Putting the elephant back in the herd: elephant relative quantity judgments match those of other species

The ability to discriminate between quantities has been observed in many species. Typically, when an animal is given a choice between two sets of food, accurate performance (i.e., choosing the larger amount) decreases as the ratio between two quantities increases. A recent study reported that elephants did not exhibit ratio effects, suggesting that elephants may process quantitative information in a qualitatively different way from all other nonhuman species that have been tested (Irie-Sugimoto et al. in Anim Cogn 12:193-199, 2009). However, the results of this study were confounded by several methodological issues. We tested two African elephants (Loxodonta africana) to more thoroughly investigate relative quantity judgment in this species. In contrast to the previous study, we found evidence of ratio effects for visible and nonvisible sequentially presented sets of food. Thus, elephants appear to represent and compare quantities in much the same way as other species, including humans when they are prevented from counting. Performance supports an accumulator model in which quantities are represented as analog magnitudes. Furthermore, we found no effect of absolute magnitude on performance, providing support against an object-file model explanation of quantity judgment.     

A test of the bidirectional association between sleep and mood in bipolar disorder and insomnia

The present study investigates sleep, mood, and the proposed bidirectional relationship between the two in psychiatric disorders. Participants with interepisode bipolar disorder (n = 49), insomnia (n = 34), and no psychiatric history (n = 52) completed seven consecutive days of sleep diaries and mood measures. The interepisode bipolar and insomnia participants exhibited greater sleep disturbance than the healthy control individuals. Negative mood was equally heightened in both interepisode bipolar disorder and insomnia, and there were no differences between the three groups in positive mood. Total wake time was associated with next morning negative mood in bipolar disorder, whereas evening negative mood was associated with subsequent total wake time in both bipolar disorder and insomnia. Additionally, positive mood was associated with subsequent total wake time for the insomnia group. Results support the theory that disruptions in nighttime sleep and daytime mood may be mutually maintaining and suggest the potential importance of transdiagnostic or universal processes.     

Mere presence is not enough: Responsive support in a virtual world

When individuals are faced with novel or threatening situations, the presence of a trusted companion should reduce anxiety and promote feelings of security. Attachment theory assumes, however, that mere presence is not sufficient for establishing security; an attachment figure must also be attentive and emotionally responsive. To test this idea, participants came to the lab with their romantic partner and completed a threatening cliff-walking task in a digital immersive virtual environment. The presence and nonverbal support behavior (attentive vs. inattentive) of their partner was experimentally manipulated. Results indicated that participants in the attentive-partner condition experienced the task as less stressful than those who were alone; they also reported feeling more secure during the task and were less vigilant of their partner's behavior compared to those in the inattentive-partner condition. Those in the inattentive-partner condition felt less cared for and kept greater physical distance from their partner on a subsequent task. These findings suggest that human beings are predisposed to monitor their social environment for signs of responsiveness, and that perceived responsiveness, not mere presence, is the key modulator of emotional security.     

Comparison between immigrant and Spanish native-born pathological gambling patients

The study compared clinical, psychopathological, and personality profiles between immigrants and Spanish native-born pathological gambling patients. A total of 1,601 native-born and 133 immigrant patients attending treatment at a specialized hospital unit were administered a battery of questionnaires during clinical assessment. Outcome measures were compared between both groups and the incremental predictive accuracy of the area of origin was examined using a regression model. Native-born Spaniards showed a mean 2.6 yr. greater duration of the disorder, while immigrants scored higher on South Oaks Gambling Screen, frequency of going to casinos, and total money spent (in a single day and/or to recover losses). General psychopathology and personality scores did not differ between the cohorts. However, immigration from Asia had a statistically significantly incremental validity for pathological gambling in South Oaks Gambling Screen scores. Both cohorts shared more similarities than differences in their gambling profiles.     

