Processing deficits for familiar and novel faces in patients with left posterior fusiform lesions.
Bottom Line: Identification of famous faces was found to be compromised in both expressive and receptive tasks.Interestingly, discrimination of faces that varied in terms of feature identity was considerably better in these patients and it was performance in this condition that was related to the size of the length effects shown in reading.These results suggest that the sequential part-based processing strategy that promotes the length effect in the reading of these patients also allows them to discriminate between faces on the basis of feature identity, but processing of second-order configural information is most compromised due to their left pFG lesion.
Affiliation: Research Centre in Brain and Behaviour, Liverpool John Moores University, UK.Show MeSH
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Mentions: The stimuli used have been reported elsewhere (Mondloch et al., 2002). To summarise, a grayscale photograph of a single face (called “Jane”) was modified and three sets of face stimuli (feature identity, feature spacing and contour spacing – see Fig. 5) were created to create twelve new versions (“Jane's sisters”). To tap featural processing, four modified faces in the feature-identity set were created by replacing either Jane's eyes, mouth, or both with the features of the same length from different females. Such modifications have insignificant effects on second-order processing because the size and location of individual features remain constant. To tap second-order processing, four modified faces in the feature-spacing set were created by adjusting the spacing between the eyes up or down from the original, the eyes closer together or farther apart, and the mouth up or down. This modification covered variations in spacing among adult female faces in the population, without being so large that the faces appeared malformed or unnatural (Farkas, 1981). The four modified faces in the contour-spacing set were created by adjusting the external contour, pasting the internal portion of the original face within the outer contour of four different females. This modification changes the frame of the face and hence necessarily also the spacing between features and the external contour (e.g., spacing from the bottom of the mouth to the chin contour). Both the feature-spacing and contour-spacing modifications have negligible effects on information about local features. The control “cousin” stimuli consisted of Jane and three different female faces, hence varied on all dimensions. All stimuli were 10.2 cm wide and 15.2 cm high (5.7° × 9.1° from the testing distance of 100 cm).
Affiliation: Research Centre in Brain and Behaviour, Liverpool John Moores University, UK.