Magnitude comparison in preschoolers: what counts? Influence of perceptual variables

This study examined numerosity comparison in 3-year-old children. Predictions derived from the analog numerical model and the object-file model were contrasted by testing the effects of size and ratio between numerosities to be compared. Different perceptual controls were also introduced to evaluate the hypothesis that comparison by preschoolers is based on correlated perceptual variables rather than on number per se. Finally, the relation between comparison performance and verbal counting knowledge was investigated. Results showed no evidence that preschoolers use an analog number magnitude or an object-file mechanism to compare numerosities. Rather, their inability to compare sets controlled for surface area suggests that they rely on perceptual cues. Furthermore, the development of numerosity-based representations seems to be related to some understanding of the cardinality concept.     

Which processes are involved in cognitive procedural learning?

Procedural memory is characterised by a relative resistance to pathology, making its assessment of the utmost importance. However, few studies have looked at the cognitive processes involved in cognitive procedural learning. In an initial experiment, we studied the role of different cognitive functions in massed cognitive procedural learning. Our results confirmed the existence of three separate learning phases and, for the first time, demonstrated the involvement of episodic memory and executive functions in the first learning phase. In a second experiment, we studied the effect of distributed learning conditions on the dynamics of procedural learning. This second study confirmed our results but showed that these conditions slow down the process of cognitive procedural learning. Our overall findings call into question the status of functionally autonomous memory system that is currently allotted to procedural memory, and suggest that the role of nonprocedural cognitive components should be taken into account in patient rehabilitation.     

Prevalence of bulimic behaviors and trends in eating attitudes among Turkish late adolescents

The eating attitudes and the prevalence of bulimic behaviors in a group of 300 late adolescents were investigated using the key questions from the Bulimia Investigatory Test, Edinburgh (BITE), and additional questions. Only four subjects (1.3%) scored above the cut-off point on the BITE, and prevalence rates of males and females were the same. Results showed that higher symptom scale scores were associated with the emergence of binge eating behavior and high energy intake. Females were less likely than males to see themselves as normal eaters and more likely to feel "miserable" when they binge. Higher score groups evidenced more dieting behavior than other groups and also more abnormal eating behavior. It was concluded that the prevalence of bulimic behaviors in Turkish late adolescents was low, but there was an increasing risk since they share Western ideals of slimness and engage in dieting.     

The relative deprivation-gratification continuum and the attitudes of South Africans toward immigrants: a test of the V-curve hypothesis

It has long been established that there is a linear and positive relationship between relative deprivation and prejudice. However, a recent experiment suggests that the converse of relative deprivation, relative gratification, may also be associated with prejudice (S. Guimond & M. Dambrun, 2002). Specifically, the evidence suggests that the usual test for a linear relationship between relative deprivation-gratification and prejudice might conceal the existence of a bilinear relationship. This function, labeled the V-curve hypothesis, predicts that both relative deprivation and relative gratification are associated with higher levels of prejudice. This hypothesis was tested with a representative sample of South Africans (N=1,600). Results provide strong support for the V-curve hypothesis. Furthermore, strength of ethnic identification emerged as a partial mediator for the effect of relative gratification on prejudice.     

Multistable syllables as enacted percepts: a source of an asymmetric bias in the verbal transformation effect

Perceptual changes are experienced during rapid and continuous repetition of a speech form, leading to an auditory illusion known as the verbal transformation effect. Although verbal transformations are considered to reflect mainly the perceptual organization and interpretation of speech, the present study was designed to test whether or not speech production constraints may participate in the emergence of verbal representations. With this goal in mind, we examined whether variations in the articulatory cohesion of repeated nonsense words--specifically, temporal relationships between articulatory events--could lead to perceptual asymmetries in verbal transformations. The first experiment displayed variations in timing relations between two consonantal gestures embedded in various nonsense syllables in a repetitive speech production task. In the second experiment, French participants repeatedly uttered these syllables while searching for verbal transformation. Syllable transformation frequencies followed the temporal clustering between consonantal gestures: The more synchronized the gestures, the more stable and attractive the syllable. In the third experiment, which involved a covert repetition mode, the pattern was maintained without external speech movements. However, when a purely perceptual condition was used in a fourth experiment, the previously observed perceptual asymmetries of verbal transformations disappeared. These experiments demonstrate the existence of an asymmetric bias in the verbal transformation effect linked to articulatory control constraints. The persistence of this effect from an overt to a covert repetition procedure provides evidence that articulatory stability constraints originating from the action system may be involved in auditory imagery. The absence of the asymmetric bias during a purely auditory procedure rules out perceptual mechanisms as a possible explanation of the observed asymmetries.     

The effect of timing of a perturbation on the execution of a lifting movement

Anticipation to the mass magnitude is important in lifting, but underestimation of a mass, in contrast to overestimation, does not cause major movement disturbances. This may be caused by corrections in muscle activity before the object is actually lifted. This study was designed to assess the importance of these corrections during the loading phase for the execution of a lifting movement when the mass is underestimated. Ten subjects lifted a box (1.6 kg), of which the mass was increased by 10 kg without them knowing so. The mass was added either before the box had been lifted from the ground (perturbation before lift-off, PBL) or right perturbation after lift-off (PAL). In the PBL condition back muscle activity was increased before lift-off. Even though this early corrective response could obviously not occur in the PAL condition, the lifting movement was executed without clear problems. In sum, corrections in muscle activity before lift-off are not necessary for adequate correction of a perturbation induced by an unexpected heavier object.     

Fear of storms and hurricanes in Antillean and Belgian children

The present study assessed fear of hurricanes in children who had been confronted with this natural event (i.e., Antillean children, n=161). Their fear levels were compared to those of children who are unfamiliar with such an event (i.e., Belgian children, n=185). Antillean children reported significantly higher levels of fear of storms than Belgian children did, thus providing support for the notion that exposure to dangerous events promotes children's fears of those events. Surprisingly, however, Antillean children had lower scores on the 'Hurricanes' item than Belgian children. Plausibly, differences in how children interpreted this item may have accounted for this unexpected finding. That is, ratings of Antillean children were probably based on actual experiences with hurricanes, whereas scores of Belgian children presumably reflected appraisal of threat in case they would be confronted with such an event. Implications of this finding for the assessment of childhood fears are briefly discussed.     

Dogs' (Canis familiaris) responsiveness to human pointing gestures

In a series of 3 experiments, dogs (Canis familiaris) were presented with variations of the human pointing gesture: gestures with reversed direction of movement, cross-pointing, and different arm extensions. Dogs performed at above chance level if they could see the hand (and index finger) protruding from the human body contour. If these minimum requirements were not accessible, dogs still could rely on the body position of the signaler. The direction of movement of the pointing arm did not influence the performance. In summary, these observations suggest that dogs are able to rely on relatively novel gestural forms of the human communicative pointing gesture and that they are able to comprehend to some extent the referential nature of human pointing.