Effects of cognitive abilities on metapopulation connectivity

Connectivity among demes in a metapopulation depends on both the landscape's and the focal organism's properties (including its mobility and cognitive abilities). Using individual-based simulations, we contrast the consequences of three different cognitive strategies on several measures of metapopulation connectivity. Model animals search suitable habitat patches while dispersing through a model landscape made of cells varying in size, shape, attractiveness and friction. In the blind strategy, the next cell is chosen randomly among the adjacent ones. In the near-sighted strategy, the choice depends on the relative attractiveness of these adjacent cells. In the far-sighted strategy, animals may additionally target suitable patches that appear within their perceptual range. Simulations show that the blind strategy provides the best overall connectivity, and results in balanced dispersal. The near-sighted strategy traps animals into corridors that reduce the number of potential targets, thereby fragmenting metapopulations in several local clusters of demes, and inducing sink-source dynamics. This sort of local trapping is somewhat prevented in the far-sighted strategy. The colonization success of strategies depends highly on initial energy reserves: blind does best when energy is high, near-sighted wins at intermediate levels, and far-sighted outcompetes its rivals at low energy reserves. We also expect strong effects in terms of metapopulation genetics: the blind strategy generates a migrant-pool mode of dispersal that should erase local structures. By contrast, near- and far-sighted strategies generate a propagule-pool mode of dispersal and source-sink behavior that should boost structures (high genetic variance among- and low variance within local clusters of demes), particularly if metapopulation dynamics is also affected by extinction-colonization processes. Our results thus point to important effects of the cognitive ability of dispersers on the connectivity, dynamics and genetics of metapopulations.

Did tool-use evolve with enhanced physical cognitive abilities?

The use and manufacture of tools have been considered to be cognitively demanding and thus a possible driving factor in the evolution of intelligence. In this study, we tested the hypothesis that enhanced physical cognitive abilities evolved in conjunction with the use of tools, by comparing the performance of naturally tool-using and non-tool-using species in a suite of physical and general learning tasks. We predicted that the habitually tool-using species, New Caledonian crows and Galápagos woodpecker finches, should outperform their non-tool-using relatives, the small tree finches and the carrion crows in a physical problem but not in general learning tasks. We only found a divergence in the predicted direction for corvids. That only one of our comparisons supports the predictions under this hypothesis might be attributable to different complexities of tool-use in the two tool-using species. A critical evaluation is offered of the conceptual and methodological problems inherent in comparative studies on tool-related cognitive abilities.

A randomized controlled trial of the effectiveness of a Computer-Assisted Cognitive Remediation (CACR) program in adolescents with psychosis or at high risk of psychosis: Short term and long term outcomes

The present study investigates the short- and long-term outcomes of a computer-assisted cognitive remediation (CACR) program in adolescents with psychosis or at high risk. 32 adolescents participated in a blinded 8-week randomized controlled trial of CACR treatment compared to computer games (CG). Clinical and neuropsychological evaluations were undertaken at baseline, at the end of the program and at 6-month. At the end of the program (n = 28), results indicated that visuospatial abilities (Repeatable Battery for the Assessment of Neuropsychological Status, RBANS; P = .005) improved signifi cantly more in the CACR group compared to the CG group. Furthermore, other cognitive functions (RBANS), psychotic symptoms (Positive and Negative Symptom Scale) and psychosocial functioning (Social and Occupational Functioning Assessment Scale) improved signifi cantly, but at similar rates, in the two groups. At long term (n = 22), cognitive abilities did not demonstrated any amelioration in the control group while, in the CACR group, signifi cant long-term improvements in inhibition (Stroop; P = .040) and reasoning (Block Design Test; P = .005) were observed. In addition, symptom severity (Clinical Global Improvement) decreased signifi cantly in the control group (P = .046) and marginally in the CACR group (P = .088). To sum up, CACR can be successfully administered in this population. CACR proved to be effective over and above CG for the most intensively trained cognitive ability. Finally, on the long-term, enhanced reasoning and inhibition abilities, which are necessary to execute higher-order goals or to adapt behavior to the ever-changing environment, were observed in adolescents benefi ting from a CACR.

