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Child-directed speech has long been known to influence children's vocabulary learning. However, while we know that caregiver utterances differ from those directed at adults in various ways, little is known about any differences in the lexical properties of child-directed and adult-directed utterances. We compare over half a million word tokens from adult speech directed at children (from caregiver--child transcriptions) to the same quantity directed at adults. We show that child-directed speech contains greater numbers of words that are lower in phonemic length, higher in frequency, lower in phonotactic probability, and higher in neighborhood density than adult-directed speech; furthermore, child-directed speech explains over twice the variability of children's productive noun vocabularies than adult-directed speech. These findings indicate that children's word production is clearly influenced by the characteristics of the words spoken directly to them and that researchers need to be wary of using adult-directed language corpora when calculating lexical measures.

Socially disruptive behavior during peer interactions in early childhood is detrimental to children's social, emotional, and academic development. Few studies have investigated the developmental underpinnings of children's socially disruptive behavior using genetically sensitive research designs that allow examination of parent-on-child and child-on-parent (evocative genotype-environment correlation [rGE]) effects when examining family process and child outcome associations. Using an adoption-at-birth design, the present study controlled for passive genotype-environment correlation and directly examined evocative rGE while examining the associations between family processes and children's peer behavior. Specifically, the present study examined the evocative effect of genetic influences underlying toddler low social motivation on mother-child and father-child hostility and the subsequent influence of parent hostility on disruptive peer behavior during the preschool period. Participants were 316 linked triads of birth mothers, adoptive parents, and adopted children. Path analysis showed that birth mother low behavioral motivation predicted toddler low social motivation, which predicted both adoptive mother-child and father-child hostility, suggesting the presence of an evocative genotype-environment association. In addition, both mother-child and father-child hostility predicted children's later disruptive peer behavior. Results highlight the importance of considering genetically influenced child attributes on parental hostility that in turn links to later child social behavior. Implications for intervention programs focusing on early family processes and the precursors of disrupted child social development are discussed.

Empirical research examining the situational characteristics of gambling and their effect on gambling behaviour is limited but growing. This experimental pilot investigation reports the first ever empirical study into the combined effects of both music and light on gambling behaviour. While playing an online version of roulette, 56 participants took part in one of four experimental conditions (14 participants in each condition); (1) gambling with fast tempo music under normal (white) light, (2) gambling with fast tempo music under red light, (3) gambling with slow tempo music under normal (white) light, and (4) gambling with slow tempo music under red light. Risk (dollars spent) per spin and speed of bets were measured as indicators of gambling behaviour. Significant main effects were found for speed of bets in relation to musical tempo, but not light. No significant effects were found for risk per spin for either of the two independent variables. A significant interaction between light and music for speed of bets was shown. Planned comparisons revealed that fast tempo music under red light resulted in faster gambling. These findings are discussed along with the methodological limitations, and potential implications for various stakeholders including the gambling industry and practitioners.

Experience is positively related to performance, but it is less clear whether experience might also minimise the deleterious effects of anxiety and arousal in stressful situations. One hundred and twenty-seven UK firearms officers of different experience levels participated in an experiment examining the extent to which anxiety affects performance during a bi-annual qualification shoot. Performance and anxiety were compared on a low-arousal development shoot and a high-arousal qualification shoot; qualification shoot failure would result in removal from operational duties. Heart rate and responses to the State-Trait Anxiety questionnaire were examined in relation to shooting performance. Less experienced officers demonstrated significantly higher baseline corrected mean heart rates, higher anxiety levels and lower accuracy than their more experienced counterparts, who maintained accuracy, despite a significant increase in heart rate during the qualification compared to the development shoot. The results, some of the first to examine British firearms officers in their natural training environment, suggest experience reduces the physiological impact of arousal on performance in pressurised situations. We discuss options for reducing the impact on performance in less experienced officers. [ABSTRACT FROM AUTHOR]

The cost of searching for two visual targets simultaneously was compared against two separate single-target searches using exposure time and accuracy measures within a staircase procedure. Dual-target search for all stimuli (colour, shape and orientation) exhibited a loss of accuracy for one target. For orientation and shape, this dual-target cost in accuracy was extreme, with chance-level performance on one target. For colour, dual-target search exhibited an additional cost in search time, with search requiring a longer exposure than the summed time required for two single-target searches. An additional search-time cost was also found for orientation targets when irrelevant colour variation was added to the display. In conclusion, dual-target search for dissimilar targets is accompanied by an accuracy cost. Furthermore, colour variation, whether task-relevant or not, leads to an additional cost in processing speed. The results suggest that a divided-effort strategy would improve performance in search tasks such as X-ray baggage screening. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Independent-resource models of visual short-term memory (VSTM) predict an inverse relationship between recall accuracy and the number of values for separate visual features (e.g., Wang et al., 2017). Slot models in contrast, predict all-or-none recall of separate features for objects that are encoded in VSTM (e.g., Luck & Vogel, 1997). The current study contrasted these predictions using a change detection task for objects that varied in their colour and orientation. Observers were cued to attend colour or orientation and the distribution of the attended and unattended feature was varied across objects in the display. Observers' accuracy to change on each dimension was equated using a staircase procedure. Comparisons of d' indicated change-discriminability was sensitive to the distribution of the attended but not the unattended feature. Pupil dilation during the retention period was i) larger on attend-colour than attend-orientation trials, ii) sensitive to the distribution of the attended feature across objects and iii) negatively associated with d'. These findings are consistent with independent-resource models of VSTM. The data also demonstrate dependencies between changes in pupil dilation during the retention of non-spatial features, and signal theoretic indices of change-discriminability, for objects that vary on attended and unattended features. [ABSTRACT FROM AUTHOR]