Knowledge that Transforms

Attention biases sensory processing toward neurons containing information about behaviorally relevant events. These attentional biases apparently reflect the combined influence of feature enhancement and suppression. We examined the separate influence of enhancement and suppression in visual processing by determining whether responses to an unattended flicker were modulated when the flicker features matched target features at the attended location, competed with those features, or were neutral. We found that suppression primarily modulated parietal networks with a preferred frequency in the lower alpha band (f2=8 Hz), and enhancement primarily influenced parietal networks with a preferred frequency in the upper alpha band (f2=12 Hz). These responses were coupled with perception, with large responses to the unattended flicker leading to subsequently detected targets when the target features matched the flicker features (i.e., during enhancement). Our results suggest that enhancement and suppression are two distinct processes that work together to shape visual perception.

Purity is commonly regarded as being physically embodied in the color white, with even trivial deviations from whiteness indicating a loss of purity. In three studies, we explored the implications of this "white = pure" association for disgust, an emotion that motivates the detection and avoidance of impurities that threaten purity and cleanliness. We hypothesized that disgust tunes perception to prioritize the light end of the light-dark spectrum, which results in a relative hypersensitivity to changes in lightness in this range. In studies 1 and 2, greater sensitivity to disgusting stimuli was associated with greater ability to make subtle gray-scale discriminations (e.g., detecting a faint gray stimulus against a white background) at the light end of the spectrum relative to ability to make subtle gray-scale discriminations at the dark end of the spectrum. In study 3, after viewing disgusting images, disgust-sensitive individuals demonstrated a heightened ability to detect deviations from white. These findings suggest that disgust not only motivates people to avoid impurities, but actually makes them better able to see them.

In this article, we present evidence supporting the hypothesis that the local mechanism of simultaneous color contrast is the same as the mechanism responsible for the crispening effect and the gamut expansion effect. A theoretically important corollary of this hypothesis is that the basic characteristics of simultaneous contrast are at odds with traditional laws. First, this hypothesis implies that the direction of the simultaneous contrast effect in color space is given by the vector from surround to target and not--as traditionally assumed--by the hue complementary to that of the surround. Second, it implies that the size of the simultaneous contrast effect depends on the difference between the target and surround colors in a way that challenges Kirschmann's fourth law. The widespread belief in the traditional laws, we argue, is due to the confounding influence of temporal adaptation.

In two experiments, we tested for a causal link between thought speed and risk taking. In Experiment 1, we manipulated thought speed by presenting neutral-content text at either a fast or a slow pace and having participants read the text aloud. In Experiment 2, we manipulated thought speed by presenting fast-, medium-, or slow-paced movie clips that contained similar content. Participants who were induced to think more quickly took more risks with actual money in Experiment 1 and reported greater intentions to engage in real-world risky behaviors, such as unprotected sex and illegal drug use, in Experiment 2. These experiments provide evidence that faster thinking induces greater risk taking.

Understanding memory performance under different operational conditions is critical in many occupational settings. To examine the effect of physical exertion on memory for a witnessed event, we placed two groups of law-enforcement officers in a live, occupationally relevant scenario. One group had previously completed a high-intensity physical-assault exercise, and the other had not. Participants who completed the assault exercise showed impaired recall and recognition performance compared with the control group. Specifically, they provided significantly less accurate information concerning critical and incidental target individuals encountered during the scenario, recalled less briefing information, and provided fewer briefing updates than control participants did. Exertion was also associated with reduced accuracy in identifying the critical target from a lineup. These results support arousal-based competition accounts proposing differential allocation of resources under physiological arousal. These novel findings relating to eyewitness memory performance have important implications for victims, ordinary citizens who become witnesses, and witnesses in policing, military, and related operational contexts.

An ideal empathizer may attend to another person's behavior in order to understand that person, but it is also possible that accurately understanding other people involves top-down strategies. We hypothesized that perceivers draw on stereotypes to infer other people's thoughts and that stereotype use increases perceivers' accuracy. In this study, perceivers (N = 161) inferred the thoughts of multiple targets. Inferences consistent with stereotypes for the targets' group (new mothers) more accurately captured targets' thoughts, particularly when actual thought content was also stereotypic. We also decomposed variance in empathic accuracy into thought, target, and perceiver variance. Although past research has frequently focused on variance between perceivers or targets (which assumes individual differences in the ability to understand other people or be understood, respectively), the current study showed that the most substantial variance was found within targets because of differences among thoughts.

Human aging is associated with decline in cognitive and physical functioning. Although pulmonary function predicts long-term performance (up to 10 years) on measures of cognitive function, recent data suggest the opposite relationship: Cognitive decline predicts self-reported physical limitations. In the study reported here, we utilized dual-change-score models to determine the directional relationship between pulmonary and cognitive function. Our sample consisted of 832 participants (ages 50-85 years at baseline), who were assessed in up to seven waves of testing across 19 years as part of the longitudinal Swedish Adoption/Twin Study of Aging. Changes in pulmonary function led to subsequent changes in fluid cognitive function, specifically, in tasks reflecting psychomotor speed and spatial abilities. There was no evidence that declines in cognitive function led to subsequent declines in pulmonary function. Thus, these data indicate a directional relationship from decreased pulmonary function to decreased cognitive function, a finding that underscores the importance of maintaining pulmonary function to ensure cognitive performance.

in front of the cups so that the children could watch as she hid the ball but could not see the particular cup she baited. She announced that she had finished and removed the barrier. Both actors faced the camera throughout the rest of the trial. The children were randomly assigned to three conditions. In the point condition (n = 16; mean age = 3 years 11 months), the two actors simultaneously pointed to different cups. In the grasp condition (n = 16; mean age = 4 years 0 months), they simultaneously grasped the tops of different cups. We used grasping as a comparison gesture because young children understand that it, like pointing, is intentional and object directed (Woodward, 1999). However, it is not often used communicatively, and so may not be as likely as pointing to lead to the misattribution of knowledge. In the baseline condi- tion (n = 16; mean age = 3 years 11 months), the two actors simply sat with their hands in their laps. After the actors ges- tured (or not), the experimenter paused the video and asked, Who knows where the ball is? One actor hid the ball on the first and fourth trials; the other actor did so on the middle two trials.

When humans learn that the presence of a cue predicts the likelihood of an outcome, they can exploit this learned predictiveness, such that formation of subsequent associations between that cue and new outcomes is facilitated. Could such enhanced selection for association arise early enough to facilitate low-level visual processing? In a test of this possibility, adult volunteers first engaged in a value-learning task involving faces that were differentially predictive of monetary wins or losses. Later, in a simple recognition task, these faces were briefly presented for a variable duration and then masked. The critical presentation duration needed to produce criterion-level recognition was measured to index the visual processing speed for each learned face. Critical duration was significantly shorter for stimuli with high learned predictiveness than for stimuli with low learned predictiveness, regardless of whether they were associated with wins or losses. These results show that neural mechanisms involved in predicting future outcomes are able to modulate visual processing efficiency, probably via cortical feedback processes.