Lecture 14: Stimulus Control of Behaviour Flashcards
A molecular explanation for higher response rates on VR vs. VI schedules is provided by…
- Reinforcement of short inter-response times
Presentation of a CS paired with an appetitive outcome while instrumental responding for the outcome results in…
- Increased instrumental responding (CS with appetitive outcome is adding to instrumental responding; paired with outcome = higher levels of responding)
Conditioned suppression is a form of…
- Pavlovian-to-Instrumental transfer
- Stimulus associated with aversive outcome suppresses ongoing instrumental behaviour
What is stimulus control of behaviour?
- Behaviour that has been reinforced in the presence of one stimulus is controlled by the presence/absence of that stimulus
- Behaviour that has been reinforced in the presence, but not necessarily by that stimulus
- Stimulus that has been present controls that behaviour
- Variations in stimulus can cause variations in that behaviour
Why do some pigeons respond to the red circle and some to white triangle?
- Individual variability in stimulus control of behaviour (differential responding)
- Neither were dependent on compound stimulus (one element over another)
What does differential responding indicate?
- Pigeons treated each stimulus element as distinct from the other (stimulus discrimination)
What does it mean if there is no stimulus discrimination?
- There is no stimulus control
- Organism must be able to distinguish one stimulus from other stimuli in order for that stimulus to be in control of that behaviour
When does responding generalize to other stimuli?
- Generalizes on basis of similarity to training stimulus
- Opposite to stimulus discrimination
- Organism shows stimulus generalization if it responds in a manner similar
- Fail to respond differentially to stimuli similar to original
What is a stimulus generalization gradient?
- Provides precise information about how much of a change in a stimulus is required for pigeons to respond differently
- Decrease in control of behaviour as stimulus becomes more different than training stimulus
What is stimulus control of behaviour limited by?
- Limited by sensory capacity
- Must consider both model organism and individual
- Ex. rats have poor visual acuity, but use odours instead
- Ex. colour blindness
What is overshadowing?
- Relative salience/strength or ease of learning about one element of a stimulus may suppress learning about the other one
- Tests of nicotine and light separately show dose-dependence of stimulus control of drug and corresponding decrease in light control of behaviour
What is elemental stimulus control of behaviour?
- Stimulus-element approach
- Considering a compound stimulus, each ‘piece’ is treated separately
- Assumption is that these elements are treated by the organism as separate entities, not whole experience
What is configural stimulus control of behaviour?
- Configural-cue approach
- Considers stimulus elements as important not because of individuality, but because of how each contributes to the whole
- Elements may not even be identifiable when stimulus compound is presented
- Ex. individual instruments in an orchestra
What type of compound stimulus control of behaviour is found when there is a decrease in responding elicited by the light element alone when it isn’t compared to when it is paired with nicotine during training?
- Support for configural account of stimulus control of behaviour
What would happen in an elemental case of stimulus control of behaviour?
- One element should be sufficient to elicit full response in elemental case (light should elicit same level of responding separately as combined with nicotine)
- Complete reliance on one or the other component of a compound stimulus
What leads to a discriminative stimulus?
- Stimulus discrimination training
- Works for both Pavlovian and operant conditioning
What is an example of Stimulus Discrimination Training?
- Drug discrimination
- Used to help understand pharmacology of drugs
- Can see what mechanism a compound might have on particular receptor systems
- Vehicle pretreatment and training drug treatment for each lever, then test drug pretreatment (which lever do they respond to?)
What do the idealized data look like representing possible outcomes in drug discrimination?
- Full generalization = lowest dose responds to drug lever
- Larger dose is needed for less potent drug
- Partial generalization = level of responding never reaches that of training drug
- No generalization = no responding to drug lever
What happens when the dose is decreased in a drug discrimination study?
- Accurate responding decreases
- Lower salience, takes longer to acquire control over behaviour
- How TD-like is test substance?
- At lower dose, differently acting opioid agonist starts to substitute for TD
- Pharmacological specificity of its discriminative stimulus properties also decreases
- Rat may attend to a stimulus complex that is no longer exclusive to narcotic drugs
What was the result of a drug discrimination study in humans?
- Tramadol discrimination is acquired when 80% session-appropriate responding occurred in 4 consecutive sessions
- Tramadol can function as an interoceptive discriminative stimulus in humans
- Individual variability in its efficacy
- Mu opioid receptor activation underlies these discriminative properties as naloxone shows a dose dependent blockade of the effects
What is a multiple schedule of reinforcement?
- A different schedule of reinforcement may be in effect during different stimuli
- Ex. VI when light is on, FR when tone is presented
What is positive patterning?
- Whenever each of 2 stimuli occur individually, they are not reinforced
- However, reinforcement occurs whenever 2 stimuli are presented simultaneously
What is the negative patterning procedure?
- Similar to positive patterning
- Role of reinforced/nonreinforced is reversed
- Reinforcement is available when cues are presented individually
- Not when they appear simultaneously
What is learned in discrimination training?
- One possibility is to learn to respond whenever S+ is present and not respond otherwise
- Another possibility is to learn to suppress responding during S- but respond whenever S- was absent (lead to more responding during S+ than S- but without learning anything about S+)
