Estimation of indifference curves in the Marschak-Machina triangle a direct test of the “fanning out” hypothesis

The ongoing debate on the correct modelling of economic behaviour under risk makes heavy expositional use of the 'Marschak-Machina Triangle'. This has also been used when constructing tests of the various competing theories. In this paper, we adopt a more direct approach - by estimating subjects' indifference maps in the Triangle. Employing an interview technique, we find that most subjects have maps which are nearly consistent with those implied by Subjective Expected Utility theory.     

Do capuchin monkeys use weight to select hammer tools?

The extent to which tool-using animals take into account the properties of the tool is little explored. The use of percussors to crack open encapsulated fruit is a complex form of tool use, the choice of an adequate tool being a critical aspect in success. Several properties (e.g., material, resistance, friability, shape and weight) affect the suitability of an object to open a hard-shelled nut, with weight being amongst the most important factors. In general, heavier tools require fewer strikes to crack open a nut.     

Suggested visual hallucinations in and out of hypnosis

We administered suggestions to see a gray-scale pattern as colored and a colored pattern in shades of gray to 30 high suggestible and eight low suggestible students. The suggestions were administered twice, once following the induction of hypnosis and once without an induction. Besides rating the degree of color they saw in the stimuli differently, participants also rated their states of consciousness as normal, relaxed, hypnotized, or deeply hypnotized. Reports of being hypnotized were limited to highly suggestible participants and only after the hypnotic induction had been administered. Reports of altered color perception were also limited to high suggestibles, but were roughly comparable regardless of whether hypnosis had been induced. These data indicate that suggestible individuals do not slip into a hypnotic state when given imaginative suggestions without the induction of hypnosis, but nevertheless report experiencing difficult suggestions for profound perceptual alterations that are pheonomenologically similar to what they report in hypnosis.     

ACACIA: an agent-based program for simulating behavior to reach long-term goals

We present ACACIA, an agent-based program implemented in Java StarLogo 2.0 that simulates a two-dimensional microworld populated by agents, obstacles and goals. Our program simulates how agents can reach long-term goals by following sensorial-motor couplings (SMCs) that control how the agents interact with their environment and other agents through a process of local categorization. Thus, while acting in accordance with this set of SMCs, the agents reach their goals through the emergence of global behaviors. This agent-based simulation program would allow us to understand some psychological processes such as planning behavior from the point of view that the complexity of these processes is the result of agent–environment interaction.     

Extended multisensory space in blind cane users

In the present work, we investigated whether an auditory peripersonal space exists around the hand and whether such a space might be extended by a brief tool-use experience or by long-term experience using a tool in everyday life. To this end, we studied audio-tactile integration in the space around the hand and in far space, in blind subjects who regularly used a cane to navigate and in sighted subjects, before and after brief training with the cane. In sighted subjects, auditory peripersonal space was limited to around the hand before tool use, then expanded after tool use, and contracted backward after a resting period. In contrast, in blind subjects, peri-hand space was immediately expanded when they held the cane but was limited to around the hand when they held a short handle. These results suggest that long-term experience with the cane induces a durable extension of the peripersonal space.     

Response of captive lowland gorillas (Gorilla gorilla gorilla) to different housing conditions: testing the aggression-density and coping models

Several studies have suggested that primates react differently to spatial reduction. In this article, the authors tested some general hypotheses on primate response to spatial reduction by studying the Apenheul lowland gorillas (Gorilla gorilla gorilla; Apeldoorn, the Netherlands). The frequency of conflicts did not greatly change between the 2 housing settings, thus not supporting the density- aggression model. Indoor, gorillas performed touching behavior more often and increased their level of reconciliation. These findings support the coping model. Indoor, the gorillas also maintained broader interindividual distances by increasing the levels of sitting alone, avoidance, and dismissing behaviors. In conclusion, the Apenheul gorillas modified selectively the distribution of some patterns typical of their behavioral repertoire in response to a high-density condition. Both avoidance and coping tactics were used, thus revealing high levels of behavioral flexibility in this species.     

Relationships between identity domains and life satisfaction in minority and majority youth in Albania,Bulgaria, Czech Republic,Kosovo, and Romania

Abstract

The purpose of this study was to examine relationships between identity domains (educational and relational identity) and life satisfaction in a cross-national perspective, by targeting minority (Roma) and majority youth in Albania, Bulgaria, Czech Republic, Kosovo, and Romania. Based on the three-factor identity formation model, we investigated the interplay between three identity processes (i.e., commitment, in-depth exploration, and reconsideration of commitment) and life satisfaction. Participants were 1860 adolescents aged 12–19 years from Albania (n = 350), Bulgaria (n = 398), the Czech Republic (n = 293), Kosovo (n = 542), and Romania (n = 277). They completed self-reports of the Utrecht-Management of Identity Commitments Scale (U-MICS) and the Life Satisfaction Scale (SWLS). We adopted a structural equation modelling approach to test (a) measurement invariance of identity and life satisfaction models across groups and (b) associations between identity domains (educational and relational) and life satisfaction. Findings indicated measurement invariance for identity and life satisfaction measures across cultural groups. In the total sample, life satisfaction was consistently associated with high commitment, high in-depth exploration, and low reconsideration of commitment in the educational identity domain. Sample-specific associations highlighted important cultural differences. Implications of these findings for identity and well-being in minority and mainstream youth across the countries under investigation are discussed.     

Error monitoring is related to processing internal affective states

Detecting behavioral errors is critical for optimizing performance. Here, we tested whether error monitoring is enhanced in emotional task contexts, and whether this enhancement depends on processing internal affective states. Event-related potentials were recorded in individuals with low and high levels of alexithymia—that is, individuals with difficulties identifying and describing their feelings. We administered a face word Stroop paradigm (Egner, Etkin, Gale, & Hirsch, 2008) in which the task was to classify emotional faces either with respect to their expression (happy or fearful; emotional task set) or with respect to their gender (female or male; neutral task set). The error-related negativity, a marker of rapid error monitoring, was enhanced in individuals with low alexithymia when they adopted the emotional task set. By contrast, individuals with high alexithymia did not show such an enhancement. Moreover, in the high-alexithymia group, the difference in the error-related negativities between the emotional and neutral task sets correlated negatively with difficulties identifying their own feelings, as measured by the Toronto Alexithymia Scale. These results show that error-monitoring activity is stronger in emotional task contexts and that this enhancement depends on processing internal affective states.