A visual conflict hypothesis for global-local visual deficits in Williams Syndrome: simulations and data

Individuals with Williams Syndrome demonstrate impairments in visuospatial cognition. This has been ascribed to a local processing bias. More specifically, it has been proposed that the deficit arises from a problem in disengaging attention from local features. We present preliminary data from an integrated empirical and computational exploration of this phenomenon. Using a connectionist model, we first clarify and formalize the proposal that visuospatial deficits arise from an inability to locally disengage. We then introduce two empirical studies using Navon-style stimuli. The first explored sensitivity to local vs. global features in a perception task, evaluating the effect of a manipulation that raised the salience of global organization. Thirteen children with WS exhibited the same sensitivity to this manipulation as CA-matched controls, suggesting no local bias in perception. The second study focused on image reproduction and demonstrated that in contrast to controls, the children with WS were distracted in their drawings by having the target in front of them rather than drawing from memory. We discuss the results in terms of an inability to disengage during the planning stage of reproduction due to over-focusing on local elements of the current visual stimulus

Three-month-olds, but not newborns, prefer own-race faces

Adults are sensitive to the physical differences that define ethnic groups. However, the age at which we become sensitive to ethnic differences is currently unclear. Our study aimed to clarify this by testing newborns and young infants for sensitivity to ethnicity using a visual preference (VP) paradigm. While newborn infants demonstrated no spontaneous preference for faces from either their own- or other-ethnic groups, 3-month-old infants demonstrated a significant preference for faces from their own-ethnic group. These results suggest that preferential selectivity based on ethnic differences is not present in the first days of life, but is learned within the first 3 months of life. The findings imply that adults’ perceptions of ethnic differences are learned and derived from differences in exposure to own- versus other-race faces during early developmen

The Faces in Infant-Perspective Scenes Change over the First Year of Life

Mature face perception has its origins in the face experiences of infants. However, little is known about the basic statistics of faces in early visual environments. We used head cameras to capture and analyze over 72,000 infant-perspective scenes from 22 infants aged 1-11 months as they engaged in daily activities. The frequency of faces in these scenes declined markedly with age: for the youngest infants, faces were present 15 minutes in every waking hour but only 5 minutes for the oldest infants. In general, the available faces were well characterized by three properties: (1) they belonged to relatively few individuals; (2) they were close and visually large; and (3) they presented views showing both eyes. These three properties most strongly characterized the face corpora of our youngest infants and constitute environmental constraints on the early development of the visual system

Effect of partial occlusion on newborns' face preference and recognition

Many studies have shown that newborns prefer (e.g. Goren, Sarty & Wu, 1975; Valenza, Simion, Macchi Cassia & Umilt\ue0, 1996) and recognize (e.g. Bushnell, Say & Mullin, 1989; Pascalis & de Schonen, 1994) faces. However, it is not known whether, at birth, faces are still preferred and recognized when some of their parts are not visible because hindered by other configurations, that is when faces are partly occluded. Also, it is not known whether newborns\u2019 preference for an upright over an inverted face and newborns\u2019 face recognition are differentially affected depending on the salience of the occluded face features. Seventy-seven newborns (mean age of 43.5 hrs) were tested using the preferential looking (Experiment 1) and the habituation techniques (Experiment 2). Results demonstrated that newborns prefer and recognize occluded faces even if some portions of them are not available, at least when the hindered features are not salient. On the contrary, these abilities are affected by obscuring high salience facial features (i.e. eyes). However, while in the case of face detection, eyes occlusion completely prevented newborns\u2019 face detection, in the case of face recognition an analogous stimulus manipulation heavily impaired, but did not totally preclude, newborns\u2019 recognition performance. The data collected improve our comprehension of newborns\u2019 way of processing and encoding information to detect and recognize faces