Active versus passive proprioceptive straight-ahead pointing in normal subjects

Eighty blindfolded healthy female subjects participated in an active and a passive straight-ahead pointing task to study the estimation of the subjective sagittal middle in the presence or absence of an active haptic exploration. Subjects were to point straight-ahead with their left or right index finger starting from different right- or left-sided locations, while performing either an active movement or with the hand being passively moved by the examiner. Results showed: (i) a significant effect of the hand used only on the active straight-ahead pointing task performance; (ii) a significant effect of the starting position both on the active and passive pointing performance; (iii) a significant correlation between the two protocols only in terms of spatial bias (algebraic error) but not in terms of precision (absolute errors). These results are discussed with regards to normal and neuropsychological studies of the egocentric frame of reference.     

Which factors affect hand selection in children's grasping in hemispace? Combined effects of task demand and motor dominance

Sixty-five right- and left-handed preschool and school children were tested on three reach-to-grasp tasks of different levels of complexity, performed in three space locations. Our goal was to evaluate how the effect of attentional information related to object location interacts with task complexity and degree of handedness on children's hand selection. Results revealed a shift to the non-preferred hand in the contralateral hemispace, which was more or less pronounced according to the level of task complexity. The subject's degree of handedness also influenced this shift, since strongly lateralized children exhibited a greater use of their preferred hand than less lateralized ones for actions in the contralateral hemispace. These findings confirm that hand selection is to some extent adaptable to task demand and environmental context.     

A spatial modality effect in serial memory

In 2 experiments, the authors tested whether the classical modality effect-that is, the stronger recency effect for auditory items relative to visual items-can be extended to the spatial domain. An order reconstruction task was undertaken with four types of material: visual-spatial, auditory-spatial, visual-verbal, and auditory-verbal. Similar serial position curves were obtained regardless of the nature of the to-be-remembered sequences, with the exception that a modality effect was found with spatial as well as with verbal materials. The results are discussed with regard to a number of models of short-term memory.     

Episodic and semantic remote autobiographical memory in ageing

Many laboratory studies have demonstrated an age effect on episodic memory which is in contrast with the preservation of semantic memory. The aim of this study was the assessment of age effects on autobiographical memory according to the length of the retention interval, taking into account the episodic and semantic components. A total of 52 subjects, aged between 40 and 79, were divided into four age groups. They were tested with a sophisticated autobiographical questionnaire consisting of two tasks, one involving the recall of semantic information and another the recall of episodic events. Results revealed that episodic recall deteriorated more with age and retention interval than semantic recall. These data, gathered using an ecological test, confirm age differences demonstrated by laboratory tests on the episodic-semantic distinction. Furthermore, the profile of results obtained for the recall of specific detailed events, and analysed according to age of encoding, confirms the distribution of episodic memories across the lifespan, as modelled by Rubin, Wetzler, and Nebes (1986) with the cue-word technique.     

Visual distraction and visuo-spatial memory: a sandwich effect

The functional characteristics of visuo-spatial serial memory and its sensitivity to irrelevant visual information are examined in the present study, through the investigation of the sandwich effect (e.g., Hitch, 1975). The memory task was one of serial recall for the position of a sequence of seven spatially and temporally separated dots. The presence of irrelevant dots interpolated with to-be-remembered dots affected performance over most serial positions (Experiment 1) but that effect was significantly reduced when the interpolated dots were distinct from the to-be-remembered dots by colour and shape (Experiment 2). Parallels are made between verbal and spatial serial memory, and the reduction of the sandwich effect is discussed in terms of the contribution of perceptual organisation and attentional factors in short-term memory.     

Conscious recollection in autobiographical memory: an investigation in schizophrenia

Whether or not conscious recollection in autobiographical memory is affected in schizophrenia is unknown. The aim of this study was to address this issue using an experiential approach. An autobiographical memory enquiry was used in combination with the Remember/Know procedure. Twenty-two patients with schizophrenia and 22 normal subjects were asked to recall specific autobiographical memories from four lifetime periods and to indicate the subjective states of awareness associated with the recall of what happened, when and where. They gave Remember, Know or Guess responses according to whether they recalled these aspects of the event on the basis of conscious recollection, simply knowing, or guessing. Results showed that the frequency and consistency of Remember responses was significantly lower in patients than in comparison subjects. In contrast, the frequency of Know responses was not significantly different, whereas the frequency of patients' Guess responses was significantly enhanced. It is concluded that the frequency and consistency of conscious recollection in autobiographical memory is reduced in patients with schizophrenia.