Answers to Simulations of the Rescorla-Wagner Model Acquisition ...

Answers to Simulations of the Rescorla-Wagner Model
Acquisition
Simulate five trials of acquisition (e.g., ToneFood). Assume that the
associative strength of the tone begins at 0 and that k for the tone = .4
Trial ΔV
tone
V
tone
1 0.40 .40
2 .24 .64
3 .14 .78
4 .09 .87
5 .05 .92
Extinction
Simulate five trials of extinction (e.g., Toneno Food). Assume that the
associative strength of the tone begins at 1 and that k for the tone = .4
Trial ΔV V tone
tone
1 -0.40 .60
2 -.24 .36
3 -.14 .22
4 -.09 .13
5 -.05 .08

Blocking
Group Exp: Simulate five Phase 1 trials (AUS) followed by five Phase
2 trials of blocking (e.g., ABUS). Assume that k A = .3 and k B = .3.
Also assume that the associative strength of CSs A and B are initially 0.
Keep in mind that the associative strength of CS A carries over from
Phase 1 to Phase 2.
Group Phase 1 Phase 2 Test B
Exp AUS ABUS cr
Con --- ABUS CR
Phase 1
Trial ΔV A V A
1 0.30 .30
2 .21 .51
3 .15 .66
4 .10 .76
5 .07 .83
Phase 2
Trial ΔV A V A ΔV B V B
1 0.05 .88 .05 .05
2 .02 .90 .02 .07
3 .01 .91 .01 .08
4 .00 .91 .00 .08
5 .00 .92 .00 .08

Control Group
Group Control: Simulate five Phase 2 trials (e.g., ABUS). Assume that
kA = .3 and k B = .3. Also assume that the associative strength of CSs
A and B are initially 0. Keep in mind that the control group does not
receive Phase 1 training.
Phase 2
Trial ΔV A V A ΔV B V B
1 0.30 .30 0.30 .30
2 .12 .42 .12 .42
3 .05 .47 .05 .47
4 .02 .49 .02 .49
5 .01 .49 .01 .49
Compare conditioning to CS B across the experimental and control
groups. Why does CS B condition more in the control group relative to
the experimental group? Discuss in terms of surprise.

Overshadowing
Simulate five trials of overshadowing for both the Overshadowing and
Control Groups. Remember that the control group receives conditioning
of CS B only. Assume that k A = .3 and k B = .1 (i.e., A is more salient
than B). Assume that the associative strengths of CSs A and B are
initially 0.
Group Training Test Observe
Overshadowing AbUS b cr
Control bUS b CR
Group Experimental
Trial ΔV A V A ΔV B V B
1 0.30 .30 0.10 .10
2 .18 .48 .06 .16
3 .11 .59 .04 .20
4 .06 .65 .02 .22
5 .04 .69 .01 .23

Group Control
Trial ΔV A V A ΔV B V B
1 n/a n/a 0.10 .10
2 n/a n/a .09 .19
3 n/a n/a .08 .27
4 n/a n/a .07 .34
5 n/a n/a .07 .41
Compare conditioning to CS B across the overshadowing and control
groups. Why does CS B condition more in the control group relative to
the overshadowing group? Discuss in terms of surprise.

Overexpectation
Simulate five trials of overexpectation for the experimental group only.
Assume that Phase 1 training (AUS, BUS training is complete). For
this simulation simulate 5 trials of Phase 2 (ABUS). Assume that k A =
.2 and k B = .2 and that the associative strength of both A and B are
equal to 1 following Phase 1 (i.e., Va = 1 and Vb = 1).
Group Phase 1 Phase 2 Test Observe
Overexpectation A-->US / B-->US AB-->US b cr
Control A-->US / B-->US no training b CR
Group Overexpectation (Phase 2)
Trial ΔV A V A ΔV B V B
1 -.20 .80 -.20 .80
2 -.12 .68 -.12 .68
3 -.07 .61 -.07 .61
4 -.04 .56 -.04 .56
5 -.03 .54 -.03 .54
How does the associative strength of CSs A and B change compared to
the control group (the associative strength of CSs A and B at the end of
Phase 1)? Why does CS B elicit a weaker conditioned response in the
Overexpectation group relative to the control group? Discuss in terms of
surprise.

Other simulations:
Be able to simulate and conceptualize the US-preexposure effect in
terms of the Rescorla-Wagner model. Hint: it is the same as blocking
except that the context acts as CS A.