Skinner (1938) produced a set of data that led him to conclude the effects of punishment
on the response probability would be only indirect. In the main experiment conducted at
the time, the initial suppressive effects of punishment (“bar slap”) disappeared after the
second session of extinction. This data is still used as a proof in favor of asymmetric
interpretations of punishment. The present study is a systematic replication of Skinner
(1938) with four manipulations: (a) use of electric shock as aversive stimulus; (b)
adoption of 10 sessions in the baseline; (c) the adoption of five extinction sessions; (d)
introduction of a yoked group with non-contingent shock. Two experiments were
conducted, A and B. In Experiment A, 20 rats were divided into two groups, punished
group (APUN) and control group (ACON). The rats were submitted to a training
session to the feeder and to lever-press shaping session followed by three sessions of FI-
4min., all lasting 60 min. Later, two sessions of extinction of 120 minutes were carried
out. To APUN, superimposed to extinction during the first 10 minutes of the first
extinction session, each lever-press produced an electric shock. In Experiment B, 30 rats
were divided also into three groups, punished (2PUN), control (2CON) and yoked
group (2ACO). The experiment started with a magazine and lever-press training
session, followed by ten sessions of FI-4min., all lasting 60 min. Later, the subjects
were subject to five sessions of extinction (60 minutes each). To 2PUN, superimposed
to extinction during the first 10 minutes of the first session of extinction, each leverpress produced an electric shock. For 2ACO shocks were delivered according to the
moment the paired subject from the punished group received it. During each session it
was recorded the number of lever pressing per minute contrasting the analysis of
Skinner (1938) with Boe and Church (1967) intergroup and intragroup. The results
showed that, for all the manipulations performed, there was no response recovery after
punishment was discontinued. This suggests it is possible to produce lasting punishment
effects provided that certain methodological steps are adopted.
|
