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| International Paper Session - Timing and Counting |
| Sunday, May 27, 2007 |
| 9:00 AM–10:20 AM |
| Randle A |
| Area: EAB |
| Chair: Andrew T. Fox (Central Michigan University) |
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| SET or LeT? Testing Two Timing Models. |
| Domain: Basic Research |
| LUIS L. OLIVEIRA (University of Minho), Joana Rodrigues Arantes Da Silva (University of Minho), Armando Machado (University of Minho) |
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| Abstract: In order to contrast two models of timing, Scalar Expectancy Theory (SET) and Learning to Time (LeT), 8 naïve pigeons (Columba livia) were exposed to a double temporal bisection procedure. On Type 1 trials, they learned to choose a red key following a 1.5-s signal, and a green key following a 6-s signal; on Type 2 trials, they learned to choose a blue key after a 6-s signal and a yellow key after a 24-s signal. The signals used consisted of a horizontal bar for Type 1 trials and a vertical bar for Type 2 trials. On the next phase, pigeons learned a new bisection task, in which they had to choose between colors blue and green, both previously associated with the same stimulus duration, but with different types of bars. The sample stimulus in this task ranged from 1.5 to 24 seconds. Results show that the visual cue did not affect the pigeons' decisions based on timing variables, as the preference for the green key increases with the duration of the test signal, a result consistent with LeT, but not with SET. |
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| Counting Categorically: Modelling Performance in a Numerical Reproduction Procedure. |
| Domain: Basic Research |
| LAVINIA CM TAN (University of Canterbury), Randolph C. Grace (University of Canterbury) |
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| Abstract: Previous research using a numerical reproduction procedure has shown pigeons were able to perform absolute discriminations of number. Relative response accuracy increased with increases in number, consistent with results found in human counting. Coefficients of variation decreased as a function of the square root of average response number, whereas responding in nonhuman and nonverbal numerical and timing tasks exhibit scalar variability. We propose a prototype category-learning model that successfully accounts for the main features of these data, including predictions of average response number, response distributions in baseline and transfer trials, and the decreasing CVs. Additional experiments to test predictions of the model are reported. |
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| Errorless Learning of a Temporal Bisection Task. |
| Domain: Basic Research |
| JOANA RODRIGUES ARANTES DA SILVA (University of Minho), Randolph C. Grace (University of Canterbury), Armando Machado (University of Minho) |
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| Abstract: To contrast trial and error learning and errorless learning, we used a temporal bisection task. Pigeons were trained in a discrimination in which pecks in a red key after a 2-s signal and a green key after a 10-s signal were reinforced. Then, pigeons were presented with three types of tests. First, they were exposed to intermediate durations (from 2 s to 10 s) and given a choice between both keys (stimulus generalization test). Second, a delay from 1 s to 16 s was included between the offset of the signal and the onset of the choice keys (delay test). Finally, pigeons learned a new discrimination in which the stimuli were switch (reversal test). |
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