Centre–surround inhibition is a general aspect of famous-person recognition: Evidence from negative semantic priming from clearly visible primes

A centre–surround attentional mechanism was proposed by Carr and Dagenbach (Journal of Experimental Psychology: Learning, Memory, and Cognition 16: 341–350, 1990) to account for their observations of negative semantic priming from hard-to-perceive primes. Their mechanism cannot account for the observation of negative semantic priming when primes are clearly visible. Three experiments (Ns = 30, 46, and 30) used a familiarity decision with names of famous people, preceded by a prime name with the same occupation as the target or with a different occupation. Negative semantic priming was observed at a 150- or 200-ms SOA, with positive priming at shorter (50-ms) and longer (1,000-ms) SOAs. In Experiment 3, we verified that the primes were easily recognisable in the priming task at an SOA that yielded negative semantic priming, which cannot be predicted by the original centre–surround mechanism. A modified version is proposed that explains transiently negative semantic priming by proposing that centre–surround inhibition is a normal, automatically invoked aspect of the semantic processing of visually presented famous names.     

Is variability in mate choice similar for intelligence and personality traits? Testing a hypothesis about the evolutionary genetics of personality

This study tests the hypothesis presented by Penke, Denissen, and Miller (2007a) that condition-dependent traits, including intelligence, attractiveness, and health, are universally and uniformly preferred as characteristics in a mate relative to traits that are less indicative of condition, including personality traits. We analyzed between-culture mean standard deviations of preference ratings and rankings provided by nearly 10,000 people in 37 cultures for 18 characteristics in a potential mate. Contrary to the hypothesis, preferences for traits indicating agreeableness and conscientiousness were not more variable than preferences for intelligence, and preferences for traits indicating low neuroticism were more uniform than preferences for intelligence. Discussion addresses implications of these results for hypotheses about the evolutionary genetics of intelligence and personality.     

Perceived Stress and Comorbid Illness Predict Depressive Symptomatology in People with Coeliac Disease

A high prevalence of depression is found in people with coeliac disease (CD). People with CD who are depressed are less likely to manage their illness effectively, which may lead to complications. Identification of variables associated with depression in people with CD may facilitate early detection and intervention. Participants were 749 members (125 males, 622 females) of the Queensland Coeliac Society (aged 18–88 years), recruited via a mailout. Participants completed the Modified Zung Self‐Rating Depression Scale, the Perceived Stress Scale, and the Perceived Consequences Subscale (from the Revised Illness Perception Questionnaire). Stress (p = .001) and comorbid medical illness (p = .01) were significantly associated with depression in CD. The current study made an original contribution to the body of literature by identifying stress and comorbid medical illness as predictors of depression in CD.     

Movement kinematics affect action prediction: comparing human to non-human point-light actions

The influence of movement kinematics on the accuracy of predicting the time course of another individual's actions was studied. A human point-light shape was animated with human movement (natural condition) and with artificial movement that was more uniform regarding velocity profiles and trajectories (artificial condition). During brief occlusions, the participants predicted the actions in order to judge after occlusion whether the actions were continued coherently in time or shifted to an earlier or later frame. Error rates and reaction times were increased in the artificial compared to the natural condition. The findings suggest a perceptual advantage for movement with a human velocity profile, corresponding to the notion of a close interaction between observed and executed movement. The results are discussed in the framework of the simulation account and alternative interpretations are provided on the basis of correlations between the velocity profiles of natural and artificial movements with prediction performance.     

Associations between parental educational/occupational levels and cognitive performance in Spanish adolescents: the AVENA study

We examined the associations between parental educational/occupational levels and cognitive performance in Spanish adolescents. Cognitive performance was measured by a validated Scholar Aptitudes test in 2,162 participants. Parental educational and occupational levels were positively associated with all specific cognitive abilities and the overall score (p<001 to .04). The odds ratios of having a high cognitive performance (top quartile) in adolescents with high parental educational level were 1.6 to 1.7 times higher than for those with a low parental educational level. Similarly, the odds ratios were 1.9 to 2.4 times higher for adolescents with high parental occupational level. These findings suggest an association between parental educational/occupational levels and cognitive performance in Spanish adolescents and support the parents' role in the creation of a stimulating intellectual environment.