Experimental evidence for action imitation in killer whales (Orcinus orca)

Comparative experimental studies of imitative learning have focused mainly on primates and birds. However, cetaceans are promising candidates to display imitative learning as they have evolved in socioecological settings that have selected for large brains, complex sociality, and coordinated predatory tactics. Here we tested imitative learning in killer whales, Orcinus orca. We used a ‘do-as-other-does’ paradigm in which 3 subjects witnessed a conspecific demonstrator’s performance that included 15 familiar and 4 novel behaviours. The three subjects (1) learned the copy command signal ‘Do that’ very quickly, that is, 20 trials on average; (2) copied 100 % of the demonstrator’s familiar and novel actions; (3) achieved full matches in the first attempt for 8–13 familiar behaviours (out of 15) and for the 2 novel behaviours (out of 2) in one subject; and (4) took no longer than 8 trials to accurately copy any familiar behaviour, and no longer than 16 trials to copy any novel behaviour. This study provides experimental evidence for body imitation, including production imitation, in killer whales that is comparable to that observed in dolphins tested under similar conditions. These findings suggest that imitative learning may underpin some of the group-specific traditions reported in killer whales in the field.     

The Relationship Between Sexual Orientation and Gender Identification Among Males in a Cross-Cultural Analysis in Brazil, Turkey and Thailand

This study measures and compares the level of congruency between male sexual orientation and gender identification using the Kinsey Scale in three cultures: Brazil (Florianópolis), Turkey (Istanbul) and Thailand (Bangkok) with social class as the control mechanism. Quantitative techniques are utilized in comparing the self-evaluation of sexual orientation and gender identification among young men with same-sex, opposite-sex and both-sex orientations or behaviors. Results: In all three cultures, homosexuals were much more likely than bisexuals or heterosexuals to enjoy receiving anal sex and performing fellatio. Bisexual and heterosexual men, as expected, reported enjoying vaginal penetration and cunnilingus more than homosexual men. Same-sex oriented male self-evaluations of homosexual orientation and feminine gender identification scored similarly on the Kinsey Scale (0–6) in all three countries. These data support the traditional identity trichotomy used in the field: homosexuality, bisexuality and heterosexuality. When controlling for nationality only small differences were found amongst the participants; however, social class or level of education did have a significant effect on the relationship between self-evaluation of sexual orientation and gender identification.     

So why can’t you intend to drink the toxin?

In this paper I revisit Gregory Kavka’s Toxin Puzzle and propose a novel solution to it. Like some previous accounts, mine postulates a tight link between intentions and reasons but, unlike them, in my account these are motivating rather than normative reasons, i.e. reasons that explain (rather than justify) the intended action. I argue that sensitivity to the absence of possible motivational explanations for the intended action is constitutive of deliberation-based intentions. Since ordinary rational agents display this sensitivity, when placed in the toxin scenario they will believe that there is no motivational explanation for actually drinking the toxin and this is why they can’t form the intention to drink it in the first place. I thus argue that my Motivating-Explanatory Reason Principle correctly explains the toxin puzzle, thereby revealing itself as a genuine metaphysical constraint on intentions. I also explore at length the implications of my account for the nature of intention and rational agency.     

Coping with HIV Related Stigma and Well-Being

The goal of this study was to analyze the relationships to be found among stigma perception, active and avoidant coping strategies, and subjective and psychological well-being in a sample of 133 people with HIV. The results showed that stigma perception and avoidant coping strategies (venting, self-blame, denial, behavioural disengagement and substance use) were positively associated, whereas, both stigma perception and avoidant coping were negatively associated with different measures of well-being (affect balance, self-acceptance and environmental mastery). These negative relationships between stigma perception and the three well-being measures were mediated by the use of avoidant coping strategies. Results suggest that psychosocial intervention programs for people who report psychological distress arising from prejudice must be aimed at developing appropriate ways to deal with this prejudice. Intervention programs should also include strategies to directly increase well-being since from a positive psychology viewpoint certain interventions have been shown to do so, and HIV research has also shown that well-being is associated with lower mortality rates.     

Body size and body esteem in women: The mediating role of possible self expectancy

We predicted that an expectancy of acquiring a feared fat self and an expectancy of acquiring a hoped-for thin self both mediate the impact of body size on women's body esteem. We also predicted that the mediating pathway through the feared fat self would be stronger than that through the hoped-for thin self. A community sample of 251 women reported their age, height, weight, and completed measures of body esteem and expectancy perceptions of acquiring the feared fat and hoped-for thin selves. Bayesian Structural Equation Modeling (SEM) demonstrated that expectancies about the feared fat self and about the hoped-for thin self mediated the relationship between body size and body esteem. Bayesian SEM also revealed that the pathway through the feared fat self was stronger than that through the hoped-for thin self. Implications for future research and the development of eating pathology are discussed.     

Evidence suggests vocal production learning in a cross-fostered Risso’s dolphin (<Emphasis Type="Italic">Grampus</Emphasis><Emphasis Type="Italic">griseus</Emphasis>)

Vocal learning is a rare skill in mammals, and we have limited information about the contexts in which they use it. Previous studies suggested that cetaceans in general are skilled at imitating sounds, but only few species have been studied to date. To expand this investigation to another species and to investigate the possible influence of the social environment on vocal learning, we studied the whistle repertoire of a female Risso’s dolphin (Grampus griseus) that was stranded at an early age and was subsequently raised in a group of bottlenose dolphins (Tursiops truncatus). We show that this cross-fostered animal produced vocal signals more akin to those of its Tursiops poolmates than those of Risso’s dolphins in the wild. This is one of very few systematic cross-fostering studies in cetaceans and the first to suggest vocal production learning in the Risso’s dolphin. Our findings also suggest that social experience is a major factor in the development of the vocal repertoire in this species.     

Algorithmic complexity for psychology: a user-friendly implementation of the coding theorem method

Kolmogorov-Chaitin complexity has long been believed to be impossible to approximate when it comes to short sequences (e.g. of length 5-50). However, with the newly developed coding theorem method the complexity of strings of length 2-11 can now be numerically estimated. We present the theoretical basis of algorithmic complexity for short strings (ACSS) and describe an R-package providing functions based on ACSS that will cover psychologists’ needs and improve upon previous methods in three ways: (1) ACSS is now available not only for binary strings, but for strings based on up to 9 different symbols, (2) ACSS no longer requires time-consuming computing, and (3) a new approach based on ACSS gives access to an estimation of the complexity of strings of any length. Finally, three illustrative examples show how these tools can be applied to psychology.     

Abduction in economics: a conceptual framework and its model

We discuss in this paper the scope of abduction in Economics. The literature on this type of inference shows that it can be interpreted in different ways, according to the role and nature of its outcome. We present a formal model that allows to capture these various meanings in different economic contexts.