Conflict and postconflict behaviour in two lemur species with different social organizations (Eulemur fulvus and Eulemur macaco): A study on captive groups

Although the brown lemur (Eulemur fulvus) and the black lemur (Eulemur macaco) share many life parameters and are genetically closed, they show considerable difference in social organization. Dominance relationships with no systematic effect of gender characterize the former, whereas the latter is based on female dominance. The present study was done on two captive groups of brown lemurs and one semi–free‐ranging group of black lemurs. To reveal links between the specific pattern of social organization and agonistic behaviors, agonistic interactions were analyzed for each species as for their context of occurrence, symmetry, initiation, and outcome. The effect of gender in the initiation of conflicts appeared as the only notable interspecific difference, aggression being mostly initiated by females in E. macaco and by males in E. fulvus. Conflict outcome was generally in favor of the initiator, regardless of gender in both species. The analysis of postconflict behaviors revealed conciliatory processes in the brown lemur, whereas reconciliation seemed to be absent in the black lemur, a characteristic shared with the ring‐tailed lemur (Lemur catta), another lemur species with female dominance. Aggr. Behav. 28:62–74, 2002. © 2002 Wiley‐Liss, Inc.     

The relationships between perceived control and episodic memory in adulthood: a review

The goal of the current paper is to review the literature on the relationships between perceived control and episodic memory throughout adulthood. More specifically, three major questions are pursued: (1) Are higher levels of perceived control related to better memory performance? (2) Is the relationship between perceived control and memory similar or different as a function of age? (3) Does perceived control moderate memory decline? Although there is a great deal of evidence that perceived control and episodic memory are positively related in adulthood, the current review showed that very few studies have investigated whether age moderated this relationship. Moreover, only a limited number of studies have explored the role of perceived control in memory decline, and the results are inconsistent. We suggest some avenues for future research that could help understand by which mechanisms, and under what circumstances, perceived control and episodic memory are related across the lifespan.     

Influence of achievement goals and self‐efficacy on students' self‐regulation and performance

It is widely admitted that low self‐efficacy has a detrimental impact on the functioning and performance of a person mainly concerned with performance goals but has no impact when a person is mainly concerned with learning goals (Dweck, 1986 ). However, results from both correlational and experimental studies are divergent. Since these studies examined very few indicators of participants' cognitive functioning, they may have failed to detect those aspects that could be more vulnerable to a negative impact of the combination of performance goals and low self‐efficacy. Another concern is the lack of most studies to clearly distinguish the type of performance goal examined, particularly the performance‐avoidance versus the performance‐approach goal. In the current study, we decided to focus on performance‐approach and learning goals in order to examine how self‐efficacy intervenes in their effects on participants' self‐regulation and performance on a cognitive task. One hundred and forty participants (85 females and 55 males) were examined. They were randomly assigned either to the learning or the performance‐approach goals condition. In each condition, half of the participants received feedback aimed at inducing either high or low self‐efficacy beliefs with regard to the task prior to executing it aloud. Examination of participants' verbal reports, direct observation of some of their behaviours while solving the task, and responses to a retrospective questionnaire allowed the assessment of several indicators of their self‐regulation and performance. As already reported by many studies, self‐efficacy influenced various aspects of participants' self‐regulation and performance. However, contrary to Dweck's hypothesis ( 1986 ), when interaction effects between self‐efficacy and goals were observed, they always involved learning instead of performance‐approach goals. Findings of this study suggest that the nature of the goal might not matter as much as its personal significance or value.     

Memory and learning in children with 22q11.2 deletion syndrome: evidence for ventral and dorsal stream disruption?

This study examined memory functioning in children and adolescents with 22q11.2 Deletion Syndrome (DS; velocardiofacial syndrome). An overall verbal better than nonverbal memory pattern was evident on the Test of Memory and Learning (TOMAL), with children with 22q11.2 DS performing significantly below their siblings and children with low average IQ but similar to children with autism on facial memory. Children with 22q11 DS also performed significantly below their siblings on tests of verbal working memory. Children with autism performed significantly poorer than the siblings of children with 22q11.2 DS only on their recall of stories. Delayed recall was significantly poorer in children with 22q11.2 DS and children with autism, compared to sibling controls. Although there were no significant group differences on tests of multiple trial verbal or visual learning, a relative weakness was noted with multiple trial visual learning in children with 22q11.2 DS and their siblings, suggesting that an alternative or interactive factor other than the deletion may account for the relatively better verbal compared to nonverbal memory abilities. Deficits in facial memory in children with both 22q11.2 DS and autism suggest disruptions in ventral temporal pathways such as between fusiform gyrus and parahippocampal/hippocampal regions whereas deficits in verbal working memory in children with 22q11.2 DS implicates dorsolateral prefrontal regions, both intimating aberrant white matter pathways.     

