Spontaneous Metacognition in Rhesus Monkeys.

Metacognition is the ability to think about thinking. Although monitoring and controlling one's knowledge is a key feature of human cognition, its evolutionary origins are debated. In the current study, we examined whether rhesus monkeys (Macaca mulatta; N = 120) could make metacognitive inferences in a one-shot decision. Each monkey experienced one of four conditions, observing a human appearing to hide a food reward in an apparatus consisting of either one or two tubes. The monkeys tended to search the correct location when they observed this baiting event, but engaged in information seeking-by peering into a center location where they could check both potential hiding spots-if their view had been occluded and information seeking was possible. The monkeys only occasionally approached the center when information seeking was not possible. These results show that monkeys spontaneously use information about their own knowledge states to solve naturalistic foraging problems, and thus provide the first evidence that nonhumans exhibit information-seeking responses in situations with which they have no prior experience.

Human compulsivity: A perspective from evolutionary medicine.

Biological explanations address not only proximal mechanisms (for example, the underlying neurobiology of obsessive-compulsive disorder), but also distal mechanisms (that is, a consideration of how particular neurobiological mechanisms evolved). Evolutionary medicine has emphasized a series of explanations for vulnerability to disease, including constraints, mismatch, and tradeoffs. The current paper will consider compulsive symptoms in obsessive-compulsive and related disorders and behavioral addictions from this evolutionary perspective. It will argue that while obsessive-compulsive disorder (OCD) is typically best conceptualized as a dysfunction, it is theoretically and clinically valuable to understand some symptoms of obsessive-compulsive and related disorders in terms of useful defenses. The symptoms of behavioral addictions can also be conceptualized in evolutionary terms (for example, mismatch), which in turn provides a sound foundation for approaching assessment and intervention.

Using robots to understand animal cognition.

In recent years, robotic animals and humans have been used to answer a variety of questions related to behavior. In the case of animal behavior, these efforts have largely been in the field of behavioral ecology. They have proved to be a useful tool for this enterprise as they allow the presentation of naturalistic social stimuli whilst providing the experimenter with full control of the stimulus. In interactive experiments, the behavior of robots can be controlled in a manner that is impossible with real animals, making them ideal instruments for the study of social stimuli in animals. This paper provides an overview of the current state of the field and considers the impact that the use of robots could have on fundamental questions related to comparative psychology: namely, perception, spatial cognition, social cognition, and early cognitive development. We make the case that the use of robots to investigate these key areas could have an important impact on the field of animal cognition.

The string-pulling paradigm in comparative psychology.

String pulling is one of the most widely used paradigms in comparative psychology. First documented 2 millennia ago, it has been a well-established scientific paradigm for a century. More than 160 bird and mammal species have been tested in over 200 studies with countless methodological variations. The paradigm can be used to address a wide variety of issues on animal cognition; for example, what animals understand about contact and connection as well as whether they rely on perceptual feedback, grasp the functionality of strings, generalize across conditions, apply their knowledge flexibly, and possess insight. Mammals are typically tested on a horizontal configuration, birds on a vertical one, making the studies difficult to compare; in particular, pulling a string vertically requires better coordination and attention. A species' performance on the paradigm is often influenced by its ecology, especially concerning whether limbs are used for foraging. Many other factors can be of importance and should be considered. The string-pulling paradigm is easy to administer, vary, and apply to investigate a wide array of cognitive abilities. Although it can be and has been used to compare species, divergent methods and unclear reporting have limited its comparative utility. With increasing research standards, the paradigm is expected to become an even more fundamental tool in comparative psychology.

Factors that distinguish college students with depressive symptoms with and without suicidal thoughts.

BACKGROUND: Suicide among college students is a significant public health concern. Although suicidality is linked to depression, not all depressed college students experience suicidal ideation (SI). The primary aim of this study was to determine potential factors that may distinguish college students with depressive symptoms with and without SI. METHODS: A total of 287 undergraduate college students with substantial depressive symptoms (Beck Depression Inventory [BDI] total score >13) with and without SI were compared across psychiatric and functional outcome variables. Independent sample t tests were conducted for each outcome variable using the suicide item of the BDI as a dichotomous (ie, zero vs nonzero score) grouping variable. RESULTS: Relative to students with substantial depressive symptoms without SI, those with SI were more symptomatic overall, having significantly higher levels of depressive symptoms, hopelessness, and anxiety. However, contrary to our expectations, nonsuicidal and suicidal students did not differ on measures of everyday functioning (ie, cognitive and physical functioning and grade point average). CONCLUSIONS: Our findings suggest that SI among college students is associated with increased subjective distress but may not adversely impact physical or cognitive functioning or academic performance.

