A general parameter
- N, the number of
animals in any given condiditon. An imprinting score will
be yielded for each of n birds tested in any experimental condidtion.
That is, n is equal to the number of subjects in any given group.
Discrete controllable variables
Below is a set of factors that are conceived of as having an influence
on the strength of the social bond formed in imprinting. Each may be
a more or less potent conditioner, depending on the level or the type
chosen and the interrelated influence of the remaining factors. A
general strategy would be to select factors that you judge might have
an enhancing or inhibiting effect on the phenomenon. Each factor is
represented as a variable with a relatively small number of states or
values.
- Rearing condition
- Type of target
- Number of tests
of the same subject. A primary distinction between instinctive
behavior and learned behavior is that the former is a complex series
or pattern of responses that occurs without prior practice. A
proposition that comes to mind is that should imprinting be wholly a
matter of an instinctually released response, then the influence of
learning should be minimal. This proposition can be tested, in part,
by giving subjects more than one test--this is equivalent to practice
and practice usually leads to learning. The question is "Will
learning occur?" To put the question in another way, "Can animals
learn to imprint better with practice or is the strength of the
response bound by genetic determinants?" A word of caution is in
order: While practice usually does result in learning, there is almost
always a specific reinforcer (positive or negative) provided for the
performance of the task. In the present setting no reinforcing event
is available to the experimenter.
Instead of proximities being
measured on only one test, they may be measured for each subject on up
to six tests. These tests are administered at intervals of one hour.
A point to be noted here is that in the extreme case when all 6 tests
are run, the subject is about 6 hours older on the last test than it
was on the first.
- Levels of psychological arousal. Conceived of in terms of
alertness of enhanced neurological functioning or ability to
discriminate, levels of arousal in the organism may be critical to the
perception or processing of the stimuli that the animal subsequently
becomes attached to.
- Method of inducing arousal level changes. Two
techniques for the manipulation of arousal in young birds have been
suggested. The first of these is the mechanical application of an
additional amount of external stimulation when the subject is in a
position to view the imprinting target. Sudden loud noises of varying
intensity or the administration of optimal levels of electric shock
have been employed in this context. On the other hand, the
administration of certain drugs seems to produce variable arousal
effects. The injection of amphetamines raises arousal while the
presence of barbiturates reduces arousal.
- Locomotor ability One of the characteristics
associated with the age or physical condition of animals as young as
those used in this problem is simply a varying ability to get from one
place to another. Clearly, birds that have just hatched cannot walk
as rapidly or with as much direction as their older species mates.
Moreover, animals at any age may have physical defects not obvious to
the experimenter which may impede movement.
Given that our
definition of imprinting is an operational one, i.e. a tendency to
move toward and stay near an imprinting target, one may wish to
obtain a sample of subjects more or less alike in this respect.
- Age of bird
Select values for the variables.
Return to the explanation of the imprinting expersim.
Return to the expersim index.
Comments to: Gary.McClelland@Colorado.EDU
Revised: 8 January 2001
File: expersim/imprintvars.html
|