Theory of mind and cognitive processes in aging and Alzheimer type dementia: a systematic review.

OBJECTIVES: Theory of mind (ToM) performance in aging and dementia of the Alzheimer type (DAT) has been a growing interest of researchers and recently, theoretical trends in ToM development have led to a focus on determining the cognitive skills involved in ToM performance. The aim of the present review is to answer three main questions: How is ToM assessed in aging and DAT? How does ToM performance evolve in aging and DAT? Do cognitive processes influence ToM performance in aging and DAT? METHOD: A systematic review was conducted to provide a targeted overview of recent studies relating ToM performance with cognitive processes in aging and DAT. RESULTS: RESULTS suggest a decrease in ToM performance, more pronounced in complex ToM tasks. Moreover, the review points up the strong involvement of executive functions, especially inhibition, and reasoning skills in ToM task achievement. CONCLUSION: Current data suggest that the structure of ToM tasks itself could lead to poor performance, especially in populations with reduced cognitive abilities.

Cognitive efficacy of quetiapine in early-onset first-episode psychosis: a 12-week open label trial.

Twenty-three adolescents with psychotic disorders, aged from 13 to 18 years, participated in a 12-week open label trial (17 adolescents completed the study) in order to examine the impact of quetiapine on clinical status and cognitive functions (encompassing processing speed, attention, short-term memory, long-term memory and executive function). An improvement in Clinical Global Impression and Positive and Negative Symptom Scale (P's ≤ 0.001) was observed. In addition, after controlling for amelioration of symptoms, a significant improvement was observed on one executive function (P = 0.044; Trail Making Part B). The remaining cognitive abilities showed stability. In addition, we observed an interaction between quetiapine doses (>300 mg/day or <300 mg/day) and time, where lower doses showed more improvement in verbal short-term memory (P = 0.048), inhibition abilities (P = 0.038) and positive symptoms (P = 0.020). The neuropsychological functioning of adolescents with psychotic disorders remained mainly stable after 12 weeks of treatment with quetiapine. However, lower doses seemed to have a better impact on two components of cognition (inhibition abilities and verbal short-term memory) and on positive symptoms.

Male cognitive performance declines in the absence of sexual selection.

Sexual selection is responsible for the evolution of male ornaments and armaments, but its role in the evolution of cognition--the ability to process, retain and use information--is largely unexplored. Because successful courtship is likely to involve processing information in complex, competitive sexual environments, we hypothesized that sexual selection contributes to the evolution and maintenance of cognitive abilities in males. To test this, we removed mate choice and mate competition from experimental populations of Drosophila melanogaster by enforcing monogamy for over 100 generations. Males evolved under monogamy became less proficient than polygamous control males at relatively complex cognitive tasks. When faced with one receptive and several unreceptive females, polygamous males quickly focused on receptive females, whereas monogamous males continued to direct substantial courtship effort towards unreceptive females. As a result, monogamous males were less successful in this complex setting, despite being as quick to mate as their polygamous counterparts with only one receptive female. This diminished ability to use past information was not limited to the courtship context: monogamous males (but not females) also showed reduced aversive olfactory learning ability. Our results provide direct experimental evidence that the intensity of sexual selection is an important factor in the evolution of male cognitive ability.

A Randomized Controlled Trial of the Effectiveness of Computer-Assisted Cognitive Remediation (CACR) in Adolescents with Psychosis or at High Risk of Psychosis.

Background: Computer assisted cognitive remediation (CACR) was demonstrated to be efficient in improving cognitive deficits in adults with psychosis. However, scarce studies explored the outcome of CACR in adolescents with psychosis or at high risk. Aims: To investigate the effectiveness of a computer-assisted cognitive remediation (CACR) program in adolescents with psychosis or at high risk. Method: Intention to treat analyses included 32 adolescents who participated in a blinded 8-week randomized controlled trial of CACR treatment compared to computer games (CG). Cognitive abilities, symptoms and psychosocial functioning were assessed at baseline and posttreatment. Results: Improvement in visuospatial abilities was significantly greater in the CACR group than in CG. Other cognitive functions, psychotic symptoms and psychosocial functioning improved significantly, but at similar rates, in the two groups. Conclusion: CACR can be successfully administered in this population; it proved to be effective over and above CG for the most intensively trained cognitive ability.

