Visual motion disambiguation by a subliminal sound

There is growing interest in the effect of sound on visual motion perception. One model involves the illusion created when two identical objects moving towards each other on a two-dimensional visual display can be seen to either bounce off or stream through each other. Previous studies show that the large bias normally seen toward the streaming percept can be modulated by the presentation of an auditory event at the moment of coincidence. However, no reports to date provide sufficient evidence to indicate whether the sound bounce-inducing effect is due to a perceptual binding process or merely to an explicit inference resulting from the transient auditory stimulus resembling a physical collision of two objects. In the present study, we used a novel experimental design in which a subliminal sound was presented either 150 ms before, at, or 150 ms after the moment of coincidence of two disks moving towards each other. The results showed that there was an increased perception of bouncing (rather than streaming) when the subliminal sound was presented at or 150 ms after the moment of coincidence compared to when no sound was presented. These findings provide the first empirical demonstration that activation of the human auditory system without reaching consciousness affects the perception of an ambiguous visual motion display.     

Locating attractiveness in the face space: Faces are more attractive when closer to <Emphasis Type="Italic">their</Emphasis> group prototype

Face attractiveness relates positively to the mathematical averageness of a face, but how close attractive faces of varying groups are to their own and to other-group prototypes in the face space remains unclear. In two studies, we modeled the locations of attractive and unattractive Caucasian, Asian, and African faces in participants’ face space using multidimensional scaling analysis. In all three sets of faces, facial attractiveness significantly increased with the absolute proximity of a face to its group prototype. In the case of Caucasian and African faces (Study 1), facial attractiveness also tended to increase with the absolute proximity of a face to the other-group prototype. However, this association was at best marginal, and it became clearly nonsignificant when distance to the own-group prototype was controlled for. Thus, the present research provides original evidence that average features of faces contribute to increasing their attractiveness, but only when these features are average to the group to which a face belongs. The present research also offers further support to face space models of people’s mental representations of faces.     

Preference for attractive faces in human infants extends beyond conspecifics

Human infants, just a few days of age, are known to prefer attractive human faces. We examined whether this preference is human-specific. Three- to 4-month-olds preferred attractive over unattractive domestic and wild cat (tiger) faces (Experiments 1 and 3). The preference was not observed when the faces were inverted, suggesting that it did not arise from low-level image differences (Experiments 2 and 3). In addition, the spontaneous preference for attractive tiger faces influenced performance in a recognition memory task involving attractive versus unattractive tiger face pairings (Experiment 4). The findings suggest that infant preference for attractive faces reflects the activity of general processing mechanisms rather than a specific adaptation to mate choice.     

Hidden profiles and the consensualization of social stereotypes: how information distribution affects stereotype content and sharedness

We examined the impact of the distribution of information regarding social groups on the formation of shared stereotypes within triads in two studies. Three‐person groups discussed which of three groups (A, B, and C) was the most able and the most sociable. In Study 1, some of the information about these three groups was available to all group members (shared) whereas the remainder was distributed among group members (unique). Based on the total profile, there was more evidence of group A being sociable and of group B being able than of A being able and B sociable. In Study 1 (n = 58), sampling was manipulated as ‘representative’ (information in line with the overall differences was shared) or ‘unrepresentative’ (only information contradicting these differences was shared). In a third condition, all items of information were shared. Emerging stereotypes were directly influenced by sampling of information independently of the discussion. As well as this, the discussion consensualized initial stereotypes. In Study 2 (n = 52), sampling was always unrepresentative and we manipulated the labels associated with the target groups in such a way that the stereotype associated with the label was either inconsistent or consistent with the overall differences between the target groups. In the inconsistent condition, participants were more likely to discuss information that violated stereotypical expectations, and to be less influenced by sampling as a result of discussion. Altogether, these findings suggest that information sampling directly affects the consensualization of social stereotypes. Copyright © 2003 John Wiley & Sons, Ltd.     

Lesions of the dorsal subiculum and the dorsal hippocampus impaired pattern separation in a task using distinct and overlapping visual stimuli

The contribution of the dorsal subiculum (DS) and of the dorsal hippocampus (DH) to memory for distinct and overlapping visual stimuli was examined. Rats with selective lesions of the DS or the DH were compared to sham-operated rats on a delayed matching-to-place task guided by distal visual cues in a modified radial-arm maze. Overlapping distal visual cues could be perceived from three arm entrances (adjacent arms) and a unique set of distal cues were more likely to be seen from the other two arm entrances (distinct arms). Rats with DS lesions were impaired on trials with baited adjacent arms, but not on trials with baited distinct arms. Rats with DH lesions were impaired on both types of trials. These results suggest that the DS and the DH are necessary for pattern separation and that they may have different contributions to memory.     

Intentions and interactive transformations of decision problems

In this paper I study two ways of transforming decision problems on the basis of previously adopted intentions, ruling out incompatible options and imposing a standard of relevance, with a particular focus on situations of strategic interaction. I show that in such situations problems arise which do not appear in the single-agent case, namely that transformation of decision problems can leave the agents with no option compatible with what they intend. I characterize conditions on the agents’ intentions which avoid such problematic scenarios, in a way that requires each agent to take account of the intentions of others.     

The Origins of Face Processing in Humans: Phylogeny and Ontogeny

ABSTRACT— Faces are crucial for nonverbal communication in humans and related species. From the first moments of life, newborn infants prefer to look at human faces over almost any other form of stimuli. Since this finding was first observed, there has been much debate regarding the "special" nature of face processing. Researchers have put forward numerous developmental models that attempt to account for this early preference and subsequent maturation of the face processing system. In this article, we review these models and their supporting evidence drawing on literature from developmental, evolutionary, and comparative psychology. We conclude that converging data from these fields strongly suggests that face processing is conducted by a dedicated and complex neural system, is not human specific, and is unlikely to have emerged recently in evolutionary history.     

Metrics on spaces of finite trees

With the increasing popularity of hierarchical clustering methods in behavioral science, there is a need for ways of quantitatively comparing different tree structures on the same set of items. We employ lattice-theoretic methods to construct a variety of metrics on spaces of trees and to analyze their properties. Certain of these metrics are applied to data from Fillenbaum and Rapoport (1971) on the semantic structure of common English kin terms. This application shows that tree metrics can be used to select a componential analysis which is maximally consistent with an empirically derived set of trees.