Wild bearded capuchin (Sapajus libidinosus) select hammer tools on the basis of both stone mass and distance from the anvil

Contemporary optimization models suggest that animals optimize benefits of foraging and minimize its costs. For wild bearded capuchins (Sapajus libidinosus), nut-cracking entails cost related to lifting the heavy stone and striking the nut and additional cost to transport the stone if it is not already on the anvil. To assess the role of stone mass and transport distance in capuchins’ tool selection, we carried out three field experiments. In Experiment 1, we investigated whether transport distance affected choice of a tool by positioning two stones of the same mass close and far from the anvil. Capuchins consistently selected the closer stone, effectively reducing transport costs. In Experiment 2, we examined the trade-off between the cost of transport and the effectiveness in cracking by positioning two stones of different mass close and far from the anvil. Most subjects significantly preferred the closer stone, regardless of mass, whereas others preferred the heavier stone regardless of transport distance. In Experiment 3, we changed transport distance of both stones while maintaining the same distance ratios as in Experiment 2. Capuchins maintained the preferences expressed in Experiment 2, with the exception of one subject. Overall, our findings indicate that (1) individuals vary in their sensitivity to distance of transport, (2) a few meters are perceived as a substantive cost by some monkeys, and (3) monkeys’ body mass affects their decisions. We also developed a non-dimensional Preference index (P) defined as a function of the stone mass and the transport distance to describe monkey’s choice.     

Distinct processing for pictures of animals and objects: evidence from eye movements

Many studies have suggested that emotional stimuli orient and engage attention. There is also evidence that animate stimuli, such as those from humans and animals, cause attentional bias. However, categorical and emotional factors are usually mixed, and it is unclear to what extent human context influences attentional allocation. To address this issue, we tracked participants' eye movements while they viewed pictures with animals and inanimate images (i.e., category) as focal objects. These pictures had either negative or neutral emotional valence, and either human body parts or nonhuman parts were near the focal objects (i.e., context). The picture's valence, arousal, position, size, and most of the low-level visual features were matched across categories. The results showed that nonhuman animals were more likely to be attended to and to be attended to for longer times than inanimate objects. The same pattern held for the human contexts (vs. nonhuman contexts). The effects of emotional valence, category, and context interacted. Specifically, in images with a negative valence, focal animals and objects with human context had comparable numbers of gaze fixations and gaze duration. These results highlighted the attentional bias to animate parts of a picture and clarified that the effects of category, valence, and picture context interacted to influence attentional allocation.     

High Behavioral Approach System (BAS) sensitivity, reward responsiveness, and goal-striving predict first onset of bipolar spectrum disorders: a prospective behavioral high-risk design

A prospective, behavioral high-risk design provided a theoretically guided examination of vulnerability to first onset of bipolar spectrum disorder based on the Behavioral Approach System (BAS) model. Adolescents (ages 14-19) at an "age of risk" for bipolar disorder onset were screened on BAS sensitivity by interviewers blind to current symptoms, lifetime history, and family history of psychopathology. Participants were selected with high versus moderate levels of BAS sensitivity and administered a lifetime diagnostic interview. Those with a bipolar spectrum disorder, psychosis, or hypomanic episode with onset prior to the BAS sensitivity assessment were excluded. High BAS (n = 171) and moderate BAS (n = 119) sensitivity participants in the final sample completed baseline measures of symptoms, goal-setting, and reward responsiveness and were followed prospectively with semistructured diagnostic interviews every 6 months. Consistent with the vulnerability hypothesis of the BAS model of bipolar disorder, high BAS participants had a greater likelihood, and shorter time to onset, of bipolar spectrum disorder than moderate BAS participants across an average of 12.8 months of follow-up (12.9% vs. 4.2%), controlling for baseline depressive and hypomanic symptoms, and family history of bipolar disorder. High reward responsiveness on a behavioral task and ambitious goal-striving for popular fame and financial success (but not impulsivity) also predicted first onset of bipolar spectrum disorder controlling for the covariates and BAS risk group, and ambitious goal-striving partially mediated the BAS risk group effect. We discuss implications of the findings for the BAS model of bipolar disorder and early intervention efforts.     

