Spontaneous discrimination of small quantities: shoaling preferences in angelfish (<Emphasis Type="Italic">Pterophyllum scalare</Emphasis>)

The ability to quantify, i.e. to estimate quantity, may provide evolutionary advantages in some contexts and has been demonstrated in a variety of animal species. In a prior study, we showed that angelfish (Pterophyllum scalare) were able to discriminate between groups (shoals) in which a large number of conspecifics swam preferring to join the larger of the two. Our results implied that angelfish can compare relative shoal sizes likely on the basis of some quantitative attributes of the shoal. Here, also using a binary preference test, we examined whether angelfish are able to discriminate between shoals of small numbers of conspecifics, and if so whether their performance reveals a comparable underlying mechanism to that proposed for discrimination of small quantities in human and non-human animals, namely the possible precursor of the ability to count. Our results demonstrate that fish reliably chose 4 versus 1, 3 versus 1, 2 versus 1 and 3 versus 2 individuals, but were at chance performance level when having to choose between 4 versus 3, 5 versus 4 and 6 versus 5. Findings also reveal that the density of the fish in the stimulus shoals did not significantly affect the performance of experimental angelfish. These results are compatible with the hypothesis of the existence of an object-file mechanism to discriminate small quantities in vertebrates and provide evidence for spontaneous discrimination of up to three elements in angelfish, a similar limit to that found in human and non-human animals. The findings add to the growing body of data, suggesting that the mechanisms underlying discrimination between different quantities of items may be shared across different taxa and have an evolutionary ancient origin.     

Recording vocalizations with Bluetooth technology

We propose a method for capturing vocalizations that is designed to avoid some of the limiting factors found in traditional bioacoustical methods, such as the impossibility of obtaining continuous long-term registers or analyzing amplitude due to the continuous change of distance between the subject and the position of the recording system. Using Bluetooth technology, vocalizations are captured and transmitted wirelessly into a receiving system without affecting the quality of the signal. The recordings of the proposed system were compared to those obtained as a reference, which were based on the coding of the signal with the so-called pulse-code modulation technique in WAV audio format without any compressing process. The evaluation showed p < .05 for the measured quantitative and qualitative parameters. We also describe how the transmitting system is encapsulated and fixed on the animal and a way to video record a spider monkey’s behavior simultaneously with the audio recordings.     

When believing is seeing: the role of predictions in shaping visual perception

The study investigated the influence of predictions on perception-in particular, how strong but erroneous prediction coupled with poor sensory data can trigger misperceptions. Using signal detection, we tested whether predictions induced by a semantic cue change the recognition threshold (criterion) or the subjectively perceived differences between stimuli (sensitivity). In a series of 3 experiments, participants observed pictures of (a) real objects distorted to various extents (targets), (b) noise with elements corresponding to meaningful objects (foils), or (c) nonsense images (noise). Stimuli were preceded either by a semantic cue or by a blank screen with equal probability. Presence of the cue resulted in a more liberal criterion, but only for targets and foils. The cue decreased sensitivity between the distorted targets, but increased sensitivity between the targets and noise-that is, the cue increased between-class differences, but decreased within-class differences. When there was no correspondence between prediction and the sensory input, prediction actually increased the chances of correctly rejecting noise. The influence of the cue was strongest for the moderately distorted targets and foils-when uncertainty related to the bottom-up input was the highest.     

Implicit and explicit self-esteem discrepancies in paranoia and depression

The main purpose of the present study was to examine implicit and explicit self-esteem (SE) in patients with persecutory delusions. In samples of paranoid patients, depressed patients, and healthy controls, implicit SE was assessed using the experimental go/no-go association task, whereas explicit SE was measured using 2 self-reporting questionnaires: the self-worth subscale of the World Assumption Scale (Janoff-Bulman, 1989) and the self-acceptance subscale of the Scales of Psychological Well-Being (Ryff & Keyes, 1995). Our analysis revealed that depressed patients showed lower explicit SE than did paranoid and healthy control participants. However, participants with persecutory delusions had significantly lower implicit SE scores than did healthy controls. We interpret the discrepancies observed between overt and covert measures in the paranoid group as psychological defense mechanisms. The present study stresses the clinical and theoretical importance of the use of implicit measures in psychopathology.     

