Conditioned suppression of an avoidance response

A signal followed by shock was presented at irregular intervals during a free-operant avoidance schedule. The effects of this procedure were studied in terms of the rate of unavoided shock in the presence and absence of the signal and the rate of response before and during the signal. Three shock intensities were employed. Response enhancement as well as response suppression were observed; irrespective of changes in responding, shock rates substantially increased during signalled periods compared to non-signalled periods. Shock rates in non-signalled periods were generally higher than during training.     

Lever holding under free-operant avoidance

Rate of response under a free-operant avoidance procedure decreases as the response-shock interval increases. The present experiment demonstrated an inverse relation between rate of response and lever-holding time. An invariance was found in the total time per session that a subject was in contact with the lever. It is suggested that lever-holding behavior may be as sensitive as response rate to changes in the response-shock interval.     

The Racial Components of "Race-Neutral" Crime Policy Attitudes

Past studies have found evidence of a connection between race and crime in the minds of many white Americans, but several gaps remain in our knowledge of this association. Here, a multimethod approach was used to examine more closely the racial component of whites' support for ostensibly race-neutral crime policies. Conventional correlational analysis showed that negative stereotypes of African Americans—specifically, the belief that blacks are violent and lazy—are an important source of support for punitive policies such as the death penalty and longer prison terms. A survey experiment further showed that negative evaluations of black prisoners are much more strongly tied to support for punitive policies than are negative evaluations of white prisoners. These findings suggest that when many whites think of punitive crime policies to deal with violent offenders, they are thinking of black offenders.     

Effects of cycle length on performance on a temporally defined avoidance schedule

Three rats were trained on a temporally defined avoidance schedule logically similar to a fixed-interval, limited-hold positive reinforcement schedule. This avoidance schedule was composed of time periods during which responses had no scheduled consequences alternating with time periods during which a response precluded shock. As with fixed-interval length and response rate on positive reinforcement schedules, an inverse relationship was obtained between the length of the no-consequence interval and response rate during the no-consequence interval. An inverse relationship was also obtained between the length of the no-consequence interval and the per cent of shocks avoided. A rate increase within the no-consequence interval, similar to that typically produced by fixed-interval positive reinforcement procedures, was displayed by one of the rats where the no-consequence interval was at intermediate values and frequency of shock was relatively high. The introduction of a discriminative stimulus correlated with the avoidance interval produced typical discriminated avoidance behavior as well as alterations in temporal patterning of responses during the no-consequence interval in the two rats exposed to this procedure. These alterations in temporal patterning disappeared when the discriminative stimulus was removed. The results were consonant with those reported in the literature involving food reinforcement and fixed-interval, limited-hold schedules.