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     

Mathematical structures and psychological measurements

The nature of psychological measurements in relation to mathematical structures and representations is examined. Some very general notions concerning algebras and systems are introduced and applied to physical and number systems, and to measurement theory. It is shown that the classical intensive and extensive dimensions of measurements with their respective ordinal and additive scales are not adequate to describe physical events without the introduction of the notions of dimensional units and of dimensional homogeneity. It is also shown that in the absence of these notions, the resulting systems of magnitudes have only a very restricted kind of isomorphism with the real number system, and hence have little or no mathematical representations. An alternative in the form of an extended theory of measurements is developed. A third dimension of measurement, the supra-extensive dimension, is introduced; and a new scale, the multiplicative scale, is associated with it. It is shown that supra-extensive magnitudes do constitute systems isomorphic with the system of real numbers and that they alone can be given mathematical representations. Physical quantities are supra-extensive magnitudes. In contrast, to date, psychological quantities are either intensive or extensive, but never of the third kind. This, it is felt, is the reason why mathematical representations have been few and without success in psychology as contrasted to the physical sciences. In particular, the Weber-Fechner relation is examined and shown to be invalid in two respects. It is concluded that the construction of multiplicative scales in psychology, or the equivalent use of dimensional analysis, alone will enable the development of fruitful mathematical theories in this area of investigation.The editors of this journal should perhaps point out that unanimous agreement with the arguments and points of view expressed in this article is not anticipated. They believe, however, that its publication may stimulate needed thinking and clarification of problems basic to psychological measurement and thus serve the purpose for which the journal was founded.     

A l'occasion du renouvellement de l'annee

Sans résumé     

Personality and Behavior in Social Dilemmas: Testing the Situational Strength Hypothesis and the Role of Hypothetical Versus Real Incentives

Previous research aimed at testing the situational strength hypothesis suffers from serious limitations regarding the conceptualization of strength. In order to overcome these limitations, the present study attempts to test the situational strength hypothesis based on the operationalization of strength as reinforcement contingencies. One dispositional factor of proven effect on cooperative behavior, social value orientation (SVO), was used as a predictor of behavior in four social dilemmas with varying degree of situational strength. The moderating role of incentive condition (hypothetical vs. real) on the relationship between SVO and behavior was also tested. One hundred undergraduates were presented with the four social dilemmas and the Social Value Orientation Scale. One‐half of the sample played the social dilemmas using real incentives, whereas the other half used hypothetical incentives. Results supported the situational strength hypothesis in that no behavioral variability and no effect of SVO on behavior were found in the strongest situation. However, situational strength did not moderate the effect of SVO on behavior in situations where behavior showed variability. No moderating effect was found for incentive condition either. The implications of these results for personality theory and assessment are discussed.     

Self-Criticism and Depressive Symptoms Mediate the Relationship Between Emotional Experiences With Family and Peers and Self-Injury in Adolescence

Although the relationship between negative childhood experiences, peer victimization, depressive symptoms, and Non-Suicidal Self-Injury (NSSI) is widely recognized, the mechanisms involved are not fully understood, especially among adolescents. This study aims to test the mediating role of both self-criticism and depressive symptoms in the relationship between memories of negative or positive experiences, current peer victimization, and NSSI. The sample consists 854 Portuguese adolescents, 451 female and 403 male, with ages between 12 and 18 years (M = 14.89; SD = 1.79), from middle and secondary schools. Participants answered self-report measures. Results from path analysis showed that memories of negative experiences, the absence of positive memories with family in childhood and peer victimization indirectly impact on NSSI through self-criticism and depressive symptoms. In addition, these stressful experiences led to depressive symptoms through self-criticism. Lastly, the most severe form of self-criticism indirectly impacts on NSSI through depressive symptoms, even though it also has a strong direct effect. It suggests that negative experiences with parents and peer victimization, as well as the absence of positive memories with family, have a negative impact on NSSI when these experiences are linked with a sense of self-hatred and depressive symptoms.     