Cognition and psychopathology in nonagenarians and centenarians living in geriatric nursing homes in Switzerland: a focus on anosognosia.

BACKGROUND: The number of nonagenarians and centenarians is rising dramatically, and many of them live in nursing homes. Very little is known about psychiatric symptoms and cognitive abilities other than memory in this population. This exploratory study focuses on anosognosia and its relationship with common psychiatric and cognitive symptoms. METHODS: Fifty-eight subjects aged 90 years or older were recruited from geriatric nursing homes and divided into five groups according to Mini-Mental State Examination scores. Assessment included the five-word test, executive clock-drawing task, lexical and categorical fluencies, Anosognosia Questionnaire-Dementia, Neuropsychiatric Inventory, and Charlson Comorbidity Index. RESULTS: Subjects had moderate cognitive impairment, with mean ± SD Mini-Mental State Examination being 15.41 ± 7.04. Anosognosia increased with cognitive impairment and was associated with all cognitive domains, as well as with apathy and agitation. Subjects with mild global cognitive decline seemed less anosognosic than subjects with the least or no impairment. Neither anosognosia nor psychopathological features were related to physical conditions. CONCLUSIONS: Anosognosia in oldest-old nursing home residents was mostly mild. It was associated with both cognitive and psychopathological changes, but whether anosognosia is causal to the observed psychopathological features requires further investigation.

Is sociality driven by the costs of dispersal or the benefits of philopatry? A role for kin-discrimination mechanisms.

The role of ecological constraints in promoting sociality is currently much debated. Using a direct-fitness approach, we show this role to depend on the kin-discrimination mechanisms underlying social interactions. Altruism cannot evolve under spatially based discrimination, unless ecological constraints prevent complete dispersal. Increasing constraints enhances both the proportion of philopatric (and thereby altruistic) individuals and the level of altruistic investments conceded in pairwise interactions. Familiarity-based discrimination, by contrast, allows philopatry and altruism to evolve at significant levels even in the absence of ecological constraints. Increasing constraints further enhances the proportion of philopatric (and thereby altruistic) individuals but not the level of altruism conceded. Ecological constraints are thus more likely to affect social evolution in species in which restricted cognitive abilities, large group size, and/or limited period of associative learning force investments to be made on the basis of spatial cues.

Clinicopathologic correlates in the oldest-old: Commentary on "No disease in the brain of a 115-year-old woman".

den Dunnen et al. [den Dunnen, W.F.A., Brouwer, W.H., Bijlard, E., Kamphuis, J., van Linschoten, K., Eggens-Meijer, E., Holstege, G., 2008. No disease in the brain of a 115-year-old woman. Neurobiol. Aging] had the opportunity to follow up the cognitive functioning of one of the world's oldest woman during the last 3 years of her life. They performed two neuropsychological evaluations at age 112 and 115 that revealed a striking preservation of immediate recall abilities and orientation. In contrast, working memory, retrieval from semantic memory and mental arithmetic performances declined after age 112. Overall, only a one-point decrease of MMSE score occurred (from 27 to 26) reflecting the remarkable preservation of cognitive abilities. The neuropathological assessment showed few neurofibrillary tangles (NFT) in the hippocampal formation compatible with Braak staging II, absence of amyloid deposits and other types of neurodegenerative lesions as well as preservation of neuron numbers in locus coeruleus. This finding was related to a striking paucity of Alzheimer disease (AD)-related lesions in the hippocampal formation. The present report parallels the early descriptions of rare "supernormal" centenarians supporting the dissociation between brain aging and AD processes. In conjunction with recent stereological analyses in cases aged from 90 to 102 years, it also points to the marked resistance of the hippocampal formation to the degenerative process in this age group and possible dissociation between the occurrence of slight cognitive deficits and development of AD-related pathologic changes in neocortical areas. This work is discussed in the context of current efforts to identify the biological and genetic parameters of human longevity.

