stimulus control of operant behavior discrimination generalization generalization gradients peak...
TRANSCRIPT
Stimulus Control of Operant Behavior
Discrimination
Generalization
Generalization Gradients
Peak Shift
Concepts
Overview of stimulus control of operant behavior
I. Operant Discrimination
Known as the study of discrimination learning or stimulus control
Discriminative stimulus - Signals that reinforcement will be forthcoming if the response occurs (S+ or Sd)
Signals that reinforcement will not be available, even if the response occurs (S)
Discrimination
Animals learn to demonstrate differential patterns to responding to different stimulus conditions
II. Generalization
Similar patterns of responding to similar stimulus conditions
The opposing qualities of discrimination
Predictiveness and Redundancy
Conditioning will occur to the stimulus which most predictive
An especially salient CS may overshadow the other stimuli
Overshadowing
Depends upon nature of the environment, the past history of the animal and similar issues
Highly salient stimulus qualities often overshadow other stimuli
Specific features of the stimulus may be attended to
Attention Training
Relevance must be learned Behavior must be demonstrated Transfer of training studies
– Paying attention is a separate part of the discrimination learning
Attention Training
Dimensional shift learning paradigm– Intradimensional shift - Train to CS+
quality, shift to different type of same dimension (e.g. shift from red to blue for CS+)
– Extradimensional shift - Train to CS+ quality, shift to different dimension (e.g. from color to shape for CS+)
IV. Process of Generalization
Extinction builds to CS+ and inhibition builds to CS-
Early work of Spence 1936, 1937; and Hull 1943, 1952
According to Spence’s theory, excitation and inhibition add together in an algebraic fashion
V. Natural Concepts
Concepts are related by unifying or common properties
Abstract concepts– “Same” or “different”– Often not limited to specific concrete
qualities
V. Natural Concepts
Wittgenstein in 1953 It is not clear what specific features or
qualities are being responded to What is a dog? What are the qualities of “dogginess?”
V. Natural Concepts
Herrnstein work in the 1980s Demonstrated discrimination of natural
objects by pigeons Sort stimuli by water, trees or a particular
person Organisms as simple as pigeons can
reliably demonstrate this discrimination
Learning Theory and Memory
Are there behavioral ways to describe remembering and knowing?
Some procedures include delayed matching to sample– Matching accuracy decreases as a function
of time
Matching Accuracy Over Time and Sample Duration
PercentageCorrect
Seconds
100
50
14 sec sample
8 sec sample
4 sec sample
Working Memory
Memory is an active process– Susceptible to interference
Retroactive interference - interfering stimulus comes after the stimulus to be remembered
Proactive interference - interfering stimulus comes before the stimulus to be remembered
Working Memory
Symbolic matching works as effectively as direct stimulus matching– For example, red to vertical lines is
remembered as well as red to red– Directed forgetting - stimulus learning is
followed by a signal that the stimulus is to be remembered or not
– It appears memory is an active process