for Phase II of the cycle, where, after 1 minute of baseline bar-pressing, only the tone stimulus
was presented. Since the tone was previously paired with shock, it should suppress bar-pressing
behavior to some extent. Over a series of A-Bcycles, however, the subject should learn that
shock is never administered in Phase II and that Box Bis therefore a “safe” box. Thus, for later
cycles there should be less suppression on the no-shock trials.
Group L-A-Bwas treated in the same way as Group A-Bexcept that these animals pre-
viously had had experience with a situation in which a light, rather than a tone, had been
paired with shock. Because of this previous experience, the authors expected the animals490 Chapter 14 Repeated-Measures Designs
Table 14.11 Analysis of conditioned suppression (Lower scores represent greater suppression.)
(a 1 ) Data
Cycle
1 234
Phase Phase Phase Phase
Subject
Group I II I II I II I II Mean
A-B 1* 28 22 48 22 50 14 48 29.125
21 21 16 40 15 39 11 56 27.375
15 17 13 35 22 45 1 43 23.875
30 34 55 54 37 57 57 68 49.000
11 23 12 33 10 50 8 53 25.000
16 11 18 34 11 40 5 40 21.875
7 26 29 40 25 50 14 56 30.875
0 22 23 45 18 38 15 50 26.375
MeanAB 12.625 22.750 23.500 41.125 20.000 46.125 15.625 51.750 29.188
A-A 1 6 16 8 9 14 11 33 12.250
37 59 28 36 34 32 26 37 36.125
18 43 38 50 39 15 29 18 31.250
1 298655156.375
44 25 28 42 47 46 33 35 37.500
15 14 22 32 16 23 32 26 22.500
0 3 7 17 6 9 10 15 8.375
26 15 31 32 28 22 16 15 23.125
MeanAA 17.750 20.875 22.375 28.125 23.125 20.750 20.250 24.250 22.188
L-A-B 33 43 40 52 39 52 38 48 43.125
4 35 9 42 4 46 23 51 26.750
32 39 38 47 24 44 16 40 35.000
17 34 21 41 27 50 13 40 30.375
44 52 37 48 33 53 33 43 42.875
12 16 9 39 9 59 13 45 25.250
18 42 3 62 45 49 60 57 42.000
13 29 14 44 9 50 15 48 27.750
MeanLAB 21.625 36.250 21.375 46.875 23.750 50.375 26.375 46.500 34.141
Total 17.333 26.625 22.417 38.708 22.292 39.083 20.750 40.833 28.505
- Decimal points have been omitted in the table, but included in the calculations.