This study aimed to investigate whether variable patterns of responses can be acquired and maintained by negative reinforcement under an avoidance contingency. Six male Wistar rats were exposed to sessions in which behavioral variability was reinforced according to a Lag contingency: Sequences of three responses on two levers had to differ from one, two or three previous sequences for shocks to be avoided (Lag 1, Lag 2 and Lag 3, respectively). Performance under the Lag conditions was compared with performance on a Yoke condition in which the animals received the same reinforcement frequency and distribution as in the Lag condition but behavioral variability was not required. The results showed that most of the subjects varied their sequences under the Lag contingencies, avoiding shocks with relatively high probability (≥ 0.7). Under the Yoke procedure, responding continued to occur with high probability, but the behavioral variability decreased. These results suggest that behavioral variability can be negatively reinforced.

O objetivo deste artigo é analisar os aspectos comportamentais da pandemia de COVID-19. São abordadas as variáveis que controlam o comportamento de prevenir-se. Destacam-se algumas contingências gerais, que afetam o comportamento de virtualmente todas as pessoas, bem como algumas que atingem grupos diferenciados em função de classe social, gênero e raça. O papel exercido pelas agências controladoras mídia e governo também são objeto de análise, buscando-se indicar como elas favorecem ou dificultam a instalação e manutenção de classes de comportamentos relacionadas à prevenção da COVID-19. Espera-se que, no seu conjunto, este artigo demonstre que a Análise do Comportamento tem muito a oferecer para a compreensão e enfrentamento dessa pandemia.Palavras-chave: COVID-19; pandemia; prevenção; Análise do Comportamento.

This study aimed to investigate the effects of a chronic mild stress (CMS) protocol on operant discrimination learning. Twelve male Wistar rats were separated into 2 groups: CMS and control (n ϭ 6). CMS subjects underwent a stress protocol, whereas control subjects remained in their cages with food and water ad libitum. After this period, all subjects underwent successive discrimination training sessions. Water and sucrose preference tests were conducted for both groups. There were no differences between groups in the liquid preference tests (p Ͻ .4), and discrimination learning (p Ͻ .7). However, CMS subjects showed higher response frequency than control subjects during the discrimination training (p Ͻ .004). Data suggest that exposure to CMS protocol can alter locomotor performance without affecting the discrimination accuracy.

RESUMO Este artigo buscou examinar algumas das contribuições das neurociências para o estudo da discriminação de estímulos. Foram discutidos experimentos relacionados a processos discriminativos envolvendo (a) estimulação cerebral como estímulo antecedente e consequente, (b) atividade neural como resposta, (c) lesão cerebral, (d) drogas e (e) mudanças no cérebro em função do treino discriminativo. Argumenta-se que a integração entre dados comportamentais e (neuro) fisiológicos tem se mostrado uma estratégia promissora para um entendimento mais completo sobre o comportamento dos organismos.

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