On the nature of identity fusion: insights into the construct and a new measure

Previous research has documented the consequences of feeling fused with a group; here we examine the nature of identity fusion. Specifically, we sought to determine what fusion is and the mediating mechanisms that lead fused individuals to make extraordinary sacrifices for their group. Guided by the assumption that fusion emphasizes the extent to which people develop relational ties to the group, we developed a measure designed to capture feelings of connectedness and reciprocal strength with the group. In 10 studies, the newly developed scale displayed predicted relationships with related measures, including an earlier (pictorial) measure of fusion and a measure of group identification. Also as expected, fusion scores were independent of several measures of personality and identity. Moreover, the scale predicted endorsement of extreme progroup behaviors with greater fidelity than did an earlier pictorial measure of identity fusion, which was, in turn, superior to a measure of group identification. Earlier evidence that the personal and social selves of fused persons are functionally equivalent was replicated, and it was shown that feelings of agency and invulnerability mediated the effects of fusion on extreme behavior. Finally, Spanish- and English-language versions of the verbal fusion scale showed similar factor structure as well as evidence of convergent, discriminant, and predictive validity in samples of Spaniards and Americans, as well as immigrants from 22 different countries. This work advances a new perspective on the interplay between social and personal identity.     

Hope in Africa? Social representations of world history and the future in six African countries

Data on social representations of world history have been collected everywhere in the world except sub-Saharan Africa. Two studies using open-ended data involving university students from six African countries fill this gap. In Study 1, nominations from Cape Verde and Mozambique for the most important events in world history in the past 1000 years were dominated by war and politics, recency effects, and Western-centrism tempered by African sociocentrism on colonization and independence. The first three findings replicated previous research conducted in other parts of the world, but the last pattern contrasted sharply with European data. Study 2 employed a novel method asking participants how they would begin the narration of world history, and then to describe a major transition to the present. Participants most frequently wrote about the evolution of humanity out of Africa, followed by war and then colonization as a beginning, and then replicated previous findings with war, colonization, and technology as major transitions to the present. Finally, when asked about how they foresaw the future, many participants expressed hope for peace and cooperation, especially those facing more risk of collective violence (Burundi and Congo). A colonial/liberation narrative was more predominant in the data from former Portuguese colonies (Angola, Cape Verde, and Guinea-Bissau) than from former Belgian colonies (Burundi and Congo).     

Analysis of movement patterns by elite male players of beach volleyball

The aim of this study was to analyse and compare movement pattems and direction of locomotion in professional men's beach volleyball. A quantitative analysis of beach volleyball play was carried out for 10 players in the European Beach Volleyball Championship 2005. Video recordings were made of the 1,997 movements in 4 matches. Analysis showed that male players used more offensive than defensive movement patterns. Defensive movement patterns were more blocks and defense than receptions. Offensive movement patterns were more attack and placements than attack preparation moves. Advance was the direction of locomotion most used. Identifying and understanding such movement patterns are vital to defining specific, effective training strategies for men's beach volleyball players.     

Cost-effectiveness of Internet-based cognitive behavior therapy vs. cognitive behavioral group therapy for social anxiety disorder: results from a randomized controlled trial

Social anxiety disorder (SAD) is highly prevalent and associated with a substantial societal economic burden, primarily due to high costs of productivity loss. Cognitive behavior group therapy (CBGT) is an effective treatment for SAD and the most established in clinical practice. Internet-based cognitive behavior therapy (ICBT) has demonstrated efficacy in several trials in recent years. No study has however investigated the cost-effectiveness of ICBT compared to CBGT from a societal perspective, i.e. an analysis where both direct and indirect costs are included. The aim of the present study was to investigate the cost-effectiveness of ICBT compared to CBGT from a societal perspective using a prospective design. We conducted a randomized controlled trial where participants with SAD were randomized to ICBT (n = 64) or CBGT (n = 62). Economic data were assessed at pre-treatment, immediately following treatment and six months after treatment. Results showed that the gross total costs were significantly reduced at six-month follow-up, compared to pre-treatment in both treatment conditions. As both treatments were equivalent in reducing social anxiety and gross total costs, ICBT was more cost-effective due to lower intervention costs. We conclude that ICBT can be more cost-effective than CBGT in the treatment of SAD and that both treatments reduce societal costs for SAD.     

Comparison of two self-regulated and strategic instructional programs for improving writing competence

This study compared the efficacy of two versions of an instructional program aimed at developing strategic and self-regulated writing competence. In the full version, strategy instruction, students were taught strategies for producing effective text, using a combination of direct (explicit, declarative, metacognitive knowledge) instruction, teacher modeling, and collaborative and individual practice. In a modeling-only version, direct instruction was omitted. 72 Spanish 6th grade students were taught in one of three groups: Full Strategy Instruction (N=24); Modeling only (N=25), and a normal curriculum (no strategy instruction) control (N=23). Pre and posttest measures of written texts, self-efficacy and self-knowledge of writing were taken. Pre and posttest scores on writing ability tests indicated similar improvement in both intervention groups, relative to control, in both holistic measures of text quality and in counts of text features associated with mature, reader-focused composition. We found no differences between intervention groups. These findings suggest that modeling and student practice alone are sufficient to develop effective writing strategies in typically-developing 6th grade students.