Adaptation to continuous perturbation of balance: progressive reduction of postural muscle activity with invariant or increasing oscillations of the center of mass depending on perturbation frequency and vision conditions

We investigated the adaptation of balancing behavior during a continuous, predictable perturbation of stance consisting of 3-min backward and forward horizontal sinusoidal oscillations of the support base. Two visual conditions (eyes-open, EO; eyes-closed, EC) and two oscillation frequencies (LF, 0.2 Hz; HF, 0.6 Hz) were used. Center of Mass (CoM) and Center of Pressure (CoP) oscillations and EMG of Soleus (Sol) and Tibialis Anterior (TA) were recorded. The time course of each variable was estimated through an exponential model. An adaptation index allowed comparison of the degree of adaptation of different variables. Muscle activity pattern was initially prominent under the more challenging conditions (HF, EC and EO; LF, EC) and diminished progressively to reach a steady state. At HF, the behavior of CoM and CoP was almost invariant. The time-constant of EMG adaptation was shorter for TA than for Sol. With EC, the adaptation index showed a larger decay in the TA than Sol activity at the end of the balancing trial, pointing to a different role of the two muscles in the adaptation process. At LF, CoM and CoP oscillations increased during the balancing trial to match the platform translations. This occurred regardless of the different EMG patterns under EO and EC. Contrary to CoM and CoP, the adaptation of the muscle activities had a similar time-course at both HF and LF, in spite of the two frequencies implying a different number of oscillation cycles. During adaptation, under critical balancing conditions (HF), postural muscle activity is tuned to that sufficient for keeping CoM within narrow limits. On the contrary, at LF, when vision permits, a similar decreasing pattern of muscle activity parallels a progressive increase in CoM oscillation amplitude, and the adaptive balancing behavior shifts from the initially reactive behavior to one of passive riding the platform. Adaptive balance control would rely on on-line computation of risk of falling and sensory inflow, while minimizing balance challenge and muscle effort. The results from this study contribute to the understanding of plasticity of the balance control mechanisms under posture-challenging conditions.     

People believe each other to be selfish hedonic maximizers

Current computational models of theory of mind typically assume that humans believe each other to selfishly maximize utility, for a conception of utility that makes it indistinguishable from personal gains. We argue that this conception is at odds with established facts about human altruism, as well as the altruism that humans expect from each other. We report two experiments showing that people expect other agents to selfishly maximize their pleasure, even when these other agents behave altruistically. Accordingly, defining utility as pleasure permits us to reconcile the assumption that humans expect each other to selfishly maximize utility with the fact that humans expect each other to behave altruistically.     

Grandparent-grandchild contact and attitudes toward older adults: moderator and mediator effects

Two studies tested the intergroup contact hypothesis in the context of the grandparent-grandchild relationship. The hypothesis suggests that contact with an out-group member has more influence on attitudes toward the out-group when group memberships are salient. In Study 1, the predicted link was found but only for grandparents with whom the grandchild had more frequent contact. The second study examined only the most frequent grandparent relationship and replicated the effect. This study also investigated the role of various mediators of the link between quality of contact and attitudes, as well as quality of contact and perceived out-group variability. Perspective taking, anxiety, and accommodation mediated the effects of contact on attitudes, whereas individuation and self-disclosure mediated the effects of contact on perceived out-group variability. Moderated mediational analysis indicated that the moderating effect of group salience occurs between quality of contact and the mediator, not between the mediator and attitudes.     

The moderating role of internalising negative emotionality in the relation of self-regulation to social adjustment in Italian preschool-aged children

The purpose of this study was to examine the moderating role of internalising negative emotionality (i.e., anxious, concerned, and embarrassed displays) in the association between children's self-regulation and social adjustment. Seventy-four Italian children (44 girls, 30 boys; M age?=?35.05 months, SD?=?3.57) were assessed using two self-regulation tasks. Internalising negative emotionality was assessed through observations of children's emotion expressions during the tasks. Teachers evaluated children's social competence and internalising and externalising problems. Results demonstrated that among children who exhibited internalising negative emotionality, self-regulation was positively associated with social competence and negatively related to externalising problems. Our results suggest that self-regulation may play a crucial role for social adjustment when children show emotions such as anxiety and embarrassment during challenging situations.     

