Laterality effects in the spinning dancer illusion: The viewing‐from‐above bias is only part of the story

The ‘silhouette illusion’, representing the silhouette of a female dancer pirouetting about her vertical axis, is a bistable stimulus created by Japanese web designer Nobuyuki Kayahara. Although the dancer can be perceived as spinning either clockwise or counterclockwise, the clockwise rotation is usually preferred. Troje and McAdam (i‐Perception, 2010, 1, 143) showed that this clockwise bias can be attributed to the tendency to assume a viewpoint from above rather than from below, given that the dancer is portrayed from a vantage point that is not perpendicular to the axis of rotation. Here, we tested whether another possible factor contributing to the observers’ interpretation of this bistable stimulus might be the tendency to perceive movements of the right rather than the left foot. We confirmed both the viewing‐from‐above bias and our hypothesis. The bias to perceive movements of the right leg might be a generalization to lower limbs of a perceptual frequency effect already observed for upper limbs. Such a perceptual and attentional bias towards the right hand/foot could account for the greater ability to predict the outcome of sport actions when observing right‐ rather than left‐limbed movements, and thus the left‐handers' and left‐footers' advantage observed in a variety of interactive sports.     

Drug Use Among Immigrant and Non‐immigrant Adolescents: Immigrant Paradox,Family and Peer Influences

The present study compared immigrant and Italian native adolescents with regard to drug use. Additionally, we analysed the role of family and peer risk and protective factors for drug use. Participants included 2533 Italian native and immigrant adolescents (mean age = 17.19, SD = 1.6; 66.7% male). Results showed that immigrant adolescents reported lower levels of marijuana and pharmaceutical drug abuse than non‐immigrant adolescents. These results confirm the so‐called immigrant paradox phenomenon: the counterintuitive finding that although immigrants often live under challenging conditions and reported lower economic affluence compared with nationals, some health outcomes have not always corresponded to their relative disadvantage. Immigrant adolescents also reported higher level of parental control and lower levels of affiliation with deviant peers, but lower levels of child disclosure, parental solicitation and parental knowledge. Socio‐economic status and parental monitoring showed equivalent effects on drug use for immigrant and non‐immigrant adolescents. Results have implications for preventive interventions for immigrant adolescents and families, including the need to develop programmes that leverage the benefits of the immigrant paradox for immigrant communities. Future research should analyse the processes that lead to lower levels of drug use in immigrant adolescents and investigate the influence of friendship networks on immigrant adolescent drug use behaviour. Copyright © 2015 John Wiley & Sons, Ltd.     

Post-stroke depression: Main phenomenological clusters and their relationships with clinical measures

Objectives: To investigate the principal psychopathological dimensions of post-stroke depression (PSD) through the assessment of the factorial structure of the Post-Stroke Depression Rating Scale (PSDRS). Methods: We enrolled ninety-eight subjects with PSD, who underwent the PSDRS, MMSE and Barthel Index. Information about demographic, clinical, and neuroanatomical factors was collected. Results: The factor analysis extracted three factors accounting for 63.4% of the total variance, and identified as: 1) "Depressive and Anxious Symptoms" (DAS); 2) "Lack of Emotional Control" (LEC); 3) "Reduced Motivation" (RM). On multivariate statistics, DAS severity was predicted by previous history of mood disorders and Barthel Index; LEC severity was predicted by Barthel Index; RM severity was predicted by age. Conclusions: The PSDRS displayed a reliable factor structure that agreed with previous interpretation of PSD. In particular, core depressive symptoms seem to be related to premorbid personality and functional status, whereas apathy/anhedonia may be connected to brain aging.     

Emerging perception of causality in action-and-reaction sequences from 4 to 6 months of age: Is it domain-specific?

Two experiments (N=136) studied how 4- to 6-month-olds perceive a simple schematic event, seen as goal-directed action and reaction from 3 years of age. In our causal reaction event, a red square moved toward a blue square, stopping prior to contact. Blue began to move away before red stopped, so that both briefly moved simultaneously at a distance. Primarily, our study sought to determine from what age infants see the causal structure of this reaction event. In addition, we looked at whether this causal percept depends on an animate style of motion and whether it correlates with tasks assessing goal perception and goal-directed action. Infants saw either causal reactions or noncausal delayed control events in which blue started some time after red stopped. These events involved squares that moved either rigidly or nonrigidly in an apparently animate manner. After habituation to one of the four events, infants were tested on reversal of the habituation event. Spatiotemporal features reversed for all events, but causal roles changed only in reversed reactions. The 6-month-olds dishabituated significantly more to reversal of causal reaction events than to noncausal delay events, whereas younger infants reacted similarly to reversal of both. Thus, perceptual causality for reaction events emerges by 6 months of age, a younger age than previously reported but, crucially, the same age at which perceptual causality for launch events has emerged in prior research. On our second question, animate/inanimate motion had no effect at any age, nor did significant correlations emerge with our additional tasks assessing goal perception or goal-directed object retrieval. Available evidence, here and elsewhere, is as compatible with a view that infants initially see A affecting B, without differentiation into physical or psychological causality, as with the standard assumption of distinct physical/psychological causal perception.     