Three essays on leadership

ABSTRACT Samuel Bendahan, John Antonakis, Christian Zehnder, and François Pralong The relationship between power and immoral decisions has been discussed extensively by scientists and philosophers alike. Although the exercise of power is ubiquitous in social hierarchies, direct evidence on the impact of power on decision making is scarce. We use laboratory experiments to study whether more power leads to corruption. We manipulate power in the context of leader decision-making authority involving monetary stakes. Prior to the experiment, we also gathered extensive data on psychological and endocrinological individual differences. We find that an increase of power caused leaders to be more likely to engage in destructive, selfish behaviour, although the same subjects did not behave in this manner before their level of power was increased. We also show how individual differences affect the initial level of destructive behaviour and the corruption process. WHAT'S RIGHT FOR THE LEFT MAY NOT BE RIGHT FOR THE RIGHT: VALUE CONGRUENCE AND CHARISMA IN POLITICAL LEADERSHIP Samuel Bendahan ABSTRACT Value congruence between leaders and followers is important not only for follower commitment but also as part of the attributions followers make of leaders. I theorized that transformational leadership, which often is referred to as being value driven and having strong moral foundations, has differential effects depending on the values of the follower and whether these values are congruent with what the leader espouses. I designed an experiment to analyze how the political values of followers and leaders can influence followers' attributions regarding leaders. Within the context of political leadership, I found that transformational leaders were seen as more prototypical. Value congruence predicted prototypicality, which was strongly related to follower intentions to vote for the leader. Furthermore, followers with left-wing political values were more influenced by prototypical leaders than were followers with right-wing political values, presumably because of moral overtones of both left-wing ideology and transformational leadership. JUDGING LEADERSHIP POTENTIAL IN AN INTERVIEW: MODERATING EFFECT OF INTERVIEWER INTELLIGENCE ON INTERVIEWER COGNITIVE BUSYNESS, CANDIDATE PERFORMANCE-CUES EFFECTS, AND CANDIDATE ETHNICITY Samuel Bendahan, Philippe Jacquart, and John Antonakis ABSTRACT A large body of literature suggests that interviewers do not accurately rate candidates when using unstructured interviews and evaluation procedures that affect pre-interview expectations; however, the process by which these biases are produced is not well understood. We theorized several reasons for the sub-par performance of the unstructured interview. These factors, which we manipulated in the context of a videotaped interview of a candidate applying for a leadership position, include evaluator cognitive load, pre-interview performance cues regarding the candidate, and the ethnicity of the candidate. We also controlled for the intelligence of the evaluator. We found a significant four-way interaction between the manipulated factors and evaluators' cognitive abilities. The effects of the manipulated factors were all significantly less for evaluators who were high on general intelligence.

