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| International Symposium - Behavioral Variability |
| Tuesday, May 27, 2008 |
| 10:30 AM–11:50 AM |
| Metra |
| Area: EAB; Domain: Basic Research |
| Chair: Josele Abreu-Rodrigues (Universidade de Brasília) |
| Discussant: Manoel Rodrigues-Neto (The Ohio State University) |
| Abstract: Although the focus of the behavior-analytic literature has been the understanding of steady-state conditions, studies in which behavioral variability is the subject of investigation itself also can be found. It has been demonstrated that response variation is amenable to selection by reinforcement: When reinforcers are contingent on variability, organisms behave variably; when reinforcers are contingent on stereotypy, organisms behave repetitively. Such demonstrations of reinforcement control suggest that variability can be a dimension of operant behavior, a finding that was investigated further in the studies included in the present symposium. These studies show that choice is influenced by the degree of variation required for reinforcement, and that a history with variation or repetition differentially affects rule discovery and sensitivity to response-independent reinforcers. |
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| Behavioral Variation in the Context of Choice. |
| ALESSANDRA SOUZA (Universidade de Brasília and Instituto de Educação), Josele Abreu-Rodrigues (Universidade de Brasília) |
| Abstract: Choice between vary and repeat contingencies of reinforcement is affected by the variability requirement. That is, the more stringent the variability criterion, the greater the preference for the repeat contingency. The goal of the present study was to extend this finding to situations in which subjects choose between two vary contingencies. Pigeons’ responses on two concurrently available keys according to a VI 30-s schedule (initial links) produced the onset of one of two terminal links. The terminal-link performance consisted of sequences of four responses distributed in two operanda. In the FIXED terminal link, a specific variability criterion was maintained throughout the conditions; in the VARIED terminal link, the variability criterion was manipulated across conditions. Reinforcement rates were the same in both terminal links. The results showed that choice between vary contingencies was affected by the variability requirement such that subjects tended to prefer low variability requirements. |
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| Variation and Repetition: Sensitivity to Response-Independent Reinforcers. |
| JOSELE ABREU-RODRIGUES (Universidade de Brasília), Paula Natalino (Universidade de Brasília) |
| Abstract: The present study aimed to investigate whether reinforcement histories with different degrees of behavior variability, with and without instructions, would produce differential effects upon subsequent exposure to response-independent events. In the Training Phase, college students were required to emit five-letter sequences. For the VAR and VAR-I groups, to be reinforced a sequence had to be different from the 10 previous ones; for the REP and REP-I groups, reinforcers were contingent to a specific sequence. Both VAR-I and REP-I groups received accurate instructions about the reinforcement contingencies. In the Testing Phase, all groups were exposed to sequence-independent reinforcers. The results showed that, during the Training Phase, the VAR and VAR-I groups presented higher levels of behavioral variation than the REP and REP-I groups. With the exposure to independent reinforcers, the level of sequence variation was not altered for the VAR and VAR-I groups, but it increased for the REP and REP-I groups. In both phases, the presence or absence of instructions did not affect differentially sequence variation. It was concluded that a baseline of behavioral repetition is more sensitive to response-independent reinforcers than a baseline of behavioral variation. |
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| The Effects of Variation and Repetition upon Rule Discovery. |
| JOSELE ABREU-RODRIGUES (Universidade de Brasília), Juliana Brasiliense Vilela (Universidade de Brasília) |
| Abstract: The present study evaluated the effects of a history with variation and repetition upon rule discovery in subsequent reinforcement contingencies. Twenty college students were required to emit eight-response sequences. In the Training Phase, for the VAR group, a sequence was reinforced only when it has occurred no more than 15% of the trials; for the REP group, only a specific sequence was reinforced; and for the IND group, reinforcers were delivered independently of the sequence. The CTR group was not exposed to this phase. In the Testing Phase, all groups were exposed to four different reinforcement criteria. Also, all participants were required to describe each one of the reinforcement criteria (rules). During the Training Phase, the VAR group presented higher levels of behavioral variation than the REP and IND groups. During the Testing Phase, the VAR and CTR groups showed a greater number of accurate rules than the REP and IND groups. These results suggest that a history with low levels of behavioral variation may impair rule discovery. |
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