Changes in repeated references: Collaboration or repetition effects?

According to the Clark & Wilkes-Gibbs' collaborative model of reference, the repetition of a referential communication task produces changes in the making of references (decreasing number of words and of turns with the passing trials, increasing number of definite references and of labels), and these changes are interpreted as revealing the outgrowth of a collaborative process aiming at mutual understanding at the lowest cost. Using a repeated referential paradigm but without any physically present interlocutor, the present study aimed at answering the question of whether these changes are attributable to the mere repetition of the referential task. In adifferent addressee (DA) condition, the subjects were told before each new trial that what they would say would be presented later to another person; in asame addressee 9SA) condition, the subjects were told before each new trial that what they would say would be presented to the same person. With the passing trials, the subjects in the DA condition produced more and more words, but did not use any definite references or labels: These observations have no common point with the ones obtained within a conversational framework. The data obtained from speakers in the SA condition were only slightly different and far from being close to the ones gained in referential dialogues: The number of words remains constant, there was only a slight increase of definite references, and there were no labels. Repetition itself clearly cannot account for the changes in referring that have been reported in recent studies of how subjects cooperate in the making of references.This research was partly supported by a project grant from the National Fund for Scientific Research (Belgium) to Y. Chantraine, research assistant at the University of Louvain in Belgium.     

Phonological processing of words in right- and left-handers

It is commonly accepted that phonology is the exclusive domain of the left hemisphere. However, this pattern of lateralization, which posits a right visual field advantage, has been questioned by several studies. In fact, certain factors such as characteristics of the stimuli and subjects' handedness can modulate the right visual field advantage. Thus, the goal of this study was to compare the hemispheric dynamics of right-handers and left-handers during a divided visual field presentation of words that varied in terms of their phonological transparency. For non-transparent words, the left hemisphere seems more competent in both handedness groups. With regard to transparent words, the right hemisphere of both groups also appears competent. Surprisingly, left-handers achieved optimal processing with a functionally isolated left hemisphere, whereas right-handers needed the participation of both hemispheres. The pattern of performance cannot be fully explained by either the callosal or the direct access model.     

Neurofunctional (re)organization underlying narrative discourse processing in aging: evidence from fNIRS

Relatively few studies have analyzed the mechanisms underlying the cognitive changes that affect language in the elderly, and fewer have done so for narrative discourse. The goal of this study was to explore the neurofunctional changes associated with aging for different components of narrative discourse. Functional near-infrared spectroscopy (fNIRS) and behavioral data on 10 younger adults and 10 healthy elderly participants were collected. Ten younger adults in a non-proficient second language condition were included to explore the possibility that the age-related neurofunctional reorganization partly expresses demanding resource allocation. Results show within- and across-hemispheric differences in the neurofunctional pattern of activation in the older participants with reference to the younger ones, partially shared with the low-proficiency young adults, providing support for the recognized mechanisms underlying neural reserve and compensation. fNIRS was shown to be appropriate for studying the age-related neurofunctional reorganization of complex cognitive abilities.     

Confirming the three-factor structure of the quality of relationships inventory within couples

The current study further validates the Quality of Relationships Inventory (QRI; G. R. Pierce, I. G. Sarason, & B. R. Sarason, 1991) by evaluating its factor structure in a sample of 572 partners from 286 couples. Confirmatory factor analysis was used to compare 3 different models of the QRI and to investigate the invariance of the factor structure of the QRI across gender and across relationship satisfaction. Analyses revealed that a 3-factor solution--consisting of 3 different but interrelated factors (a 7-item support factor, a 12-item conflict factor, and a 6-item depth factor)--best accounted for the data. The authors' findings suggest that full metric invariance holds across gender and across relationship satisfaction in the female subsample, whereas only partial metric invariance could be established for relationship satisfaction in the male subsample.     

GPS analysis of human locomotion: further evidence for long-range correlations in stride-to-stride fluctuations of gait parameters

During free walking, gait is automatically adjusted to provide optimal mechanical output and minimal energy expenditure; gait parameters, such as cadence, fluctuate from one stride to the next around average values. It was described that this fluctuation exhibited long-range correlations and fractal-like patterns. In addition, it was suggested that these long-range correlations disappeared if the participant followed the beep of metronome to regulate his or her pace. Until now, these fractal fluctuations were only observed for stride interval, because no technique existed to adequately analyze an extended time of free walking. The aim of the present study was to measure walking speed (WS), step frequency (SF) and step length (SL) with high accuracy (<1 cm) satellite positioning method (global positioning system or GPS) in order to detect long-range correlations in the stride-to-stride fluctuations. Eight participants walked 30 min under free and constrained (metronome) conditions. Under free walking conditions, DFA (detrended fluctuation analysis) and surrogate data tests showed that the fluctuation of WS, SL and SF exhibited a fractal pattern (i.e., scaling exponent alpha: 0.5 < alpha < 1) in a large majority of participants (7/8). Under constrained conditions (metronome), SF fluctuations became significantly anti-correlated (alpha < 0.5) in all participants. However, the scaling exponent of SL and WS was not modified. We conclude that, when the walking pace is controlled by an auditory signal, the feedback loop between the planned movement (at supraspinal level) and the sensory inputs induces a continual shifting of SF around the mean (persistent anti-correlation), but with no effect on the fluctuation dynamics of the other parameters (SL, WS).     

Cerebral hemispheres and selective attention

The present paper is intended to discuss critically the integration model of the functional interhemispheric relation that has become dominant in neuropsychology with the development, in the last two decades, of split-brain studies.While the split-brain research has undoubtedly produced new experimental methodologies, the current theorizing in this area has been contrastingly conservative. The present paper examines some of its basic assumptions, in particular that the corpus callosum is an association pathway devoted to interhemispheric transmission of information, and that the disconnected cerebral hemispheres function in a parallel way. It is shown that these assumptions have only low consistency both with split-brain behavior and with the normal organization of the fore-brain connectivity.In the early seventies, theoretical novelty has emerged from another research field with Kinsbourne's interpretation of laterality effects in normal man. His concept of asymmetrical hemispheric arousal is shown to be supported, with some reservations, by evidence in this field. But this dynamical concept has a more general value and there are signs that current ideas about the functional relation between the cerebral hemispheres are presently deeply transformed.