Angry faces hold the eyes

Efficient processing of complex social and biological stimuli associated with threat is crucial for survival. Previous studies have suggested that threatening stimuli such as angry faces not only capture visual attention, but also delay the disengagement of attention from their location. However, in the previous studies disengagement of attention was measured indirectly and was inferred on the basis of delayed manual responses. The present study employed a novel paradigm that allows direct examination of the delayed disengagement hypothesis by measuring the time it takes to disengage the eyes from threatening stimuli. The results showed that participants were indeed slower to make an eye movement away from an angry face presented at fixation than from either a neutral or a happy face. This finding provides converging support that the delay in disengagement of attention is an important component of processing threatening information.     

Face adaptation to gender: Does adaptation transfer across age categories?

We examined gender adaptation effects for the faces of children and adults and measured the transfer of these effects across age categories. Face gender adaptation is defined by a bias to classify the gender of a gender-neutral face to be opposite to that of an adapting face. An androgynous face, for example, appears male following adaptation to a female face. Participants adapted to male or female faces from the two age categories and classified the gender of morphed adult and child faces from a male–female morph trajectory. Gender adaptation effects were found for children's and adults’ faces and for the transfer between the age categories. The size of these effects was comparable when participants adapted to adult faces and identified the gender of either adult or child faces, and when participants adapted to child faces and identified the gender of child faces. A smaller adaptation effect was found when participants adapted to a child's face but identified the gender of an adult's face. The results indicate an interconnected and partially shared representation of the gender information for child and adult faces. The lack of symmetry in adaptation transfer between child and adult faces suggests that adaptation to adult faces is more effective than adaptation to child faces in activating a gender representation that generalizes across age categories.     

Learning influences the encoding of static and dynamic faces and their recognition across different spatial frequencies

Studies on face recognition have shown that observers are faster and more accurate at recognizing faces learned from dynamic sequences than those learned from static snapshots. Here, we investigated whether different learning procedures mediate the advantage for dynamic faces across different spatial frequencies. Observers learned two faces—one dynamic and one static—either in depth (Experiment 1) or using a more superficial learning procedure (Experiment 2). They had to search for the target faces in a subsequent visual search task. We used high-spatial frequency (HSF) and low-spatial frequency (LSF) filtered static faces during visual search to investigate whether the behavioural difference is based on encoding of different visual information for dynamically and statically learned faces. Such encoding differences may mediate the recognition of target faces in different spatial frequencies, as HSF may mediate featural face processing whereas LSF mediates configural processing. Our results show that the nature of the learning procedure alters how observers encode dynamic and static faces, and how they recognize those learned faces across different spatial frequencies. That is, these results point to a flexible usage of spatial frequencies tuned to the recognition task.     

The relationship between apparent motion and object files

Object files (OFs) play an important role in theories of mid-level vision. On some influential views, OFs operate and persist only via spatiotemporal continuity. One open question concerns what occurs when direct spatiotemporal continuity is absent: Do OFs move in accordance with any motion correspondence ultimately resolved? Specifically, do OFs accord with apparent motion (AM) correspondences, which arise despite a lack of continuous spatiotemporal stimulation? In Experiment 1, subjects were presented with an AM display consisting of two circles that, across two frames, were seen as moving between two noncontiguous locations. The two objects were primed with two symbols and were then moved in a single step; a third symbol appeared, and could either match the symbol from the closer or the further object. We found a robust object specific preview benefit (OSPB) for the shorter path, in other words, the path along which AM was perceived. In order to control for the possibility that priming occurs at any nearby object, in Experiment 2, the original two objects never disappeared, but two new objects appeared in the would-be AM locations. No AM was perceived, and no OSPB obtained. In the third experiment the OSPB effect persisted even when motion along the shorter path included an unlikely featural transformation (circles turning into squares). In Experiment 4, which was nearly identical to Experiment 2, no OSPB obtained despite unique featural matches between the initial and new objects, seemingly because no AM was perceived. In Experiment 5, we failed to find an effect of featural priming, even when distance between the objects was equated. Finally, we extended the OSPB effect to two additional kinds of AM—line motion (Experiment 6) and phi motion (Experiment 7), supplying strong evidence that AM correspondences and OF correspondences are controlled by the same basic rules.     

Emotional modulation of attention orienting by gaze varies with dynamic cue sequence

ABSTRACT

Recent gaze cueing studies using dynamic cue sequences have reported increased attention orienting by gaze with faces expressing fear, surprise or anger. Here, we investigated whether the type of dynamic cue sequence used impacted the magnitude of this effect. When the emotion was expressed before or concurrently with gaze shift, no modulation of gaze-oriented attention by emotion was seen. In contrast, when the face cue averted gaze before expressing an emotion (as if reacting to the object after first localizing it), the gaze orienting effect was clearly increased for fearful, surprised and angry faces compared to neutral faces. Thus, the type of dynamic sequence used, and in particular the order in which the gaze shift and the facial expression are presented, modulate gaze-oriented attention, with maximal modulation seen when the expression of emotion follows gaze shift.     

