Biasing decision making by means of retrieval practice

Decision making requires the recruitment of several cognitive processes. So far, however, few studies have dealt with the role of inhibitory control in this domain. In this study, we aim to examine this issue in a memory-based decision task by using an adaptation of the retrieval practice paradigm (Anderson, Bjork, & Bjork, 1994 Anderson, M. C., Bjork, R. A. and Bjork, E. L. 1994. Remembering can cause forgetting: Retrieval dynamics in long-term memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20: 1063–1087. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). The retrieval-induced forgetting found through this task is normally explained in terms of inhibition. Specifically, we analyse how retrieval practice may affect what alternatives are selected as well as the choice probability and attribute recall. Our data show a relation between the recall impairment of the attributes due to retrieval practice and biased decisions.     

Ontogenetic dissociation between habit learning and recognition memory in capuchin monkeys (Cebus apella)

The performance of young and adult capuchin monkeys (Cebus apella) on a Concurrent Discrimination Learning (CDL) test and a Delayed Non-Matching to Sample (DNMS) task were investigated. Results indicate that all subjects were able to learn the CDL test with 20-pairs simultaneously and retain this stimulus/reward association within 24-h interval. In contrast, young subjects did not perform the DNMS task with the same proficiency as adults. While adults' scores were above chance across all memory test delays, the young capuchin monkeys performed the test by chance level. These results support the hypothesis that these two tasks require different cognitive processes mediated by two independent neural systems with a differentiated ontogenetic development. Moreover, they provide evidence that this dissociation occurs not only in humans and Old World monkeys but also in the New World capuchin monkeys indicating that this species can be a valuable alternative model for investigations of the neurobiological basis of memory.     

Dysmorphic concern and behavioural impairment related to body image in adolescents

This study examined a moderated mediation model testing whether dysmorphic concern is related to behaviour altered to change appearance. This relationship is potentially mediated by depressive symptomatology (dysphoria and self-esteem) and ideas of reference about “laughing, commenting” and “attention, appearance,” and each mediated relationship moderated by sex. The sample was made up of 3377 adolescents from 12 to 18 years old (M_age = 14.52; SD = 1.65, 56.5% girls). The results showed that dysphoria and ideas of reference about “laughing, commenting” and “attention, appearance” partially mediated the relationship between dysmorphic concern and behavioural impairment related to body image. The relationship with dysphoria was moderated by sex, such that the mediation effect was stronger in girls than in boys. This result implies that girls who are worried about some characteristic of their appearance and show dysphoria are at greater risk of altered behaviour involving avoidance or controlling their appearance than boys. In addition, a possible risk of body dysmorphic disorder (3.45% of the sample) was found, with very prominent hiding behaviour using clothing or control behaviours, such as frequent weighing and looking at oneself in the mirror too much. Implications of these findings are discussed.     

The socialization of the gifts of tongues and healing in Mexican Pentecostalism

Mexican Pentecostalism emphasizes both speaking in tongues and faith healing as religious manifestations which believers should have. Although they are considered to be given by the Holy Spirit, these practices imply a socialization with the collective of followers. The analysis of pentecostal groups in the urban environment of Mexico City and in the rural Totonac Indian communities shows that these religious practices and beliefs are very similar in the two areas mentioned. It is necessary for the pentecostal believer to learn the ‘proper’ way to speak in tongues and to heal the sick, in order to separate followers from other religions which compete with pentecostalism by offering ritual possession and alternative forms of curing human suffering. In Mexico, popular spiritualism, the Catholic charismatic movement and traditional Indian curers all offer direct competition for pentecostalism. The religious mobility further complicates this situation. The important role of public discourse and testimony is also dealt with here.     

Sexual differences in memory in shiny cowbirds

Avian brood parasites depend on other species, the hosts, to raise their offspring. During the breeding season, parasitic cowbirds (Molothrus sp.) search for potential host nests to which they return for laying a few days after first locating them. Parasitic cowbirds have a larger hippocampus/telencephalon volume than non-parasitic species; this volume is larger in the sex involved in nest searching (females) and it is also larger in the breeding than in the non-breeding season. In nature, female shiny cowbirds Molothrus bonariensis search for nests without the male’s assistance. Here we test whether, in association with these neuroanatomical and behavioural differences, shiny cowbirds display sexual differences in a memory task in the laboratory. We used a task consisting of finding food whose location was indicated either by the appearance or the location of a covering disk. Females learnt to retrieve food faster than males when food was associated with appearance cues, but we found no sexual differences when food was associated with a specific location. Our results are consistent with the view that parasitism and its neuroanatomical correlates affect performance in memory tasks, but the effects we found were not in the expected direction, emphasising that the nature of avian hippocampal function and its sexual differences are not yet understood. Received: 30 April 1998 / Accepted after revision: 5 September 1998     

Limits to preference and the sensitivity of choice to rate and amount of food

Studies of choice holding food‐amount ratio constant while varying food‐rate ratio within sessions showed that local changes in preference depend on relative amount of food. The present study investigated whether sensitivity of choice to food‐rate ratio and sensitivity to food‐amount ratio are independent of one another when food‐rate ratios are varied across sessions and food‐amount ratios are varied within sessions. Food deliveries for rats’ presses on the left and right levers were scheduled according to three different food‐rate ratios of 1:1, 9:1, and 1:9; each food‐rate ratio lasted for 106 sessions and was arranged independently of seven food‐amount ratios (7:1, 6:2, 5:3, 4:4, 3:5, 2:6, and 1:7 food pellets) occurring within sessions in random sequence. Each amount ratio lasted for 10 food deliveries and was separated from another by a 60‐s blackout. Sensitivity to rate ratio was high (1.0) across food deliveries. Sensitivity to amount ratio was low when food rates were equal across alternatives, but was high when rate ratio and amount ratio opposed one another. When rate ratio and amount ratio went in the same direction, choice ratio reached an elevenfold limit which reduced sensitivity to approximately zero. We conclude that three factors affect sensitivity to amount: (1) the limit to preference, (2) the equal effect on preference of amounts greater than four pellets, and (3) the absence of differential effects of switches in amount in the equal‐rates (1:1) condition. Taken together, these findings indicate that rate and amount only sometimes combine independently as additive variables to determine preference when amount ratios vary frequently within sessions.