Age Differences in the Magnitude of the Attentional Blink

When people attend to a target in a rapid sequence of items, their perception of a subsequent target is impaired for about 500 ms. This is termed the attentional blink. In the present experiment, a dual task rapid serial presentation task (Raymond, Shapiro & Arnell, 1992) was used as a measure of inhibitory function of younger and older adults. We found that the attentional blink was larger among older adults as compared to younger adults, supporting Hasher and Zacks' (1988) inhibitory deficit hypothesis and current models of the attentional blink.     

Sex Differences in Cognition are Stable Over a 10-Year Period in Adulthood and Old Age

ABSTRACT

Sex differences in declarative memory and visuospatial ability are robust in cross-sectional studies. The present longitudinal study examined whether sex differences in cognition were present over a 10-year period, and whether age modified the magnitude of sex differences. Tests assessing episodic and semantic memory, and visuospatial ability were administered to 625 nondemented adults (initially aged 35–80 years), participating in the population-based Betula study at two follow-up occasions. There was stability of sex differences across five age groups and over a 10-year period. Women performed at a higher level than men on episodic recall, face and verbal recognition, and semantic fluency, whereas men performed better than women on a task-assessing, visuospatial ability. Sex differences in cognitive functions are stable over a 10-year period and from 35 to 90 years of age.     

A PET meta‐analysis of object and spatial mental imagery

Neuroimaging studies have described the functional neuroanatomy of mental imagery. Taken separately, specific studies vary in the nature of the task used and are limited by statistical power and sensitivity. We took advantage of a multistudy PET database of 54 subjects acquired in our laboratory to reveal the neural bases of spatial versus object mental imagery tasks. Our first goal was to evaluate to what extent the activated foci elicited by both object and spatial studies overlap. A second aim was to compare activations elicited by spatial imagery tasks to those elicited by object imagery tasks. We also explored applying regression analyses to the relationships between the scores on the Mental Rotations Test (MRT) and changes in regional cerebral blood flow (rCBF) during spatial and object imagery tasks. This meta‐analysis yielded the following observations: (1) both spatial and object imagery tasks shared a common neural network composed of occipitotemporal (ventral pathway) and occipitoparietal (dorsal pathway) regions and also by a set of frontal regions (related to memory); (2) the superior parietal cortex was more strongly implicated during spatial imagery; (3) object imagery specifically engaged the anterior part of the ventral pathway, including the fusiform, parahippocampal, and hippocampal gyrus; (4) object imagery activated the early visual cortex, whereas spatial imagery induced a deactivation of the early visual cortex; (5) blood flow values in some of the regions noted above were positively correlated with scores on the MRT: the higher the subjects performed on the MRT, the more pronounced the rCBF was in these regions. These results may reconcile some of the apparent discrepancies among previous studies concerning the activation of early visual cortex in mental imagery. They also contribute to a better knowledge of the neural bases of object and spatial mental imagery.     

Invited Address at the Occasion of the Bertelson Award 2005 Impairments in visual discrimination in amnesia: Implications for theories of the role of medial temporal lobe regions in human memory

A prominent and long-standing view of human long-term memory is that structures within the medial temporal lobe (MTL) work together to support the acquisition of memory for facts and events. In contrast to this view, recent studies in rats and non-human primates suggest dissociations in function between regions comprising the MTL. Evidence in support of such specialisation in humans, however, has been inconclusive, leading some researchers to propose that human MTL functions as a unitary system uniquely specialised for the acquisition and storage of long-term memory. This paper reviews some of the key studies from the animal and human literature that support an account of functional differentiation and discusses the different theoretical positions that have emerged from their findings. A series of recent experiments in humans designed to determine whether there is functional homogeneity in MTL regions across species are also reviewed and an alternative account of human memory—in which long-term memory is dependent upon representations distributed throughout the human brain rather than one specialised system—is proposed.     

Influence analysis of structural equation models with polytomous variables

The estimation of model parameters in structural equation models with polytomous variables can be handled by several computationally efficient procedures. However, sensitivity or influence analysis of the model is not well studied. We demonstrate that the existing influence analysis methods for contingency tables or for normal theory structural equation models cannot be applied directly to structural equation models with polytomous variables; and we develop appropriate procedures based on the local influence approach of Cook (1986). The proposed procedures are computationally efficient, the necessary bits of the proposed diagnostic measures are readily available following an usual fit of the model. We consider the influence of an individual cell frequency with respect to three cases: when all parameters in an unstructured model are of interest, when the unstructured polychoric correlations are of interest, and when the structural parameters are of interest. We also consider the sensitivity of the parameters estimates. Two examples based on real data are presented for illustration.The work described in this paper was partially supported by a Chinese University of Hong Kong Postdoctoral Fellows Scheme and a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (RGC Ref. No. CUHK4186/98P). We are indebted to P.M. Bentler and M.D. Newcomb for providing the data set, Michael Leung for his assistance, and the Editor and the referees for some very valuable comments.     

