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.     

Customer reactions to encountering consecutive service failures

According to previous studies, many consumers in Taiwan have experienced consecutive service failures. Despite these failures, many consumers still remain loyal to a service provider for a variety of reasons, such as money deposits, contractual agreements, associated costs, time constrains, and health concerns. We attempt to investigate the emotional reactions and expectations of consumers after they have experienced two consecutive service failures. Our findings reveal that for high‐involvement services, although customers display strong negative emotional reactions after each service failure, the reaction to the second service failure is less intensive than that to the first one. Furthermore, our findings show that as long as the products or services remain in use, customers tend to retain high levels of expectation in regard to the service provider. Copyright © 2012 John Wiley & Sons, Ltd.     

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.     

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.     

Psychometric properties of Attitudes Towards Lesbians and Gay Men Scale with Chinese university students

The 10-item Attitudes Towards Lesbian and Gay Men Scale was translated into traditional Chinese, with slight modification in item wordings (by replacing the words such as "lesbians" with "female homosexuals" and "gay men" with "male homosexuals"). Data were collected with a convenient sample of 462 Chinese undergraduate students in social work training programmes from three Hong Kong universities. Analysis of the data showed responses to the scale and its two subscales were internally consistent and a one-factor structure was found on the total scale and separately on each of its two subscales. Differences by religious belief and sex were observed using the total scale scores, as in previous studies using this scale. Researchers could consider using this scale with Hong Kong Chinese and in subsequent cross-cultural studies involving a wider range of Chinese respondents.     

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.     

Effects of speed of word processing on semantic access: the case of bilingualism

Bilingual speakers generally manifest slower word recognition than monolinguals. We investigated the consequences of the word processing speed on semantic access in bilinguals. The paradigm involved a stream of English words and pseudowords presented in succession at a constant rate. English-Welsh bilinguals and English monolinguals were asked to count the number of letters in pseudowords and actively disregard words. They were not explicitly told that pairs of words in immediate succession were embedded and could either be semantically related or not. We expected that slower word processing in bilinguals would result in semantic access indexed by semantic priming. As expected, bilinguals showed significant semantic priming, indexed by an N400 modulation, whilst monolinguals did not. Moreover, bilinguals were slower in performing the task. The results suggest that bilinguals cannot discriminate between pseudowords and words without accessing semantic information whereas monolinguals can dismiss English words on the basis of subsemantic information.     

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.     

The relation of self-supporting personality, enacted social support, and perceived social support

This study examines the relational model of self-supporting personality, enacted social support, and perceived social support in a sample of 482 Chinese high school students using the Self-Supporting Personality Scale for Adolescent Students (SSPS-AS), the Social Support Rating Scale (SSRS), and the Multidimensional Scale of Perceived Social Support (MSPSS). Results from the cross-sectional structural equation analyses revealed that interpersonal initiative, interpersonal openness, personal openness and personal initiative predicted perceived social support through the mediating role of enacted social support, while interpersonal responsibility, interpersonal flexibility, and personal initiative predicted perceived social support directly. Thus, the hypothesized relational model of personality, enacted social support, and perceived social support was supported. The positive relational schema may be the main underpinning of the relation of self-supporting personality, enacted social support, and perceived social support. Culture also may influence the relation.     

Self-organized criticality and learning a new coordination task

The purpose of this study was to investigate the hypothesis that a self-organized criticality (SOC) practice condition would have a higher improvement rate in performance outcome than a typical progressive difficulty of practice regimen. The roller ball task was used where participants undergo a phase transition from failure to successful performance after sufficient practice. The findings from two experiments showed that the SOC condition had the fastest rate of improvement and the highest performance success level. The success probability in the SOC practice regime was close to the theoretically predicted value of 50%. It appears that the SOC practice condition - by scaling task difficulty to skill level in a self-controlled adaptive strategy - facilitates the learning of new movement coordination pattern by keeping the participant close to the parameter region of the transition of the movement dynamics.