Evolution of decision-making and learning under fluctuating social environments

The capacity to learn to associate sensory perceptions with appropriate motor actions underlies the success of many animal species, from insects to humans. The evolutionary significance of learning has long been a subject of interest for evolutionary biologists who emphasize the bene¬fit yielded by learning under changing environmental conditions, where it is required to flexibly switch from one behavior to another. However, two unsolved questions are particularly impor¬tant for improving our knowledge of the evolutionary advantages provided by learning, and are addressed in the present work. First, because it is possible to learn the wrong behavior when a task is too complex, the learning rules and their underlying psychological characteristics that generate truly adaptive behavior must be identified with greater precision, and must be linked to the specific ecological problems faced by each species. A framework for predicting behavior from the definition of a learning rule is developed here. Learning rules capture cognitive features such as the tendency to explore, or the ability to infer rewards associated to unchosen actions. It is shown that these features interact in a non-intuitive way to generate adaptive behavior in social interactions where individuals affect each other's fitness. Such behavioral predictions are used in an evolutionary model to demonstrate that, surprisingly, simple trial-and-error learn¬ing is not always outcompeted by more computationally demanding inference-based learning, when population members interact in pairwise social interactions. A second question in the evolution of learning is its link with and relative advantage compared to other simpler forms of phenotypic plasticity. After providing a conceptual clarification on the distinction between genetically determined vs. learned responses to environmental stimuli, a new factor in the evo¬lution of learning is proposed: environmental complexity. A simple mathematical model shows that a measure of environmental complexity, the number of possible stimuli in one's environ¬ment, is critical for the evolution of learning. In conclusion, this work opens roads for modeling interactions between evolving species and their environment in order to predict how natural se¬lection shapes animals' cognitive abilities. - La capacité d'apprendre à associer des sensations perceptives à des actions motrices appropriées est sous-jacente au succès évolutif de nombreuses espèces, depuis les insectes jusqu'aux êtres hu¬mains. L'importance évolutive de l'apprentissage est depuis longtemps un sujet d'intérêt pour les biologistes de l'évolution, et ces derniers mettent l'accent sur le bénéfice de l'apprentissage lorsque les conditions environnementales sont changeantes, car dans ce cas il est nécessaire de passer de manière flexible d'un comportement à l'autre. Cependant, deux questions non résolues sont importantes afin d'améliorer notre savoir quant aux avantages évolutifs procurés par l'apprentissage. Premièrement, puisqu'il est possible d'apprendre un comportement incorrect quand une tâche est trop complexe, les règles d'apprentissage qui permettent d'atteindre un com¬portement réellement adaptatif doivent être identifiées avec une plus grande précision, et doivent être mises en relation avec les problèmes écologiques spécifiques rencontrés par chaque espèce. Un cadre théorique ayant pour but de prédire le comportement à partir de la définition d'une règle d'apprentissage est développé ici. Il est démontré que les caractéristiques cognitives, telles que la tendance à explorer ou la capacité d'inférer les récompenses liées à des actions non ex¬périmentées, interagissent de manière non-intuitive dans les interactions sociales pour produire des comportements adaptatifs. Ces prédictions comportementales sont utilisées dans un modèle évolutif afin de démontrer que, de manière surprenante, l'apprentissage simple par essai-et-erreur n'est pas toujours battu par l'apprentissage basé sur l'inférence qui est pourtant plus exigeant en puissance de calcul, lorsque les membres d'une population interagissent socialement par pair. Une deuxième question quant à l'évolution de l'apprentissage concerne son lien et son avantage relatif vis-à-vis d'autres formes plus simples de plasticité phénotypique. Après avoir clarifié la distinction entre réponses aux stimuli génétiquement déterminées ou apprises, un nouveau fac¬teur favorisant l'évolution de l'apprentissage est proposé : la complexité environnementale. Un modèle mathématique permet de montrer qu'une mesure de la complexité environnementale - le nombre de stimuli rencontrés dans l'environnement - a un rôle fondamental pour l'évolution de l'apprentissage. En conclusion, ce travail ouvre de nombreuses perspectives quant à la mo¬délisation des interactions entre les espèces en évolution et leur environnement, dans le but de comprendre comment la sélection naturelle façonne les capacités cognitives des animaux.

Use of neuroenhancement drugs: prevalence, frequency and use expectations in Switzerland

Objective: The present study investigates the use expectations, prevalence and frequency of neuroenhancement drug (ND) use among the Swiss male population, separating college students from others. Methods: Young Swiss men were invited to participate in the Cohort Study on Substance Use Risk Factors. A total of 5,967 participants responded to questions on six types of NDs (wakefulness medication, antidepressants, Alzheimer's disease medication, Parkinson's disease medication, attention deficit-hyperactivity disorder (ADHD) medication, and beta-blockers). The frequency of use depending on five expectations (to enhance wakefulness, attention, memory, concentration and stress reduction) was analyzed for a twelve-month period. Results: (1) About 3% of the sample indicated use of at least one ND; (2) ADHD medication was the most prevalent; (3) The type of ND preferred differed depending on academic status (4). Quantitatively, over the year, college student users used ND much less frequently than other users. Conclusions: Prevalence of ND use is low in Switzerland relative to other countries such as the United States. Patterns of ND use differed depending on academic status, suggesting that while college student ND users tended to do so rarely (probably to enhance cognitive abilities for exams), non-college male users used other NDs more frequently (probably to "get high").