Integration of base rates and new information in an abstract hypothesis‐testing task

In two studies, we investigated how people use base rates and the presence versus the absence of new information to judge which of two hypotheses is more likely. Participants were given problems based on two decks of cards printed with 0–4 letters. A table showed the relative frequencies of the letters on the cards within each deck. Participants were told the letters that were printed on or absent from a card the experimenter had drawn. Base rates were conveyed by telling participants that the experimenter had chosen the deck by drawing from an urn containing, in different proportions, tickets marked either ‘deck 1’ or ‘deck 2’. The task was to judge from which of the two decks the card was most likely drawn. Prior probabilities and the evidential strength of the subset of present clues (computed as ‘weight of evidence’) were the only significant predictors of participants’ dichotomous (both studies) and continuous (Study 2) judgments. The evidential strength of all clues was not a significant predictor of participants’ judgments in either study, and no significant interactions emerged. We discuss the results as evidence for additive integration of base rates and the new present information in hypothesis testing.     

Estimating time to contact and impact velocity when catching an accelerating object with the hand

To catch a moving object with the hand requires precise coordination between visual information about the target's motion and the muscle activity necessary to prepare for the impact. A key question remains open as to if and how a human observer uses velocity and acceleration information when controlling muscles in anticipation of impact. Participants were asked to catch the moving end of a swinging counterweighted pendulum, and resulting muscle activities in the arm were measured. The authors also simulated muscle activities that would be produced according to different tuning strategies. By comparing data with simulations, the authors provide evidence that human observers use online information about velocity but not acceleration when preparing for impact.     

Inner speech sustains predictable task switching: direct evidence in adults

It has been proposed that inner speech supports task selection in task-switching studies, especially when the need for endogenous control is increased. This has been established through the suppression of inner speech in cognitive-flexibility tasks that leads to poorer performance. The aim of this study is to quantify the role of inner speech in a flexibility task by using surface laryngeal electromyography, which, contrary to previous studies, enables participants to freely verbalise the tasks. We manipulated endogenous and exogenous flexibility in a mathematical switching task paradigm. Experiment 1 shows that inner speech acts as a support for switching and is recruited more often when the tasks are of an endogenous type. The main result of Experiment 2 that language is recruited more for the mixing cost than for the switch cost (regardless of the endogenous factor) extends past findings obtained through articulatory suppression.     

Pharmacotherapy of aphasia: myth or reality?

Pharmacotherapy of aphasia had been discussed for the last twenty years with first bromocriptine and amphetamine and then serotoninergic, GABAergic and cholinergic agents. Here, we reviewed the MEDLINE available reports of drug therapy for aphasia. So far, proofs of efficiency were found indubitable for none of the studied molecules. However, some of them showed limited efficiency (piracetam and amphetamine). Moreover, drug therapies for aphasia were less efficient alone than when they were associated with speech therapy.     

Presence as determined by fractal perceptual-motor dynamics.

This paper presents a tentative model of the role of perceptual-motor dynamics in the emergence of the feeling of presence. A new method allowing the measure of how gaze probes three-dimensional space in immersion is used to support this model. Fractal computations of gaze behavior are shown to be more effective than standard computations of eye movements in predicting presence.     

Analyzing feature distinctiveness in the processing of living and non-living concepts in Alzheimer’s disease

The conceptual structure account (CSA) is a model specifying the role of the living and non-living domain dichotomy in the structure of semantic memory. According to this model, feature distinctiveness and the perceptual–functional inter-correlation of concepts are assumed to play a major role in impairing the ability to discriminate between living and non-living concepts in Alzheimer’s disease (AD). The hypothesis was tested in this study by using naming and sorting tasks traditionally considered as assessing distinctiveness, and a property verification task where distinctiveness and perceptual–functional inter-correlation were objectively controlled against norms especially created for this purpose. Alzheimer’s patients (n = 59) with minimal, mild or moderate dementia and normal elderly adults (n = 31) participated in the study. Overall, the findings did not support the CSA predictions. They revealed a distinctiveness effect on response accuracy with shared features dominating distinctive features regardless of domain. They also revealed more difficulties in the tasks involving effortful processes. The results stress the need to consider both cognitive demands of tasks and structural aspects of knowledge in the evaluation of semantic memory in AD.     

Technological and medical advances: implications for health psychology.

Behavioral telehealth, health informatics, organ and tissue transplantation, and genetics are among the areas that have been affected by advances in technology and medicine. These areas illustrate the opportunities and the challenges that new developments can pose to health psychologists. Each area is discussed with respect to implications for practice, research, public policy, and education and training: recommendations are provided.     

New knowledge for old credences: Asymmetric information search about in-group and out-group members

Three experiments examined how people gather information on in-group and out-group members. Previous studies have revealed that category-based expectancies bias the hypothesis-testing process towards confirmation through the use of asymmetric-confirming questions (which are queries where the replies supporting the prior expectancies are more informative than those falsifying them). However, to date there is no empirical investigation of the use of such a question-asking strategy in an intergroup context. In the present studies, participants were asked to produce (Study 1) or to choose (Studies 2 and 3) questions in order to investigate the presence of various traits in an in-group or an out-group member. Traits were manipulated by valence and typicality. The results revealed that category-based expectancies do not always lead to asymmetric-confirming testing: whereas participants tended to ask questions that confirmed positive in-group and negative out-group stereotypical attributes, they used a more symmetric strategy when testing for the presence of negative in-group or positive out-group traits. Moreover, Study 3 also revealed a moderation effect of in-group identification. The findings point to the role played by motivational factors associated with preserving a positive social identity. Possible consequences of these hypothesis-testing processes in preserving a positive social identity for intergroup relations are discussed.