Object localisation and frames of reference

In this paper, we explore which spatial frames of reference, egocentric or allocentric, are used to locate objects either in relation to ourselves (i.e. subject-to-object localisation) or to other objects (i.e. object-to-object localisation). In particular, we wanted to know whether the same or different frames of reference are used in these two different kinds of localisation after learning the environment in an egocentric way. Egocentric frames of reference are determined by the position of the person in relation to the spatial layout, whereas allocentric frames of reference are centred on the environment or on objects, independent of a persons position. We hypothesised that subject-to-object localisation is based on egocentric spatial representations, whereas object-to-object localisation is based on allocentric spatial representations. Participants were asked to study eight common objects, placed in a circle. Next, half of the participants had to point to an object in relation to their imagined position (egocentric condition) and the other half to an object in relation to another object (allocentric condition). The overall results show no difference between subject-to-object and object-to-object localisation. In both cases, access to positions corresponding to the front/back body axis was facilitated, in terms of both latency and error. Moreover, participants were able to retrieve objects positions better from the perspective from which they had learned the spatial array than from new perspectives. These results support the conclusion that egocentric coordinates, which are selected on the basis of our body-centred experience of the environment, define spatial representations underlying both subject-to-object and object-to-object localisation.     

Predicting cognitive styles from spatial abilities

Previous studies on spatial memory reveal that people represent spatial information in 3 different forms: landmark, route, and survey. The aim of this work was to assess spatial abilities in order to predict a person's cognitive style. In order to do this we used 9 different spatial tasks, which were linked with these 3 forms of spatial representations. We found that the 9 spatial tasks are able to distinguish different levels of spatial ability.     

Updating and inhibition processes in working memory: a comparison between Alzheimer's type dementia and frontal lobe focal damage

A large debate has recently focused on the componential nature of the working-memory system (), as evidenced by functional-imaging studies and by using more sophisticated experimental paradigms. The present work aims at further disentangling the role and effects of central executive (CE) and of phonological loop (PL). It is suggested that maintaining active verbal information mostly relates to an intact PL, while the inhibition of interfering information preponderantly involves the CE. To distinguish these effects, two groups of brain damaged patients were administered with an updating task. Frontal lobe patients showed major difficulties in inhibiting interfering information, an ability requiring an involvement of the CE component. In contrast, Alzheimer's dementia patients evidenced a relative impairment in maintaining relevant information, requiring the intervention of the PL.     

To imitate or not to imitate? How the brain can do it, that is the question!

In this paper the authors discuss the most prominent views addressing the issue of how we imitate actions. It is argued that the existing theories lay along a continuum, with the direct mapping approach at one end (Butterworth, 1990; Gray, Neisser, Shapiro, & Kouns, 1991) the Active Intermodal Matching approach (Melzoff & Moore, 1997) in the middle, and the goal-directed theory (Bekkering, Wohlsh?ger, & Gattis, 2000) and the dual route theory (Rumiati & Tessari, 2002) at the opposite end. Interestingly the latter views can account for behaviors that cannot be explained by invoking the direct mapping or the Active Intermodal Matching approach.     

What language says about the psychology of events

Despite the variety of verb meanings, linguistic research on their syntax and semantics has shown that they can be categorized into a finite and surprisingly small number of event types. More recently, research in the psycholinguistics of language acquisition and processing has emphasized the relevance of event type. The wider implication of these findings is that the conceptual fluidity of verbal concepts is confined by the fundamental structures of mental grammar, shedding light on this important interface between cognition and syntactic organization.     

Frequency format facilitates reasoning in simple numerical tasks

This study examined whether it is easier to reason in terms of frequencies or with percentages for simple numerical tasks. Research on probabilistic reasoning has shown that humans can draw correct inferences when problems are presented in terms of natural frequencies but not when in percentages. Whether the same effect can be observed in other numerically simple tasks which are not probabilistic was studied with 40 undergraduate students who volunteered for the experiment (13 men, 27 women; M age of 23 yr.). In a simple numerical task involving frequencies or percentages (N=20), their performance showed representation in frequencies facilitates the task.     

A kinematic analysis of age-related changes in grasping to use and grasping to move common objects

Grasping is a complex action which requires high-level motor control. Although the impact of aging on grasping has been investigated in some studies, to date little is known as to how the aging process interacts with the purpose of the movement. The aims of the present study were (i) to investigate the effect of aging on grasping movements, and to explore on how this effect is modulated by (ii) the goal of the task, and by (iii) the characteristics of the target such as its location in the visual field, its orientation and its size. Young and elderly adults were asked to grasp to move or to grasp to use objects of different sizes and orientations, presented either in the central or the peripheral visual field. Movement duration did not differ between the two groups. However, elderly participants required a longer approach phase and showed a different grasping strategy, characterized by larger grip aperture and smaller percentage of wrist rotation in comparison to young adults. Elderly adults showed a decrease in accuracy when grasping objects presented in the peripheral, but not in the central visual field. A similar modulation of the kinematic parameters consisting in longer planning and execution phases in the grasp to use in comparison to the grasp to move condition was observed in both groups, suggesting that the effect of aging might be minimized and compensated in more goal-directed tasks.