A study of acculturation in psychotic and non-psychotic immigrants living in Athens.

BACKGROUND: Acculturation is the phenomenon that results when a group with one culture comes into continuous contact with a host culture. AIMS: To investigate the correlation between acculturation and psychotic symptomatology in a group of immigrants suffering from psychosis and to explore differences in demographic factors related with the acculturation process between individuals with and without psychosis. METHODS: Sixty-five patients and 317 non-psychotic immigrants were interviewed using the Immigrant Acculturation Scale (IAS) and a structured questionnaire for demographic data. The Positive and Negative Syndrome Scale (PANSS), the Calgary Depression Scale for Schizophrenia (CDSS) and the Global Assessment of Functioning (GAF) were also administered to all immigrants suffering from psychosis. RESULTS: Total IAS scores, as well as IAS everyday life scores, were positively correlated with GAF scores. IAS everyday life score in the patient group related with religion, marital status, gender and years in Greece, while in the non-psychosis group it was related with gender and years in Greece. IAS wishful orientation/nostos (the strong desire for one's homeland) related with religion in both groups. The IAS identity in the psychosis group did not show any significant relation with any of the variables, while in the non-patient group, it was related with marital status, gender and years in Greece. Age, duration of residence in Greece and higher adoption of Greek ethnic identity were the variables that differentiated the two groups of immigrants. CONCLUSION: Acculturation in immigrants suffering from psychosis could be seen as a process that does not correlate strongly with the severity of the symptomatology but is probably influenced by different set of factors.

The highs and lows of theoretical interpretation in animal-metacognition research.

Humans feel uncertain. They know when they do not know. These feelings and the responses to them ground the research literature on metacognition. It is a natural question whether animals share this cognitive capacity, and thus animal metacognition has become an influential research area within comparative psychology. Researchers have explored this question by testing many species using perception and memory paradigms. There is an emerging consensus that animals share functional parallels with humans' conscious metacognition. Of course, this research area poses difficult issues of scientific inference. How firmly should we hold the line in insisting that animals' performances are low-level and associative? How high should we set the bar for concluding that animals share metacognitive capacities with humans? This area offers a constructive case study for considering theoretical problems that often confront comparative psychologists. The authors present this case study and address diverse issues of scientific judgement and interpretation within comparative psychology.

Do actions speak louder than words? A comparative perspective on implicit versus explicit meta-cognition and theory of mind.

Research in non-human animal (hereafter, animal) cognition has found strong evidence that some animal species are capable of meta-cognitively monitoring their mental states. They know when they know and when they do not know. In contrast, animals have generally not shown robust theory of mind (ToM) capabilities. Comparative research uses methods that are non-verbal, and thus might easily be labelled 'implicit' using the terminology of traditional human cognition. However, comparative psychology has developed several non-verbal methods that are designed to test for aspects of meta-cognition that - while perhaps not fully explicit - go beyond the merely implicit or associative. We believe similar methods might be useful to developmental researchers who work with young children, and may provide a sound empirical alternative to verbal reports. Comparative psychology has moved away from all-or-none categorical labels (e.g., 'implicit' vs. 'explicit') towards a theoretical framework that contains a spectrum of mental abilities ranging from implicit to explicit, and from associative to cognitive to fully conscious. We discuss how this same framework might be applied to developmental psychology when it comes to implicit versus explicit processing and ToM.

A history of the behavior program at the Jackson laboratory: an overview.

The behavior program at the Jackson laboratory in Bar Harbor, ME, flourished from 1945 through the late 1960s and was unique in the history of comparative psychology. The canine project was conducted on ~300 dogs of five purebred breeds reared under controlled conditions and tested on a predetermined schedule. This enabled a detailed study of genetic and environmental effects and their interaction as well as a variety of other problems in midsized mammals. I provide a comprehensive, though brief, overview of the origins, development, operation, and decline of the program. Although it was begun within a genetic framework, the role of both genetic and experiential influences came to be emphasized. An important additional part of the program entailed extensive studies of inbred strains of house mice (Mus musculus) and of deer mice (Peromyscus maniculatus). The work at the Jackson Laboratory had a significant impact on various aspects of comparative psychology.

More men run relatively fast in U.S. road races, 1981-2006: a stable sex difference in non-elite runners.

