Avoidance of hot air blast in Rattus norvegicus.

The hegemonic use of electric shock as an aversive stimulus limits what is known about the generality of avoidance behavior and related phenomena. The purpose of this study was to investigate the effects of using the hot air blast (HAB) instead of electric shock as an aversive stimulus in avoidance conditioning. Four male Wistar rats were exposed to a discrete-trial procedure.

Negative reinforcement of behavioral variability without previous training with positive reinforcement.

In a previous study, Fonseca Júnior and Hunziker (2017) provided evidence of the control of behavioral variability by avoidance contingencies. However, their study presented three methodological weaknesses: (1) only one contingency reversal was conducted in the experimental design adopted, (2) the lever press was shaped using a positive reinforcement procedure, and (3) the intermittency of reinforcement between Lag n and Yoke conditions was not successfully equaled. The present study aimed to overcome these three methodological limitations.

Behavioral variability as avoidance behavior.

This study aimed to investigate whether variable patterns of responses can be acquired and maintained by negative reinforcement under an avoidance contingency. Six male Wistar rats were exposed to sessions in which behavioral variability was reinforced according to a Lag contingency: Sequences of three responses on two levers had to differ from one, two or three previous sequences for shocks to be avoided (Lag 1, Lag 2 and Lag 3, respectively). Performance under the Lag conditions was compared with performance on a Yoke condition in which the animals received the same reinforcement frequency and distribution as in the Lag condition but behavioral variability was not required.