Perceptual reasons

The two main theories of perceptual reasons in contemporary epistemology can be called Phenomenalism and Factualism. According to Phenomenalism, perceptual reasons are facts about experiences conceived of as phenomenal states, i.e., states individuated by phenomenal character, by what it’s like to be in them. According to Factualism, perceptual reasons are instead facts about the external objects perceived. The main problem with Factualism is that it struggles with bad cases: cases where perceived objects are not what they appear (illusions, broadly speaking) or where there is no perceived object at all (hallucinations). The main problem with Phenomenalism is that it struggles with good cases: cases where everything is perfectly normal and the external object is correctly perceived, so that one’s perceptual beliefs are knowledge. In this paper we show that there is a theory of perceptual reasons that avoids the problems for Factualism and Phenomenalism. We call this view Propositionalism. We use ‘proposition’ broadly to mean the entities that are contents of beliefs and other doxastic attitudes. The key to finding a middle ground between Phenomenalism and Factualism, we claim, is to allow our reasons to be false in bad cases. Despite being false, they are about the external world, not our phenomenal states.     

Is Age Just a Number? Cognitive Reserve as a Predictor of Divergent Thinking in Late Adulthood

The purpose of the study was to test a model of causal relationships among cognitive reserve (CR), personality variables such as Neuroticism and Openness to experience, and divergent thinking (DT), independently evaluating performance in different domains (verbal and graphic). It was hypothesized that CR, Openness, and Neuroticism would each directly influence verbal and graphic DT. A total of 135 subjects between 55 and 84 years old participated in the study and were interviewed in individual sessions. For a correct fit Neuroticism was eliminated from the measurement model. The goodness-of-fit indexes of the measurement model, the adequate composite reliability index and the discriminant validity supported the viability of the structural equation model (SEM). The goodness-of-fit indexes confirmed the existence of a significant effect of CR and Openness to experience in predicting both verbal and graphic DT. The three CR indicators had high loadings in their theoretical factor, with the observed variables study-work and WAIS vocabulary showing the highest loads. In summary, subjects with CR and Openness to experience were more flexible and original when solving verbal problems, and to a lesser degree, graphic problems.     

Differences in false recollection according to the cognitive reserve of healthy older people

We present an associative recognition experiment comparing three samples of healthy people (young people, older people with high cognitive reserve [HCR], and older people with low cognitive reserve [LCR], with each sample consisting of 40 people), manipulating stimuli repetition during the study phase. The results show significant differences among the three samples in their overall performance. However, these differences are not due to a different use of familiarity, but rather due to a different way of using recollection: although there are no differences in the hit rates between the HRC and LRC samples, the LCR group makes significantly more recollective false alarms than the HCR group. Moreover, repetition provokes an increase in the recollective false alarms in the LCR group, but this does not occur in the group of young people or in the HCR group. These findings are explained in terms of recollection-based monitoring errors and seem to provide support for the cognitive reserve hypothesis.     

Source Monitoring and Executive Function in 2.5- to 3-Year-Olds

Hala, Brown, McKay, and San Juan (2013) found that children as young as 2.5 years of age demonstrated high levels of accuracy when asked to recall whether they or the experimenter had carried out a particular action. In the research reported here, we examined the relation of early-emerging source monitoring to executive function abilities. Participants were children aged 2.5- to 3-years old. For the source-monitoring procedure, we used the Hala et al. (2013) task in which children and the experimenter took turns placing a total of 20 items on a model farm (encoding phase). For the source memory test, children were asked who had placed each item (retrieval phase). Executive function measures included assessments of working memory, delay-inhibitory control, and conflict-inhibitory control. The main finding was that inhibitory control measures were significantly related to performance on the source-monitoring task. This relation held for the conflict-inhibitory control measures even when controlling for age and vocabulary. The findings of this research suggest that even at the early age of 2.5 years, development of executive control is linked to the emergence of source-monitoring ability.     

Predictive model for early math skills based on structural equations

Early math skills are determined by higher cognitive processes that are particularly important for acquiring and developing skills during a child's early education. Such processes could be a critical target for identifying students at risk for math learning difficulties. Few studies have considered the use of a structural equation method to rationalize these relations. Participating in this study were 207 preschool students ages 59 to 72 months, 108 boys and 99 girls. Performance with respect to early math skills, early literacy, general intelligence, working memory, and short‐term memory was assessed. A structural equation model explaining 64.3% of the variance in early math skills was applied. Early literacy exhibited the highest statistical significance (β = 0.443, p < 0.05), followed by intelligence (β = 0.286, p < 0.05), working memory (β = 0.220, p < 0.05), and short‐term memory (β = 0.213, p < 0.05). Correlations between the independent variables were also significant (p < 0.05). According to the results, cognitive variables should be included in remedial intervention programs.