Infants aren't biased toward fearful faces.

Grossmann's argument for the "fearful ape hypothesis" rests on an incomplete review of infant responses to emotional faces. An alternate interpretation of the literature argues the opposite, that an early preference for happy faces predicts cooperative learning. Questions remain as to whether infants can interpret affect from faces, limiting the conclusion that any "fear bias" means the infant is fearful.

Valence, arousal, and dominance ratings for facial stimuli.

A total of 1,363 images from seven sets of facial stimuli were normed using the self-assessment manikin procedure. Each participant provided valence, arousal, and dominance ratings for 120-130 faces displaying various emotional expressions (e.g., happiness, sadness). The current work provides a large database of normed ratings for facial stimuli that complements the existing International Affective Picture System and the Affective Norms for English Words that were developed to provide a normative set of emotional ratings for photographs and words, respectively. This new database will increase experimental control in studies examining the perception, processing, and identification of emotional faces.

The effect of vertical and horizontal symmetry on memory for tactile patterns in late blind individuals.

Visual stimuli that exhibit vertical symmetry are easier to remember than stimuli symmetric along other axes, an advantage that extends to the haptic modality as well. Critically, the vertical symmetry memory advantage has not been found in early blind individuals, despite their overall superior memory, as compared with sighted individuals, and the presence of an overall advantage for identifying symmetric over asymmetric patterns. The absence of the vertical axis memory advantage in the early blind may depend on their total lack of visual experience or on the effect of prolonged visual deprivation. To disentangle this issue, in this study, we measured the ability of late blind individuals to remember tactile spatial patterns that were either vertically or horizontally symmetric or asymmetric. Late blind participants showed better memory performance for symmetric patterns. An additional advantage for the vertical axis of symmetry over the horizontal one was reported, but only for patterns presented in the frontal plane. In the horizontal plane, no difference was observed between vertical and horizontal symmetric patterns, due to the latter being recalled particularly well. These results are discussed in terms of the influence of the spatial reference frame adopted during exploration. Overall, our data suggest that prior visual experience is sufficient to drive the vertical symmetry memory advantage, at least when an external reference frame based on geocentric cues (i.e., gravity) is adopted.

Event-related potentials (ERPs) to schematic faces in adults and children.

Event-related potentials (ERPs) were recorded from 4-year-old 8-10-year-old children and adults to a schematic face, inverted face and jumbled face. The subjects were instructed to fixate the stimuli and no other response was required. The schematic face and inverted face were shown with a frequency of 20% each and the remaining presentations (60%) were of the jumbled face. P1 and N170 peak latency were measurable in the children and adults. These peaks were at longer latencies in the children. P3 was measurable in the adults and 8-10-year-old children but not the 4-year-olds. The adults had larger and longer latency P1 and smaller amplitude N170 to the inverted face than the other faces. In contrast, the P1 was unaffected by inversion in the children and the N170 was not smaller to the inverted or jumbled face. It is concluded that this result reflects developmental differences in the processing of configuration, with the children relying on an under-specified configuration of the face.

Aging and bilateral symmetry detection.

The salience of bilateral symmetry varies as a function of the orientation of the symmetry axis. Vertical symmetry is most salient, followed by horizontal and then oblique orientations. We tested symmetry detection in different age groups to determine whether performance of this intermediate-level visual task is affected by normal, nonpathological aging. We tested forty participants and analyzed the results with respect to age group and symmetry orientation (vertical, horizontal, and 45 degree oblique). There was a vertical symmetry detection advantage for all participants, where sensitivity was highest for vertical symmetry, followed by horizontal symmetry, and then the oblique symmetry. Sensitivity to symmetry did not differ for the two younger age groups (aged 19-39 and 40-60), but declined significantly for the group aged 61-70, and declined again for the oldest group aged 71-80. This age-related difference in sensitivity to symmetry was not reflected in a measure of bias, where there were no differences as a function of age.