Mood-induced shifts in attentional bias to emotional information predict ill- and well-being

Previous research has suggested that biased attention toward emotional (typically threatening) stimuli contributes to ill-being (e.g., high levels of anxiety), but its contribution to well-being is less clear. The researchers assessed naturalistic shifts in attentional bias toward threatening and pleasant schematic face cues in response to five induced mood states in college students. They also assessed state anxiety and satisfaction with life concurrently and 3 weeks later. Controlling for concurrent anxiety, a fear-induced shift in attention to threatening cues was associated with increased levels of later anxiety. Controlling for concurrent life satisfaction, a happiness-induced shift in attention to emotional cues (both threatening and pleasant) was associated with increased levels of later life satisfaction. These results suggest that mood-induced changes in deployment of attention to emotional information may accumulate in ways that impact psychological functioning, yet these effects depend on mood state and the emotional cues afforded by the context.     

Attention and the subjective expansion of time

During brief, dangerous events, such as car accidents and robberies, many people report that events seem to pass in slow motion, as if time had slowed down. We have measured a similar, although less dramatic, effect in response to unexpected, nonthreatening events. We attribute the subjective expansion of time to the engagement of attention and its influence on the amount of perceptual information processed. We term the effect time's subjective expansion (TSE) and examine here the objective temporal dynamics of these distortions. When a series of stimuli are shown in succession, the low-probability oddball stimulus in the series tends to last subjectively longer than the high-probability stimulus even when they last the same objective duration. In particular, (1) there is a latency of at least 120 msec between stimulus onset and the onset of TSE, which may be preceded by subjective temporal contraction; (2) there is a peak in TSE at which subjective time is particularly distorted at a latency of 225 msec after stimulus onset; and (3) the temporal dynamics of TSE are approximately the same in the visual and the auditory domains. Two control experiments (in which the methods of magnitude estimation and stimulus reproduction were used) replicated the temporal dynamics of TSE revealed by the method of constant stimuli, although the initial peak was not apparent with these methods. In addition, a third, control experiment (in which the method of single stimuli was used) showed that TSE in the visual domain can occur because of semantic novelty, rather than image novelty per se. Overall, the results support the view that attentional orienting underlies distortions in perceived duration.     

Chinese and Americans see opposite apparent motions in a Chinese character

The perceived direction of apparent motion can be influenced by both "top-down" factors, such as expectation, and by "bottom-up" or stimulus-driven factors, such as grouping (Tse, P., Cavanagh, P. & Nakayama, K. (1998). The role of parsing in high-level motion processing. In T. Watanabe, High-level motion processing - computational, neurobiological and psychophysical perspectives. Cambridge, MA: MIT Press). Here we report the results of a single experiment that pitted top-down cues against bottom-up cues in an apparent motion sequence over the successive strokes of a Chinese character. Although each stroke was in fact presented all at once, subjects raised in China tended to see apparent motion over a single stroke in the direction it would have taken when drawn by hand, even though bottom-up cues drive a percept of apparent motion in the opposite direction for observers unfamiliar with the Chinese language. There is therefore a learned component to motion perception arising from top-down expectations capable of overriding bottom-up cues to motion.     

Effect of surface medium on visual search for orientation and size features

By using a visual search task, this study examined the encoding of orientation and size for stimuli defined in five different surface media: luminance, color, texture, relative motion, and binocular disparity. Results indicated a spatially parallel analysis of size and orientation features for all surface media, with the possible exception of binocular disparity. The data also revealed a search rate asymmetry in the orientation task for all media: Parallel or shallow search functions were obtained for oblique targets in vertical distractors, whereas steeper serial search functions were obtained for vertical targets in oblique distractors. No consistent asymmetry was found for the large and small targets in the size task. There seemed to be common principles of coding in all these different media, suggesting either a single analysis of shape features applied to a common representation or multiple analyses, one for each surface medium, with each extracting a similar set of features. The shared coding principles may facilitate the use of redundancy across media to reduce ambiguities in the locations and shapes of contours in the visual scene.     

Shape from shadows

The colors, textures, and shapes of shadows are physically constrained in several ways in natural scenes. The visual system appears to ignore these constraints, however, and to accept many patterns as shadows even though they could not occur naturally. In the stimuli that we have studied, the only requirements for the perception of depth due to shadows were that shadow regions be darker than the surrounding, nonshadow regions and that there be consistent contrast polarity along the shadow border. Three-dimensional shape due to shadows was perceived when shadow areas were filled with colors or textures that could not occur in natural scenes, when shadow and nonshadow regions had textures that moved in different directions, or when they were presented on different depth planes. The results suggest that the interpretation of shadows begins with the identification of acceptable shadow borders by a cooperative process that requires consistent contrast polarity across a range of scales at each point along the border. Finally, we discuss how the identification of a shadow region can help the visual system to patch together areas that are separated by shadow boundaries, to identify directions of surface curvature, and to select a preferred three-dimensional interpretation while rejecting others.     

Familiarity and pop-out in visual search

In this paper, we report that when the low-level features of targets and distractors are held constant, visual search performance can be strongly influenced by familiarity. In the first condition, a was the target amid as distractors, and vice versa. The response time increased steeply as a function of number of distractors (82 msec/item). When the same stimuli were rotated by 90° (the second condition), however, they became familiar patterns— and —and gave rise to much shallower search functions (31 msec/item). In the third condition, when the search was for a familiar target, (or ), among unfamiliar distractors, (or ), the slope was about 46 msec/item. In the last condition, when the search was for an unfamiliar target, (or ), among familiar distractors, s (or s), parallel search functions were found with a slope of about 1.5 msec/item. These results show that familiarity speeds visual search and that it does so principally when the distractors, not the targets, are familiar.     

Mental rotation, physical rotation, and surface media.

Subjects made mirror-normal discriminations on alphanumeric characters shown in different orientations in the picture plane. Either the characters or the background rotated during stimulus presentation in Experiments 1-3. Character rotation in the direction of mental rotation facilitated mental rotation, whereas rotation in the opposite direction inhibited it. In Experiment 4, characters were presented in different surface media so as to stimulate only one representation at a time. Mental rotation performance was similar whether the stimuli were defined by luminance, color, texture, relative motion, or binocular disparity, suggesting that mental rotation occurs at a level beyond that of the independent analyses of these different media. These results support those of Experiments 1-3 in excluding the participation of low-level motion analysis centers in the mental rotation processes.