Stimulus Control of Behavior Notes

Stimulus Control Of Behavior

• Everyday behaviors of organisms are influenced by environmental stimuli.
  • Example: In libraries, students refrain from talking.
  • Example: Animals adapt their behavior based on environmental changes (e.g., taking cover in rain).

Understanding Stimulus Control

• An organism is under "stimulus control" when its behavior is influenced by specific stimuli.
• Reynolds (1961) studied this with pigeons responding to different stimuli under variable interval (VI) schedules.
  • Experiment with a white triangle on a red background.
  • Demonstrated differential responding to stimuli, showing stimulus discrimination.

Stimulus Generalization

• Definition: Stimulus generalization occurs when an animal responds similarly to different stimuli.
  • Discovered by Pavlov during classical conditioning.
  • Example: Animals trained with a specific tone respond to similar tones based on frequency.
  • Closer frequencies lead to larger conditioned responses (CR).

Measuring Stimulus Generalization

• Stimulus generalization gradients measure sensitivity to changes in learned stimuli.
• Guttman & Kalish (1956) contributed early studies on stimulus generalization.
• Gradients indicate the strongest stimulus control and response to stimuli:
  • A steep gradient indicates high control.
  • A flat gradient indicates no control, as the organism responds similarly to all stimuli.

Factors Influencing Stimulus Control

• Salient Stimuli: More noticeable stimuli can overshadow less salient ones if presented together (overshadowing).
  • Pavlov found the salient stimulus dominates learning.
• Type of Reinforcement: Influences which stimuli gain control based on type (appetitive vs. aversive).
  • Example: Light CS paired with food, tone CS paired with shock.

Type of Instrumental Response

• Control also depends on the animal's required response type.
  • Dobrzecka et al. (1966) indicated that location-differentiated responses were controlled by spatial stimuli, while quality-differentiated responses were controlled by the quality of stimuli.

Stimulus Discrimination Training

• Stimulus discrimination training effectively brings behavior under control of specific stimuli.
  • Example: Rats learning eyeblink conditioning. Tone A+ (paired with shock) vs. Tone B- (not paired).
  • Subjects learned to blink to Tone A+ but not B-.

Effects of Discrimination Training

• Jenkins and Harrison (1960, 1962) experimented with pigeons:
  • Group differences in pecking for tones: one tone rewarded, another not.
  • Greatest stimulus control occurs with effective discrimination training across varied dimensions.

Interoceptive Cues in Discrimination Training

• Pigeons can also distinguish between drug-induced states and non-drug states.
  • Schall et al. (1996) demonstrated the capacity for discrimination between drug states.

Stimulus Elements vs. Configural Cues

• Conditioning with compound stimuli can involve:
  • Stimulus-element approach: perceiving elements (e.g., white triangle vs. red background) separately.
  • Configural-cue approach: viewing complexity as a whole.
  • Overshadowing and generalization decrement explored within these frameworks.

What Is Learned In Discrimination Training?

• Behavioral strategies for responding to stimuli:
  • Respond to S+ only.
  • Do not respond to S-.
  • Differentiate by responding selectively according to stimuli presence.

Spence’s Theory of Discrimination Learning

• Kenneth Spence (1936) proposed that animals learn both excitatory (S+) and inhibitory (S-) response tendencies.
• Generalization gradients based on response tendencies show effectiveness:
  • Overlapping gradient effects between S+ and S- can lead to peak shifts.

Conditional Relations and Contextual Control

• Behavior may be influenced by contextual cues.
  • Akins (1998) demonstrated specific associations based on context (e.g., sexual reinforcement).
• Training in different contexts can lead to variations in response and reward associations.

Conditional Control in Pavlovian Conditioning

• Conditional relations require modulators to indicate when reinforcement occurs.
  • Example: Noise can signal food following a light.
• Occasion setters provide context but do not directly elicit responses without reinforcement.

Discrepancies in Inhibition and Occasion Setting

• Occasion setting illustrates interactions between positive US signals (S+) and negative (S-).
• Light as a modulator shows enhanced responses to noise, exploring the complexity of conditioned inhibition versus excitation.