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Biomedical subjects

S de Schonen

Publications and source records attributed to S de Schonen.

8 recordsLinked to original sources
PubMed1991

Visual field asymmetries for pattern processing are present in infancy. A comment on T. Hatta's study on children's performances.

From a study on 4 to 6 year-old children, Hatta (Hatta, Neuropyschologia 28, 1053-1062, 1990) concludes that (a) a left visual-field advantage develops at age 4 to 5 years in visuo-spatial stimulus recognition, and (b) since both the right visual-field advantage for verbal and the left visual-field advantage for visuo-spatial material develop at the same age, there is no support for the claim that the left and right hemispheres develop differentially. We contest these conclusions on the basis of our own infant studies which have shown a right visual-field advantage in 4 to 9 month-old infants for individual face recognition and more recently, for some aspects of visual patterns.

Child, Preschool↗
PubMed1991

Hemispheric asymmetries in visual pattern processing in infancy.

A right hemisphere advantage was observed in a previous study of 4- to 9-month old infants presented with a face discrimination task (de Schonen & Mathivet, 1990). The present study was designed to investigate pattern processing by the two hemispheres and the interhemispheric communication of this processing. Infants aged 4 to 9 months were tested with divided visual field presentations in one or two discrimination tasks. Under both task conditions, the infants had to discriminate between two patterns in which only two local components differed. Under one condition the components of the patterns were arranged so as to produce a face-like pattern. Under the other condition the same components were arranged into arbitrary patterns that were not "good form" patterns. No performance asymmetry was observed with the arbitrary patterns; whereas, a right hemisphere (RH) disadvantage was observed with the face-like patterns compared with both the RH performances on the arbitary patterns and the left hemisphere (LH) performances on the face-like patterns. These results show that the RH advantage for individual face recognition is not due to a general immaturity or inability of the LH in pattern processing at this period of development, nor to a more specific inability in a local mode of pattern processing. On the other hand, the RH does not completely lack local processing capacity, but is at a disadvantage when this local mode of processing has to be used with face-like (or good form) patterns. The interhemispheric communication of visual discrimination learning was tested by measuring learning transfer between the visual fields. Contrary to de Schonen and Bry's study (1987) on faceness recognition, no data in favor of interhemispheric communication were recorded in the present study.

Attention↗
PubMed1990

Hemispheric asymmetry in a face discrimination task in infants.

A right-hemisphere advantage in a mother's face recognition task in infants aged between 4 and 10 months was found to exist by de Schonen, Gil de Diaz, and Mathivet. The present study was designed to test (a) whether the right-hemisphere advantage would still prevail if the task requirements were different from those in the previous study, and (b) whether any information was communicated from one hemisphere to the other. 18-42-week-old infants were presented with an operant conditioning situation where they had to discriminate between their mother's and a stranger's face within one visual hemifield. Transfer of learning from one visual hemifield to the other was also measured. The results confirm the existence of a right-hemisphere advantage in discriminating between face stimuli. This advantage was weaker in the female than in the male population. No hemispheric transfer of learning was observed to occur.

Arousal↗
PubMed1987

Interhemispheric communication of visual learning: a developmental study in 3-6-month old infants.

Infants aged 12-26 weeks (3-6 months) were presented with a visual category discrimination learning task (normal vs scrambled faces) in the right or left visual field. Once they had reached the learning criterion, they were tested for transfer to the untrained visual field in order to establish whether visual experience can be communicated to the opposite hemisphere. Transfer of learning was found to occur in infants aged 19-26 weeks but not in younger ones. Neural pathways possibly forming the channels for this communication are discussed.

Aging↗
PubMed1986

Self-recognition: a study of a population without mirrors.

The study of the influence of familiarity with mirrors on children's capacity to identify their reflected images permitted differentiation between two problems that confront the child in the mirror situation: (a) the identity of the image and (b) the capacity to relate mirror space to real space. Sixty children, 6 to 26 months old, without previous experience with mirrors, were observed systematically while discovering their mirror image and a reflected object. Their behavior was compared to a control group with habitual mirror familiarity. The results suggest that (a) self-recognition in the mirror is independent of the child's familiarity with reflecting surfaces and (b) the capacity to relate mirror to real space seems to be strongly influenced by previous experience with mirrors.

Affect↗
PubMed1978

Central and peripheral object distances as determinants of the effective visual field in early infancy.

While visually fixating on a central, coloured object, thirty-six infants aged between two and five months were presented with a peripheral target to the right or to the left of midline. Both objects were presented at two distances: either 30 or 90 cm from the infant. The extent of the effective visual field was measured by the presence and the latency of saccadic shifts of gaze from the fixation object toward the target object placed at varying degrees of eccentricity. The effective visual field expanded between two and four months. Near peripheral targets were detected at greater angles of eccentricity than those more distant, but this effect was modified both by age and by the distance of central fixation. For two- and three-month infants the effective visual field was most reduced when the central fixation object was placed at 30 cm and the target object at 90 cm. The ability to respond to peripheral objects more distant than the fixation object develops after three months.

Age Factors↗