More than just perception–action recalibration: Walking through a virtual environment causes rescaling of perceived space

Egocentric distances in virtual environments are commonly underperceived by up to 50 % of the intended distance. However, a brief period of interaction in which participants walk through the virtual environment while receiving visual feedback can dramatically improve distance judgments. Two experiments were designed to explore whether the increase in postinteraction distance judgments is due to perception–action recalibration or the rescaling of perceived space. Perception–action recalibration as a result of walking interaction should only affect action-specific distance judgments, whereas rescaling of perceived space should affect all distance judgments based on the rescaled percept. Participants made blind-walking distance judgments and verbal size judgments in response to objects in a virtual environment before and after interacting with the environment through either walking (Experiment 1) or reaching (Experiment 2). Size judgments were used to infer perceived distance under the assumption of size–distance invariance, and these served as an implicit measure of perceived distance. Preinteraction walking and size-based distance judgments indicated an underperception of egocentric distance, whereas postinteraction walking and size-based distance judgments both increased as a result of the walking interaction, indicating that walking through the virtual environment with continuous visual feedback caused rescaling of the perceived space. However, interaction with the virtual environment through reaching had no effect on either type of distance judgment, indicating that physical translation through the virtual environment may be necessary for a rescaling of perceived space. Furthermore, the size-based distance and walking distance judgments were highly correlated, even across changes in perceived distance, providing support for the size–distance invariance hypothesis.     

The Impact of Benefit Finding and Leadership on Combat-Related PTSD Symptoms

Benefit finding and unit leadership have been identified as buffers against the negative effects of combat exposure on posttraumatic stress disorder (PTSD) symptoms. However, little is known about how these different buffers work together to protect military personnel from the negative effects of combat. We examined benefit finding and leadership as buffers of the combat–PTSD symptoms link in a sample of recently returned combat veterans (N?=?583). Results revealed that when higher levels of noncommissioned officer (NCO) leadership and benefit finding (BF) were reported, fewer PTSD symptoms were endorsed. Additionally, BF buffered the relationship between combat stress and PTSD symptoms, but only under conditions of supportive officer leadership. Implications of these findings for military settings are discussed.     

Aggressive behavior,related conduct problems,and variation in genes affecting dopamine turnover

A number of dopamine‐related genes have been implicated in the etiology of violent behavior and conduct problems. Of these genes, the ones that code for the enzymes that influence the turnover of dopamine (DA) have received the most attention. In this study, we investigated 12 genetic polymorphisms in four genes involved with DA functioning (COMT, MAOA and MAOB, and DβH) in 179 incarcerated male Russian adolescents and two groups of matched controls: boys without criminal records referred to by their teachers as (a) “troubled‐behavior‐free” boys, n=182; and (b) “troubled‐behavior” boys, n=60. The participants were classified as (1) being incarcerated or not, (2) having the DSM‐IV diagnosis of conduct disorder (CD) or not, and (3) having committed violent or nonviolent crimes (for the incarcerated individuals only). The findings indicate that, although no single genetic variant in any of the four genes differentiated individuals in the investigated groups, various linear combinations (i.e., haplotypes) and nonlinear combinations (i.e., interactions between variants within and across genes) of genetic variants resulted in informative and robust classifications for two of the three groupings. These combinations of genetic variants differentiated individuals in incarceration vs. nonincarcerated and CD vs. no‐CD groups; no informative combinations were established consistently for the grouping by crime within the incarcerated individuals. This study underscores the importance of considering multiple rather than single markers within candidate genes and their additive and interactive combinations, both with themselves and with nongenetic indicators, while attempting to understand the genetic background of such complex behaviors as serious conduct problems. Aggr. Behav. 36:158–176, 2010. © 2010 Wiley‐Liss, Inc.     

Impact of average household income and damage exposure on post‐earthquake distress and functioning: A community study following the February 2011 Christchurch earthquake

