The effects of fixed-ratio (FR) and differential-reinforcement-of-low-rate (DRL) schedule histories on behavioral persistence were studied in three experiments with pigeons. After exposure to a multiple FR DRL schedule (baseline), either one of two prefeeding amounts were effected under the same schedule (test condition of Experiment 1), under extinction (test condition of Experiment 2), and under fixed-interval (FI) schedules (test condition of Experiment 3). FR response rates generally were less persistent than DRL response rates in Experiments 1 and 2, with the opposite occurring in Experiment 3. Regardless of the test schedules, FR response rates decreased and were less persistent under the large than under the small prefeeding amount. Rates under Experiment 1 and portions of Experiment 3 were completed by the first author, under the supervision of the second author, in partial fulfillment of the requirements of a Masters degree in Psychology at Universidade de Brasília, Brazil. The research was supported by a grant from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) to the first author, and by an undergraduate scholarship from Universidade de Brasília (Programa de Iniciação Científica [PIBIC-UnB]) to the third author. We thank Andy Lattal for his contributions to the method, and Leticia Faria for help with data collection. Portions of these data were presented at the 38 th Annual Convention of the Association for Behavior Analysis International,

The effects of the response-reinforcer dependency on resistance to change were studied in three experiments with rats. In Experiment 1, lever pressing produced reinforcers at similar rates after variable interreinforcer intervals in each component of a two-component multiple schedule. Across conditions, in the fixed component, all reinforcers were response-dependent; in the alternative component, the percentage of response-dependent reinforcers was 100, 50 (i.e., 50% response-dependent and 50% response-independent) or 10% (i.e., 10% response-dependent and 90% response-independent). Resistance to extinction was greater in the alternative than in the fixed component when the dependency in the former was 10%, but was similar between components when this dependency was 100 or 50%. In Experiment 2, a three-component multiple schedule was used. The dependency was 100% in one component and 10% in the other two. The 10% components differed on how reinforcers were programmed. In one component, as in Experiment 1, a reinforcer had to be collected before the scheduling of other response-dependent or independent reinforcers. In the other component, response-dependent and -independent reinforcers were programmed by superimposing a variable-time schedule on an independent variable-interval schedule. Regardless of the procedure used to program the dependency, resistance to extinction was greater in the 10% components than in the 100% component. These results were replicated in Experiment 3 in which, instead of extinction, VT schedules replaced the baseline schedules in each multiple-schedule component during the test. We argue that the relative change in dependency from Baseline to Test, which is greater when baseline dependencies are high rather than low, could account for the differential resistance to change in the present experiments. The inconsistencies in results across the present and previous experiments suggest that the effects of dependency on resistance to change are not well understood. Additional systematic analyses are important to further understand the effects of the response-reinforcer relation on resistance to change and to the development of a more comprehensive theory of behavioral persistence.

The effects of reinforcement rates of alternative responding on resurgence were studied in two experiments with rats. In both experiments, left-and right-lever pressing were reinforced according to a multiple schedule in the Training and Alternative Reinforcement phase, respectively. In the Test phase, reinforcers were discontinued. In Experiment 1, reinforcement rates were similar between components in the Training phase, and different between components in the Alternative Reinforcement phase. This latter difference was manipulated parametrically across conditions. Resurgence occurred more frequently (i.e., in more sessions) and was of greater magnitude (i.e., response rates were relatively higher) in the rich (i.e., higher reinforcement rate) than in the lean (i.e., lower reinforcement rate) component. Additionally, for two of the four rats, the magnitude of resurgence in both components was positively related to reinforcement rates in the Alternative-Reinforcement phase. In Experiment 2, reinforcement rates were different between components in the Training phase, and similar between components in the Alternative Reinforcement phase. Across conditions, the This research was supported by a postdoctoral fellowship (PNPD-CAPES) to Carlos Cançado. We thank Ademar Gonçalves and Hugo Gomes Vieira for help with data collection. We also thank the students in the Experimental Analysis of