Role of proprioceptive information in movement programming and control in 5 to 11-year old children

The role of proprioceptive inputs in the control of goal-directed movements was examined, by means of the tendon vibration technique, in 5 to 11-year old children performing a serial pointing task. Children pointed, with movements of various amplitudes and at various positions, by alternating wrist flexions and extensions. Tendon vibration was applied to both agonist and antagonist muscles to perturb relevant muscular proprioceptive inputs during the static or dynamic phase of the task, i.e., during stops on targets or during movement execution. Constant and variable amplitude errors as well as constant position error were evaluated. Vibratory perturbation applied during movement execution resulted in a similar reduction in movement amplitude, yielding an increased constant error in all age groups and a systematic position error in the direction of the movement starting point. Perturbing proprioception during static phases preceding movement resulted in an age-related increase in the variable amplitude error, which was maximal in 5-year old children performing extension movements. The results were interpreted in terms of the use of proprioceptive information in the feedforward and feedback based components of movement control in children. In particular, the results indicated (1) developmental changes in the relative weighting of each component, (2) an increased capacity to move from one strategy to the other, depending on the availability of information, and (3) developmental changes from an alternated to an integrated control of amplitude and position in serial pointing.     

Cognitive slowing and learning of target detection skills in pre-demented subjects

Alzheimer's disease produces a generalized slowing of cognitive processing increasing with the progression of dementia. However little is known about this phenomenon in the pre-demented stages. Our purpose was to investigate cognitive slowing in pre-demented subjects and their ability to develop target detection skills while performing a cancellation task. The results on 16 pre-demented subjects and 32 matched controls show that cognitive slowing is already present 3 years before subjects fulfill dementia criteria, at a stage where errors are still not different between pre-demented and control subjects. Additionally, the two groups significantly improved their time performances all along the test suggesting that both groups including the pre-demented group were able to progressively acquire a target detection skill.     

Spatial ability and home-range size: examining the relationship in Western men and women (Homo sapiens)

In mammals, spatial sex differences may have coevolved with sex differences in the size of home ranges. This study first evaluated whether, in keeping with most mammals and traditional human (Homo sapiens) societies, home ranges are larger in male than in female Westerners. Second, it established whether navigation patterns are associated with a broader set of spatial abilities in men than in women. Results showed that current male home ranges surpass female home ranges. Ranging was also positively correlated with achievement in tests of mental rotation, surface development, and location memory among men only, whereas it was associated with embedded figures scores in both sexes. Overall, these findings substantiate the adaptive role of several spatial sex differences in humans.     

On the way to assess emotions in animals: do lambs (Ovis aries) evaluate an event through its suddenness, novelty, or unpredictability?

Appraisal theories provide a framework that gives insight into emotions and could allow comparisons across species. According to these theories, events are first evaluated on their suddenness, novelty, and unpredictability. The authors examined the ability of lambs (Ovis aries) to evaluate an event according to these 3 criteria through 3 tests. The lambs responded to suddenness with a startle response coupled with an increase in heart rate and to novelty with an orientation response coupled with an increase of vagal activity. There was no clear evidence that lambs can detect the predictability of an event. Those results support the usefulness of appraisal theories to assess emotion in animals.     

Have sex differences in spatial ability evolved from male competition for mating and female concern for survival?

Drawing on the theoretical and empirical foundations of two evolutionary models, we argue that, among humans and other mammals, a twofold selection process would parsimoniously account for sex-linked advantages in spatial contexts. In males, a superiority for both solving navigation-related spatial problems and understanding physical principles that apply to the behavior of projectiles could have been inherited from mating-oriented male competition involving extensive ranging and agonistic displays. In females, a form of superior spatial memory may have been shaped in relation to a costly reproduction system compelling them to safeguard their survival and that of their offspring by fostering low-risk strategies consisting of restricted navigation as well as concentration on nearby spatial cues. Based on the combined action of competition and survival pressures, we submit new predictions as to spatial sex differences in several species including humans.     

Age-related differences in the visual processes implied in perception and action: distance and location parameters

The aim of the two present experiments was to examine the ontogenetic development of the dissociation between perception and action in children using the Duncker illusion. In this illusion, a moving background alters the perceived direction of target motion. Targets were held stationary while appearing to move in an induced displacement. In Experiment 1, 30 children aged 7, 9, and 12 years and 10 adults made a perceptual judgment or pointed as accurately as possible, with their index finger, to the last position of the target. The 7-year-old children were more perceptually deceived than the others by the Duncker illusion but there were no differences for the goal-directed pointing movements. In Experiment 2, 50 children aged 7, 8, 9, 10, and 11 years made a perceptual judgment or reproduced as accurately as possible, with a handle, the distance traveled by the target. Participants were perceptually deceived by the illusion, judging the target as moving although it was stationary. When reproducing the distance covered by the target, children were unaffected by the Duncker illusion. Our results suggest that the separation of the allocentric visual perception pathway from the egocentric action pathway occurs before 7 years of age.