Attentional distraction and time perception in children

The purpose of the present study was to test the effect of attentional distraction on temporal bisection performance in 5‐ and 8‐year‐old children. During a first learning phase, children were trained to discriminate on a temporal bisection task a short standard duration (2 sec) from a long one (8 sec), presented as visual stimuli. Later, in a second testing phase, intermediate durations (3, 4, 5, 6, 7 s), including the standard durations, were presented. Children's task still was to report if it was a short standard duration or a long one. In addition, during the non‐standard duration, a distracter either did or did not appear. Results showed increasing proportions of “it is the long standard duration” (response “long”) with increasing stimulus durations in both distracter and non‐distracter conditions. However, psychophysical functions were flatter in the 5‐year‐olds than in the 8‐year‐olds, revealing their lower sensibility to time. Nevertheless, the 5‐year‐olds' proportion of long responses was higher under the distracter than in the non‐distracter condition. Consequently, the point of subjective equality (PSE), corresponding to the stimulus duration to which the subject produced 50% of responses of “long” was lower under the distracter condition as compared to the non‐distracter condition. Conversely, for the 8‐year‐olds, the PSE was significantly higher in the distracter than in the non‐distracter condition. Five‐year old children overestimated the time in the presence of an attentional distracter, whereas 8‐year olds tended to underestimate it. The leftward shift and the rightward shift of the PSE in the 5‐ and the 8‐year‐olds, respectively, were accounted for by limited‐capacity attention in the five‐year olds.     

Effect of normal aging on the manipulation of information in working memory

The goal of this study is to examine the central executive of working memory in normal aging, specifically focusing on its capacities to manipulate or modify the format of the to-be-recalled material. The central executive was measured with the alphabetical span procedure, during which subjects were asked to recall a random series of words in their alphabetical order. The storage demand was equalized across subjects by adjusting the list lengths according to individual span. Experiments 1, 2, and 3 showed that elderly subjects were not impaired in manipulating information, relative to young controls, even when the difficulty of the task was increased. In Experiment 4, validity was tested by asking young subjects to perform the task under the conditions of full or divided attention. Alphabetical recall was more impaired than direct recall during the divided attention condition, which suggests a larger involvement of the central executive component in the former. These results are discussed in relation to the hypothesis of a central executive impairment being associated with normal aging.     

Emotional Desensitization to Violence Contributes to Adolescents’ Violent Behavior

Many adolescents are exposed to violence in their schools, communities and homes. Exposure to violence at high levels or across multiple contexts has been linked with emotional desensitization, indicated by low levels of internalizing symptoms. However, the long-term consequences of such desensitization are unknown. This study examined emotional desensitization to violence, together with externalizing problems, as mediators of the relationship between exposure to violence in pre-adolescence and violent behavior in late adolescence. A community sample of youth (N?=?704; 48 % female; 76 % African American, 22 % Caucasian) reported on their exposure to violence in multiple settings at ages 11, 13 and 18. Internalizing and externalizing problems were assessed at ages 11 and 13; violent behavior was measured at age 18. Structural Equation Modeling showed that exposure to high levels of violence at age 11 was associated with lower levels of internalizing problems (quadratic effect) at age 13, as was exposure to violence across multiple contexts (linear effect). In turn, fewer internalizing problems and more externalizing problems at age 13 predicted more violent behavior at age 18. The results suggest that emotional desensitization to violence in early adolescence contributes to serious violence in late adolescence.     

Idiosyncratic Deals and Helping Behavior: The Moderating Role of I-deal Opportunity for Co-workers

Purpose

This study draws from social comparison theory to explore why and under which circumstances individuals receiving idiosyncratic deals (i-deals) are likely to help their co-workers.

Design

Data were collected with an alumni association of engineers. Participants completed two questionnaires (N = 182 at Time 2).

Findings

We find that the relationship between i-deals and helping behavior is not direct, but is mediated by organizational-based self-esteem. This relationship is stronger when i-deal recipients believe that their co-workers do not have the opportunity to get i-deals for themselves.

Implications

I-deal recipients are expected to help their colleagues because helping colleagues is consistent with the positive self developed thanks to i-deals. When co-workers have the opportunity to get i-deals for themselves, social comparison between the i-deal recipient and colleagues is likely to be more salient, which strengthen the indirect relationship between i-deal and helping behavior.

Originality

This study tests i-deals from the vantage point of social comparison theory rather than from the perspective of social exchange. We thereby provide a richer account of the complexities involved in helping behavior. By exploring contextual variables that are likely to trigger social comparisons, we also expect to better understand the circumstances under which i-deals are likely to be associated with helping behavior.

     

Magnitude of force perception errors during static contractions of the knee extensors in healthy young and elderly individuals

The accuracy of force perception during muscular contraction has not been studied extensively, despite its importance in rehabilitation and training. The purpose of this study was to quantify the errors made by healthy young and elderly individuals in their perceptions of force produced at the knee. Four different tasks were used to evaluate the perception of force and the effect of a sensory-motor reference and simultaneous contraction on the accuracy of perception. The absolute errors were similar between groups, with values of 11.9% to 16.3%, depending on the task. The raw perception errors were greater for high levels of force (>50% of the maximal voluntary contraction, or MVC), indicating an overestimation of the forces produced for both groups. At 70% MVC, the sensory-motor reference reduced raw perception errors, and the simultaneous contraction improved the accuracy of force production. Healthy young and elderly individuals had about the same capacity to judge the muscular force of their knee extensors. Therapists involved in the training of active?elderly?individuals should be aware that the accuracy of force perception is not perfect and that these clients have the same ability as young individuals to perceive their knee extension strength.     

