Evelin Bertin

Social-cognitive skills between 5 and 10 months of age.

Joint attention skills are an important part of human cultural learning. However, little is known about the emergence and meaning of these skills in early ontogeny. The development of, and relation among, various joint attention skills was assessed. Seventy-two 5 to 10-month-old infants were tested on a variety of joint attention tasks. Intercorrelations among these tasks were sparse, which puts into question the meaning of these various skills. In addition, the majority of infants exhibited some joint attention skill before 9 months of age, which points to a more gradual development of joint attention skills than suggested by previous research.

Discrepancy detection and developmental changes in attentional engagement in infancy

Abstract The processing of discrepancies in visual arrays is fundamental to basic visual processes such as figure-ground segregation and object recognition. In six experiments, we examined this function in 3- and 5.5-month-olds. In Experiment 1, 5.5-month-olds detected a textural discrepancy induced by changes in individual color and shape features but not one induced by changes in relations among these features. These results suggest that, in infancy, as in adulthood, there are differences in the processes that detect featural discrepancies versus those that detect discrepancies in relations among features. Experiments 2, 3A, and 3B suggested that, unlike in the case of 3-month-olds in prior studies, textural and singleton discrepancies in arrays that 5.5-month-olds detect do not hold their attention in the presence of other attention-seeking cues. A comparison of the performance of 3- and 5.5-month-olds in Experiments 4A and 4B confirmed the presence of this developmental change. Altogether, these results indicate that infants’ detection of color and shape textural discrepancies is consistent with models of adult visual processing that posit a preattentive system for processing features and a resource-demanding attentional system for processing relations among features. They also suggest that the ability to disengage attention from a discrepancy and deploy it at another location develops between 3 and 5.5 months of age.

Figural goodness, stimulus heterogeneity, similarity and object segregation in infancy

The segregation of objects from other objects in visual arrays is a fundamental function of our visual system. Research suggests that adults’ detection of a target among nontargets is affected by the heterogeneity of array elements and the resulting changes in target–nontarget and nontarget–nontarget similarities. We examined the effects of heterogeneity and similarity on object segregation in infancy. In Experiment 1, 5.5-month-olds detected a misoriented element in an array when the array elements were spatially arranged in a ‘good’ configuration but not when they were arranged in a ‘poor’ configuration. In Experiment 2, infants detected a vertical line in a homogeneous array of 55° or 125° lines, but failed to do so in a heterogeneous array of 55° and 125° lines. Thus, heterogeneity in both the arrangement and identity of array elements affected infants’ discrepancy detection. Because the average target–nontarget similarity was the same in the two conditions of Experiment 2, the results also indicated that nontarget–nontarget similarity independently affects discrepancy detection in infancy. These results are consistent with models of object segregation by adults, and suggest that stimulus heterogeneity and similarity have analogous effects on object segregation at 5.5 months of age and in adulthood.