Do infants have a sense of fairness?

Two experiments examined infants' expectations about how an experimenter should distribute resources and rewards to other individuals. In Experiment 1, 19-month-olds expected an experimenter to divide two items equally, as opposed to unequally, between two individuals. The infants held no particular expectation when the individuals were replaced with inanimate objects, or when the experimenter simply removed covers in front of the individuals to reveal the items (instead of distributing them). In Experiment 2, 21-month-olds expected an experimenter to give a reward to each of two individuals when both had worked to complete an assigned chore, but not when one of the individuals had done all the work while the other played. The infants held this expectation only when the experimenter could determine through visual inspection who had worked and who had not. Together, these results provide converging evidence that infants in the 2nd year of life already possess context-sensitive expectations relevant to fairness.     

What Do North American Babies Hear? A large‐scale cross‐corpus analysis

A range of demographic variables influences how much speech young children hear. However, because studies have used vastly different sampling methods, quantitative comparison of interlocking demographic effects has been nearly impossible, across or within studies. We harnessed a unique collection of existing naturalistic, day‐long recordings from 61 homes across four North American cities to examine language input as a function of age, gender, and maternal education. We analyzed adult speech heard by 3‐ to 20‐month‐olds who wore audio recorders for an entire day. We annotated speaker gender and speech register (child‐directed or adult‐directed) for 10,861 utterances from female and male adults in these recordings. Examining age, gender, and maternal education collectively in this ecologically valid dataset, we find several key results. First, the speaker gender imbalance in the input is striking: children heard 2–3× more speech from females than males. Second, children in higher‐maternal education homes heard more child‐directed speech than those in lower‐maternal education homes. Finally, our analyses revealed a previously unreported effect: the proportion of child‐directed speech in the input increases with age, due to a decrease in adult‐directed speech with age. This large‐scale analysis is an important step forward in collectively examining demographic variables that influence early development, made possible by pooled, comparable, day‐long recordings of children's language environments. The audio recordings, annotations, and annotation software are readily available for reuse and reanalysis by other researchers.     

Do private gestures have a self-regulatory function? A case study

One of the most fascinating phenomena in early development is that babies not only understand signs others direct to them and later use them to communicate with others, but they also come to direct the same signs towards themselves in a private way. Private gestures become "tools of thought". There is a considerable literature about private language, but almost nothing about private gestures. Private gestures pose an intriguing communicative puzzle: they are communicative, but with the self. In this paper we study two types of private gestures (signs) before language: (1) private ostensive gestures and (2) private pointing gestures. We show in a case study of one child between 12 and 18 months of age that both are used with a self-reflexive function, as a way of "thinking" what to do, in order to solve a problem in the conventional use of an object. The private gestures become self-reflexive signs.     

Do infants understand simple arithmetic? A replication of Wynn (1992)

Numerical competence in 5-month-old infants is investigated using a violation-of-expectation paradigm. An experiment is reported which replicates the findings of Wynn (1992). In additional conditions, 5-month-olds are shown to be sensitive to impossible outcomes following addition or subtraction operations on small sets of objects, regardless of identity changes. Results support Wynn's interpretation that infants' responses are based on arithmetical ability. An alternative explanation, that infants' responses are based on their knowledge of the principles of physical object behavior, is also discussed.     

Does overall reinforcer rate affect discrimination of time‐based contingencies?

Overall reinforcer rate appears to affect choice. The mechanism for such an effect is uncertain, but may relate to reinforcer rate changing the discrimination of the relation between stimuli and reinforcers. We assessed whether a quantitative model based on a stimulus‐control approach could be used to account for the effects of overall reinforcer rate on choice under changing time‐based contingencies. On a two‐key concurrent schedule, the likely availability of a reinforcer reversed when a fixed time had elapsed since the last reinforcer, and the overall reinforcer rate was varied across conditions. Changes in the overall reinforcer rate produced a change in response bias, and some indication of a change in discrimination. These changes in bias and discrimination always occurred quickly, usually within the first session of a condition. The stimulus‐control approach provided an excellent account of the data, suggesting that changes in overall reinforcer rate affect choice because they alter the frequency of reinforcers obtained at different times, or in different stimulus contexts, and thus change the discriminated relation between stimuli and reinforcers. These findings support the notion that temporal and spatial discriminations can be understood in terms of discrimination of reinforcers across time and space.     

