Left gaze bias in humans, rhesus monkeys and domestic dogs

While viewing faces, human adults often demonstrate a natural gaze bias towards the left visual field, that is, the right side of the viewee’s face is often inspected first and for longer periods. Using a preferential looking paradigm, we demonstrate that this bias is neither uniquely human nor limited to primates, and provide evidence to help elucidate its biological function within a broader social cognitive framework. We observed that 6-month-old infants showed a wider tendency for left gaze preference towards objects and faces of different species and orientation, while in adults the bias appears only towards upright human faces. Rhesus monkeys showed a left gaze bias towards upright human and monkey faces, but not towards inverted faces. Domestic dogs, however, only demonstrated a left gaze bias towards human faces, but not towards monkey or dog faces, nor to inanimate object images. Our findings suggest that face- and species-sensitive gaze asymmetry is more widespread in the animal kingdom than previously recognised, is not constrained by attentional or scanning bias, and could be shaped by experience to develop adaptive behavioural significance.     

卫生经济学视野中的医患合谋

从分析医患合谋道德风险的影响因素入手,结合卫生经济学的供给曲线和需求曲线探讨产生医患合谋道德风险的原因和规避策略.发现医疗保险的供给方(保险机构)、医疗服务的提供方(医疗服务机构)和医疗保险的被保险方(医疗保险的消费者,即接受医疗服务的消费者或患者)三者之间信息不对称是导致道德风险的重要因素,保险基金风险更多是来自医疗服务提供方的道德风险.建议从建立信息公开制度,加强监督;加强激励,遏制道德风险;运用技术,规范行为三方面规范医疗服务提供方的行为.     

The role of regional heterogeneity in age-related differences in functional hemispheric asymmetry: an fMRI study

Neuroimaging literature has documented age-related hemispheric asymmetry reduction in frontal regions during task performances. As most studies employed working memory paradigms, it is therefore less clear if this pattern of neural reorganization is constrained by working memory processes or it would also emerge in other cognitive domains which are predominantly lateralized. Using blocked functional magnetic resonance imaging (fMRI), the present study used a homophone judgment task and a line judgment task to investigate age-related differences in functional hemispheric asymmetry in language and visuospatial processing respectively. Young and older adults achieved similar task accuracy although older adults required a significantly longer time. Age-related functional hemispheric asymmetry reduction was found only in dorsal inferior frontal gyrus and was associated with better performance when the homophone condition was contrasted against fixation, and not line condition. Our data thus highlights the importance of considering regional heterogeneity of aging effects together with general age-related cognitive processes.     

The modulation of stimulus structure on visual field asymmetry effects: The case of Chinese character recognition

Recent research suggests that visual field (VF) asymmetry effects in visual recognition may be influenced by information distribution within the stimuli for the recognition task in addition to hemispheric processing differences: Stimuli with more information on the left have a right VF (RVF) advantage because the left part is closer to the centre, where the highest visual acuity is obtained. It remains unclear whether visual complexity distribution of the stimuli also has similar modulation effects. Here we used Chinese characters with contrasting structures—left-heavy, symmetric, and right-heavy, in terms of either visual complexity of components or information distribution defined by location of the phonetic component—and examined participants' naming performance. We found that left-heavy characters had the largest RVF advantage, followed by symmetric and right-heavy characters; this effect was only observed in characters that contrasted in information distribution, in which information for pronunciation was skewed to the phonetic component, but not in those that contrasted only in visual complexity distribution and had no phonetic component. This result provides strong evidence for the influence of information distribution within the stimuli on VF asymmetry effects; in contrast, visual complexity distribution within the stimuli does not have similar modulation effects.     

道德概念垂直空间隐喻理解中的映射:双向性及不平衡性

通过4个实验考察道德概念垂直空间隐喻理解中的映射机制和特征。实验1采用空间Stroop范式,发现被试判断完道德词后,对判断随后呈现在屏幕上方或下方字母的反应时的差异不显著,没有发现词汇类型对空间位置的影响。实验2采用有意识迫选法,要求被试出声读出屏幕中央的道德词后,对屏幕上方或下方的希腊语非词进行二择一迫选,发现被试读出道德词后倾向于选择屏幕上方的非词,读出不道德词后倾向于选择屏幕下方的非词。实验3仍采用Stroop范式,发现被试做出空间"上"的判断后,对随后道德词的词义判断反应时显著快于不道德词,做出空间"下"的判断后,对不道德词的反应时显著快于道德词。实验4探讨空间位置是否会对判断人物的道德性产生影响,结果发现被试倾向于认为屏幕上方的人物是道德的,而屏幕下方的人物是不道德的。4个实验的结果表明,在道德概念垂直空间隐喻的理解中,映射的方式是灵活的、双向的,既可以由始源域向目标域映射,也可以由目标域向始源域映射,但两个方向上的映射力量是不平衡的。     