Na Análise Experimental do Comportamento três procedimentos são comumente descritos como “custo da resposta”. Eles envolvem (a) aumento do esforço físico necessário para emissão de uma resposta operante; (b) aumento no requerimento para o reforçamento (comumente o aumento no número de respostas exigidas em um programa de reforço de razão); e (c) a perda de reforçadores condicionais (como pontos ou fichas) contingente à resposta operante. O objetivo do artigo foi analisar algumas pesquisas experimentais que empregaram procedimentos que exemplificam estas três definições de custo de resposta, discutindo suas diferenças, semelhanças e implicações para a Análise do Comportamento. Apesar de algumas semelhanças em relação aos efeitos comportamentais destes três tipos de procedimentos, puderam ser observadas algumas características distintas, tanto no delineamento experimental quanto nos efeitos comportamentais observados. Assim, recomenda-se cautela em descrever como “custo da resposta” os efeitos obtidos, visto que não foram encontradas evidências empíricas suficientes que indiquem que estes procedimentos produzem efeitos comportamentais funcionalmente equivalentes.

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RESUMO -O presente estudo investigou se a precisão da instrução afetaria os efeitos da iniqüidade de reforços. Trinta estudantes universitários, separados em duplas, escolheram entre trabalhar sozinho ou competir com o parceiro. Na alternativa individual, os pontos foram distribuídos igualmente entre os participantes; na alternativa de competição, a distribuição de pontos foi manipulada no decorrer das condições de modo que o Participante 1 ganhava mais pontos que o Participante 2, ou vice-versa. Algumas duplas receberam informação completa sobre a distribuição de pontos (instrução precisa); outras receberam informação indicando que, algumas vezes, um participante receberia mais pontos que o outro (instrução imprecisa); e, as demais, não receberam nenhuma informação (sem instrução). A instrução imprecisa produziu escolha acentuada por competição para ambos participantes, a instrução precisa gerou escolhas sensíveis às manipulações na iniqüidade e, na ausência de instruções, ambos resultados foram observados. Foi concluído que a instrução precisa gerou estratégias mais eficientes de fuga e esquiva da iniqüidade.Palavras-chave: competição; instrução; iniqüidade. Instructions and Inequity Between Reinforcers: Effects Upon Competitive BehaviorABSTRACT -The present study investigated whether the precision of instructions alter the effects of reinforcement inequity. Thirty university students, separated in dyads, chose between working alone or competing with their partner. During the individual alternative, points were distributed equally between participants; during the competitive alternative, points distribution was manipulated across conditions such that Participant 1 received a greater number of points than Participant 2, and viceversa. The dyads received complete information on points distribution (precise instruction group), vague information indicating only that sometimes one participant would win more points than the other (imprecise instruction group), or no information about points distribution (no instruction group). Imprecise instruction produced an accentuated choice for competition for both participants while the precise instruction generated choices that changed with manipulations in inequity. In the absence of instructions, both results were observed. It was concluded that precise instruction generated more efficient strategies of escape and avoidance from inequity.

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To investigate how operant and alternative food arranged by different schedules interact to determine response rates and patterns when the sources of food are the same or different, six experiments were delineated. The effects of the number of food sources were investigated in Experiments 1-4. In Experiments 1 and 2, a variable-interval (VI) schedule was used to program the operant food, while the fixed-time (FT-Experiment 1) or the variable-time (VT-Experiment 2) alternative food was delivered from the same or a different source than that of the operant food. Experiments 3 and 4 were identical to Experiments 1 and 2, except that the operant food was arranged by a differentialreinforcement-of-low-rates (DRL) schedule. The effects of the schedule delivering the alternative food were investigated in Experiments 5 and 6. In Experiment 5, food arranged according to a FT or a VT schedule was superimposed to another source of that delivering the VI-scheduled food. In Experiment 6, the baseline schedule was DRL. Response rates were lower when the operant and alternative food were delivered from different sources, but did not differ systematically depending on the schedule delivering the alternative food. Response patterns were most commonly negatively accelerated when the alternative-food schedule was FT. Peaks during the first tenth of the alternativefood interval were also observed, and were more pronounced when the DRL was used to arrange the operant food. The results are discussed in terms the discriminative properties of the alternative-food presentations, determined by the temporal arrangement of this food, the schedule arranging the operant food, and the separation of alternative-and operant-food sources.