Human responding on random-interval schedules of response-cost punishment: the role of reduced reinforcement density

Abstract

An experiment with adult humans investigated the effects of response-contingent money loss (response-cost punishment) on monetary-reinforced responding. A yoked-control procedure was used to separate the effects on responding of the response-cost contingency from the effects of reduced reinforcement density. Eight adults pressed buttons for money on a three-component multiple reinforcement schedule. During baseline, responding in all components produced money gains according to a random-interval 20-s schedule. During punishment conditions, responding during the punishment component conjointly produced money losses according to a random-interval schedule. The value of the response-cost schedule was manipulated across conditions to systematically evaluate the effects on responding of response-cost frequency. Participants were assigned to one of two yoked-control conditions. For participants in the Yoked Punishment group, during punishment conditions money losses were delivered in the yoked component response independently at the same intervals that money losses were produced in the punishment component. For participants in the Yoked Reinforcement group, responding in the yoked component produced the same net earnings as produced in the punishment component. In 6 of 8 participants, contingent response cost selectively decreased response rates in the punishment component and the magnitude of the decrease was directly related to the punishment schedule value. Under punishment conditions, for participants in the Yoked Punishment group response rates in the yoked component also decreased, but the decrease was less than that observed in the punishment component, whereas for participants in the Yoked Reinforcement group response rates in the yoked component remained similar to rates in the no-punishment component. These results provide further evidence that contingent response cost functions similarly to noxious punishers in that it appears to suppress responding apart from its effects on reinforcement density.

Keywords: humans; random-interval schedules; response-cost punishment; response-independent punishment; yoked-control procedure.

Fig 1

Mean response rates in the punishment component (filled bars) and yoked component (open bars) plotted for the final three sessions of each condition as a proportion of responding in the no-punishment component under baseline (BL) and response-cost conditions. The RI schedule value indicates the response-cost schedule. Error bars show standard deviations. Successive exposures to a condition are plotted left to right. For P 99, conditions in which the punishment magnitude was increased to $0.05 are indicated by asterisks. For P87, the asterisk above the first RI 5-s response-cost condition indicates a condition in which the participant was erroneously exposed to yoked punishment. Axes are individually scaled.

Fig 2

Responses per min in the no-punishment (filled circles), punishment (open circles), and yoked (filled triangles) components during the final three sessions of each baseline (BL) and response-cost condition. Conditions are presented in order of exposure. The RI value indicates the response-cost schedule (in seconds). For P 99, only conditions after which the punishment magnitude was increased to $0.05 are shown (see Table 3). Axes are individually scaled.

Fig 3

Obtained cents per min (total earned minus total lost) in each component across baseline (BL) and response-cost conditions. Error bars show standard deviations. Successive exposures to a condition are plotted left to right. The RI schedule value indicates the response-cost schedule. See Table 1 for reinforcer and punisher magnitudes. For P 99, only conditions after which the punishment magnitude was increased to $0.05 are shown (see Table 1).

Fig 4

Scatter plots of obtained cents per min (total earned minus total lost) plotted against responses per min in the punishment component during each session in baseline, RI 20-s, RI 10-s, and RI 5-s response-cost conditions. Solid lines are regression lines. For the RI 20-s condition, the second (dashed) regression line shows the relationship between response rate and net reinforcement when data from P 99 are omitted. See text for details.

Fig 5

Latencies for the first response in each component across conditions. Data are the average values of the final 3 sessions of all exposures to a condition. Error bars show standard deviations. Axes are individually scaled.

Fig 6

Cumulative responses during baseline, RI 20-s, RI 10-s, and RI 5-s response-cost conditions for P103 and P100 in no-punishment (No Punish), punishment (Punish), and yoked (Yoked) components. Filled circles indicate money deliveries; backslashes indicate money losses (response cost). Axes are individually scaled.

Fig 7

Cumulative responses during RI 10-s response-cost conditions for P51, P63, P87, and P99 in no-punishment (No Pun or NP), punishment (Pun or P), and yoked (Yoke) components. Filled circles indicate money deliveries; backslashes indicate money losses (response cost). Axes are individually scaled.