Recent studies indicate that more men than women run fast relative to sex- specific world records and that this sex difference has been historically stable in elite U.S. runners. These findings have been hypothesized to reflect an evolved male predisposition for enduring competitiveness in "show-off" domains. The current study tests this hypothesis in non-elite runners by analyzing 342 road races that occurred from 1981-2006, most in or near Buffalo, NY. Both absolutely and as a percentage of same-sex finishers, more men ran relatively fast in most races. During the 1980s, as female participation surged, the difference in the absolute number of relatively fast men and women decreased. However, this difference was stable for races that occurred after 1993. Since then, in any given race, about three to four times as many men as women ran relatively fast. The stable sex difference in relative performance shown here for non-elites constitutes new support for the hypothesis of an evolved male predisposition for enduring competitiveness.

Origins of spatial, temporal and numerical cognition: Insights from comparative psychology.

Contemporary comparative cognition has a large repertoire of animal models and methods, with concurrent theoretical advances that are providing initial answers to crucial questions about human cognition. What cognitive traits are uniquely human? What are the species-typical inherited predispositions of the human mind? What is the human mind capable of without certain types of specific experiences with the surrounding environment? Here, we review recent findings from the domains of space, time and number cognition. These findings are produced using different comparative methodologies relying on different animal species, namely birds and non-human great apes. The study of these species not only reveals the range of cognitive abilities across vertebrates, but also increases our understanding of human cognition in crucial ways.

Controlled studies of chimpanzee cultural transmission.

Following the first long-term field studies of chimpanzees in the 1960s, researchers began to suspect that chimpanzees from different African populations varied in their behavior, and that some of these variations were transmitted through social learning, thus suggesting culture. Additional reports of chimpanzee culture have since accumulated, which involve an increasing amount of behavioral variation that has no obvious ecological or genetic explanation. To date, close to 50 cultural variants have been reported, including subsistence behavior, tool-use, communication signals, and grooming patterns. Nevertheless, field studies lack the experimental controls and manipulations necessary to conclusively demonstrate that the observed variation results from differential invention and social transmission of behavior. This would require that behavioral variants have been learned from others, a question best addressed in a controlled experimental setting. The following chapter details a series of experimental studies at Yerkes National Primate Research Center of Emory University. In each case, the behavior of two captive groups (each N=12 individuals) was compared before and after the introduction of a novel foraging behavior by a trained conspecific "inventor." The studies were designed to investigate (i) the conditions under which chimpanzees learn from one another, (ii) how behaviors are transmitted, (iii) how cultures are maintained over generations. The results emphasize the importance of integrating both fieldwork and experimental approaches. Previous studies have reported deficits in chimpanzees' cultural capacities, but did so after testing them with human models, which are largely irrelevant to the problem at hand. A representative understanding of culture can only be gained when efforts are made to create a naturalistic learning environment in which chimpanzees have opportunities to learn spontaneously from conspecifics in a familiar social setting.

[Classification statistical techniques: an applied and comparative study]. / Técnicas estadísticas de clasificación: un estudio comparativo y aplicado.

The aim of this article is to assess and compare three classification statistical techniques--logistic regression, discriminant analysis and classification trees--to identify the personality characteristics associated with the risk of suffering from ischemic cardiovascular acute episodes (ICAE). The sample comprised 313 participants, men and women, aged from 36 to 80. Participants were divided into two groups: a clinical group of patients (n = 143) who were diagnosed as suffering from ICAE, and a control group (n = 170). Both groups were equated in gender, age, socio-economic and educational level. In view of the comparative study of the analytical procedures, we recommend classification trees as the best choice, as it was the most accurate for the individuals in the clinical group, a simple data analysis and a meaningful clinical interpretation. The predictive validity analysis of the MCMI-II allowed the construction of a reduced version made up of 9 personality scales from the 22 scales in the original version. Thus, we could identify the patients with a higher probability of suffering from ICAE, and additionally, generate an empirical model comprising seven and five personality profiles associated, respectively, with the increase and the decrease of the probability of suffering from ICAE.

The comparative psychology of same-different judgments by humans (Homo sapiens) and monkeys (Macaca mulatta).

The authors compared the performance of humans and monkeys in a Same-Different task. They evaluated the hypothesis that for humans the Same-Different concept is qualitative, categorical, and rule-based, so that humans distinguish 0-disparity pairs (i.e., same) from pairs with any discernible disparity (i.e., different); whereas for monkeys the Same-Different concept is quantitative, continuous, and similarity-based, so that monkeys distinguish small-disparity pairs (i.e., similar) from pairs with a large disparity (i.e., dissimilar). The results supported the hypothesis. Monkeys, more than humans, showed a gradual transition from same to different categories and an inclusive criterion for responding Same. The results have implications for comparing Same-Different performances across species--different species may not always construe or perform even identical tasks in the same way. In particular, humans may especially apply qualitative, rule-based frameworks to cognitive tasks like Same-Different.