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| Molar and Molecular Factors in Aversive Control |
| Monday, May 25, 2009 |
| 10:30 AM–11:50 AM |
| North 228 |
| Area: EAB; Domain: Experimental Analysis |
| Chair: Michael Perone (West Virginia University) |
| Discussant: Michael Perone (West Virginia University) |
| Abstract: This symposium will report and discuss recent experimental research concerned with long-term (molar) and short-term (molecular) influences on behavior controlled by punishment and negative reinforcement. Of particular interest are experimental analyses of the differential punishment of long or short interresponse times and the role of shock-frequency reduction in the reinforcing efficacy of timeout from avoidance. |
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| Generalized versus Localized Effects of Shock: The Role of Shock Intensity and Interresponse Times Followed by Shock |
| JESSICA B. LONG (University of Pittsburgh at Greensburg) |
| Abstract: Although response-dependent shock often suppresses responding, response facilitation occasionally occurs. Four experiments investigated how shock intensity and the interresponse that produce shock interact to determine responding. Lever pressing by rats was maintained by a variable-interval 40-s schedule of food presentation. Shock was delivered on a differential schedule. In Experiments 1 and 2, long interresponse times produced shock. In Experiments 3 and 4, short interresponse times produced shock. The range of interresponse times eligible for shock was raised across or within phases, and shock intensity was raised from 0.05 mA to 0.4mA or 0.8 mA. Whether shock suppressed or facilitated responding depended on the shock schedule. When long interresponse times produced shock, low shock intensities facilitated responding and suppressed long Interresponse times. High shock intensities had the opposite effect. When short interresponse times produced shock, shock suppressed responding and short Interresponse times. Higher shock intensities produced the greatest suppression. In three of the four experiments, raising the range of interresponse times eligible for shock enhanced these effects. The current data support previous findings on the selective punishment of interresponse times but suggest that whether shock facilitates or suppresses responding depends on both shock intensity and the interresponse times followed by shock. |
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| Negative Reinforcement by Timeout from Avoidance: The Roles of Shock-Frequency
Reduction and Response-Effort Reduction |
| ANNE M FOREMAN (West Virginia University) |
| Abstract: Timeout from avoidance is an effective reinforcer, but the reason is not firmly established. The present experiment eliminated the reduction in shocks that occurs from time-in to timeout while maintaining the reduction in avoidance responding that occurs from time-in to timeout, thus allowing for the assessment of shock-frequency reduction independently of response effort. Rats responded on concurrent schedules of avoidance and timeout. Pressing the right lever postponed shocks according to a schedule with a response-shock interval of 30 s and a shock-shock interval of 5 s, and pressing the left lever produced 2-min timeouts according to a variable-interval 45-s schedule. In the experimental conditions, shocks were delivered during the timeouts. In the Local-Yoking condition, there was no short term change in the rate of shocks from time-in to timeout. The number and temporal location of shocks in the 2-min timeout duplicated the number and temporal location of shocks in the 2 min of time-in preceding the timeout. In the Molar-Yoking condition, the overall rate of shocks in time-in and timeout was the same. The schedule of shocks during the time-in portion of the previous session was played back during the timeouts of the following session. Early data suggest that rates of responding to produce timeouts are maintained when shocks are delivered during the timeouts in both the Local-Yoking and Molar-Yoking conditions. |
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| The Shock Remains the Same but Timeout Responding Sure is Changing |
| CHAD M. GALUSKA (College of Charleston) |
| Abstract: One-factor accounts of responding maintained by timeout from shock avoidance emphasize the importance of the shock-frequency reduction afforded by the timeout. Two experiments are reviewed which demonstrate that rats’ responding maintained by timeout from avoidance (timeout responding) can be modified by manipulations that do not affect the prevailing rate of shock. In Experiment 1, increasing the duration of warning signals of impending but avoidable shock increased both avoidance and timeout responding without systematically altering the obtained shock rate. In Experiment 2, after establishing a baseline in which rats could avoid shock by responding on one lever and produce timeout by responding on the other, the avoidance contingency was removed altogether and response-independent shocks were yoked from the baseline condition. Timeout responding actually decreased, even though the shock-frequency reduction afforded by the timeout remained the same and a competing response had been removed. Together, these results provide converging evidence that timeout responding is sensitive to variables other than the degree of shock-frequency reduction associated with the timeout. Perhaps the reinforcing functions of timeout are derived from the respite from the avoidance activity that timeout permits. |
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