Context and the interpretation of likelihood information: the role of intergroup comparisons on perceived vulnerability

Four experiments investigated how people's perceptions about a group's (e.g., women's) vulnerability to a disease are influenced by information about the prevalence of the disease in a comparable group (e.g., men). Participants read symptom and prevalence infomation about fictitious diseases before answering questions regarding target group vulnerability. Participants used the prevalence rate for a nontarget group as an immediate comparison standard for intuitively interpreting the degree of vulnerability of a target group, resulting in robust contrast effects. Experiments 3 and 4 illustrated that these contrast effects can cause a person's intuitive perceptions about a group's vulnerability to selected diseases to conflict with his or her knowledge of the prevalence rates for the diseases. The results support a distinction between 2 components of psychological uncertainty-beliefs in objective probability and more intuitive perceptions of certainty.     

Ability evaluation by proxy: role of maximal performance and related attributes in social comparison

Four experiments tested the effects of information about a proxy's related attributes and maximal effort in social comparisons of ability. In Study 1, a proxy's prior performance at maximal effort exerted systematic effects on participants' personal performance predictions for a novel task. When information about the proxy's effort was ambiguous (Study 2). information about related attribute similarity was used in the formulation of performance predictions. In Studies 3 and 4, 2-way interaction terms revealed that participants used related attribute information in generating performance predictions when the proxy's maximum effort was unknown. However, related attribute information was disregarded when proxy's maximum effort was unambiguous. Results were consistent with the proxy comparison model of ability self-evaluation (L. Wheeler, R. Martin, & J. Suls, 1997).     

Visual habituation at five months: short-term reliability of measures obtained with a new polynomial regression criterion

Using a new polynomial regression criterion, the authors investigated empirically the short-term reliability of infants' visual habituation measures. Twenty-one 5-month-old infants were tested twice with a 1-day interval. Results revealed many reliable habituation measures, a reliable reaction to novelty measure, and a new reliable measure of interest. The 2nd-order polynomial regression criterion probably produced this improvement because it uses all of the available looking time data.     

Developmental and content effects in reasoning with causal conditionals

Two predictions derived from Markovits and Barrouillet's (2001) developmental model of conditional reasoning were tested in a study in which 72 twelve-year-olds, 80 fifteen-year-olds, and 104 adults received a paper-and-pencil test of conditional reasoning with causal premises ("if cause P then effect Q"). First, we predicted that conditional premises would induce more correct uncertainty responses to the Affirmation of the consequent and Denial of the antecedent forms when the antecedent term is weakly associated to the consequent than when the two are strongly associated and that this effect would decrease with age. Second, uncertainty responding to the Denial of the antecedent form ("P is not true") should be easier when the formulation of the minor premise invites retrieval of alternate antecedents ("if something other than P is true"). The results were consistent with the hypotheses and indicate the importance of retrieval processes in understanding developmental patterns in conditional reasoning with familiar premises.     

Modeling of human posturokinetic movements by a linear feedback system: relations among feedback coefficients

This study describes a method of modeling human trunk and whole body backward bending and suggests a possible neural control strategy. The hypothesis was that the control system can be modeled as a linear feedback system, in which the torque acting at a given joint is a function of the state variables (angular positions and angular velocities). The linear system enabled representation of the feedback system by a gain matrix. The matrix was computed from the kinematics recorded by a movement analysis system and from the joint torques calculated by inverse dynamics. To validate the control model, a comparison was made between the angular kinematics yielded by the model and the experimental data. Moreover, for all subjects, the same relationships between feedback coefficients were found although gain values were different. The study showed that the feedback system is an appropriate model of the strategy from performing an accurate controlled trunk or whole body backward bending in the sagittal plane.     

The effect of sensitization and coping style on post-traumatic stress symptoms and quality of life: two longitudinal studies

The present study investigated the effects of multiple trauma exposure and coping style on post-traumatic stress symptoms and quality of life. It was hypothesized that sensitization would occur in subjects repeatedly exposed to life-threatening situations (study 1), and different coping styles would act as a resilience or facilitating factor in symptom development (study 2). The results showed that the single-exposure group revealed a decrease in trauma specific stress reactions from three weeks to four months, with a persistent reduction at 12-month follow-up, while the repeated-exposure group showed an increase in symptom reporting over the 12-month period. The same pattern emerged for perceived quality of life-measured by the General Health Questionnaire (GHQ-30). The second study revealed a correlation between scores on avoidant-focused coping style and the Impact of Event Scale-avoidance dimension, Post-traumatic Symptom Scale and GHQ-30. Furthermore, only subjects with a dominant coping style of emotion-focused or task-focused coping showed a reduction in trauma-specific symptom scores over time.     

Lack of association of computer use and ability with spontaneous mental visualization

Relationships between frequency of computer use or ability to use the computer effectively with the tendency to construct and process visual mental images were investigated by administering a computer-use questionnaire and a visualization questionnaire to a sample of 185 Italian and Spanish undergraduates. Analysis did not support associations between either (a) frequent computer use of any kind or (b) high competence in using the computer for various purposes and spontaneous use of imagery.     

Satisfiability Testing for Boolean Formulas Using Δ-trees

The tree-based data structure of -tree for propositional formulas is introduced in an improved and optimised form. The -trees allow a compact representation for negation normal forms as well as for a number of reduction strategies in order to consider only those occurrences of literals which are relevant for the satisfiability of the input formula. These reduction strategies are divided into two subsets (meaning- and satisfiability-preserving transformations) and can be used to decrease the size of a negation normal form A at (at most) quadratic cost. The reduction strategies are aimed at decreasing the number of required branchings and, therefore, these strategies allow to limit the size of the search space for the SAT problem.     

Is there an effect of handedness on the position of the egocentric reference?

Forty normal subjects (20 left-handed; 20 right-handed) were submitted to a proprioceptive straight ahead pointing task while blindfolded to study the effect of the hand used and of the hand preference on the estimation of the subjective sagittal middle. Results showed that left-handed and right-handed subjects both deviated to the left of the objective sagittal middle and presented an effect of the hand used and of the starting point affecting their straight ahead performance in a similar way. In all subjects whatever their manual preference, using the left hand and starting 30 degrees to left induced a tendency to deviate to the same side, whereas using the right hand and starting 30 degrees to right induced a tendency to place the subjective middle to the right of the objective middle. These results are interpreted with regard to the hypothesis of a cortical control of the position of the egocentric reference.