Parents' structuring of children's daily lives in relation to the quality and stability of children's friendships

This study focused on the implications of parents' structuring of their children's home lives for the friendships of their children. Participants were 224 elementary‐school children (108 girls and 116 boys) from four grade levels in two schools in Aix‐en‐Provence, France. Most of the families were of middle or high socio‐economic status. The participating children were seen twice during the same school year in order to assess the stability of their friendship choices and the quality of their friendships. We used Lautrey's (1989) questionnaire in order to assess the parents' styles in the structuring of family life and related child‐rearing practice. This questionnaire delineates three structuring styles: 1) rigid, characterized by considerable imposition of routines with little leeway for exceptional circumstances; 2) flexible, in which established routines can be modified as circumstances dictate; and 3) laissez‐faire, characterized by an absence of predictability and routine. We measured friendship quality by means of Friendship Quality Scale developed by Bukowski, Hoza, and Boivin (1989). This scale consists of 23 items representing five dimensions: companionship, help, security, closeness and conflict. This tool was designed to elicit children's perceptions of a specific relationship with a friend. Results indicated a significant link between parenting style and both of the dimensions of child friendship we studied. Children from homes characterized by a laissez‐faire style of parenting have friendships with more positive features than children from homes with flexible or rigid styles. We also found that friendships were generally less stable and rated as less positive than in similar studies conducted in other countries.     

Attentional distraction and time perception in children

The purpose of the present study was to test the effect of attentional distraction on temporal bisection performance in 5‐ and 8‐year‐old children. During a first learning phase, children were trained to discriminate on a temporal bisection task a short standard duration (2 sec) from a long one (8 sec), presented as visual stimuli. Later, in a second testing phase, intermediate durations (3, 4, 5, 6, 7 s), including the standard durations, were presented. Children's task still was to report if it was a short standard duration or a long one. In addition, during the non‐standard duration, a distracter either did or did not appear. Results showed increasing proportions of “it is the long standard duration” (response “long”) with increasing stimulus durations in both distracter and non‐distracter conditions. However, psychophysical functions were flatter in the 5‐year‐olds than in the 8‐year‐olds, revealing their lower sensibility to time. Nevertheless, the 5‐year‐olds' proportion of long responses was higher under the distracter than in the non‐distracter condition. Consequently, the point of subjective equality (PSE), corresponding to the stimulus duration to which the subject produced 50% of responses of “long” was lower under the distracter condition as compared to the non‐distracter condition. Conversely, for the 8‐year‐olds, the PSE was significantly higher in the distracter than in the non‐distracter condition. Five‐year old children overestimated the time in the presence of an attentional distracter, whereas 8‐year olds tended to underestimate it. The leftward shift and the rightward shift of the PSE in the 5‐ and the 8‐year‐olds, respectively, were accounted for by limited‐capacity attention in the five‐year olds.     

Early locus of a linguistic variable in a fast priming task

The syllable and the morpheme are known to be important linguistic variables, but is such information involved in the early stages of word recognition? Syllable‐morpheme information was manipulated in the early stage of word naming by means of the fast priming paradigm. The letters in the prime were printed in a mixture of lower‐ and upper‐case letters. The change from lower to upper case occurred either at a syllable‐morpheme boundary, before the boundary, or after it (e.g., reTAKE, rETAKE, or retAKE) creating either an intact pair or a broken one. The target was always in lower case (e.g., retake). The results of Experiments 1 and 2 revealed that intact syllable and morpheme information facilitated word naming at a short Stimulus Onset Asynchrony (below awareness) but not at a long SOA, suggesting that the use of such information is automatic. A second set of experiments attempted to determine if syllable information alone could facilitate word processing. In Experiments 3 and 4, monomorphemic words were divided either at, before, or after the syllable boundary (e.g., rePEL, rEPEL, or repEL). The primes were all pseudomorphemic in the sense that the initial syllables could appear as a morpheme in other words (e.g., restate) but were not morphemic in the target words (e.g., repel). The second syllable was neither morphemic nor pseudomorphemic. Using the same SOAs as in Experiments 1 and 2, intact syllables were found to be facilitative at the short SOA, but not at the long SOA. Thus, the syllable plays a role in an early stage of word recognition. Whether morphemes that are not syllables are facilitative is still to be determined in this paradigm.     

The Role of Prototypical Situations in the Perceptions of Prejudice of African Americans1

Inman and Baron (1996) found that African Americans and Whites possess prototypes for racist behavior that involve Whites oppressing African Americans. However, prototypical content may be more detailed and specific for African Americans because of differing cultural experiences. In the present experiment, undergraduates read stories about interpersonal encounters representing prototypical and nonprototypical situations. Actor race ambiguity was manipulated by the presence or absence of photographs. As expected, Whites tended to make equal ratings of prejudiced behavior for prototypical and nonprototypical situations. However, African Americans perceived more prejudice in prototypical vignettes than in nonprototypical vignettes. They also perceived stronger prejudicial displays and more dispositional motivation for targets in prototypical vignettes. The results suggest that African Americans have heightened sensitivity to prejudice in specific situations, a factor that may contribute to racial confrontations and misunderstandings.