Chimpanzees really know what others can see in a competitive situation

Chimpanzee’s perspective-taking abilities are currently disputed. Here we show that in some food competition contexts, subordinate chimpanzees do take the visual perspective of dominant individuals, preferentially targeting a hidden piece of the food that the dominant cannot see over a piece that is visible to both individuals. However, the space where the animals compete is critical in determining whether subjects demonstrate this skill. We suggest that competition intensity, as mediated by these spatial factors, may play an important role in determining the strategy chimpanzees utilize in competitive contexts. Since some strategies may not require visual perspective taking in order to be successful, chimpanzees may not always demonstrate this skill. Differences in spatial arrangement may therefore account for the conflicting results of past studies.     

Exercise motivation in university community members: a behavioural intervention

The purpose of this study was to examine how exercise level, exercise motives, and barriers changed from the baseline phase to the follow-up phase after a behavioural and cognitive intervention aimed at increasing exercise. Seventy-five members of our university community (43 subjects in the control group and 32 in the experimental group), all of whom received cognitive feedback, agreed to complete the baseline phase. Only the experimental group received behavioural feedback and a free-access gym ticket with personal training in order to facilitate their adherence to exercise. The results suggest that a combination of behavioural and psychological techniques is an efficient strategy for increasing exercise level. In addition, the results showed that extrinsic motivation predominates the early stages of change-of-exercise behaviour, and that intrinsic motivation is important for progression towards maintenance. Subjects who decreased their exercise level increased their extrinsic exercise motivation and subjects who increased their exercise level decreased the barriers related to intrinsic motivation. These findings indicate that, in order to facilitate exercise adherence, feedback about motives for undertaking exercise is needed, combined with advice about how to improve physical condition. This combination could help eliminate certain barriers that hinder engaging in an active and healthy life-style.     

Supervisors safety response: a multisample confirmatory factor analysis

Supervisors Safety Response (SSR) has been closely linked to workplace safety, and, as perceived by workers, it is considered to be one of the most influential issues with regard to employees compliance with safety behaviours. This study defines and tests a bifactorial and a monofactorial model of the SSR. Two facets of the SSR were measured: (a) supervisors response toward workers safe or unsafe behaviour and (b) supervisors safety attitudes and behaviours applied to their own work. In three samples of injured blue-collar workers ( N(1) = 110, N(2) = 123, N(3) = 104), multisample confirmatory factor analyses, using maximum likelihood estimation, were conducted to test both the bifactorial and the monofactorial model. Both models provide an overall good fit, but parsimony and the high correlation between factors in the bifactorial model support the monofactorial model. Attention is drawn to the measurement of the SSR as a diagnostic tool useful in selecting intervention goals, specifically integrating supervisors safety behaviour.     

Making inferences about the location of hidden food: social dog, causal ape

Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of object choice tasks. In each task, the location of hidden food was indicated for subjects by some kind of communicative, behavioral, or physical cue. On the basis of differences in the ecologies of these 2 genera, as well as on previous research, the authors hypothesized that dogs should be especially skillful in using human communicative cues such as the pointing gesture, whereas apes should be especially skillful in using physical, causal cues such as food in a cup making noise when it is shaken. The overall pattern of performance by the 2 genera strongly supported this social-dog, causal-ape hypothesis. This result is discussed in terms of apes' adaptations for complex, extractive foraging and dogs' adaptations, during the domestication process, for cooperative communication with humans.     

Gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus) encode relevant problem features in a tool-using task

Two important elements in problem solving are the abilities to encode relevant task features and to combine multiple actions to achieve the goal. The authors investigated these 2 elements in a task in which gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus) had to use a tool to retrieve an out-of-reach reward. Subjects were able to select tools of an appropriate length to reach the reward even when the position of the reward and tools were not simultaneously visible. When presented with tools that were too short to retrieve the reward, subjects were more likely to refuse to use them than when tools were the appropriate length. Subjects were proficient at using tools in sequence to retrieve the reward.     

All great ape species follow gaze to distant locations and around barriers

Following the gaze direction of conspecifics is an adaptive skill that enables individuals to obtain useful information about the location of food, predators, and group mates. In the current study, the authors compared the gaze-following skills of all 4 great ape species. In the 1st experiment, a human either looked to the ceiling or looked straight ahead. Individuals from all species reliably followed the human's gaze direction and sometimes even checked back when they found no target. In a 2nd experiment, the human looked behind some kind of barrier. Results showed that individuals from all species reliably put themselves in places from which they could see what the experimenter was looking at behind the barrier. These results support the hypothesis that great apes do not just orient to a target that another is oriented to, but they actually attempt to take the visual perspective of the other.     

Twelve- and 18-month-olds copy actions in terms of goals

In the context of an imitation game, 12- and 18-month-old infants saw an adult do such things as make a toy mouse hop across a mat (with sound effects). In one condition (House), the adult ended by placing the mouse in a toy house, whereas in another condition (No House) there was no house present at the final location. Infants at both ages usually simply put the mouse in the house (ignoring the hopping motion and sound effects) in the House condition, presumably because they interpreted the adult's action in terms of this final goal and so ignored the behavioral means. In contrast, infants copied the adult's action (both the hopping motion and the sound effects) when no house was present, presumably because here infants saw the action itself as the adult's only goal. From very early, infants' social learning is flexible: infants focus on and copy either the end or the means of an adult action as required by the context.     

On Łukasiewicz's Four-Valued Modal Logic

ukasiewicz's four-valued modal logic is surveyed and analyzed, together with ukasiewicz's motivations to develop it. A faithful interpretation of it in classical (non-modal) two-valued logic is presented, and some consequences are drawn concerning its classification and its algebraic behaviour. Some counter-intuitive aspects of this logic are discussed in the light of the presented results, ukasiewicz's own texts, and related literature.     

Estudio socio-espacial de las relaciones de afinidad en un grupo de gorilas (Gorilla,gorilla, gorilla) cautivos

Resumen

El uso del espacio refleja las relaciones que existen entre los individuos de un grupo. La afinidad entre el macho adulto y las hembras adultas es importante para que los grupos de gorilas sean estables. Se han estudiado las relaciones de afinidad en un grupo de 5 gorilas (1 macho adulto, 3 hembras adultas y 1 hembra joven) mediante medidas espaciales. Los resultados indican que existe una baja cohesión grupal, donde el macho no se distingue por tener las relaciones fuertes con las hembras adultas. La hembra joven es la más afín al macho y a las demás hembras. Las relaciones entre las hembras adultas son débiles. Posibles explicaciones a los resultados y algunas consideraciones metodológicas son discutidas.