A method for the definition of a self-awareness behavior dimension with clinical subjects: A latent trait analysis

The main scope of the present study was to devise a method in order to define a dimension characteristic of self-awareness behaviors with clinical subjects. To do so, I adopted a latent trait methodological approach. I studied the way patients expressed their treatment requests through their behaviors, both during their admission to a medical center in Northern Italy and after a period of treatment that involved an integrated (psychoanalytical and pharmacological) approach. The subjects were 48 females suffering from affective disorders, often combined with personality disorders. Five self-awareness indicators were identified, based both on interviews conducted with the patients and on the literature on the subject. The data gathered were analyzed by means of the many-facet Rasch model (Linacre, 1989). The results confirmed the existence of a self-awareness dimension characterized by the five indicators. Moreover, there was evidence that an improvement in self-awareness occurred during the pretreatment to posttreatment time period for both the affective disorders with personality problems patients and the affective disorders without personality problems patients. The estimation of bias/interactions showed the existence of specific behavioral differences between the two groups of patients. This study demonstrates the appropriateness of the methodological tool adopted, opening new expectations with regard to the integration of two approaches—psychoanalytical and pharmacological ones—in the treatment of psychiatric subjects.     

The Editing Density of Moving Images Influences Viewers’ Time Perception: The Mediating Role of Eye Movements

The present study examined whether cinematographic editing density affects viewers’ perception of time. As a second aim, based on embodied models that conceive time perception as strictly connected to the movement, we tested the hypothesis that the editing density of moving images also affects viewers’ eye movements and that these later mediate the effect of editing density on viewers’ temporal judgments. Seventy participants watched nine video clips edited by manipulating the number of cuts (slow- and fast-paced editing against a master shot, unedited condition). For each editing density, multiple video clips were created, representing three different kinds of routine actions. The participants’ eye movements were recorded while watching the video, and the participants were asked to report duration judgments and subjective passage of time judgments after watching each clip. The results showed that participants subjectively perceived that time flew more while watching fast-paced edited videos than slow-paced or unedited videos; by contrast, concerning duration judgments, participants overestimated the duration of fast-paced videos compared to the master-shot videos. Both the slow- and the fast-paced editing generated shorter fixations than the master shot, and the fast-paced editing led to shorter fixations than the slow-paced editing. Finally, compared to the unedited condition, editing led to an overestimation of durations through increased eye mobility. These findings suggest that the editing density of moving images by increasing the number of cuts effectively altered viewers’ experience of time and add further evidence to prior research showing that performed eye movement is associated with temporal judgments.     

Attentional Orienting to Emotional Faces Moderates the Association Between Callous-Unemotional Traits and Peer-Nominated Aggression in Young Adolescent School Children

Callous-unemotional (CU) traits are associated with aggressive behavior but preliminary research suggests this relationship is modified by patterns of emotional processing. This study examined whether attentional orienting to emotional faces moderated the association between CU traits and peer-nominated aggression in 251 middle school students (53% females, mean age = 13.24 years, SD = 0.73). Attentional orienting was assessed using an emotional faces (i.e., angry, fearful, happy, sad, and neutral) variant of the dot-probe task. Students also completed a self-report measure of CU traits and their classmates made peer nominations of aggression. Logistic regression analyses showed that peer-nominated aggression was positively related to CU traits at low levels of attentional orienting to angry faces, whereas aggression was unrelated to CU traits at high levels of attentional orienting to angry faces. That is, peer-nominated aggression was greatest for youth high on CU traits who were not engaged by angry faces. These findings support the importance of considering different patterns of emotional responding when studying the association between CU traits and aggressive behavior in youth.