Knowledge that Transforms

This study explores whether the cognitive advantage associated with bilingualism in executive functioning extends to young immigrant children challenged by poverty and, if it does, which specific processes are most affected. In the study reported here, 40 Portuguese-Luxembourgish bilingual children from low-income immigrant families in Luxembourg and 40 matched monolingual children from Portugal completed visuospatial tests of working memory, abstract reasoning, selective attention, and interference suppression. Two broad cognitive factors of executive functioning-representation (abstract reasoning and working memory) and control (selective attention and interference suppression)-emerged from principal component analysis. Whereas there were no group differences in representation, the bilinguals performed significantly better than did the monolinguals in control. These results demonstrate, first, that the bilingual advantage is neither confounded with nor limited by socioeconomic and cultural factors and, second, that separable aspects of executive functioning are differentially affected by bilingualism. The bilingual advantage lies in control but not in visuospatial representational processes.

Military experience is an important turning point in a person's life and, consequently, is associated with important life outcomes. Using a large longitudinal sample of German males, we examined whether personality traits played a role during this period. Results indicated that personality traits prospectively predicted the decision to enter the military. People lower in agreeableness, neuroticism, and openness to experience during high school were more likely to enter the military after graduation. In addition, military training was associated with changes in personality. Compared with a control group, military recruits had lower levels of agreeableness after training. These levels persisted 5 years after training, even after participants entered college or the labor market. This study is one of the first to identify life experiences associated with changes in personality traits. Moreover, our results suggest that military experiences may have a long-lasting influence on individual-level characteristics.

Can neural responses of a small group of individuals predict the behavior of large-scale populations? In this investigation, brain activations were recorded while smokers viewed three different television campaigns promoting the National Cancer Institute's telephone hotline to help smokers quit (1-800-QUIT-NOW). The smokers also provided self-report predictions of the campaigns' relative effectiveness. Population measures of the success of each campaign were computed by comparing call volume to 1-800-QUIT-NOW in the month before and the month after the launch of each campaign. This approach allowed us to directly compare the predictive value of self-reports with neural predictors of message effectiveness. Neural activity in a medial prefrontal region of interest, previously associated with individual behavior change, predicted the population response, whereas self-report judgments did not. This finding suggests a novel way of connecting neural signals to population responses that has not been previously demonstrated and provides information that may be difficult to obtain otherwise.

Math anxiety is a negative emotional reaction to situations involving mathematical problem solving. Math anxiety has a detrimental impact on an individual's long-term professional success, but its neurodevelopmental origins are unknown. In a functional MRI study on 7- to 9-year-old children, we showed that math anxiety was associated with hyperactivity in right amygdala regions that are important for processing negative emotions. In addition, we found that math anxiety was associated with reduced activity in posterior parietal and dorsolateral prefrontal cortex regions involved in mathematical reasoning. Multivariate classification analysis revealed distinct multivoxel activity patterns, which were independent of overall activation levels in the right amygdala. Furthermore, effective connectivity between the amygdala and ventromedial prefrontal cortex regions that regulate negative emotions was elevated in children with math anxiety. These effects were specific to math anxiety and unrelated to general anxiety, intelligence, working memory, or reading ability. Our study identified the neural correlates of math anxiety for the first time, and our findings have significant implications for its early identification and treatment.

Young children help other people, but it is not clear why. In the current study, we found that 2-year-old children's sympathetic arousal, as measured by relative changes in pupil dilation, is similar when they themselves help a person and when they see that person being helped by a third party (and sympathetic arousal in both cases is different from that when the person is not being helped at all). These results demonstrate that the intrinsic motivation for young children's helping behavior does not require that they perform the behavior themselves and thus "get credit" for it, but rather requires only that the other person be helped. Thus, from an early age, humans seem to have genuine concern for the welfare of others.

The experimental record of the last three decades shows that children under 4 years old fail all sorts of variations on the standard false-belief task, whereas more recent studies have revealed that infants are able to pass nonverbal versions of the task. We argue that these paradoxical results are an artifact of the type of false-belief tasks that have been used to test infants and children: Nonverbal designs allow infants to keep track of a protagonist's perspective over a course of events, whereas verbal designs tend to disrupt the perspective-tracking process in various ways, which makes it too hard for younger children to demonstrate their capacity for perspective tracking. We report three experiments that confirm this hypothesis by showing that 3-year-olds can pass a suitably streamlined version of the verbal false-belief task. We conclude that young children can pass the verbal false-belief task provided that they are allowed to keep track of the protagonist's perspective without too much disruption.

Prior research has demonstrated that the display of agentic behaviors, such as dominance, can produce backlash against female leaders because of the incongruence between these behaviors and prescribed gender roles. The current study was designed to fill a gap in existing research by investigating whether these well-established findings are moderated by race. Results revealed that dominant Black female leaders did not create the same backlash that dominant White female leaders did. Experimental evidence confirmed that White female (and Black male) leaders were conferred lower status when they expressed dominance rather than communality, whereas Black female (and White male) leaders were not. These findings highlight the importance, and complexity, of considering the intersection of gender and race when examining penalties for and proscriptions against dominant behavior of female leaders.

Psychosocial stress precipitates a wide spectrum of diseases with major public-health significance. The fight-or-flight response is generally regarded as the prototypic human stress response, both physiologically and behaviorally. Given that having positive social interactions before being exposed to acute stress plays a preeminent role in helping individuals control their stress response, engaging in prosocial behavior in response to stress (tend-and-befriend) might also be a protective pattern. Little is known, however, about the immediate social responses following stress in humans. Here we show that participants who experienced acute social stress, induced by a standardized laboratory stressor, engaged in substantially more prosocial behavior (trust, trustworthiness, and sharing) compared with participants in a control condition, who did not experience socioevaluative threat. These effects were highly specific: Stress did not affect the readiness to exhibit antisocial behavior or to bear nonsocial risks. These results show that stress triggers social approach behavior, which operates as a potent stress-buffering strategy in humans, thereby providing evidence for the tend-and-befriend hypothesis.

A century of research on the development of walking has examined periodic gait over a straight, uniform path. The current study provides the first corpus of natural infant locomotion derived from spontaneous activity during free play. Locomotor experience was immense: Twelve- to 19-month-olds averaged 2,368 steps and 17 falls per hour. Novice walkers traveled farther faster than expert crawlers, but had comparable fall rates, which suggests that increased efficiency without increased cost motivates expert crawlers to transition to walking. After walking onset, natural locomotion improved dramatically: Infants took more steps, traveled farther distances, and fell less. Walking was distributed in short bouts with variable paths--frequently too short or irregular to qualify as periodic gait. Nonetheless, measures of periodic gait and of natural locomotion were correlated, which indicates that better walkers spontaneously walk more and fall less. Immense amounts of time-distributed, variable practice constitute the natural practice regimen for learning to walk.

Recent research suggests that refraining from cheating in tempting situations requires self-control, which indicates that serving self-interest is an automatic tendency. However, evidence also suggests that people cheat to the extent that they can justify their unethical behavior to themselves. To merge these different lines of research, we adopted a dual-system approach that distinguished between the intuitive and deliberative cognitive systems. We suggest that for people to restrict their dishonest behavior, they need to have enough time and no justifications for self-serving unethical behavior. We employed an anonymous die-under-cup task in which participants privately rolled a die and reported the outcome to determine their pay. We manipulated the time available for participants to report their outcome (short vs. ample). The results of two experiments support our prediction, revealing that the dark side of people's automatic self-serving tendency may be overcome when time to decide is ample and private justifications for dishonesty are not available.