Knowledge that Transforms

International audience

Although 50 years of research demonstrate that friendly intergroup contact reduces intergroup prejudice, the findings are based solely on self-reported, explicit prejudice. In two parallel experiments examining intergroup contact and prejudice-between Whites and Blacks in the United States (Experiment 1) and between Christians and Muslims in Lebanon (Experiment 2)-we examined whether intergroup status differences moderate contact effects on implicit prejudice, as well as explicit prejudice. Both experiments replicated the standard effect of contact on explicit prejudice. They also demonstrated that intergroup contact reduces implicit prejudice among low-status groups. In Experiment 1, the implicit prejudice of Blacks toward Whites (but not Whites toward Blacks) was reduced as a function of friendly contact. In Experiment 2, the implicit prejudice of Muslims toward Christians (but not Christians toward Muslims) was reduced as a function of friendly contact.

The development of cognitive control and its relation to overcoming Stroop interference was assessed in a sample (N= 65) of elementary-school children. Subjects alternately performed Stroop color-naming trials and word-reading trials. In separate blocks, the colored Stroop items were non-color words (incongruent condition) or rows of asterisks (neutral condition). Younger children showed both larger Stroop interference in error rates and a greater slowing of word reading in the incongruent condition compared with older children. We conducted analyses of response time distributions that assessed the degree of word-reading suppression applied by younger and older children. Surprisingly, these analyses indicated that younger children engaged in stronger suppression than older children. We propose that greater Stroop interference among younger children is not due to lack of ability to suppress word reading, but instead is the result of a failure to consistently maintain the task set of color naming.

Sensory adaptation and visual aftereffects have long given insight into the neural codes underlying basic dimensions of visual perception. Recently discovered perceptual adaptation effects for complex shapes like faces can offer similar insight into high-level visual representations. In the experiments reported here, we demonstrated first that face adaptation transfers across a substantial change in viewpoint and that this transfer occurs via processes unlikely to be specific to faces. Next, we probed the visual codes underlying face recognition using face morphs that varied selectively in reflectance or shape. Adaptation to these morphs affected the perception of "opposite" faces both from the same viewpoint and from a different viewpoint. These results are consistent with high-level face representations that pool local shape and reflectance patterns into configurations that specify facial appearance over a range of three-dimensional viewpoints. These findings have implications for computational models of face recognition and for competing neural theories of face and object recognition.

We studied human movement planning in tasks in which subjects selected one of two goals that differed in expected gain. Each goal configuration consisted of a target circle and a partially overlapping penalty circle. Rapid hits into the target region led to a monetary bonus; accidental hits into the penalty region incurred a penalty. The outcomes assigned to target and penalty regions and the spatial arrangement of those regions were varied. Subjects preferred configurations with higher expected gain whether selection involved a rapid pointing movement or a choice by key press. Movements executed to select one of two goal configurations exhibited the same movement dynamics as pointing movements directed at a single configuration, and were executed with the same high efficiency. Our results suggest that humans choose near-optimal strategies when planning their movement, and can base their selection of strategy on a rapid judgment about the expected gain associated with possible movement goals.

We tested the hypothesis that deficits on sensory-processing tasks frequently associated with poor reading and dyslexia are the result of impairments in external-noise exclusion, rather than motion perception or magnocellular processing. We compared the motion-direction discrimination thresholds of adults and children with good or poor reading performance, using coherent-motion displays embedded in external noise. Both adults and children who were poor readers had higher thresholds than their respective peers in the presence of high external noise, but not in the presence of low external noise or when the signal was clearly demarcated. Adults' performance in high external noise correlated with their general reading ability, whereas children's performance correlated with their language and verbal abilities. The results support the hypothesis that noise-exclusion deficits impair reading and language development and suggest that the impact of such deficits on the development of reading skills changes with age.

This study was designed to determine whether the characteristics of the neighborhood environment are related to the substitution of physical activity for sedentary behavior among youth. Fifty-eight 8- to 15-year-old youth were studied in a within-subjects crossover design with three phases: baseline, increased sedentary behavior, and decreased sedentary behavior. The relations between changes in physical activity and design, diversity, and density attributes of the neighborhood environment were determined using random coefficient models. Compared with girls, boys showed greater increases in physical activity when sedentary behaviors were reduced and greater decreases in physical activity when sedentary behaviors were increased. Greater access to parks was associated with greater physical activity when sedentary behaviors were reduced.

Disoriented 4-year-old children use a distinctive container to locate a hidden object, but do they reorient by this information? We addressed this question by testing children's search for objects in a circular room containing one distinctive and two identical containers. Children's search patterns provided evidence that the distinctive container served as a direct cue to a hidden object's location, but not as a directional signal guiding reorientation. The findings suggest that disoriented children's search behavior depends on two distinct processes: a modular reorientation process attuned to the geometry of the surface layout and an associative process linking landmarks to specific locations.

People often fail to recall the second of two visual targets presented within 500 ms in rapid serial visual presentation (RSVP). This effect is called the attentional blink. One explanation of the attentional blink is that processes involved in encoding the first target into memory are slow and capacity limited. Here, however, we show that the attentional blink should be ascribed to attentional selection, not consolidation of the first target. Rapid sequences of six letters were presented, and observers had to report either all the letters (whole-report condition) or a subset of the letters (partial-report condition). Selection in partial report was based on color (e.g., report the two red letters) or identity (i.e., report all letters from a particular letter onward). In both cases, recall of letters presented shortly after the first selected letter was impaired, whereas recall of the corresponding letters was relatively accurate with whole report.

We report performance of haptically linked dyads on a targetacquisition task, comparing it with that of the same individuals when they performed the task individually. In the dyad condition, a subject’s limb motion responds to the output of two motorcontrol systems—the subject’s own and his or her partner’s— which might be expected to complicate motor planning and efficient task execution. However, task completion times indicated that dyads performed significantly faster than individuals, even though dyad members exerted large task-irrelevant forces in opposition to one another, and despite many participants’ perceptions that their partner was an impediment. A much earlier study of teams using a pursuit rotor (Wegner & Zeaman, 1956) found a similar performance increment. Since that study, there has been little research on physically coupled dyads (Sallnas & Zhai, 2003; Shergill, Bays, Frith, & Wolpert,