Insensitivity to reward shifts in zebrafish (Danio rerio) and implications for assessing affective states

Animal Cognition - Theory and empirical findings predict that individuals in a negative affective state are more sensitive to unexpected reward loss and less sensitive to unexpected reward gain...     

Post-weaning social and cognitive performance of piglets raised pre-weaning either in a complex multi-suckling group housing system or in a conventional system with a crated sow

We studied the social and cognitive performance of piglets raised pre-weaning either in a conventional system with a sow in a farrowing crate (FC) or in a multi-suckling (MS) system in which 5 sows and their piglets could interact in a more physically enriched and spacious environment. After weaning at 4 weeks of age, 8 groups of 4 litter-mates per pre-weaning housing treatment were studied under equal and enriched post-weaning housing conditions. From each pen, one pair consisting of a dominant and a submissive pig was selected, based on a feed competition test (FCT) 2 weeks post-weaning. This pair was used in an informed forager test (IFT) which measured aspects of spatial learning and foraging strategies in a competitive context. During individual training, submissive (informed) pigs learned to remember a bait location in a testing arena with 8 buckets (the same bucket was baited in a search visit and a subsequent relocation visit), whereas dominant (non-informed) pigs always found the bait in a random bucket (search visits only). After learning their task, the informed pigs’ individual search visit was followed by a pairwise relocation visit in which they were accompanied by the non-informed pig. Effects of pre-weaning housing treatment were not distinctly present regarding the occurrence of aggression in the FCT and the learning performance during individual training in the IFT. During paired visits, informed and non-informed pigs changed their behaviour in response to being tested pairwise instead of individually, but MS and FC pigs showed few distinct behavioural differences.     

The influence of preexperimental experience on social discrimination in rats (Rattus norvegicus)

The authors used laboratory rats (Rattus norvegicus) of known relatedness and contrasting familiarity to assess the potential effect of preexperimental social experience on subsequent social recognition. The authors used the habituation-discrimination technique, which assumes that multiple exposures to a social stimulus (e.g., soiled bedding) ensure a subject discriminates between the habituation stimulus and a novel stimulus when both are introduced simultaneously. The authors observed a strong discrimination if the subjects had different amounts of preexperimental experience with the donors of the 2 stimuli but a weak discrimination if the subjects had either equal amounts of preexperimental experience or no experience with the stimuli. Preexperimental social experience does, therefore, appear to influence decision making in subsequent social discriminations. Implications for recognition and memory research are discussed.     

Foraging behaviour in domestic pigs (Sus scrofa): remembering and prioritizing food sites of different value

This experiment investigated whether domestic pigs can remember the locations of food sites of different relative value, and how a restricted retrieval choice affects their foraging behaviour. Nine juvenile female pigs were trained to relocate two food sites out of a possible eight in a spatial memory task. The two baited sites contained different amounts of food and an obstacle was added to the smaller amount to increase handling time. On each trial, a pig searched for the two baited sites (search visit). Once it had found and eaten the bait, it returned for a second (relocation) visit, in which the two same sites were baited. Baited sites were changed between trials. All subjects learnt the task. When allowed to retrieve both baits, the subjects showed no preference for retrieving a particular one first (experiment 1). When they were allowed to retrieve only one bait, a significant overall preference for retrieving the larger amount emerged across subjects (experiment 2). To test whether this preference reflected an avoidance of the obstacle with the smaller bait, 15 choice-restricted control trials were conducted. In control trials obstacles were present with both baits. Pigs continued to retrieve the larger bait, indicating they had discriminated between the two food sites on the basis of quantity or profitability and adjusted their behaviour accordingly when the relocation choice was restricted. This suggests for the first time that domestic pigs have the ability to discriminate between food sites of different relative value and to remember their respective locations.     

Decision-making under uncertainty: biases and Bayesians

Animals (including humans) often face circumstances in which the best choice of action is not certain. Environmental cues may be ambiguous, and choices may be risky. This paper reviews the theoretical side of decision-making under uncertainty, particularly with regard to unknown risk (ambiguity). We use simple models to show that, irrespective of pay-offs, whether it is optimal to bias probability estimates depends upon how those estimates have been generated. In particular, if estimates have been calculated in a Bayesian framework with a sensible prior, it is best to use unbiased estimates. We review the extent of evidence for and against viewing animals (including humans) as Bayesian decision-makers. We pay particular attention to the Ellsberg Paradox, a classic result from experimental economics, in which human subjects appear to deviate from optimal decision-making by demonstrating an apparent aversion to ambiguity in a choice between two options with equal expected rewards. The paradox initially seems to be an example where decision-making estimates are biased relative to the Bayesian optimum. We discuss the extent to which the Bayesian paradigm might be applied to the evolution of decision-makers and how the Ellsberg Paradox may, with a deeper understanding, be resolved.     

Do you see what I see? Testing horses’ ability to recognise real-life objects from 2D computer projections

Animal Cognition - The use of 2-dimensional representations (e.g. photographs or digital images) of real-life physical objects has been an important tool in studies of animal cognition. Horses are...     

Recognition of conspecific odors by laboratory rats (Rattus norvegicus) does not show context specificity

This experiment investigated how contextual cues affect recognition of conspecific odors in laboratory rats (Rattus norvegicus). Rats received 5 encounters with the same odor in the same context. For the 6th test encounter, all rats received a simultaneous presentation of the original odor and a novel odor. The authors tested 1 group of rats (context same) in the same context as before. For the remaining 2 groups, the test encounter was in a different context that 1 group (context different) had experienced but that 1 group (context novel) had not. A significant preference to investigate the novel odor by context-same and context-different rats, but not by context-novel rats, suggests that odor recognition can occur following transfer to a different, but familiar, test context, indicating a lack of context specificity.     

What should religious education in Germany be about and how does religiosity fit into this picture? An empirical study of pre-service religious education teachers’ beliefs on the aims of RE

In secularising Germany the aim of religious education (RE) is under discussion. The churches opt for denominational education familiarising the students with their own religious tradition. Humanists claim an ethical education, giving students objective information about different religions. Which perspective do students who will become RE teachers take in this discussion? Does their religiosity affect this perspective? All over Germany 1828 first-year students (with an average age of 21; 81% females; 72% Catholic and 28% Protestant) completed a relevant questionnaire. The respondents favour a RE which offers objective information. Most of them are pluralist thinkers in religious terms and show a moderate religious practice. The more relativist the students are thinking in religious terms, the more they tend to favour objective information. These findings challenge the churches’ perspective on RE, because even future RE teachers do not agree with the churches’ ideal on RE. A reformulation of this approach on cognitive level will be discussed.