Stevia preferences in Wistar rats / Preferencia gustativa de las ratas Wistar por la estevia

BACKGROUND: The Stevia rebaudiana plant is likely to become a major source of high-potency sweetener for the growing natural-food market. S. rebaudiana is the source of a number of sweet diterpenoid glycosides, but the major sweet constituents are rebaudioside A and stevioside. These two constituents have similar pharmacokinetic and metabolic profiles in rats and humans, and thus, studies carried out with either steviol glycoside are relevant to both. Other studies illustrate the diversity of voluntary sweet intake in mammals. METHOD: This study was done using a series of two-bottle tests that compared a wide range of sweetener concentrations versus saccharin concentrations and versus water. RESULTS: Wistar rats displayed preferences for stevia extract and pure rebaudioside A solutions over water at a range of concentrations (0.001% to 0.3%), and their intake peak occurred at 0.1% concentration. They also preferred solutions prepared with a commercial rebaudioside A plus erythritol mixture to water, and their peak was at 2% concentration. CONCLUSIONS: The present study provides new information about the responses of Wistar rats to stevia compounds and commercial stevia products such as Truvia. These results could help with the appropriate dosage selection for focused behavioral and physiological studies on stevia

ANTECEDENTES: la planta Stevia rebaudiana se convertirá en una de las principales fuentes de edulcorantes debido al crecimiento del consumo de productos naturales en el mercado. S. rebaudiana contiene distintos glucósidos diterpenoides, pero los que proporcionan dulzor son el rebaudiosido A y el esteviosido. Estos dos compuestos tienen perfiles farmacocinéticos y metabólicos similares en ratas y humanos. Por otro lado, hay estudios que muestran la existencia de distintos patrones de ingesta voluntaria de edulcorantes en los mamíferos. MÉTODO: se realizaron series de la prueba de libre elección entre dos botellas. Comparamos la ingesta de un rango de concentraciones de edulcorantes frente al agua y frente a sacarina. RESULTADOS: las ratas Wistar prefieren el extracto de estevia y el rebaudiosido A (concentraciones desde 0,001% hasta 0,3%) frente al agua, la ingesta máxima fue a la concentración de 0,1%. También prefieren las soluciones preparadas con el producto comercial Truvia (rebaudiósido A y eritritol) frente al agua, la ingesta máxima fue a la concentración de 2%. CONCLUSIONES: nuestro trabajo proporciona nueva información sobre la preferencia gustativa de las ratas Wistar por distintos compuestos de estevia. Estos resultados ayudarán al diseño de estudios centrados en los efectos comportamentales y fisiológicos del consumo de estevia

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.

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.

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.

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.

Wolfgang Köhler's the mentality of apes and the animal psychology of his time

In 1913, the Anthropoid Station for psychological and physiological research in chimpanzees and other apes was founded by the Royal Prussian Academy of Sciences (Berlin) near La Orotava, Tenerife. Eugene Teuber, its first director, began his work at the Station with several studies of anthropoid apes’ natural behavior, particularly chimpanzee body language. In late 1913, the psychologist Wolfgang Köhler, the second and final director of the Station, arrived in Tenerife. During his stay in the Canary Islands, Köhler conducted a series of studies on intelligent behavior in chimpanzees that would become classics in the field of comparative psychology. Those experiments were at the core of his book Intelligenzprüfungen an Menschenaffen (The Mentality of Apes), published in 1921. This paper analyzes Köhler's experiments and notions of intelligent behavior in chimpanzees, emphasizing his distinctly descriptive approach to these issues. It also makes an effort to elucidate some of the theoretical ideas underpinning Köhler's work. The ultimate goal of this paper is to assess the historical significance of Köhler's book within the context of the animal psychology of his time (AU)

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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.

Manuel Azaña y la psicología / Manuel Azaña and psychology

Manuel Azaña (1880-1940) fue Presidente de la II República española y uno de los intelectuales más influyentes de la cultura republicana. Su memoria doctoral abordó algunos de los problemas de la Psicología Social de su tiempo en relación con el tema de la responsabilidad penal de las masas. Azaña se interesó también por la Psicología durante su estancia como becario en París y mantuvo una estrecha amistad con dos de los más influyentes psicólogos españoles: Luis Simarro y Gonzalo Rodríguez Lafora. La biografía de Azaña reflejó el auge de los psicólogos españoles de principios del siglo xx y su trágica dispersión al final de la Guerra Civil Española(AU)

Manuel Azaña (1880-1940) was President of the II Spanish Republic and one of the most influential intellectuals of the Republican culture. His doctoral thesis addressed some of the social psychology problems of his time regarding the issue of the legal responsibility of the masses. Azaña also showed interest in psychology during his time as a grantee in Paris and he became a close friend of two of the most influential Spanish psychologists: Luis Simarro y Gonzalo Rodríguez Lafora. Azaña’s biography reflects the rise of Spanish psychologists of the early 20th century and their tragic dispersion at the end of the Spanish Civil War(AU)

La percepción fonética en ratas: una nueva medida de discriminación / Phonetic perception in rats: a new discrimination measure

Durante las últimas décadas se ha demostrado que la experiencia con el habla cambia la percepción fonética en humanos. Varios estudios más recientes realizados con animales han demostrado que, al igual que en los humanos, una experiencia previa con los estímulos del habla también cambia su percepción de los estímulos fonéticos. Estos estudios, en mayor o menor medida, se han basado en procedimientos con entrenamiento para medir la capacidad de discriminación fonética en los animales. En el presente estudio se realizaron dos experimentos con ratas con la intención de explorar la influencia de la exposición previa a estímulos fonéticos, usando una medida que permitiera obtener una respuesta del animal sin necesidad de un entrenamiento extenso. Los resultados mostraron que una experiencia previa con estímulos fonéticos modifica su percepción. Las ratas expuestas previamente a sonidos del mismo conjunto fonético que el usado en la fase de prueba, mostraron un nivel de generalización más alto de los estímulos cercanos al estímulo referente en comparación a un grupo de ratas previamente expuestas a un conjunto de sonidos distinto y a otro grupo de ratas no expuestas previamente a ningún sonido (AU)

During the last decades it has been demonstrated that language experience changes phonetic perception in humans. Some of the recent studies with animals have also revealed that, like humans, linguistic experience also changes phonetic perception in animals. These studies have relied on training procedures to measure phonetic discrimination. In the current study two experiments with rats were run to explore the role of phonetic pre-exposition using a training-exempt procedure. The results revealed that previous non reinforced exposure to phonetic stimuli modifies their subsequent perception. Rats previously exposed and tested with sounds from the same phonetic set showed a higher generalization level of these sounds than a group of rats previously exposed to a distinct phonetic set and a group of rats not previously exposed to any speech sound (AU)