’s high thought to be due to endorphin
release
Underlying Mechanisms
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Endorphin-blocking drugs lower the rate of
wheel running in Anorexic rats
Anorexic humans report that the effects of
Anorexia are quite similar to a drug-induced
high
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Interesting quotes see page 444 of textbook
Clinical Implications
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Treatment
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Behavioral treatments should focus on activity
levels as well as food intake
Drug treatments may involve endorphin-blocking
drugs to reduce the endorphin-high that the
disorder produces
Clinical Implications
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Prevention
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Warn people that combining stringent exercise
with dieting may cause Anorexia Nervosa
When dieting, eat several small meals per day,
rather than 1 big one
Increase exercise levels slowly (to avoid the large
drop in eating that accompanies a sharp increase)
Dieters should eat balanced meals (rats develop
Anorexia easier on a low-protein diet)
Credits
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http://www.radford.edu/~pjackson/
http://www.towson.edu/~rcraig/