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At least 505 records · Page 28Linked to original sources
PubMed2003

Lengthening the duration of response execution does not modulate blindness to action-compatible stimuli.

Action-compatible blindness refers to the finding that target stimuli are perceived less frequently if they are presented during the planning or execution of a compatible action (e.g., a left arrow presented during a left manual key press) than during an incompatible action (Müsseler & Hommel, 1997 a, b). We investigated the effect of lengthening the response execution phase in the action-compatible blindness paradigm by requiring subjects to tap a response key once or three times on the assumption that tapping three times would increase the duration of the execution phase of the response. Prior research (e.g., Stevanovski, Oriet, & Jolicoeur, 2002; Wühr & Müsseler, 2001) has shown that larger blindness effects are observed for targets presented during the execution phase of a response than after the response has been made. We investigated whether a larger blindness effect would be observed in the three-tap condition than in the one-tap condition, or whether lengthening the duration of the response would extend the time course of the blindness effect. Neither of these possibilities was supported by the data irrespective of whether the number of taps to be made was blocked or mixed within a block of trials. The results are discussed in terms of current accounts of action-compatible blindness and the possible cognitive differences between making a single response and repeating a response.

Adolescent↗
PubMed2006

Neurons in the orbitofrontal cortex encode economic value.

Economic choice is the behaviour observed when individuals select one among many available options. There is no intrinsically 'correct' answer: economic choice depends on subjective preferences. This behaviour is traditionally the object of economic analysis and is also of primary interest in psychology. However, the underlying mental processes and neuronal mechanisms are not well understood. Theories of human and animal choice have a cornerstone in the concept of 'value'. Consider, for example, a monkey offered one raisin versus one piece of apple: behavioural evidence suggests that the animal chooses by assigning values to the two options. But where and how values are represented in the brain is unclear. Here we show that, during economic choice, neurons in the orbitofrontal cortex (OFC) encode the value of offered and chosen goods. Notably, OFC neurons encode value independently of visuospatial factors and motor responses. If a monkey chooses between A and B, neurons in the OFC encode the value of the two goods independently of whether A is presented on the right and B on the left, or vice versa. This trait distinguishes the OFC from other brain areas in which value modulates activity related to sensory or motor processes. Our results have broad implications for possible psychological models, suggesting that economic choice is essentially choice between goods rather than choice between actions. In this framework, neurons in the OFC seem to be a good candidate network for value assignment underlying economic choice.

Animals↗
PubMed2006

Norm-based face encoding by single neurons in the monkey inferotemporal cortex.

The rich and immediate perception of a familiar face, including its identity, expression and even intent, is one of the most impressive shared faculties of human and non-human primate brains. Many visually responsive neurons in the inferotemporal cortex of macaque monkeys respond selectively to faces, sometimes to only one or a few individuals, while showing little sensitivity to scale and other details of the retinal image. Here we show that face-responsive neurons in the macaque monkey anterior inferotemporal cortex are tuned to a fundamental dimension of face perception. Using a norm-based caricaturization framework previously developed for human psychophysics, we varied the identity information present in photo-realistic human faces, and found that neurons of the anterior inferotemporal cortex were most often tuned around the average, identity-ambiguous face. These observations are consistent with face-selective responses in this area being shaped by a figural comparison, reflecting structural differences between an incoming face and an internal reference or norm. As such, these findings link the tuning of neurons in the inferotemporal cortex to psychological models of face identity perception.

Animals↗
PubMed2004

Beliefs and attitudes towards the consumption of sugar-free products in a sample of Italian adolescents.

OBJECTIVE: The objective of this study was to investigate beliefs and attitudes towards sugar-free products in a sample of Italian teenagers. DESIGN: A total of 10 secondary public schools in the county of Rome were randomly selected. The probability of being extracted was set proportional to the number of students. A random sample of teenagers was selected from the schools for participating in a food consumption survey. SUBJECTS: The sample included 233 adolescents, aged 15-21 y. A total of 224 adolescents agreed to participate in the study aimed at assessing beliefs and attitudes. INTERVENTIONS: Two questionnaires were completed at the first day of the last period of the 4-day food survey. The first questionnaire contained questions on attitudes and beliefs toward a healthy diet. The second questionnaire, aimed at assessing adolescents' attitudes towards the consumption of sugar-free products, was based in part on the social-psychological model of the Theory of Planned Behaviour. RESULTS: In general, the adolescents of this sample seemed to be quite uncertain in their responses. On average, they did not express an emphatic point of view with regard to the act of eating sugar-free products. The results of the assessment of relationships between the variables of the theoretical model revealed the lack of causal links among beliefs, attitudes, intention and consumption of sugar-free products. Perceived behavioural control was not a significant predictor of intention. CONCLUSIONS: The target of further studies aimed at investigating attitudes towards sugar-free products should be tailored according to the quantity of consumption of such products in order to represent a sample of frequent and high consumers of sugar-free products. SPONSORSHIP: European Commission Quality of Life and Management of Living Resources Fifth framework Programme. QLRT-1999-00155.

