U-SHAPED DEVELOPMENT IN INFANT COGNITION AND PERCEPTION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Although development is traditionally thought to follow an increasing, monotonic pattern in which infants or children improve with age, closer examination indicates that infants may regress temporarily to a lower level, subsequent to achieving a higher level of performance (Cashon & Cohen, 2003, 2004; Werker, Fennell, Corcoran, & Stager, 2002). In some cases this regression may be permanent (Pascalis, de Haan, & Nelson, 2002). Such regression patterns certainly negate the traditional notion that development only entails steady improvement. Accordingly, since these regressions are not predicted by theories, when they do appear they are usually unexpected and not understood. Given the paucity of information in this area and the critical need for elucidating this process and its consequences for predicting developmental outcomes, our overall GOAL for the proposed research is to investigate the underlying mechanisms involved in U-shaped patterns of development found during infancy. More specifically, we will determine whether such patterns reflect a domain-general, adaptive learning process that allows the infant to become more tailored to his/her environment or whether they reflect changes that are artifacts of the experimental task. When infants display a U-shaped pattern of development, it is often viewed as a result of "reorganization" (Werker & Tees, 1984). We recently argued (Cashon & Cohen, 2003; 2004) that such regressions are necessary as infants adapt to their environment. Infants must incorporate important information en route to becoming "experts" in the world around them. As a result of the reorganization process, however, infants may temporarily regress to a lower level. Two specific aims will address the GOAL of the proposed research, which is to elucidate the underlying mechanisms involved in U-shaped patterns of development during infancy. Both aims will be met by testing infants in a visual habituation task, whereby infants' looking times are measured while they view a series of faces and moving objects. Aim 1 will build upon previous research indicating that infants' face processing follows a U-shaped pattern. Aim 2 will empirically test the prediction that U-shaped development occurs prior to the development of an adaptive constraint. Aim 2 will be achieved by investigating infants' perception of form-function correlations. Aim 1 investigates the bases for the U-shaped pattern of development in infants' processing of faces. In a previous set of studies, we found that between 3 and 7 months of age, infants' processing of faces produces a U-shaped pattern with a drop in performance occurring at approximately 6 months of age (Cashon & Cohen, 2004). We argue this regression is a necessary, but temporary change resulting from overload as infants try to incorporate important information about faces. This notion is consistent with research in other areas of infant cognition and perception showing that when integrating new information infants regress to a lower level of processing (Cohen, Chaput, & Cashon, 2002). Alternatively, the apparent U-shape could be the result of 6-month-olds shifting their attention to focus exclusively on the eyes and eyebrows of a face. Aim 1 will investigate these two alternate hypotheses. It is predicted that 6 month olds will show evidence of overload and not of simply processing the eyes and eyebrows of a face. Aim 2 investigates the bases for U-shaped pattern of development in infants' processing of form-function correlations. Predictions of when U-shaped development will occur are lacking. We argue that U-shaped patterns occur just prior to perceptual of cognitive pruning. Accordingly, we would expect infants to show a U-shaped developmental pattern in their processing of form-function correlations. Previous research by Madole and Cohen (1995) indicates that infants develop an adaptive constraint on their processing these correlations between 14 and 18 months of age. Based on our hypothesis, we predict that a drop in performance occurs between these two ages. More specifically, Madole and Cohen reported finding that 14-month-olds are sensitive to the correlation between the appearance (form) of a feature of an object and its function (within-feature form-function correlation) as well as the form of one feature and the function of another (between-feature form-function correlation). Importantly, they also reported that 18-month-olds are sensitive only to the within-feature form-function correlation. Our specific prediction is that infants at approximately 16 months will regress and show no sensitivity to either correlation.