Post‐traumatic stress, depression and anxiety symptoms are common outcomes following earthquakes, and may persist for months and years. This study systematically examined the impact of neighbourhood damage exposure and average household income on psychological distress and functioning in 600 residents of Christchurch, New Zealand, 4–6 months after the fatal February, 2011 earthquake. Participants were from highly affected and relatively unaffected suburbs in low, medium and high average household income areas. The assessment battery included the Acute Stress Disorder Scale, the depression module of the Patient Health Questionnaire (PHQ‐9), and the Generalized Anxiety Disorder Scale (GAD‐7), along with single item measures of substance use, earthquake damage and impact, and disruptions in daily life and relationship functioning. Controlling for age, gender and social isolation, participants from low income areas were more likely to meet diagnostic cut‐offs for depression and anxiety, and have more severe anxiety symptoms. Higher probabilities of acute stress, depression and anxiety diagnoses were evident in affected versus unaffected areas, and those in affected areas had more severe acute stress, depression and anxiety symptoms. An interaction between income and earthquake effect was found for depression, with those from the low and medium income affected suburbs more depressed. Those from low income areas were more likely, post‐earthquake, to start psychiatric medication and increase smoking. There was a uniform increase in alcohol use across participants. Those from the low income affected suburb had greater general and relationship disruption post‐quake. Average household income and damage exposure made unique contributions to earthquake‐related distress and dysfunction.     

Clustering of drinker prototype characteristics: What characterizes the typical drinker?

Prototypes (social images) have been shown to influence behaviour, which is likely to depend on the type of image. Prototype evaluation is based on (un)desirable characteristics related to that image. By an elicitation procedure we examined which adjectives are attributed to specific drinker prototypes. In total 149 young Dutch adults (18–25 years of age) provided adjectives for five drinker prototypes: abstainer, moderate drinker, heavy drinker, tipsy, and drunk person. Twenty‐three unique adjectives were found. Multilevel latent class cluster analysis revealed six adjective clusters, each with unique and minor overlapping adjectives: ‘negative, excessive drinker,’ ‘moderate, responsible drinker,’ ‘funny tipsy drinker,’ ‘determined abstainer cluster,’ ‘uncontrolled excessive drinker,’ and ‘elated tipsy cluster.’ In addition, four respondent classes were identified. Respondent classes showed differences in their focus on specific adjective clusters. Classes could be labelled ‘focus‐on‐control class,’ ‘focus‐on‐hedonism class,’ ‘contrasting‐extremes‐prototypes class,’ and ‘focus‐on‐elation class.’ Respondent classes differed in gender, educational level and drinking behaviour. The results underscore the importance to differentiate between various prototypes and in prototype adjectives among young adults: subgroup differences in prototype salience and relevance are possibly due to differences in adjective labelling. The results provide insights into explaining differences in drinking behaviour and could potentially be used to target and tailor interventions aimed at lowering alcohol consumption among young adults via prototype alteration.     

Attention orienting effects of hesitations in speech: evidence from ERPs

Filled-pause disfluencies such as um and er affect listeners' comprehension, possibly mediated by attentional mechanisms (J. E. Fox Tree, 2001). However, there is little direct evidence that hesitations affect attention. The current study used an acoustic manipulation of continuous speech to induce event-related potential components associated with attention (mismatch negativity [MMN] and P300) during the comprehension of fluent and disfluent utterances. In fluent cases, infrequently occurring acoustically manipulated target words gave rise to typical MMN and P300 components when compared to nonmanipulated controls. In disfluent cases, where targets were preceded by natural sounding hesitations culminating in the filled pause er, an MMN (reflecting a detection of deviance) was still apparent for manipulated words, but there was little evidence of a subsequent P300. This suggests that attention was not reoriented to deviant words in disfluent cases. A subsequent recognition test showed that nonmanipulated words were more likely to be remembered if they had been preceded by a hesitation. Taken together, these results strongly implicate attention in an account of disfluency processing: Hesitations orient listeners' attention, with consequences for the immediate processing and later representation of an utterance.     

Motivational and Emotional Consequences of Self-Engagement: Voting in the 2000 U.S. Presidential Election

The role played by self-engagement in the prediction and consequences of goal-directed behavior was examined. Components of the Triangle Model of Responsibility were measured 4 days prior to the 2000 U.S. presidential election, and reported voting and reactions to the election were measured the day after the election. In support of the model, engagement in voting was highest when the guidelines for voting were perceived as clear, when the individual perceived personal control over voting, when the individual perceived voting as relevant to his or her role as a citizen, and when who won the election was important to the individual. Engagement in voting was strongly related to reports of actually voting in the election, and completely mediated the relationship between the other predictors and reported voting. Engagement was also related to a variety of behavioral activities (e.g., watching the presidential and vice-presidential debates, staying up late to watch the election results) indicative of investment in the election. Finally, being engaged in the act of voting prior to the election was strongly related to being in a heightened state of uncertainty and anxiety as a function of not knowing the outcome of the election. The importance of self-engagement in predicting behavior and emotional consequences to behavior is discussed.