Adolescent↗
PubMed1996

Predicting underage drinking and driving behaviors.

A social-psychological model of underage drinking and driving (DUI) and riding with drinking drivers (RWDD) was tested with data from a random digit dial telephone survey of 706 16-20-year-old drivers from seven western states in the United States. Consistent with the model, a structural equations analysis indicated that DUI and RWDD were primarily predicted by (a) expectancies regarding the physical risks of DUI, (b) normative beliefs about the extent to which friends would disapprove of DUI, (c) control beliefs about the ease or difficulty of avoiding DUI and RWDD and (d) drinking. Expectancies concerning enforcement had a significant effect on RWDD, but not on DUI. Among the background and environmental variables included in the analysis, only night-time driving and age had significant direct effects on DUI and RWDD. Drinking and involvement in risky driving had indirect effects on DUI and RWDD that were mediated through expectancies and normative beliefs. Males, European Americans, Latinos, respondents who drove more frequently and respondents who were less educated held beliefs that were more favorable toward DUI and RWDD, drank more and engaged more frequently in risky driving. As a result, such individuals may be at greater risk for DUI and RWDD.

Adolescent↗
PubMed2001

[Therapeutic programmes focusing on job related problems - which psychosomatic patients should participate?].

The necessity to offer special therapeutic programmes focusing on job related problems in psychosomatic rehabilitation has become increasingly evident. Which patients should participate in such programmes? This question has not yet been discussed with regard to its theoretical and methodological implications. In clinical practice the decision has been based on the therapists evaluation. 105 patients, consecutively admitted in a psychosomatic hospital were interviewed with a screening questionnaire about their job related strains and the perceived interaction between symptomatology and job. According to the literature guidelines for inclusion of psychosomatic patients to a special work hardening programme were used. Therapists were asked to independently assign their patients to the programme. The overlap between the two procedures was small. While the guidelines focussed on a high level of job strain and the patient's motivation for a job-related therapeutic approach, the therapists' decision was based on duration of inability to work, impairments at work due to the symptoms, conflicts with colleagues at work and the patient's ability to perceive problems in a differentiated manner. Considering the problem of inclusion-criteria for a work hardening programme, the highly complex constellations behind routine therapeutic decisions in psychosomatic rehabilitation became evident. To integrate medical diagnosis, symptomatology, psychological models, job strain, the patient's social situation and values, is a neglected but important goal of rehabilitation sciences and should be a base for a concept guiding the development, evaluation and establishment of work related therapeutic programmes.

Adult↗
PubMed1995

[Interaction of therapeutic effects and side effects in drug therapy of generalized anxiety disorders with low dosage fluspirilene].

The present study was designed to investigate the interaction between therapeutic effects and side-effects in fluspirilene treatment of generalised anxiety disorders (GAD). 205 outpatients received in an open trial 1.5 mg fluspirilene per week for 6 weeks. Confirming previous reports of our study group fluspirilene demonstrated marked efficacy and was generally well tolerated. However, the main finding of our study is that side effects, although rare in fluspirilene treatment, predict an unfavourable clinical outcome. This phenomenon is integrated in a psychological model implying that when GAD patients are aware of side-effects this induces anxiety. Again anxiety gives rise to somatic symptoms, both interacting in a forward loop. In conclusion, our data suggest that in the sense of Heinrich (1988) fluspirilene treatment of GAD should be guided by paying attention to possible side effects.

Adolescent↗
PubMed1989

Risk behavior-based model of the cubic growth of acquired immunodeficiency syndrome in the United States.

The cumulative number of cases of acquired immunodeficiency syndrome (AIDS) in the United States has grown as the cube of time rather than exponentially. We explain this by interactions involving partner choice and sexual frequency in a risk-behavior model with biased mixing. This leads to a saturation wave of infection moving from high- to low-risk groups. If this description is correct, then the decreasing growth rate of AIDS cases is not due to behavior changes; rather it is due to the intrinsic epidemiology of the disease.

Acquired Immunodeficiency Syndrome↗
PubMed1989

A case at last for age-phased reduction in equity.

Maximizing expected utility over a lifetime leads one who has constant relative risk aversion and faces random-walk securities returns to be "myopic" and hold the same fraction of portfolio in equities early and late in life--a defiance of folk wisdom and casual introspection. By assuming one needs to assure at retirement a minimum ("subsistence") level of wealth, the present analysis deduces a pattern of greater risk-taking when young than when old. When a subsistence minimum is needed at every period of life, the rentier paradoxically is least risk tolerant in youth--the Robert C. Merton paradox that traces to the decline with age of the present discounted value of the subsistence-consumption requirements. Conversely, the decline with age of capitalized human capital reverses the Merton effect.

Aging↗
PubMed1998

Instability of signaling resolution models of parent-offspring conflict.