客体与空间工作记忆的分离：来自皮层慢电位的证据

利用128导事件相关电位技术,采用延迟匹配任务的实验范式,测查了16名正常被试在完成客体任务和空间任务时的皮层慢电位（slow cortical potentials,简称sp成分）,实验发现：在后部脑区,客体工作记忆与空间工作记忆在慢波活动的时间上存在分离,空间任务更早的诱发出负sp成分,并且空间任务激活更多的后部脑区;左下前额叶在客体工作记忆任务与空间工作记忆任务中都有激活,并且激活强度不存在显著差异;背侧前额叶主要负责客体信息的保持与复述,但左右背侧前额叶的激活强度存在不对称性。     

Brain asymmetry and autonomic conditioning: Sensitization control

In the present experiment we report effects of cerebral asymmetry, or laterality, during classical conditioning to facial emotional stimuli. Twenty-five female subjects were presented with slides of a happy face in one visual half-field (VHF), and simultaneously a slide of an angry face in the other VHF, followed by shock as the unconditioned stimulus (UCS). To control for effects of sensitization, a new stimulus, never associated with the UCS, was introduced in the extinction phase. Dependent measures were phasic heart rate responses (HR) and skin conductance responses (SCR). The HR results showed a significant right hemisphere effect for the CS-UCS association, that was not attributable to UCS sensitization. No significant effects were found for the SCRs. The basic HR finding was a right hemisphere superiority for learning of a conditioned association.     

Is sexual-aggressive vocal communication related to asymmetric mechanisms in the brain?

In Mongolian gerbil males, a reliable asymmetric relationship has been discovered between a stereotyped ultrasonic vocalizattion and the volume of a discrete nucleus within the preoptic-anterior hypothalamic area, the sexually dimorphic area, pars compacta (SDApc). The steroid-sensitive ultrasonic, emitted at high levels during courtship interactions, is associated with the absence of aggressive encounters and appears to be necessary for the formation and maintenance of pair-bonds with females. Interactions between unfamilliar, non-pair-bonded adult male and estrous female gerbils result in male aggression, reduction of male ultrasonic calling, and disruption of normal female dartmale follow sociosexual sequences. Castration further reduces ultrasonic calling, inhibits normal sociosexual sequences, and increses aggression in interaction between unfamiliar compared to pair-bonded individuals. Bothg brain structure and lateralization of vocal function in males depend on the action of sex steroids during sexual differentiation and in adulthood. Thus, the gerbil provides a new model to study steroid-dependent lateralization of brain mechanisms of vocal behavior mediating aggressive-sexual relationships. © 1994 Wiley-Liss, Inc.     

Close to me: The importance of closeness versus superficiality in explaining the positive-negative contact asymmetry

The evidence for differential effects of positive and negative intergroup contact on prejudice is mixed. We propose that the closeness of the relationships respondents have with contact partners can explain inconsistencies in previous findings. In three studies (total N = 953), we tested the associations between positive intimate, negative intimate, positive superficial, and negative superficial contact and attitudes toward different outgroups (immigrants and gay people). We hypothesized that: (H1) the effect of positive contact would be maximized in intimate interactions; (H2) the effect of negative contact would be maximized in superficial interactions; (H3) positive intimate and negative superficial contact would have similar power in predicting attitudes. Results always supported H1, and supported H2 and H3 only with immigrants. Findings held also when controlling for category salience and agreeableness, but not for social dominance orientation, which instead strengthened the effect of negative superficial contact. Overall, findings clarify the positive–negative contact asymmetry.     

The temporal evolution of pre-stimulus slow cortical potentials is associated with an upcoming stimulus’ access to visual consciousness

Slow cortical potentials (SCPs) have been proposed to be essential for the formation of conscious experience. To examine their temporal characteristics, we recorded electroencephalography during a visual backward-masking task, which required participants to localize the missing part of a target stimulus. A subsequent confidence rating was used as a proxy for the target’s access to consciousness. Event-related potentials (ERPs) of all correct trials were determined relative to a brief period immediately before the target and then compared among consciousness levels. In an interval ranging from 2 s prior to target presentation up to this period, a negative relationship between slowly fluctuating ERP values and the level of consciousness became evident. After target presentation, high conscious awareness was characterized by an enhanced visual awareness negativity, an increased P3 component, and associated positive SCPs. Together, these findings add new evidence to the proposed role of SCPs in the emergence of visual consciousness.