Knowledge that Transforms

We compared how evaluations by out-group members and evaluations by in-group members affected participants' stress responses--their neuroendocrine reactivity, cognitive appraisals, and observed anxiety--and how participants' implicit racial bias moderated these responses. Specifically, White participants completed measures of racial bias prior to the experiment. During the experiment, participants performed speech and serial subtraction tasks in front of White or Black interviewers. Several saliva samples were obtained, and they were assayed for catabolic ("breaking down") and anabolic ("building up") hormones. Interviewers' race and participants' racial bias interacted in predicting stress responses. When interviewers were Black, lower racial bias was linked with more salutary stress responses: lower threat appraisals, less anxiety, and increased levels of anabolic hormones. When interviewers were White, no effect was found for threat appraisals or anabolic hormones, and the reverse effect was observed for anxiety. Egalitarianism may have physical and psychological benefits for people living in a diverse society.

Violent people often claim that God sanctions their actions. In two studies, participants read a violent passage said to come from either the Bible or an ancient scroll. For half the participants, the passage said that God sanctioned the violence. Next, participants competed with an ostensible partner on a task in which the winner could blast the loser with loud noise through headphones (the aggression measure). Study 1 involved Brigham Young University students; 99% believed in God and in the Bible. Study 2 involved Vrije Universiteit-Amsterdam students; 50% believed in God, and 27% believed in the Bible. In Study 1, aggression increased when the passage was from the Bible or mentioned God. In Study 2, aggression increased when the passage mentioned God, especially among participants who believed in God and in the Bible. These results suggest that scriptural violence sanctioned by God can increase aggression, especially in believers.

People possess an innate need to belong that drives social interactions. Aberrations in the need to belong, such as social anhedonia and social anxiety, provide a point of entry for examining this need. The current study used experience-sampling methodology to explore deviations in the need to belong in the daily lives of 245 undergraduates. Eight times daily for a week, personal digital assistants signaled subjects to complete questionnaires regarding affect, thoughts, and behaviors. As predicted, higher levels of social anhedonia were associated with increased time alone, greater preference for solitude, and lower positive affect. Higher social anxiety, in contrast, was associated with higher negative affect and was not associated with increased time alone. Furthermore, greater social anxiety was associated with greater self-consciousness and preference to be alone while interacting with unfamiliar people. Thus, deviations in the need to belong affect social functioning differently depending on whether this need is absent or thwarted.

The present research explored the effect of selective remembering and the resulting "silences" on memory. In particular, we examined whether unmentioned information is more likely to be forgotten by a listener if related information is recollected by the speaker than if related information is not recollected by the speaker. In a modification of the retrieval-induced forgetting paradigm, pairs of individuals studied material, but in the practice phase, only one member of each pair selectively recalled it, while the other listened. Experiment 1 employed paired associates, and Experiment 2 used stories. Experiment 3 involved not controlled practice, but free-flowing conversation. In each case, results from a final memory test established not only within-individual retrieval-induced forgetting, but also socially shared retrieval-induced forgetting. The results demonstrate that listening to a speaker remember selectively can induce forgetting of related information in the listener.

Posttraumatic stress disorder (PTSD) may develop from impaired extinction of conditioned fear responses. Exposure-based treatment of PTSD is thought to facilitate extinction learning (Charney, 2004). Fear extinction is mediated by inhibitory control of the ventromedial prefrontal cortex (vmPFC) over amygdala-based fear processes (Phelps, Delgado, Nearing, & LeDoux, 2004; Quirk, Russo, Barron, & LeBron, 2000). Most neuroimaging studies of PTSD reveal reduced vmPFC activity (particularly in rostral anterior cingulate cortex, or rACC; Lanius et al., 2001; Shin et al., 2005), and some find increased amygdala activity during threat processing (Shin et al., 2005). In addition, increased amygdala activity during fear conditioning and reduced vmPFC activity during extinction have been reported in PTSD (Bremner et al., 2005). Although PTSD patients show increased orbitofrontal and medial prefrontal activity following treatment with serotonin reuptake inhibitors (SSRIs; Fernandez et al., 2001; Seedat et al., 2004), no studies have investigated neural networks before and after exposure-based treatment of PTSD. We report the first such study. We hypothesized that symptom reduction would be associated with increased rACC activity and reduced amygdala activity during fear processing.

Social support is believed to be a universally valuable resource for combating stress, yet Asians and Asian Americans report that social support is not helpful to them, resist seeking it, and are underrepresented among recipients of supportive services. We distinguish between explicit social support (seeking and using advice and emotional solace) and implicit social support (focusing on valued social groups) and show that Asians and Asian Americans are psychologically and biologically benefited more by implicit social support than by explicit social support; the reverse is true for European Americans. Our discussion focuses on cultural differences in the construal of relationships and their implications for social support and delivery of support services.

Experience plays a crucial role in the development of face processing. In the study reported here, we investigated how faces observed within the visual environment affect the development of the face-processing system during the 1st year of life. We assessed 3-, 6-, and 9-month-old Caucasian infants' ability to discriminate faces within their own racial group and within three other-race groups (African, Middle Eastern, and Chinese). The 3-month-old infants demonstrated recognition in all conditions, the 6-month-old infants were able to recognize Caucasian and Chinese faces only, and the 9-month-old infants' recognition was restricted to own-race faces. The pattern of preferences indicates that the other-race effect is emerging by 6 months of age and is present at 9 months of age. The findings suggest that facial input from the infant's visual environment is crucial for shaping the face-processing system early in infancy, resulting in differential recognition accuracy for faces of different races in adulthood.

Playing action video games enhances several different aspects of visual processing; however, the mechanisms underlying this improvement remain unclear. Here we show that playing action video games can alter fundamental characteristics of the visual system, such as the spatial resolution of visual processing across the visual field. To determine the spatial resolution of visual processing, we measured the smallest distance a distractor could be from a target without compromising target identification. This approach exploits the fact that visual processing is hindered as distractors are brought close to the target, a phenomenon known as crowding. Compared with nonplayers, action-video-game players could tolerate smaller target-distractor distances. Thus, the spatial resolution of visual processing is enhanced in this population. Critically, similar effects were observed in non-video-game players who were trained on an action video game; this result verifies a causative relationship between video-game play and augmented spatial resolution.

Mediation models are widely used, and there are many tests of the mediated effect. One of the most common questions that researchers have when planning mediation studies is, "How many subjects do I need to achieve adequate power when testing for mediation?" This article presents the necessary sample sizes for six of the most common and the most recommended tests of mediation for various combinations of parameters, to provide a guide for researchers when designing studies or applying for grants.

This study investigated the effect of stress on cognitive control in task shifting. Subjects shifted between two tasks in an explicit cuing paradigm. Shift costs (i.e., performance decrements on task shifts relative to task repetitions) were measured for a long and a short cue-stimulus interval (CSI). Stress was varied by administering low-stress and high-stress IQ scales to two groups of subjects. In the low-stress group, shift costs were reduced with an increased CSI, a result that typically indicates anticipatory and shift-specific task-set reconfiguration. In the high-stress group, however, shift costs were independent of the CSI. This result is consistent with the idea that stress induces a change in the reconfiguration strategy, possibly to adapt to depleted resources.