Stimulus control

Question 1

Guttman & Kalish (1956)

Answer 1

Trained pigeons to peck S+ 580nm on a VI 60s schedule. Then ran a gen test. Found largest response at training stimuli and a decremental gradient either side of this. Decremental generalisation gradient.

Question 2

Jenkins & Harrison (1960)

Answer 2

Group 1) SST - non differential
1000Hz tone –> VI schedule of reinforcement
ran gen test - found very little stimulus control, a large amount of generalisation and not much discrimination
Group 2) Presence-absence training/ interdimentional
1000Hz tone –> VI schedule of reinforcement
No tone –> EXT
Found the stimulus in generalisation were under greater control, and there was more discrimination.
=Stimulus was more relevant - its presence came to be related to reinforcement, and its absence - no reinforcement.

Question 3

Peterson (1962)

Answer 3

Rearing ducklings with monochromatic vs normal light.
Ran generalisation tests after teaching them to peck a yellow key. Monochromatic light –> complete generalisation, normal –> normal discrimination and gen gradient.
But these results were not replicated

Question 4

Jenkins & Harrison (1960)

Answer 4

Prepared: colour generalisation and food
Unprepared: sound generalisation and food
-Even with trained tone = was some discrimination, showing some level of stimulus control.

Question 5

Hearst & Koresko (1968)

Answer 5

-4 groups of pigeons on single-stimulus training S+
-Line training
-S+ –> food on VI schedule
-Tested generalisation on line orientation dimension
-Varied amount of training given
2 days –> not much response or stimulus control was present although the largest response was at training stimulus
14 days –> more behaviour response and more control - higher maximum and steeper gradients

Question 6

Hanson (1959)

Answer 6

Control: SST with 550nm S+ (no S-)
Experimental: Intradimenstional training with 55nm S+ and 560nm S-
Ran gen tests with colour
--> Control: peak at training stimulus
Experimental: peak shift away from S-

Question 7

Spences theory

Answer 7

Absolute theory of stimulus control

• Excitatory and inhibitory gradients around the stimuli – summation to form post-discrimination generalisation gradient.
• Parsimonious theory
• Accounts for transposition and peak shift

Question 8

Kohler - transposition (chickens)

Answer 8

Originally trained to chose between S+ (light grey) and S- (dark grey). Following trials, chickens chose the lighter grey card (S++) and hence seemed to have learnt the rule ‘choose the lighter card’ during the training stimuli and transposed this during the testing conditions.

Question 9

Honig et al (1963)

Answer 9

Presence absence training.
Line S- group: S- with line, S+ with no line
Line S+ group: S+ with line, S- with no line.
Ran generalisation test. Found excitatory and inhibitory gradients. Excitatory gradient was steeper –> expected