Stronger evidence for own-age effects in memory for older as compared to younger adults

Three studies examined whether younger and older adults better recall information associated with their own than information related to another age group. All studies compared young and older adults with respect to incidental memory for previously presented stimuli (Studies 1 and 2: everyday objects; Study 3: vacation advertisements) that had been randomly paired with an age-related cue (e.g., photo of a young or an old person; the word "young" or "old"). All three studies found the expected interaction of participants' age and age-associated information. Studies 1 and 2 showed that the memory bias for information arbitrarily associated with one's own as compared to another age group was significant for older adults only. However, when age-relevance was introduced in a context of equal importance to younger and older adults (information about vacations paired either with pictures of young or older adults), the memory bias for one's own age group was clearly present for both younger and older adults (Study 3).     

Hippocampal tauopathy in tau transgenic mice coincides with impaired hippocampus-dependent learning and memory, and attenuated late-phase long-term depression of synaptic transmission

We evaluated various forms of hippocampus-dependent learning and memory, and hippocampal synaptic plasticity in THY-Tau22 transgenic mice, a murine tauopathy model that expresses double-mutated 4-repeat human tau, and shows neuropathological tau hyperphosphorylation and aggregation throughout the brain. Focussing on hippocampus, immunohistochemical studies in aged THY-Tau22 mice revealed prominent hyper- and abnormal phosphorylation of tau in CA1 region, and an increase in glial fibrillary acidic protein (GFAP) in hippocampus, but without signs of neuronal loss. These mice displayed spatial, social, and contextual learning and memory defects that could not be reduced to subtle neuromotor disability. The behavioral defects coincided with changes in hippocampal synaptic functioning and plasticity as measured in paired-pulse and novel long-term depression protocols. These results indicate that hippocampal tauopathy without neuronal cell loss can impair neural and behavioral plasticity, and further show that transgenic mice, such as the THY-Tau22 strain, might be useful for preclinical research on tauopathy pathogenesis and possible treatment.     

How can we enhance girls’ interest in scientific topics?

Background. Girls are considerably less interested in scientific subjects than boys. One reason may be that scientific subjects are considered to be genuinely masculine. Thus, being interested in science may threaten the self‐perception of girls as well as the femininity of their self‐image. Aims. If scientific topics that are considered to be stereotypically feminine were chosen, however, this potential threat might be overcome which, in turn, might lead to an increase in girls’ interest in science. This hypothesis was empirically tested by means of two studies. Sample. Participants were 294 (Study 1) and 190 (Study 2) Grade 8 to Grade 9 students. Method. Gender differences in students’ interest in masculine and feminine topics were investigated for a range of scientific concepts (Study 1) as well as for a given scientific concept (Study 2) for four scientific subjects (i.e., biology, physics, information technology, and statistics), respectively. Results. Both studies indicated that the mean level of girls’ scientific interest was higher when scientific concepts were presented in the context of feminine topics and boys’ level of scientific interests was higher when scientific concepts were presented in the context of masculine topics. Conclusion. Girls’ interest in science could be substantially increased by presenting scientific concepts in the context of feminine topics. Gender differences as well as individual differences in the level of interest in scientific topics may be taken into account by creating learning environments in which students could select the context in which a certain scientific concept is embedded.     

Contribution of temporal preparation and processing speed to simple reaction time in persons with Alzheimer’s disease and mild cognitive impairment

Temporal preparation was assessed in 15 Alzheimer’s disease (AD) patients, 20 persons with mild cognitive impairment (MCI) and 28 healthy older adults. Participants completed a simple reaction time task in which the preparatory interval duration varied randomly within two blocks (short versus long temporal window). Results indicated that AD and MCI patients had difficulty preparing for the shortest preparatory interval of the short temporal window. AD and MCI patients also had difficulty maintaining an optimal level of preparation up to 5 s within the short temporal window. These results suggest that AD and MCI patients might show difficulty preparing for rapidly occurring events and maintaining preparation over time. This phenomenon should be considered when using reaction time measures with such patients.     

What is the impact of the explicit knowledge of sequence regularities on both deterministic and probabilistic serial reaction time task performance?

The aim of this study was to explore the role of prior explicit sequence knowledge by comparing its influence on serial reaction time (SRT) performance with either a deterministic or a probabilistic sequence. The results confirm that, with a deterministic sequence, preliminary explicit learning improves SRT performance. On the other hand, with a probabilistic sequence, the results show no advantage for SRT performance in explicit-learning conditions. In addition, by using the process dissociation procedure (Jacoby, 1991), we show that performance on a subsequent generation task was more sustained by controlled processes for participants in the explicit-learning conditions than for those in the incidental condition. On the whole, these results, showing that the influence of explicit knowledge can be suppressed in certain specific conditions, are consistent with the intervention of both implicit and explicit mechanisms in SRT tasks, and the results also show that their relative influence can be modulated by the particular demands of the task.