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Biomedical subjects

H A Ruff

Publications and source records attributed to H A Ruff.

27 records · Page 2Linked to original sources
PubMed1984

Preterm infants' manipulative exploration of objects.

Because manipulative exploration of objects may be important to the infant's perception and conceptualization of objects, this study compared full-term infants with preterm infants who are considered to be at risk for cognitive deficits. 30 preterms at 9 months, with age corrected for prematurity, and 20 9-month-old full-terms were videotaped while they explored novel objects; the videotapes were scored for behaviors such as looking, handling, mouthing, turning the object around, fingering, transferring from hand to hand, and banging. There were no differences between the preterms and the full-terms. A "low-risk" subgroup and a "high-risk" subgroup of preterms were then compared with each other as well as to the full-terms. The low-risk subgroup was essentially the same as the full-terms. The high-risk preterms, however, fingered, rotated, and transferred the objects less than either the full-terms or the low-risk preterms. There was a relationship between manipulative exploration at 9 months and later cognitive functioning, suggesting that lower levels of manipulation may be one way in which cognitive deficits originate or are maintained.

Child, Preschool↗
PubMed1980

The development of perception and recognition of objects.

In this paper it is argued that the development of object perception in infancy involves the detection of structural invariants. Such detection is best understood in the context of dynamic events. Therefore, the role of continuous optical transformations in the infant's learning is emphasized. The effects of object motion and the infant's own activity are discussed in detail.

Child Development↗
PubMed1979

Changing role of stimulus intensity as a determinant of infants' attention.

When pairs of stimuli which varied in size or brightness and in pattern were presented to 6-, 9- and 24-wk.-olds, the visual attention of the younger infants appeared to be more influenced by size or brightness than by pattern, while the opposite was the case for the oldest infants. The results of another study suggested that the effects of size and brightness were additive for 9-wk.-olds. Finally, a third study using a subject-control procedure with successive stimulus presentation yielded results which were essentially the same as those of the first study. The results were interpreted as supporting the hypothesis that amount of stimulation is a major determinant of attention in the first 2 mo. and that its effectiveness decreases with age.

Attention↗
PubMed1978

Infant recognition of the invariant form of objects.

The developing ability to abstract and recognize the invariant form of an object was studied in 6- to 9-month-old infants. It was found that 9-month-olds were capable of recognizing the invariant form of objects. They demonstrated this ability by differentiating a variation of a familiarized object from a configurationally novel object after a period of familiarization involving other variations of the familiar object. The forms of some objects were more difficult to recognize than others, but recognition of the more difficult forms was enhanced by allowing simultaneous comparison of variations during familiarization. 6-month-olds, on the other hand, did not demonstrate recognition of the invariant form of the experimental objects.

Child Development↗
PubMed1976

Developmental changes in the infants attention to pattern detail.

To assess developmental changes in the importance of stimulus intensity and pattern detail for infants' visual attention, infants of 10, 17, and 25 wk. of age were shown pairs of stimuli equated for stimulus intensity but different in pattern detail (angles or straight lines). The youngest infants gave equivalent amounts of attention to the stimuli of each pair while the two older groups showed a significant preference for the angular stimuli. The results are interpreted as showing the increased attention to elements with development, and a possible explanation of the preference for the angle stimuli is discussed.

Age Factors↗
PubMed1976

The coordination of manipulation and visual fixation: a response to Schaffer (1975).

The present study was conducted to clarify the issues raised by Schaffer and Rubenstein about perceptual-motor integration in 6-month-old infants. The visual and motor responses to novel and familiar stimuli were measured in 12 6-month-old infants, using new measures of integration and concordance. The results indicate that the infants' responses to the stimuli were both integrated and concordant. Schaffer's conclusions, which are based on studies that show changes from 6 to 9 months of age, are discussed in light of the findings of the present study.

Child Development↗
PubMed1975

The function of shifting fixations in the visual perception of infants.

The processes underlying infants' shifts of fixation from 1 stimulus to another were explored in 3 studies. The results suggest that infants 3 months and older shift more when the 2 stimuli of a pair are similar than when they are different. Shifting is affected by stimulus repetition as well. There were age differences in the number of shifts per trial, with older infants shifting more. The possibility that shifting may facilitate stimulus recognition is discussed.

Age Factors↗