Behavioural Processes最新文献

Humans and several other species of animals have demonstrated the ability to use familiarity to recognize that they have seen images before. In prior experiments, orangutans failed to show use of familiarity in memory tasks, even when other solutions were not available. We tested for evidence of habituation, a decreased response to repeated stimuli, as a behavioral indicator that repeated images were familiar to subjects. Monkeys and orangutans selected the smallest target out of four while computerized images were presented as distractors. Latency to complete the target-finding task was compared between conditions in which the distractor image was a familiar, repeating image, a novel, never-before-seen image, or no distractor was present. Rhesus macaques showed significant habituation, and significantly more habituation than orangutans, in each of four experiments. Orangutans showed statistically reliable habituation in only one of the four experiments. These results are consistent with previous research in which orangutans failed to demonstrate familiarity. Because we expect that familiarity and habituation are evolutionarily ancient memory processes, we struggle to explain these surprising, but consistent findings. Future research is needed to determine why orangutans respond to computerized images in this peculiar way.

Musical and rhythmical abilities are poorly documented in non-human animals. Most of the existing studies focused on synchronisation performances to external rhythms. In humans, studies demonstrated that rhythmical processing (e. g. rhythm discrimination or synchronisation to external rhythm) is dependent of an individual measure: the individual tempo. It is assessed by asking participants to produce an endogenous isochronous rhythm (known as spontaneous motor tempo) without any specific instructions nor temporal cue. In non-human animal literature, studies describing spontaneous and endogenous production of motor tempo without any temporal clue are rare. This exploratory study aims to describe and compare the spontaneous motor tempo of cockatiels and jungle crows. Data were collected on spontaneous beak drumming behaviours of birds housed in laboratory. Inter beak strokes intervals were calculated from sound tracks of videos. The analyses revealed that inter beak strokes intervals are non-randomly distributed intervals and are isochronous. Recorded spontaneous motor tempos are significantly different among some cockatiels. Since we could only conduct statistical analysis with one corvid, we cannot conclude about this species. Our results suggest that cockatiels and jungle crows have individual tempos, thus encouraging further investigations.

A matching-to-sample task with a 3-sample, 2-comparison mapping has been found to engender joint control by the stimuli that signaled the samples (keylight) and the inter-trial interval (houselight), with a trade-off in the degree of control exerted by each stimulus. To learn about the boundary conditions for the establishment of that joint stimulus control, we trained pigeons in a similar task, but featuring a one-to-one sample-comparison mapping, with two samples and two comparisons. To assess their relative influences, we ran two tests where each of the stimuli was removed: in one test, no sample keylight was presented, and in the other, the ITI was spent in darkness. Results were consistent with both stimuli influencing choice but there was no clear evidence of a trade-off between them. These results suggest that sample-comparison mapping and/or total number of samples may influence how an animal directs its attention to the stimuli available.

Nonhuman animals have demonstrated various cooperative behaviors; however, many examples can be interpreted as individual contributions to a task rather than true behavioral coordination. In this study, we used the joint Simon task in rats to determine whether the presence of and task sharing with a partner affected performance in a joint activity. Rats were trained to discriminate between two auditory stimuli (3 and 12 kHz tones) and individually performed an auditory Simon task. They were paired with another rat and tested to perform half of the task, while the other rat performed the other half (joint task condition). The Simon effect was confirmed when the two rats completed half of a joint task. In contrast, when they were placed side by side but only one rat completed half of the task, the Simon effect was not observed. Further analyses revealed that the Simon effect observed in the joint task could not be explained by the simple addition of the two half tasks. In conclusion, task sharing affected individual performance in rats.

Nesting is a normal, evolutionary conserved rodent behavioural phenotype that is expressed for purposes of breeding, safety, and thermal regulation. Further, nesting is commonly assessed as marker of overall rodent health and wellbeing, with poorer nesting performance generally proposed to resemble a worse state of health. Deer mice can be bidirectionally separated with 30 % of mice presenting with excessively large nesting behaviour (LNB). All laboratory-housed deer mice are exposed to identical environmental conditions. Thus, the functional purpose of LNB remains unknown. Considering the evolutionary functions of nesting, we hypothesized that LNB will be related to an inflated drive to breed and nurse offspring. After breeding two generations of offspring from six ‘normal’ nesting (NNB) and seven LNB expressing pairs, our data showed that while as fertile as NNB expressing pairs, offspring survival of LNB mice were notably worse (67.9 % vs. 98.3 %). In conclusion, variance in nesting behaviour should be considered when animal health and wellbeing is considered, since it may point to underlying biobehavioural perturbations.

Predators and parasitoids often encounter parasitized prey or hosts during foraging. While the outcomes of such encounters have been extensively studied for insect parasitoids, the consequences of a predator encountering parasitized prey have received less attention. One extreme example involves the potter wasp Delta dimidiatipenne that frequently provision their nest with parasitized caterpillars, despite the low suitability of this prey for consumption by their offspring. This raises two main questions: (1) why do female potter wasps continue collecting parasitized caterpillars? and (2) is this an exceptional example, or do predatory insects often suffer from fitness costs due to encounters with parasitized prey? We addressed the first question using a probabilistic mathematical model predicting the value of discrimination between parasitized and unparasitized prey for the potter wasp, and the second question by surveying the literature for examples in which the parasitism status of prey affected prey susceptibility, suitability, or prey choice by a predator. The model demonstrates that only under certain conditions is discrimination against parasitized prey beneficial in terms of the potter wasp’s lifetime reproductive success. The literature survey suggests that the occurrence of encounters and consumption of parasitized prey is common, but the overall consequences of such interactions have rarely been quantified. We conclude that the profitability and ability of a predator to discriminate against parasitized prey under natural conditions may be limited and call for additional studies quantifying the outcome of such interactions.

"Pica" refers to the ingestion of non-nutritive substances by animals that would not typically consume them. The pica behavior can be utilized to investigate the internal conditions of animals' bodies. For example, rats, due to neuroanatomical reasons, cannot vomit; nevertheless, when nauseated, they ingest kaolin clay. This renders the ingestion of kaolin a practical proxy for measuring nausea in rats. The question of whether rats consume minerals other than kaolin during nauseous episodes remains unanswered. This study aims to identify a mineral better suited for detecting nausea in rats. In two experiments, nausea was induced in laboratory rats by a single dose of lithium chloride (0.15 M, 2% bw), and their mineral consumption over the 24-hour period was measured. Experiment 1 compared three minerals between rat groups: kaolin sold for nausea detection (kaolin A), kaolin for ceramics (kaolin B), and zeolite. Nauseated rats consumed all minerals, with the highest consumption occurring with kaolin B. In Experiment 2, three commercially available health soils were compared: edible kaolin, edible bentonite, and edible chalk. The most significant consumption was observed in the kaolin group, followed by the bentonite group, while nauseated rats did not consume edible chalk. These findings underscore the suitability of kaolin for nausea detection, although the extent of consumption may vary depending on the product.

The personality axis ‘exploration-avoidance’ is often measured using an open field test (OFT) from which measurements such as mobility level (e.g. distance travelled) and space use (e.g. area covered) in an unknown environment are extracted. Recently developed tracking software surprisingly includes only a measure of mobility level in their output summary. Consequently, recent articles using these software programs started to ignore a measure of space use in their determination of exploration. In this short communication, we show briefly why it is important to not overlook a measure of space use, provide an easy way to calculate such a measure, with adjustable resolution, from the available position data provided by the software and a method to determine a proxy for exploration.