Is auditory discrimination mature by middle childhood? A study using time‐frequency analysis of mismatch responses from 7 years to adulthood

Behavioural and electrophysiological studies give differing impressions of when auditory discrimination is mature. Ability to discriminate frequency and speech contrasts reaches adult levels only around 12 years of age, yet an electrophysiological index of auditory discrimination, the mismatch negativity (MMN), is reported to be as large in children as in adults. Auditory ERPs were measured in 30 children (7 to 12 years), 23 teenagers (13 to 16 years) and 32 adults (35 to 56 years) in an oddball paradigm with tone or syllable stimuli. For each stimulus type, a standard stimulus (1000 Hz tone or syllable [ba]) occurred on 70% of trials, and one of two deviants (1030 or 1200 Hz tone, or syllables [da] or [bi]) equiprobably on the remaining trials. For the traditional MMN interval of 100–250 ms post-onset, size of mismatch responses increased with age, whereas the opposite trend was seen for an interval from 300 to 550 ms post-onset, corresponding to the late discriminative negativity (LDN). Time-frequency analysis of single trials revealed that the MMN resulted from phase-synchronization of oscillations in the theta (4–7 Hz) range, with greater synchronization in adults than children. Furthermore, the amount of synchronization was significantly correlated with frequency discrimination threshold. These results show that neurophysiological processes underlying auditory discrimination continue to develop through childhood and adolescence. Previous reports of adult-like MMN amplitudes in children may be artefactual results of using peak measurements when comparing groups that differ in variance.     

Do emotions have distinct vocal profiles? A study of idiographic patterns of expression

Research on vocal expressions of emotion indicates that persons can identify emotions from voice with relatively high accuracy rates. In addition, fairly consistent vocal profiles for specific emotions have been identified. However, important methodological issues remain to be addressed. In this paper, we address the issue of whether there are individual differences in the manner in which particular emotions may be expressed vocally and whether trained speakers’ portrayals of emotion are in some sense superior to untrained speakers’ portrayals. Consistent support was found for differences across speakers in the manner in which they expressed the same emotions. No accompanying relationship was found between differences in expression and accuracy of identification of those expressions. Little evidence for the superiority of trained speakers was found. Implications of these findings for future studies of vocal expressions of emotion, as well as our understanding of emotions in general, are discussed.     

A Meta‐Analytic Investigation of the Within‐Person Self‐Efficacy Domain: Is Self‐Efficacy a Product of Past Performance or a Driver of Future Performance?

We conducted a meta‐analysis to determine whether the within‐person self‐efficacy/performance relationship is positive, negative, or null and to compare the strength of the self‐efficacy/performance and past performance/self‐efficacy within‐person relationships. The self‐efficacy/performance within‐person corrected correlation was .23 but was weak and nonsignificant (ρ = .06) when controlling for the linear trajectory, revealing that the main effect was spurious. The past performance/self‐efficacy within‐person corrected correlation was .40 and remained positive and significant (ρ = .30) when controlling for the linear trajectory. The moderator results revealed that at the within‐person level of analysis: (a) self‐efficacy had at best a moderate, positive effect on performance and a null effect under other moderating conditions (ρ ranged from –.02 to .33); (b) the main effect of past performance on self‐efficacy was stronger than the effect of self‐efficacy on performance, even in the moderating conditions that produced the strongest self‐efficacy/performance relationship; (c) the effect of past performance on self‐efficacy ranged from moderate to strong across moderating conditions and was statistically significant across performance tasks, contextual factors, and methodological moderators (ρ ranged from .18 to .52). Overall, this suggests that self‐efficacy is primarily a product of past performance rather than the driving force affecting future performance.     

Subdomains of Gender‐Related Occupational Interests: Do They Form a Cohesive Bipolar M‐F Dimension?

In four studies, with a total of 1780 male and 2969 female participants, subdomains of masculine and feminine occupations were identified from sets of occupational preference items. Identified masculine subdomains included "blue-collar realistic" (e.g., carpenter), "educated realistic" (electrical engineer), and "flashy, risk-taking" (jet pilot). Feminine subdomains included "fashion-related" (fashion model), "artistic" (author), "helping" (social worker), and "children-related" (manager of childcare center). In all studies, principal components analyses of subdomain preference scales showed that masculine subdomains were bipolar opposites of feminine subdomains. This bipolar structure emerged in analyses conducted on combined-sex groups, high-school boys, high-school girls, men, women, heterosexual men, gay men, heterosexual women, and lesbian women. The results suggest that, although there are distinct masculine and feminine occupational subdomains, gender-related occupational preferences, nonetheless, form a replicable, cohesive, bipolar individual difference dimension, which is not an artifact of studying mixed-sex or mixed-sexual-orientation groups.     

Do Americans Have a Preference for Rule‐Based Classification?

Six experiments investigated variables predicted to influence subjects’ tendency to classify items by a single property (rule‐based responding) instead of overall similarity, following the paradigm of Norenzayan et al. ( 2002 , Cognitive Science), who found that European Americans tended to give more “logical” rule‐based responses. However, in five experiments with Mechanical Turk subjects and undergraduates at an American university, we found a consistent preference for similarity‐based responding. A sixth experiment with Korean undergraduates revealed an effect of instructions, also reported by Norenzayan et al., in which classification instructions led to majority rule‐based responding but similarity instructions led to overall similarity grouping. Our American subjects showed no such difference and used similarity more overall. We conclude that Americans do not have a preference for rule responding in classification and discuss the differences between tasks that reliably show strong rule or unidimensional preferences (category construction and category learning) in contrast to this classification paradigm.     

