Effects of Ethanol on Reinforced Variations and Repetitions by Rats Under a Multiple Schedule

Abstract

Response sequences emitted by five Long-Evans rats were reinforced under a two-component multiple schedule. In the REPEAT component, food pellets were contingent upon completion of a left-left-right-right (LLRR) sequence on two levers. In the VARY component, pellets were contingent upon variable sequences (i.e., a sequence was reinforced only if it differed from each of the previous five sequences). The rats learned to emit LLRR sequences in the REPEAT component and variable sequences in VARY. Intraperitoneal injections of ethanol (1.25, 1.75, and 2.25 g/kg) significantly increased sequence variability in REPEAT, thereby lowering reinforcement probability, but had little effect on sequence variability in the VARY component. These results extend previous findings that alcohol impairs the performance of reinforced repetitions but not of reinforced variations in response sequences.

Operant variability when reinforcement is delayed

“…They also indicate a dissociation similar to that described by Grunow and Neuringer (2002): Response rates were primarily controlled by reinforcement frequencies (in Grunow & Neuringer, 2002) and delays (in the present experiment), whereas response variability was primarily controlled by reinforcement contingencies in both experiments. The results are consistent as well with previous studies showing that reinforced variability is relatively immune to adverse impact from other reinforcementweakening events (Cohen et al, 1990;Doughty & Lattal, 2001;Grunow & Neuringer, 2002;McElroy & Neuringer, 1990;Neuringer, 1991).…”

Schedule-Induced and Operant Mechanisms that Influence Response Variability: A Review and Implications for Future Investigations

“…Thus, errors were made at each position in the response sequence. Cohen, Neuringer, and Rhodes (1990) replicated the detrimental effects of ethanol on response repetition. Morgan and Neuringer (1990) showed that the topography of the target response or responses could also affect response variability.…”

Supressão condicionada sobre linhas de base de variabilidade e repetição operantes

“…Maior resistência do responder variável (com relação à manutenção da taxa de respostas e de reforços) tem sido relatada com a introdução de diferentes variáveis, como: administração de etanol (Cohen, Neuringer, & Rhodes, 1990;McElroy & Neuringer, 1990), midazolam e pentilenotetrazol (Abreu-Rodrigues, Hanna, de Mello…”

“…Os dois esquemas de reforçamento utilizados nesse estudo instalaram padrões antagônicos no que diz respeito aos seus níveis de variação, o que pode ser demonstrado pelos altos índices U do Grupo VAR em comparação com os baixos índices do Grupo REP. Esses resultados replicam os descritos na literatura para sujeitos expostos a essas contingências (Cohen et al, 1990;Doughty & Lattal, 2001;Hunziker, Yamada, Manfré & Azevedo, 2006 Para estender ainda mais os resultados já obtidos, novos estudos poderiam investigar a variabilidade e a repetição em outros tipos de contingências aversivas (como punição, esquiva). Além disso, o atual experimento poderia ser replicado com o acréscimo do procedimento acoplado, o que permitiria elucidar melhor a relação entre a taxa de respostas e reforços e a exigência dos esquemas com os índices de supressão.…”

“…Diferentemente da maioria, os esquemas de reforçamento contingentes à variabilidade ou à repetição comportamentais têm como variável dependente principal a variação (da topografia, força, ou qualquer outra dimensão) entre as respostas emitidas pelo sujeito ao longo do experimento (Neuringer, 2002;2004 (Cohen, Neuringer & Rhodes, 1990;McElroy & Neuringer, 1990) e manipulações no intervalo entre as respostas (Neuringer, 1991 …”