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

Abstract

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.

Eye contrast polarity is critical for face recognition by infants

“…Dannemiller and Stephens (1988) and Mondloch et al (1999) consistently reported that 12 week olds, but not 6 weeks olds or newborns, preferred schematic faces with positive contrast polarity over contrast reversed versions of the same stimuli. In addition, and again consistent with Farroni et al (2005), Otsuka, Hill, Kanazawa, Yamaguchi, and Spehar (2012) reported that a preference for upright over upside-down two-tone facial images disappeared when the contrast polarity of the stimuli was reversed. The disappearance of an upright face preference for contrast reversed stimuli suggests that the "faceness" of the facial images may be lost when contrast polarity is reversed.…”

The effect of contrast polarity reversal on face detection: Evidence of perceptual asymmetry from sweep VEP

“…This observation is supported by developmental studies showing that contrast polarity is essential for face detection in newborns (Farroni et al, 2005) and older infants (Otsuka et al, 2012). From a neurofunctional point of view, in adults, there is an increased latency and amplitude of the face-sensitive N170 ERP component (Bentin et al, 1996;Rossion & Jacques, 2011 for a review) to negative polarity faces (Itier & Taylor, 2002;Tomalski & Johnson, 2012).…”

“…Although one can argue that only a limited number of object categories have been tested, the consistency of the contrast polarity effect with a wide variety of ''face'' stimuli points towards specificity. More specifically, the deleterious effect of contrast negation has been demonstrated with realistic faces of different degrees of familiarity (unfamiliar, e.g., Liu et al, 1999; famous, e.g., Gilad, Meng, & Sinha, 2008; personally familiar, e.g., Bruce & Langton, 1994; experimentally familiarised, e.g., Galper, 1970) to simplified two-tone faces (i.e., Mooney faces, George et al, 1999;Otsuka et al, 2012;Phillips, Jenkins, & Morris, 1972) and even schematic stimuli arranged in a crude face-like configuration (i.e., two eyes and a mouth, Tomalski et al, 2009;Farroni et al, 2005). Both infant preference (Farroni et al, 2005;Otsuka et al, 2012) and monkey neurophysiology (Ohayon et al, 2012) show that positive contrast polarity is essential to elicit a preferential response for face/facelike stimuli.…”

“…typically darker than the skin). However, studies that have applied contrast negation to face pictures have typically used Caucasian (i.e., white skin) faces, so that contrast negation reduced the overall luminance of the stimulus (Bruce & Langton, 1994;Galper, 1970;Nasr & Tootell, 2012;Itier & Taylor, 2002;Ohayon et al, 2012;Farroni et al, 2005;Itier, Latinus, & Taylor, 2006;Nederhouser et al, 2007;Otsuka et al, 2012;Russell et al, 2006;Vuong et al, 2005;Yue et al, 2013). Hence, the representation of positive and negative contrast faces is not directly comparable in the vast majority of studies (with the exception of the a few studies that controlled for luminance: George et al, 1999;Liu et al, 1999;Tomalski & Johnson, 2012).…”

Infants’ discrimination of shapes from shading and cast shadows

“…According to this requirement, when the contrast polarity of the shadows and nonshadows is reversed, the perception of the shadows should collapse, and, consequently, the 3-D information should also collapse. In the domain of face perception, Otsuka, Hill, Kanazawa, Yamaguchi, and Spehar (2012) showed effects of contrast polarity on infants' perception. They found that 3-to 4-month-old infants preferred to view an upright two-tone face rather than an inverted two-tone face.…”