The prevalence of loneliness among adults: a case study of the United Kingdom

Within contemporary Western (post) modern societies, loneliness is seen as a problem that is particularly associated with old age. Much less attention has been given to examining variations in loneliness across age groups. We examine patterns of loneliness across adults aged 15 years and older in the United Kingdom using data from the European Social Survey. We first consider the prevalence of loneliness among the adult population; then the relationship between loneliness and a range of key risk factors, and finally the relationship with age for each of our risk factors. Loneliness demonstrates a nonlinear U-shaped distribution, with those aged under 25 years and those aged over 65 years demonstrating the highest levels of loneliness. Depression is associated with loneliness for all age groups. Poor physical health is associated with loneliness in young adult and midlife but not later life. For those in mid and later life, the quality of social engagement is protective against loneliness, while for young adults it is the quantity of social engagement. This indicates that different factors may endow vulnerability (or protect) against loneliness at different stages of life and suggests that preventative strategies or interventions that reflect these variations need to be developed.     

Visual assessment of camouflaged targets with different background similarities

The study investigated the effectiveness of different camouflage designs using a computational image quality index. Camouflaged human targets were presented on a natural landscape and the targets were designed to be similar to the landscape background with different levels of background similarity as estimated by the image index. The targets were presented in front of the observer (central 0 degrees) or at different angles in the left (-7 degrees, -14 degrees, -21 degrees) or right (+7 degrees, +14 degrees, +21 degrees) visual fields. The observer had to detect the target using peripheral vision if the target appeared in the left and right visual fields. The camouflage effectiveness was assessed by detection hit rates, detection times, and subjective ratings on detection confidence and task difficulty. The study showed that the psychophysical measures correlated well with the image similarity index, suggesting a potentially more efficient camouflage effectiveness assessment tool if the relationship between the psychophysical results and the index can be quantified in the future.     

Gelotophobia and thinking styles in Sternberg's theory'

A hypothesis was examined, that gelotophobia (the fear of being laughed at) was negatively related to Type I thinking styles and positively related to Type II thinking styles as defined in Sternberg's theory of mental self-government. 431 university students (250 women, 181 men; M age = 20.4 yr., SD = 1.2) completed self-report measures of gelotophobia (GELOPH <15>) and thinking styles (Thinking Styles Inventory-Revised). Correlation and regression analyses were conducted. The results indicated that gelotophobia was negatively and significantly related to four Type I thinking styles (legislative, judicial, liberal, and hierarchical thinking styles) and a Type III thinking style (external), while it was positively and significantly related to a Type II thinking style (conservative). Thinking styles uniquely explained 18% of the total variance in gelotophobia scores. Possible interventions from the perspective of thinking styles in the treatment of gelotophobia were discussed.     

Social Construction and its Development: Liping Yang Interviews Kenneth Gergen

Nanjing University psychologist Liping Yang interviews Kenneth Gergen on the development of social constructionist thought and practice. The conversation treats a variety of issues, including the development of constructionism as a new paradigm, qualitative research, education and other practices informed by constructionism, value loaded science, relativism, and the Taos Institute.     

Self-esteem modulates attentional responses to rejection: Evidence from event-related brain potentials

Individuals with low self-esteem have been shown to exhibit an attentional bias for social rejection cues. The present study investigated whether individuals with low self-esteem would demonstrate greater reactivity to rejection-related stimuli during an attention shifting task than was exhibited by those with high self-esteem. Individuals with low self-esteem showed higher amplitude event-related potentials (ERPs) in response to rejection cues than was observed for those with high self-esteem. These results suggest that individuals with low self-esteem allocate more attentional resources to rejection cues than those with high self-esteem. Discussion will focus on the implications of these findings for understanding the connection between low self-esteem and social rejection.     

Neural correlates of audiovisual integration of semantic category information

Previous studies have found a late frontal-central audiovisual interaction during the time period about 150-220 ms post-stimulus. However, it is unclear to which process is this audiovisual interaction related: to processing of acoustical features or to classification of stimuli? To investigate this question, event-related potentials were recorded during a words-categorization task with stimuli presented in the auditory-visual modality. In the experiment, congruency of the visual and auditory stimuli was manipulated. Results showed that within the window of about 180-210 ms post-stimulus more positive values were elicited by category-congruent audiovisual stimuli than category-incongruent audiovisual stimuli. This indicates that the late frontal-central audiovisual interaction is related to audiovisual integration of semantic category information.