Recent signaling resolution models of parent-offspring conflict have provided an important framework for theoretical and empirical studies of communication and parental care. According to these models, signaling of need is stabilized by its cost. However, our computer simulations of the evolutionary dynamics of chick begging and parental investment show that in Godfray's model the signaling equilibrium is evolutionarily unstable: populations that start at the signaling equilibrium quickly depart from it. Furthermore, the signaling and nonsignaling equilibria are linked by a continuum of equilibria where chicks above a certain condition do not signal and we show that, contrary to intuition, fitness increases monotonically as the proportion of young that signal decreases. This result forces us to reconsider much of the current literature on signaling of need and highlights the need to investigate the evolutionary stability of signaling equilibria based on the handicap principle.

Animals↗
PubMed1999

The evolution of language.

The emergence of language was a defining moment in the evolution of modern humans. It was an innovation that changed radically the character of human society. Here, we provide an approach to language evolution based on evolutionary game theory. We explore the ways in which protolanguages can evolve in a nonlinguistic society and how specific signals can become associated with specific objects. We assume that early in the evolution of language, errors in signaling and perception would be common. We model the probability of misunderstanding a signal and show that this limits the number of objects that can be described by a protolanguage. This "error limit" is not overcome by employing more sounds but by combining a small set of more easily distinguishable sounds into words. The process of "word formation" enables a language to encode an essentially unlimited number of objects. Next, we analyze how words can be combined into sentences and specify the conditions for the evolution of very simple grammatical rules. We argue that grammar originated as a simplified rule system that evolved by natural selection to reduce mistakes in communication. Our theory provides a systematic approach for thinking about the origin and evolution of human language.

Biological Evolution↗
PubMed1999

Committee proposals and restrictive rules.

I analyze a game-theoretic model of committee-legislature interaction in which a majority decision to adopt either an open or closed amendment rule occurs following the committee's proposal of a bill. I find that, in equilibrium, the closed rule is almost always chosen when the dimension of the policy space is >1. Furthermore, the difference between the equilibrium outcome and that which would have occurred under the open rule can be arbitrarily small.

Game Theory↗
PubMed1995

Attitudinal dimensions of food choice and nutrient intake.

A diet low in fat and rich in fibre has been recommended to optimize general health and in particular cardiovascular health. Health attitudes to fat and fibre were studied in relation to food and nutrient intake and sociocultural and lifestyle factors amongst the general population of Northern Ireland. The study population comprised 592 adults aged 16-64 years; health attitudes to fat and fibre were assessed by questionnaire (based on a social psychological model, which adjusted for taste and convenience factors). Dietary intake was estimated using the weighed inventory technique. Fat-phobic and fibre-philic attitudes were more prevalent in women than men. Fat-phobic attitudes in women were inversely related to intake of fat through a reduced intake of chips, butter and sausages. In contrast, men's fat-phobic attitudes were not strongly correlated with fat intake; consumption of chips and sausages was negatively associated with fat-phobic attitudes, but cake/biscuit, buns/pastries and milk consumption was positively associated with fat-phobic attitudes. Fibre-philic attitudes were positively associated with dietary fibre intake; intakes of potatoes, vegetables, wholemeal bread and breakfast cereal were positively associated with fibre-philic attitudes. There were clear sociocultural and lifestyle differences in relation to dietary attitude. These findings have implications for campaigns designed to effect population dietary change.

Adolescent↗
PubMedDate not supplied

Distributed situation awareness in dynamic systems: theoretical development and application of an ergonomics methodology.

The purpose of this paper is to propose foundations for a theory of situation awareness based on the analysis of interactions between agents (i.e. both human and non-human) in subsystems. This approach may help to promote a better understanding of technology-mediated interaction in systems, as well as helping in the formulation of hypotheses and predictions concerning distributed situation awareness. It is proposed that agents within a system each hold their own situation awareness, which may be very different from (although compatible with) that of other agents. It is argued that we should not always hope for, or indeed want, sharing of this awareness, as different system agents have different purposes. This view marks situation awareness as a dynamic and collaborative process binding agents together on tasks on a moment-by-moment basis. Implications of this viewpoint for the development of a new theory of, and accompanying methodology for, distributed situation awareness are offered.

Awareness↗
PubMed1995

The interactionist nature of drinking and driving: a structural model.

A structural model is described that examines the contributions of personal and situational determinants (interactionist theory) for the elicitation of previous self-reported drink-driving offending. Responses of 1011 UK driver's licence holders to 57 questions concerning demographics, driving experience/exposure, deterrence issues, attitudinal factors and situation specific drink-driving behaviour were subjected to a series of multiple regression analyses. Seven variables (five personal and two situational) accounting for 46% of the sample variance were shown to be significantly predictive of undetected offending behaviour. Of these age and safe driving consumption estimates were found to be best described in terms of their direct effects on offending behaviour. The relationships between general alcohol consumption and exposure to secondary level enforcement (breath test) with drink-driving behaviour have both direct and indirect effects. Two attitudinal factors referring to a belief of deterrence if random breath testing were introduced into the UK, and arranging alternative transport on a drinking occasion, as well as exposure to a drink-driving charge, show approximately proportional direct and spurious links with offending. Findings are discussed i n terms of the utility of an interactionist approach for the study of drink-driving behaviour, previous attempts at modelling drink-driving behaviour, and the implications that such results have for counter-measure development.

Adolescent↗