Abstract: AbstractThe last two decades have seen a virtual explosion in empirical research on the role of social interactions in the development of animals' behavioral repertoires, and a similar increase in attention to formal models of social learning. Here we first review recent empirical evidence of social influences on food choice, tool use, patterns of movement, predator avoidance, mate choice, and courtship, and then consider formal models of when animals choose to copy behavior, and which other animals' behavior they copy, together with empirical tests of predictions from those models.

Abstract: An immunoglobulin G (IgG) was spray-dried on a Büchi 190 laboratory spray-dryer at inlet and outlet air temperatures of 130 and 190°C, respectively. The IgG solution contains initially 115mg/ml IgG plus 50mg/ml sorbitol. After dialysis, at least 80% of low molecular weight component was removed. After spray-drying the dialyzed IgG and immediate redissolution of the powder, an increase in aggregates from 1 to 17% occurred. A major shift towards increase β-sheet structure was detected in the spray-dried solid, which, however, reverted to native structure on redissolution of the powder. A correlation between aggregation determined by size exclusion chromatography and alterations in secondary structure determined by Fourier transformation infra-red spectroscopy could not therefore be established. On spray-drying a non-dialyzed, sorbitol-containing IgG only some 0.7% aggregates were formed. The sorbitol is therefore evidently able to stabilize partially the IgG during the process of spray-drying. Addition of trehalose to the liquid feed produced quantitatively the same stabilizing action on the IgG during spray-drying as did the sorbitol. This finding again points towards a water replacement stabilization mechanism. The IgG spray-dried powder prepared from the dialyzed liquid feed showed continued substantial aggregation on dry storage at 25°C. This was substantially less in the non-dialyzed, sorbitol-containing spray-dried powder. Addition of trehalose to both dialyzed and non-dialyzed system produced substantial improvement in storage stability and reduction in aggregate formation in storage. The quantitative stabilizing effect of the trehalose was only slightly higher than that of the sorbitol. Taken together, these results indicate that both the sorbitol and trehalose stabilize the IgG primarily by a water replacement mechanism rather than by glassy immobilization. The relevance of this work is its questioning of the importance of the usually considered dominance of glassy stabilization of protein in dried systems of high glass transition temperature, such as trehalose. The low glass transition temperature sorbitol produces almost equal process and storage stability in this case.

Abstract: There are many indications and much practical knowledge about the different tasks which various breeds of dogs are selected for. Correspondingly these different breeds are known to possess different physical and mental abilities. We hypothesized that commonly kept breeds will show differences in their problem solving ability in a detour task around a V-shaped fence, and also, that breed differences will affect their learning ability from a human demonstrator, who demonstrates a detour around the fence. Subjects were recruited in Hungarian pet dog schools. We compared the results of the 10 most common breeds in our sample when they were tested in the detour task without human demonstration. There was no significant difference between the latencies of detour, however, there was a trend that German Shepherd dogs were the quickest and Giant Schnauzers were the slowest in this test. For testing the social learning ability of dogs we formed three breed groups (“utility”, “shepherd” and “hunting”). There were no significant differences between these, all the breed groups learned equally well from the human demonstrator. However, we found that dogs belonging to the “shepherd” group looked back more frequently to their owner than the dogs in the “hunting” group. Further, we have found that the age of pet dogs did not affect their social learning ability in the detour task. Our results showed that the pet status of a dog has probably a stronger effect on its cognitive performance and human related behaviour than its age or breed. These results emphasize that socialization and common activities with the dog might overcome the possible breed differences, if we give the dogs common problem solving, or social learning tasks.

Abstract: 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.