1. Experimental Psychology PSY 433
Chapter 9
Conditioning and Learning (Cont.)

2. Dressage Example
The horse responds to hand and leg cues that vary by location to signal different moves.
Horses begin to be trained at age 2 and it takes around years to be this good (this horse is 9 years old and is unusual).
Riders must be trained too, to give the right cues and not confuse a trained horse.
Behavior is shaped.

3. DVs in Learning Experiments
Response rate – number of responses as a function of time.
Response amplitude -- amount of saliva.
Response latency -- time to accomplish a response.
Time to complete a maze
Resistance to extinction -- how long it takes a response to go away once it stops being rewarded.

4. IVs in Learning Experiments
Magnitude of reinforcement (size of reward).
Delay prior to reinforcement.
Amount of deprivation (motivation to obtain the reward).
Intensity of the CS and UCS in classical conditioning.

5. Choosing an Experimental Design
Between vs within subjects designs offer different tradeoffs, but there are more than practical considerations at stake.
Choice of design may affect the actual outcome of the research.
Sometimes using a between-subjects and a within-subjects design produces different results.
Carryover effects may exist without the experimenter’s knowledge.

6. Order Effects
Order effects (practice effects) = experiencing one level affects behavior in another level
Effects of practice, boredom, fatigue
Example: Does content (biology text vs. novel) affect proofreading speed? Order is Biology-Novel
Order effects are controlled in within-subjects designs by randomizing or counterbalancing the presentation orders.

7. Order Effects in Proofreading
Group 1
Biology 1
(no practice)
(practice)
Novel 2
Group 2

8. Differential Carryover Effects
Carryover effects, differential/asymmetrical transfer effects occur when experiencing one level affects performance on the next.
The effect of the first level on the second level differs depending on which comes first.
Effect of B following A ≠ effect of A following B
Confound occurs when one level consistently precedes the other.

9. Differential Carryover Effects in Problem Solving
Group 1
Neutral
instructions 1
(no practice)
(practice) 2
Group 2
Special

10. Classical Conditioning Example
Grice and Hunter (1964) - human conditioning
UCS is air puff; UR is blinking
Vary CS intensity (loud or soft tone)
Done between-subjects or within-subjects
500 ms CS – 500 ms ISI – US
Varying CS intensity in BS design has no effect on % CR
Varying CS intensity in WS design has large effect.

12. Contrast Between Stimuli
In a WS design, subjects can compare two levels of a stimulus in the same experiment and may respond to the two stimuli differently.
This effect occurs despite the randomization and counterbalancing that were used to control for differential order effects:
First, choose a random order (LSSLSLLLS)
Then counterbalance the random order: ½ got it, ½ got the reverse (SLLSLSSSL)

14. Instrumental Conditioning Example
Bower (1961) –3 groups of rats trained to run down an alley (maze) for food.
Two IVs: kind of reward & color of maze.
Reward:
Constant 8 – got 8 pellets per maze run
Constant 1 -- got 1 pellet per maze run
Contrast – got 1 pellet in one colored maze, 8 in the other colored maze (black/white)
All 3 groups: ½ got black & ½ got white maze.

17. ABBA Counterbalancing
Define 2 conditions: A and B or S and L
In Bower’s case, 1 pellet (S) & 8 pellet (L)
Present in order: ABBA (SLLS)
If order effects are linear, they will then be distributed evenly across conditions.
If nonlinear, do not use ABBA, or give practice trials first.
Bower used both ABBA and BAAB.
Use Balanced Latin Square with >2 groups.

18. Small-n Designs
Behavior often cannot be studied in large groups (large-n designs)
Small-n frequently used in therapeutic situations
Reversal designs: ABA or ABAB
A = baseline recording of behaviors
B = introduction of treatment
IV is essentially treatment / no treatment.

19. Example: Crying Behavior
Increases
Reinforcement +
Bill crys
Adults attend
Removing the positive reinforcement (attention) extinguishes crying behavior.

20. FIG: Kanto7e 9-8, Hart data

21. Multiple Baseline Designs
Observe different behaviors, before and after learning.
Can be done two ways:
Observe multiple behaviors in one individual -- like a within-subject design
Observe a single behavior in different individuals – between-subjects
Treatments are introduced at different times.

24. Example: Siblings Compared
3 pairs of autistic vs normal siblings
Baseline -- observed target behaviors (counting, letter ID, etc)
Treatment -- trained normal sib to reinforce behaviors of autistic sib
DV -- number of correct performances of behaviors.

26. Changing Criterion Design
Instead of comparing different people or different behaviors, progress in shaping behavior over time is measured.
The target behavior needed for reinforcement is changed as a behavior is acquired.
Range-bound changing criterion – instead of a target, a range for reinforcement is established.
Distributed-criterion design – targets are spread across several behaviors.