Patterns of eye movement in matching-to-sample tasks

Abstract The present study evaluated whether during a matching-to-sample procedure (MTS), the time spent observing stimuli is related to the establishment of selection or rejection controlling relationships in human participants. It also evaluated whether different response topographies (i.e., participants using the keyboard or mouse) would influence the duration of eye fixations. Ten college students participated. The procedure established conditional relationships among six sets of abstract stimuli. Five participants selected the comparison stimuli using a computer mouse and five used a keyboard. An eye-scan device recorded eye movements throughout the training procedure. After participants completed training, probes verified whether the conditional relationships learned were controlled by selection (e.g., if A1, select B1), by rejection (e.g., if A1, reject B2), or both. All participants displayed a similar pattern of stimuli observation. Time spent observing the sample stimulus (e.g., A1) was longer than observing the comparison stimuli (e.g., B1 and B2). Time spent observing S+ (positive stimuli; e.g., B1) was longer than observing S- (negative stimuli; e.g., B2). Duration of eye fixation was not related to selection or rejection controlling relationships, but different response topographies appeared to modulate the amount of time spent observing stimuli. (AU)

Analyzing the stimulus control acquisition in simple discrimination tasks through eye movement / Análise da aquisição de controle de estímulos em tarefas de discriminação simples por meio do movimento dos olhos

In order to investigate whether simultaneous or successive presentation of stimuli is related to the duration of eye fixation (i.e., the time spent gazing a specific stimulus), this study described the eye movements of young adults in simultaneous and successive simple discrimination tasks. Using 12 landscape scenes as visual stimuli, three participants were exposed to a simple discrimination training with simultaneously presented stimuli (Si Procedure) and then to a second simple discrimination training with successively presented stimuli (Su Procedure). Another three participants were exposed to the Procedure in the opposite order. In both cases, the learning criterion was that at least 90% of the responses should be correct in one block. Eye movements were recorded during the whole experiment. Participants achieved the learning criteria in both procedures. Beyond that, eye fixation time in the Su Procedure was higher than in the Si Procedure, regardless of the training sequence. Taken together with previous results in different experiments, our findings suggest that the duration of eye fixation plays a central role in the establishment of different stimulus control topographies.

Com o objetivo de investigar se a apresentação simultânea ou sucessiva de estímulos estaria relacionada com a duração da fixação do olhar (i.e., o tempo gasto fixando um estímulo específico), este estudo descreveu os movimentos dos olhos de adultos em tarefas de discriminação simples simultâneas e sucessivas. Utilizando 12 cenas de paisagens como estímulos visuais, três participantes foram expostos a um treino de discriminação simples com estímulos apresentados simultaneamente (Procedimento Si) e, em seguida, a um segundo treino de discriminação simples com estímulos apresentados sucessivamente (Procedimento Su). Outros três participantes foram expostos ao Procedimento em ordem inversa. Em ambos os casos, uma concentração mínima de 90% das respostas ao estímulo correto, em um mesmo bloco, definia a aquisição da discriminação. Os movimentos dos olhos foram registrados durante todo o experimento. Participantes atingiram os critérios de aquisição da discriminação em ambos os procedimentos. Além disso, o tempo de fixação do olhar no Procedimento Su foi maior do que no Procedimento Si, independentemente da sequência de treino. Considerados em conjunto com resultados prévios em diferentes experimentos, nossos dados sugerem que a duração da fixação do olhar exerce um papel central no estabelecimento de diferentes topografias de controle de estímulos.

Discriminated conditioned suppression in rats

This experiment evaluated the effects of superimposing the Estes-Skinner Conditioned Emotional Response (CER) procedure on one of two components of a multiple schedule. The question was whether CER conditioning occurred under contextual control. The procedure had four experimental phases: (1) baseline of operant responding under a two-component multiple schedule (mult VI 30 VI 30), one component correlated with the house light on and the other correlated with the house light off (light/dark components), (2) introduction of tone-shock pairings during the light component only, (3) return to baseline contingencies, and (4) reintroduction of the tone (but not shock) in the light component. Three Wistar rats showed robust suppression of responding in the light component, and the suppression also partially generalized to the dark component. The suppression was stronger during the pre-aversive stimulus than during the intervals immediately before and after its presentation. Responding partially recovered under baseline contingencies, but response rates remained lower in the light component than in the dark component. Thus, under the present experimental conditions, the context in which CER conditioning occurred (i.e., the house light-illuminated chamber) also produced conditioned suppression, and contextual control of suppressed responding generalized to another context, one that shared some but not all elements of the first context (i.e., the same chamber not illuminated by a house light). These results have direct implications for our understanding of emotional conditioning produced in the laboratory and for analysis of related phenomena addressed in the clinic.