Chimpanzee (Pan troglodytes) spatial problem solving with the use of mirrors and televised equivalents of mirrors

Two adult male chimpanzees reached through a hole in the wall of their home cage and, by tracking the images of their hands and of an otherwise hidden target object in a mirror or closed-circuit television picture, moved their hands in whichever direction was necessary to make contact with the target object. They discriminated between live video images and tapes and performed effectively when the target objects were presented in novel locations and when the video picture was presented at random in different orientations. There was thus no consistent relation between the location of images on the monitor and the location of their real-world counterparts. Comparable performances in monkeys and nonprimates seem unlikely.     

Double agency and the ethics of rationing health care: a response to Marcia Angell

The arguments against doctors as "double agents" that are presented by Marcia Angell in the preceding article do not defeat the core justification for rationing some relatively high-expense, low-benefit care, and they do not enable us to conclude that clinicians should be barred from any active, substantive role in decisions to limit that care. They do, however, reveal several important conditions that need to govern cost-conscious medial practice in order to preserve an ethic of fidelity to patients: insurers' profits and providers' incomes must be fair, providers must inform patients of any economic reasons that lead to the foregoing of care, and "direct incentive" arrangements must not be used to contain costs.     

Post-event misinformation effects in a language-trained chimpanzee (Pan troglodytes)

Animal Cognition - Errors of source monitoring are widespread human memory challenges, and our memories are subject to distortion upon the presentation of subsequent misinformation. Less is known...     

Side-specificity of olfactory learning in the honeybee: generalization between odors and sides

Honeybees (Apis mellifera) can be trained to associate an odor stimulus with a sucrose reward. The neural structures involved in the detection and integration of olfactory stimuli are represented bilaterally in the brain. Little is known about the respective roles of the two sides of the brain in olfactory learning. Does each side learn independently of the other, or do they communicate, and if so, to what extent and at what level of neural integration? We addressed these questions using the proboscis extension response (PER) conditioning paradigm applied in a preparation that allows the separation of the two input sides during olfactory stimulations. Bees conditioned to two odorants A and B, one being learned on each side (A+/B+ training), showed in extinction tests rather unspecific responses: They responded to both odorants on both sides. This could be attributable to either a transfer of the learned information between sides, or to a generalization between odorants on each side. By subjecting bees to conditioning on one side only (A+/0 training), we found that the learned information is indeed transferred between sides. However, when bees were trained explicitly to give opposite values to the two odorants on the two sides (A+B-/B+A- training), they showed clear side-specific response patterns to these odorants. These results are used in the elaboration of a functional model of laterality of olfactory learning and memory processing in the honeybee brain.     

Internalization of Appearance Ideals and Cosmetic Surgery Attitudes: A Test of the Tripartite Influence Model of Body Image

The Tripartite Influence Model of Body Image was adapted to examine the role of body satisfaction, perceived pressure to have cosmetic surgery, and internalization of societal appearance ideals in understanding cosmetic surgery attitudes. Participants were 2,048 men (N?=?445) and women (N?=?1,603) American college students from Florida who completed a range of measures that assessed levels of body satisfaction, perceived appearance pressures, internalization of appearance standards, and cosmetic surgery attitudes. A structural equation model was used to test hypothesized relations independently for men and women. Results indicated a moderate-good fit to the data, with both internalization and body satisfaction mediating the effect of perceived pressures on cosmetic surgery attitudes. Invariance testing revealed significant differences in pathway estimates between samples of men and women. The findings offer further support for the Tripartite Influence Model of Body Image and indicate potential factors that may influence cosmetic surgery attitudes.     

One retrieval trial induces reconsolidation in an appetitive learning paradigm in honeybees (Apis mellifera)

Combining memory retrieval with the application of a protein synthesis-inhibitor leads to an amnestic effect that is referred to as the reconsolidation phenomenon. Several behavioural studies demonstrate that only a few or weak retrieval trials (that do not result in significant extinction) lead to this phenomenon. In contrast, many trials (that result in significant extinction) combined with a protein synthesis inhibitor result in an inhibition of the extinction memory. Based on these findings it was suggested that extinction is the boundary condition for reconsolidation: when extinction is induced the consolidation of the extinction memory is the dominant process. Recently we were not able to confirm this hypothesis in the honeybee (Apis mellifera): We did not find the reconsolidation phenomenon after one retrieval trial, but demonstrated reconsolidation after five retrieval trials that led to extinction. To exclude that this observation resembles a special case in insects we here wanted to know if one retrieval trial induces reconsolidation as it has been demonstrated before in many other species. To do so we used experimental parameters that had been used before to demonstrate consolidation in the honeybee with the exception that this time the protein synthesis-inhibitor was applied 1 h after one memory retrieval instead after acquisition. We thereby demonstrate the reconsolidation phenomenon after one retrieval trial but only when using the doubled dose of protein synthesis-inhibitor that has been used to inhibit consolidation.     

How young children and chimpanzees (Pan troglodytes) perceive objects in a 2D display: putting an assumption to the test

Object recognition research is typically conducted using 2D stimuli in lieu of 3D objects. This study investigated the amount and complexity of knowledge gained from 2D stimuli in adult chimpanzees (Pan troglodytes) and young children (aged 3 and 4 years) using a titrated series of cross-dimensional search tasks. Results indicate that 3-year-old children utilize a response rule guided by local features to solve cross-dimensional tasks. Four-year-old toddlers and adult chimpanzees use information about object form and compositional structure from a 2D image to guide their search in three dimensions. Findings have specific implications to research conducted in object recognition/perception and broad relevance to all areas of research and daily living that incorporate 2D displays.     

Actualism,ontological commitment,and possible world semantics

Actualism is the doctrine that the only things there are, that have being in any sense, are the things that actually exist. In particular, actualism eschews possibilism, the doctrine that there are merely possible objects. It is widely held that one cannot both be an actualist and at the same time take possible world semantics seriously — that is, take it as the basis for a genuine theory of truth for modal languages, or look to it for insight into the modal structure of reality. For possible world semantics, it is supposed, commits one to possibilism. In this paper I take issue with this view. To the contrary, I argue that one can take possible world semantics seriously and yet remain in full compliance with actualist scruples.     

Average group behavior does not represent individual behavior in classical conditioning of the honeybee

Conditioned behavior as observed during classical conditioning in a group of identically treated animals provides insights into the physiological process of learning and memory formation. However, several studies in vertebrates found a remarkable difference between the group-average behavioral performance and the behavioral characteristics of individual animals. Here, we analyzed a large number of data (1640 animals) on olfactory conditioning in the honeybee (Apis mellifera). The data acquired during absolute and differential classical conditioning differed with respect to the number of conditioning trials, the conditioned odors, the intertrial intervals, and the time of retention tests. We further investigated data in which animals were tested for spontaneous recovery from extinction. In all data sets we found that the gradually increasing group-average learning curve did not adequately represent the behavior of individual animals. Individual behavior was characterized by a rapid and stable acquisition of the conditioned response (CR), as well as by a rapid and stable cessation of the CR following unrewarded stimuli. In addition, we present and evaluate different model hypotheses on how honeybees form associations during classical conditioning by implementing a gradual learning process on the one hand and an all-or-none learning process on the other hand. In summary, our findings advise that individual behavior should be recognized as a meaningful predictor for the internal state of a honeybee--irrespective of the group-average behavioral performance.