Learned prediction affects body perception

Learning to recognize objects appears to depend critically on extended observation of appearance over time. Specifically, temporal association between dissimilar views of an object has been proposed as a tool for learning invariant representations for recognition. We examined heretofore untested aspects of the temporal association hypothesis using a familiar dynamic object, the human body. Specifically, we examined the role of appearance prediction (temporal asymmetry) in temporal association. In our task, observers performed a change detection task using upright and inverted images of a walking body either with or without previous exposure to a motion stimulus depicting an upright walker. Observers who were exposed to the dynamic stimulus were further divided into two groups dependent on whether the observed motion depicted forward or backward walking. We find that the effect of the motion stimulus on sensitivity is highly dependent on whether the observed motion is consistent with past experience.     

Faces as perceptual wholes: The interplay between component and configural properties in face processing

The relative dominance of component and configural properties in face processing is a controversial issue. We examined this issue by testing whether the discriminability of components predicts the discrimination of faces with similar versus dissimilar configurations. Discrimination of faces with similar configurations was determined by components discriminability, indicating independent processing of facial components. The presence of configural variation had no effect on discriminating faces with highly discriminable components, suggesting that discrimination was based on the components. The presence of configural variation, however, facilitated the discrimination of faces with more difficult-to-discriminate components, above and beyond what would be predicted by the configural or componential discriminability, indicating interactive processing. No effect of configural variation was observed in discriminating inverted faces. These results suggest that both component and configural properties contribute to the processing of upright faces and no property necessarily dominates the other. Upright face discrimination can rely on components, configural properties, or interactive processing of component and configural properties, depending on the information available and the discriminability of the properties. Inverted faces are dominated by componential processing. The finding that interactive processing of component and configural properties surfaced when the properties were of similar, not very high discriminability, suggests that such interactive processing may be the dominant form of face processing in everyday life.     

Differential activation of a central inhibition system by motion and colour distractors

ABSTRACT

The selection of relevant stimuli is partially achieved through inhibition of irrelevant distractors. Using the distractor induced blindness (DIB) paradigm, we investigated whether these inhibitory processes depend on the feature dimension that is used to define distractors. Following a pilot study that found motion and colour targets to be comparably salient, we analysed distractor effects of those two feature dimensions. In both feature dimensions, an inhibition effect depended on the number of distractors. Colour, however, was more sensitive to distractor episodes as compared to motion: The level of inhibition was more pronounced, and its activation required less distractors. The results of a control experiment provided further evidence that, in fact, the feature dimension -instead of design differences between tasks- is responsible for this observation. The dimension-sensitive bias in the activation of a central inhibition system may be attributed to a differential processing of visual signals, depending on their behavioural relevance.     

Temporal perception is enhanced for goal-directed biological actions

ABSTRACT

Research into the visual perception of goal-directed human action indicates that human action perception makes use of specialized processing systems, similar to those that operate in visual expertise. Against this background, the current research investigated whether perception of temporal information in goal-directed human action is enhanced relative to similar motion stimuli. Experiment 1 compared observers’ sensitivity to speed changes in upright human action to a kinematic control (an animation yoked to the motion of the human hand), and also to inverted human action. Experiment 2 compared human action to a non-human motion control (a tool moved the object). In both experiments observers’ sensitivity to detecting the speed changes was higher for the human stimuli relative to the control stimuli, and inversion in Experiment 1 did not alter observers’ sensitivity. Experiment 3 compared observers’ sensitivity to speed changes in goal-directed human and dog actions, in order to determine if enhanced temporal perception is unique to human actions. Results revealed no difference between human and dog stimuli, indicating that enhanced speed perception may exist for any biological motion. Results are discussed with reference to theories of biological motion perception and perception in visual expertise.     

Neural Correlates of Age-related Reduction in Visual Motion Priming

ABSTRACT

Previously we reported that priming of visual motion perception is reduced in older adults compared to younger adults (Jiang, Greenwood, & Parasuraman, 1999 Jiang, Y., Greenwood, P. and Parasuraman, R. 1999. Age-related reduction in 3-D motion priming. Psychology and Aging, 14(4): 619–626.  [Google Scholar], Psychology and Aging, 14(4), 619; Jiang, Luo, & Parasuraman, 2002b Jiang, Y., Luo, Y. J. and Parasuraman, R. 2002b. Two-dimensional visual motion priming is reduced in older adults. Neuropsychology, 16(2): 140–145.  [Google Scholar], Neuropsychology, 16(2), 140). To examine the neural mechanisms underlying this age-related effect, event-related brain potentials (ERPs) were recorded during perceptual judgments of motion directions by younger and older adults in two experiments. When judging single-step motion, both younger and older adults evoked significantly larger ERP late positive component (LPC) responses to unambiguous motion compared to LPC responses elicited by ambiguous motion. In contrast, compared to the younger adults, the older adults evoked comparable but delayed ERP responses to single motion steps. In the second experiment the younger and older groups judged the directions of two successive motion-steps (either motion priming or motion reversals). Under short (200–400 ms) stimulus onset asynchrony (SOA), the difference between the ERP responses to priming and reversal conditions was significantly larger for the younger than for the older adults. This study provides the first electrophysiological evidence that brain aging leads to delayed processing of single motion direction and visual motion priming as early as 100 ms in the early visual cortex. Age-related changes in strength and temporal characteristics of neural responses in temporal-parietal regions were particularly pronounced in older adults when successive motion signals are placed closely in time, within 400 ms.