The development of sensitivity to biological motion in noise

We investigated developmental changes in sensitivity to biological motion by asking 6-year-olds, 9-year-olds, and adults (twenty-four in each group) to discriminate point-light biological motion displays depicting one of a variety of human movements from scrambled versions of the same displays. When tested without noise dots, participants at all ages performed near ceiling levels and no differences in accuracy were found among the three age groups. Age differences emerged in the second task, in which we used a staircase procedure to determine threshold values of the number of noise dots that could be tolerated in producing a percentage correct value corresponding to a d' value of 1.4. Sensitivity to biological motion improved linearly with age (p < 0.01), with 6-year-olds performing significantly more poorly than adults. This immature performance contrasts with adult-like accuracy by 4 years of age for sensitivity to global motion (Parrish et al, 2005 Vision Research 45 827-837). The comparison implies an immaturity at 6 years of age in the neural networks involved specifically in the processing of biological motion, networks that may include the superior temporal sulcus (STS).     

Some effects of methylphenidate on stimulus control of ratio avoidance behavior in the rat

After exposure to an avoidance schedule which included a warning signal, a rat was placed on a multiple schedule in which the first component was the same as before, i.e., a single response reset the response-shock interval, delaying shock, and the second component differed only in that four bar-presses were required to postpone shock. A fixed ratio requirement of four responses (FR 4) generated behavior resembling a fixed ratio requirement of one response (FR 1) since responding was controlled by the warning signal but more shocks were received. At a dosage of 2 mg/kg, methylphenidate given intraperitoneally decreased shock frequency during FR 4 periods while FR 1 behavior was not affected; at 4 mg/kg, stimulus control of avoidance responding was impaired during both components. Results at 4 mg/kg were partially confirmed by two animals exposed to an FR 4 avoidance schedule which included a warning signal but with different parameters. Response distributions showed that methylphenidate increased response rates in the absence of the warning signal, i.e., stimulus control of ratio-avoidance behavior was impaired although the increased response rates reduced shock frequency. One hour later responses again occurred more frequently during the signal than in its absence but shocks were less frequent than during control (non-drug) periods.     

The Roles of Social Media Use and Friendship Quality in Adolescents’ Internalizing Problems and Well-being

Journal of Happiness Studies - Adolescents spend increasing amounts of time using social media, but whether social media use has a beneficial or harmful role in internalizing problems and...     

I see what you’re saying: Voice signals influence children’s judgments of direct and averted gaze

Adults use gaze and voice signals as cues to the mental and emotional states of others. We examined the influence of voice cues on children’s judgments of gaze. In Experiment 1, 6-year-olds, 8-year-olds, and adults viewed photographs of faces fixating the center of the camera lens and a series of positions to the left and right and judged whether gaze was direct or averted. On each trial, participants heard the participant-directed voice cue (e.g., “I see you”), an object-directed voice cue (e.g., “I see that”), or no voice. In 6-year-olds, the range of directions of gaze leading to the perception of eye contact (the cone of gaze) was narrower for trials with object-directed voice cues than for trials with participant-directed voice cues or no voice. This effect was absent in 8-year-olds and adults, both of whom had a narrower cone of gaze than 6-year-olds. In Experiment 2, we investigated whether voice cues would influence adults’ judgments of gaze when the task was made more difficult by limiting the duration of exposure to the face. Adults’ cone of gaze was wider than in Experiment 1, and the effect of voice cues was similar to that observed in 6-year-olds in Experiment 1. Together, the results indicate that object-directed voice cues can decrease the width of the cone of gaze, allowing more adult-like judgments of gaze in young children, and that voice cues may be especially effective when the cone of gaze is wider because of immaturity (Experiment 1) or limited exposure (Experiment 2).     

Developmental changes during childhood in single-letter acuity and its crowding by surrounding contours

Crowding refers to impaired target recognition caused by surrounding contours. We investigated the development of crowding in central vision by comparing single-letter and crowding thresholds in groups of 5-year-olds, 8-year-olds, 11-year-olds, and adults. The task was to discriminate the orientation of a Sloan letter E. Single-letter thresholds, defined as the stroke width forming the smallest discriminable E, were worse than those of adults (0.83 arcmin) at 5 years of age (1.05 arcmin) but not at older ages (8-year-olds: 0.81 arcmin; 11-year-olds: 0.78 arcmin). The maximum distances over which crowding occurred, as measured in multiples of threshold stroke width, were smaller in adults (2.83) than in the three groups of children, who did not differ from each other (5-year-olds: 7.03; 8-year-olds: 7.84; 11-year-olds: 7.13). Thus, even 11-year-olds are more affected than adults by surrounding contours despite having single-letter acuity that has been mature for several years. The stronger influence of crowding in children may be caused by immaturities in the brain areas beyond the primary visual cortex (V1) where early visual inputs are combined and may contribute to their slower reading speed.     

Romantic relationships and sexuality in adolescence and young adulthood: The role of parents,peers, and partners

The formation of romantic relationships and the engagement in sexual behaviours are considered normative and salient developmental tasks for adolescents and young adults. These developmental tasks are increasingly viewed from an ecological perspective, thus not only as individual processes, but also as strongly embedded in different social contexts, including the proximal social domains of parents, peers, and partners. This special issue brings together seven recent empirical studies on adolescents' and young adults' romantic relationships and sexuality in the context of relationships and interactions with parents, peers, and partners. In this editorial introduction, we describe two important recent changes in the theoretical perspectives on emerging romantic relationships and sexual activity: from risky behaviours to normative tasks, and from individual to contextualized processes. We then discuss recent advances in empirical research on romantic relationships and sexuality of adolescents and young adults. After that, we review the seven studies in this special issue, and discuss the contributions of these studies to the existing literature. Finally, we discuss directions for future research regarding how the interrelational perspective can be further incorporated into empirical research, and how the gap between the research fields on romantic relationships and sexuality may be bridged.     

The many faces of configural processing

Adults' expertise in recognizing faces has been attributed to configural processing. We distinguish three types of configural processing: detecting the first-order relations that define faces (i.e. two eyes above a nose and mouth), holistic processing (glueing the features together into a gestalt), and processing second-order relations (i.e. the spacing among features). We provide evidence for their separability based on behavioral marker tasks, their sensitivity to experimental manipulations, and their patterns of development. We note that inversion affects each type of configural processing, not just sensitivity to second-order relations, and we review evidence on whether configural processing is unique to faces.     

A Necessary Neologism: The Origin and Uses of Suicide

In English-speaking societies today the word suicide is the preferred term for self-inflicted death. But it has not always been so. Evidence recounted here suggests that suicide was devised by Sir Thomas Browne and first published in his book Religio Medici in 1643. Although little used at first, suicide had become established as noun and verb by the mid-18th century and was recognized by inclusion in Johnson's Dictionary. The modern world has seen an enormous increase in words and expressions derived from suicide, some of which are discussed here.