2006-06, Bhatt, Ramesh S., Hayden, Angela, Reed, Andrea, Bertin, Evelyn, Joseph, Jane

2004-09, Bertin, Evelyn, Bhatt, Ramesh S.

2001-03, Bertin, Evelyn, Bhatt, Ramesh S.

Many models of object perception posit that adults encode individual features in visual scenes before processing the conjunction relations among these features to generate holistic representations. Prior research suggests that infants detect textural discrepancies based on individual features more readily than those based on feature conjunctions. While these results suggest adult-like qualitative differences in infants' processing of features versus conjunctions, there are potential alternative explanations. We examined three such explanations: (1) failure to process one of the features that constitute the conjunction, (2) failure to encode and remember conjunction information that is necessary to detect conjunction-based textural discrepancies, and (3) the fact that conjunction-based discrepancies involve stimuli that are more similar to original stimuli than those involving feature-based discrepancies. None of these factors could explain 5.5-month-olds' superior processing of featural than conjunction-based textural discrepancies. Thus, in infancy, as in adulthood, features and conjunction relations appear to be processed by qualitatively different mechanisms.

2006-01, Bertin, Evelyn, Bhatt, Ramesh S.

2001-12-21, Bertin, Evelyn, Bhatt, Ramesh S.

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.

2005-01, Bhatt, Ramesh S., Bertin, Evelyn, Hayden, Angela, Reed, Andrea

2001-12, Bhatt, Ramesh S., Bertin, Evelyn

Adults derive 3-D information from 2-D images by initially processing local line junction cues and then combining information from many junctions. Prior research indicates that 3-month-olds are sensitive to 3-D cues in individual line junctions. In Experiment 1, we examined whether infants are sensitive to holistic combinations of line junctions that adults use to derive overall 3-D structure. Infants detected a misoriented shape in an array depicting 3-D blocks but not in 2-D patterns that contained all of the trilinear junctions of the 3-D shapes but without the connecting lines. Thus, like adults, infants exhibited sensitivity to holistic combinations of line junctions rather than to individual junctions. In Experiment 2, when confronted with two test patterns, one containing an individual novel element among 15 familiar elements and the other containing a single familiar element among 15 novel elements, infants preferred to look at the former pattern in the 3-D condition but at the latter pattern in the 2-D condition. Thus, akin to pop-out in adults, discrepancies in 3-D cues selectively engaged infants' attention. These results suggest that 3-month-olds are not only sensitive to holistic combinations of line junctions that adults use to derive 3-D information but also selectively attend to these 3-D cues in static images. s