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| International Paper Session - Choice, Timing, and Remembering |
| Monday, August 13, 2007 |
| 2:00 PM–3:20 PM |
| L2 Room 2 |
| Area: EAB |
| Chair: Douglas Elliffe (University of Auckland) |
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| Generalized Matching Does Not Describe Four-Alternative Choice. |
| Domain: Experimental Analysis |
| DOUGLAS ELLIFFE (University of Auckland), Michael C. Davison (University of Auckland), Rebecca A Sharp (University of Auckland) |
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| Abstract: Five pigeons responded on a four-key concurrent schedule with reinforcer rates in the ratio 27:9:3:1 across the keys. The keys arranging each rate changed several times during each session. Learning was rapid, and response rates were ordered perfectly with respect to reinforcer rates after very few reinforcer deliveries. The constant-ratio rule was violated, in that pairwise choice between 27 and 9 differed from choice between 9 and 3, and between 3 and 1. The generalized matching law cannot in principle describe this result, but the contingency-discriminability model can. |
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| Performance of Pigeons in a Numerical Reproduction Task with a Continuous Response Variable. |
| Domain: Experimental Analysis |
| LAVINIA CM TAN (University of Canterbury), Randolph C. Grace (University of Canterbury) |
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| Abstract: Previous research with a numerical reproduction task found pigeons were able to discriminate and reproduce numbers with variability signatures similar to those found in human verbal counting. A prototype category-learning model was developed that successfully described and predicted performance in this task. The current research involves an adaptation of the original procedure, in which numbers are reproduced as different values of a continuous response variable, not discrete responses. The greater range of variability afforded by a continuous response measure will allow finer-grained analyses of responding. This may provide a clearer picture of processes underlying numerical proficiency, as well as a more accurate test of the category-learning model. The success of the model in predicting performance in this task and results of response analyses will be discussed. |
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| Rapid Acquisition of Choice and Timing in Pigeons. |
| Domain: Experimental Analysis |
| ELIZABETH KYONKA (University of Canterbury), Randolph C. Grace (University of Canterbury) |
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| Abstract: Pigeons were trained on a concurrent-chains procedure in which the initial link associated with the shorter terminal-link delay to food changed unpredictably across sessions. In the minimal-variation condition, delays were always 10 s and 20 s, whereas in the maximal-variation condition delays were generated pseudorandomly for each session. On some terminal links, food was withheld to obtain measures of temporal control. Measures of choice (log initial-link response ratios) and timing (start and stop times on no-food trials) showed temporal control and stabilized within the first half of each session. In the maximal-variation condition, choice was a sigmoidal function of the log delay ratio, consistent with a categorical discrimination but contrary to models based on the matching law. Residuals from separate regressions of log response and log start and stop time ratios on log delay ratios were positively correlated. Overall, results support cognitive models which assume that initial-link choice is based on an ‘all or none’ decision process, and that choice and timing are mediated by a common representation of delay. Analyses are planned which will compare the predictions of different models of responding in concurrent chains. |
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