Do bilinguals have two personalities? A special case of cultural frame switching

Four studies examined and empirically documented Cultural Frame Switching (CFS; Hong, Chiu, & Kung, 1997) in the domain of personality. Specifically, we asked whether Spanish–English bilinguals show different personalities when using different languages? If so, are the two personalities consistent with cross-cultural differences in personality? To generate predictions about the specific cultural differences to expect, Study 1 documented personality differences between US and Mexican monolinguals. Studies 2–4 tested CFS in three samples of Spanish–English bilinguals, located in the US and Mexico. Findings replicated across all three studies, suggesting that language activates CFS for Extraversion, Agreeableness, and Conscientiousness. Further analyses suggested the findings were not due to anomalous items or translation effects. Results are discussed in terms of the interplay between culture and self.     

Does attention-deficit/hyperactivity disorder have a dimensional latent structure? A taxometric analysis

An understanding of the latent structure of attention-deficit/hyperactivity disorder (ADHD) is essential for developing causal models of this disorder. Although some researchers have presumed that ADHD is dimensional and others have assumed that it is taxonic, there has been relatively little research directly examining the latent structure of ADHD. The authors conducted a set of taxometric analyses using data from the NICHD Study of Early Child Care and Youth Development (ns between 667 and 1,078). The results revealed a dimensional latent structure across a variety of different analyses and sets of indicators for inattention, hyperactivity/impulsivity, and ADHD. Furthermore, analyses of correlations with associated features indicated that dimensional models demonstrated stronger validity coefficients with these criterion measures than dichotomous models. These findings jibe with recent research on the genetic basis of ADHD and with contemporary models of ADHD.     

Cultural–geographical differences in the occurrence of child physical abuse? A meta‐analysis of global prevalence

Our comprehensive meta‐analysis combined prevalence figures of child physical abuse reported in 111 studies, including 168 independent samples with a total of 9,698,801 participants. The overall estimated prevalence was 3/1000 for studies using informants and 226/1000 for studies using self‐report measures of child physical abuse, with no apparent gender differences. Methodological factors partly explained the vast variation of self‐reported prevalence rates in individual studies. The highest prevalence rates were found for studies using a broad definition of child physical abuse, studies measuring physical abuse over the longest period of 0–18 years, studies using college samples, studies in which adults served as respondents, and studies using more questions on physical abuse. Cultural–geographical factors did not seem to affect prevalence rates of physical abuse, which may be partly due to procedural factors. More crosscultural research on physical abuse is badly needed, especially in Africa and South America. We conclude that child physical abuse is a widespread, global phenomenon affecting the lives of millions of children all over the world, which is in sharp contrast with the United Nation's Convention on the Rights of the Child.     

Do aggression and rule‐breaking have different interpersonal correlates? A study of antisocial behavior subtypes,negative affect,and hostile perceptions of others

There is mounting evidence that physical aggression and nonaggressive, rule‐breaking delinquency constitute two separable though correlated subtypes of antisocial behavior. Even so, it remains unclear whether these behavioral subtypes have meaningfully different interpersonal correlates, particularly as they are subsumed within the same broad domain of antisocial behavior. To evaluate this, we examined whether hostile perceptions of others (assessed via exposure to a series of neutral unknown faces) were linked to level and type of antisocial behavior aggression vs. rule‐breaking, and moreover, whether this association persisted even when also considering the common association with negative affect (as manipulated via written recollection of one's best and worst life experiences). Analyses revealed that aggression, but not rule‐breaking, was uniquely tied to hostile perceptions of others. Furthermore, this association persisted over and above the common association of both hostile perceptions and aggression with negative affect (at both trait and state levels). Such results provide additional support for clinically meaningful differences between the behavioral subtypes of aggression and nonaggressive rule‐breaking and for the independent role of hostile perceptions in aggressive behavior. Aggr. Behav. 35:453–461, 2009. © 2009 Wiley‐Liss, Inc.     

Do observer ratings validate self-reports of intergroup contact?: A round-robin analysis

Two studies used a round-robin design to examine whether the observers made consensual judgments of targets' degree and quality of intergroup contact, and whether these consensual judgments were correlated with the targets' own self ratings, and moderated by the observability of the contact. Study 1 revealed projection/assumed similarity, with participants rating others as similar to themselves to a large extent, but also yielded evidence for the validity of whites' self-reports of direct, but not extended, intergroup contact with Asians, even when controlling for extraversion and perceived attitudes. Study 2 replicated the main results, using both Asians and Gay men as outgroups, and showed that participants' ratings discriminated between the two discrete outgroups, with measures of contact and attitude being only meaningfully related within, but not between, outgroups. Overall, these findings help to validate self-report measures of direct intergroup contact.