“Don't let the group down”: Facets of instrumentality moderate the motivating effects of groups in a field experiment

The motivating effects of group work as compared with individual work are not restricted to the research laboratory but have recently been documented in existing groups performing meaningful tasks. Freestyle swimmers at the 2008 Olympics were shown to swim faster in relay groups than in the individual competitions when their contribution was highly instrumental for the relay group (i.e., indispensable) because of their serial position in the group. The present study replicated and extended this work, aggregating a larger sample from major sports events (N = 199 freestyle swimmers) that also allowed for a competitive test between the instrumentality approach and explanations based on differences in the starting procedures of relay and individual competitions. Consistent with expectancy value models of effort expenditure in groups, swimmers were faster in the relay groups as compared with individual competitions only when (i) a swimmer's performance was highly instrumental for the group's performance (i.e., later serial position in the relay) and (ii) the group's performance was highly instrumental for a positive group outcome (i.e., the relay group had a good chance of winning a medal). The data were not consistent with an explanation of performance differences merely as a result of different starting procedures. Copyright © 2012 John Wiley & Sons, Ltd.     

Upward and downward comparison in the intermediate-status group: the role of social stratification stability

This work analyses intergroup comparison choices made by intermediate-status group members. Seventy-six psychology students were categorized in an intermediate position with respect to other faculties. Stability was manipulated at three levels: stable, upwardly unstable, and downwardly unstable. Data on strength of comparison, comparison for enhancing, comparison for evaluation, and ingroup identification were collected. Results revealed that in the stable condition, participants were equally engaged in both upward and downward comparison. In the upwardly unstable condition, participants were more likely to compare themselves with the high-status group, whereas in the downwardly unstable condition, they were more likely to choose a downward comparison. In this latter condition, both downward comparison for enhancement and in-group identification were lower than in other conditions.     

Grandiose Fantasies and Low Self-Esteem: An Experimental Study

Grandiose states of mind could be an ineffective way to cope with low self-esteem. In fact, it is possible that grandiose fantasies would tend to induce doubts about personal worth and decrease self-esteem. This study explored whether grandiose fantasies help to cope with low self-esteem. The self-reported occurrence and unpleasantness of intrusive thoughts regarding the sense of exclusion, humiliation, and low self-esteem in non-clinical individuals were assessed during self-induced grandiose fantasies and self-induced relaxation. The occurrence and unpleasantness of low self-esteem intrusions were significantly higher during grandiose fantasies, suggesting that grandiose fantasy is ineffective at combating low self-esteem.     

Lasting effects of alcohol: Subliminal alcohol cues,impairment expectancies,and math performance

Many people believe that drinking alcohol reduces cognitive performance, and prior research has shown such expectancy‐related impairment even when people merely thought that the (non‐alcoholic) drink they consumed contained alcohol. This study tested whether subliminal priming with alcohol‐related cues would similarly result in expectancy‐consistent cognitive performance decrements. Additionally, the moderating role of alcohol use was examined. After assessing participants' baseline math performance, participants were primed with alcohol‐related or neutral words and then completed a post‐treatment math task. Whereas impairment expectancies had no influence on math performance in control participants, expectancies predicted math performance for participants primed with alcohol‐related words. As hypothesized, expectancy‐consistent impairment in performance was only observed among high alcohol users. The current findings suggest that, in the presence of alcohol‐related cues in the environment, some people may perform less on cognitive tasks even in the absence of actual or assumed alcohol consumption and without being aware of it. Copyright © 2011 John Wiley & Sons, Ltd.     

Measured and predicted mechanical internal work in human locomotion

Predictive methods estimating mechanical internal work (W_int, i.e., work to accelerate limbs with respect to BCOM during locomotion) are needed in absence of experimental measurements. A previously proposed model equation predicts such a parameter based upon velocity, stride frequency, duty factor, and a compound critical term (q) accounting for limb geometry and inertial properties. That first predicted W_int estimate (PW_int) has been validated only for young males and for a limited number of horses. The present study aimed to extend the comparison between model predictions and experimentally measured W_int (MW_int) data on humans with varying gender, age, gait, velocity, and gradient. Seventy healthy subjects (males and females; 7 age groups: 6-65 years) carried out level walking and running on treadmill, at different velocities. Moreover, one of the subject groups (25-35 years) walked and ran also at several uphill/downhill gradients. Reference values of q represent the main important results: (a) males and females have similar q values; (b) q is independent on velocity and gradient. Also, different data filtering depth was found to affect MW_int and, indirectly, PW_int, thus also the reference q values here obtained (0.08 in level, 0.10 in gradient) suffer a - 20% underestimation with respect to the previous predicting model. Despite of this effect, the close match between MW_int and PW_int trends indicates that the model equation could be satisfactorily applied, in various locomotion conditions.