Perception of Mooney faces by young infants: the role of local feature visibility, contrast polarity, and motion.

We examined the ability of young infants (3- and 4-month-olds) to detect faces in the two-tone images often referred to as Mooney faces. In Experiment 1, this performance was examined in conditions of high and low visibility of local features and with either the presence or absence of the outer head contour. We found that regardless of the presence of the outer head contour, infants preferred upright over inverted two-tone face images only when local features were highly visible (Experiment 1a). We showed that this upright preference disappeared when the contrast polarity of two-tone images was reversed (Experiment 1b), reflecting operation of face-specific mechanisms. In Experiment 2, we investigated whether motion affects infants' perception of faces in Mooney faces. We found that when the faces appeared to be rigidly moving, infants did show an upright preference in conditions of low visibility of local features (Experiment 2a). Again the preference disappeared when the contrast polarity of the image was reversed (Experiment 2b). Together, these results suggest that young infants have the ability to integrate fragmented image features to perceive faces from two-tone face images, especially if they are moving. This suggests that an interaction between motion and form rather than a purely motion-based process (e.g., structure from motion) facilitates infants' perception of faces in ambiguous two-tone images.

Range- and domain-specific exaggeration of facial speech.

Is it possible to exaggerate the different ways in which people talk, just as we can caricature their faces? In this paper, we exaggerate animated facial movement to investigate how the emotional manner of speech is conveyed. Range-specific exaggerations selectively emphasized emotional manner whereas domain-specific exaggerations of differences in duration did not. Range-specific exaggeration relative to a time-locked average was more effective than absolute exaggeration of differences from the static, neutral face, despite smaller absolute differences in movement. Thus, exaggeration is most effective when the average used captures shared properties, allowing task-relevant differences to be selectively amplified. Playing the stimuli backwards showed that the effects of exaggeration were temporally reversible, although emotion-consistent ratings for stimuli played forwards were higher overall. Comparison with silent video showed that these stimuli also conveyed the intended emotional manner, that the relative rating of animations depends on the emotion, and that exaggerated animations were always rated at least as highly as video. Explanations in terms of key frame encoding and muscle-based models of facial movement are considered, as are possible methods for capturing timing-based cues.