Animal Cognition最新文献

Musicality is the predisposition to process and produce music. In human beings, processing and producing music often involves entrainment, the ability to synchronise behaviour to external auditory rhythms. Most non-human primates have limited entrainment skills; its search in other taxa has shown cases of entrainment much more advanced than any non-human primate in a few taxa, among which birds. Finding convergently-evolved entrainment abilities in several species may highlight shared evolutionary origins. Here, we investigate spontaneous vocal entrainment in rooks, a social corvid, using non-biologically relevant stimuli. We exposed individual rooks to sound sequences varying in tempo and metrical structure, and tested the effect of these two manipulations on temporal adjustments in their song. Of the 11 birds tested, eight sang while listening to the stimuli. Three of them sang often enough for us to analyse their responses to most tempos and meters. We found that two of these individuals were influenced by particular tempi and/or metrical structures: one bird produced shorter vocalisations at slower tempo and another reduced the intervals between its vocalisations upon hearing isochronous sequences with a unary metre and slow tempo. Still, the timing of the start of their vocalisations did not match accurately the timing of the beat of the stimuli. Our results provides additional data on vocal flexibility in this vocal learning species. We cannot exclude that rooks may have attempted to vocally entrain, but the possibility will require further investigations. Despite their evolutionary distance from humans, rooks, and possibly other corvids and songbirds, are interesting species for future studies on rhythmic perception, and could help shed light on convergently evolved building blocks of human musicality.

Cognitive performance in animals can be assessed through the detour task, which challenges spatial navigation, decision-making, and behavioral flexibility. The most common versions of the detour task often fail to involve processing of different environmental cues, the adjusting of behavior to varying obstacles, and motivation, factors that are likely important for cognitive performance. In this study, we aimed to validate a new method for assessing cognitive performance—a detour task with increasing levels of difficulty—using the reef fish Stegastes fuscus. We evaluated the ability of individuals to traverse a 150 cm-long tank in which barriers with doors were progressively introduced across test days, increasing task complexity and requiring flexible detour strategies. Two groups were tested: one with a conspecific as a social stimulus and one without any stimulus. The results revealed that S. fuscus employed different behavioral strategies to complete the task, suggesting spatial learning, route planning, and possible memory use, especially when the social stimulus was present. This novel detour paradigm highlights the species’ cognitive capacity to solve progressively complex spatial challenges. Understanding how stimulus respond to increasing task demands provides valuable insights into animal cognition and behavioral ecology.

The performance of detection dogs relies on their ability to detect and alert to variations of the stimuli upon which they have been trained. As such, research has tended to focus on understanding the likelihood of generalising beyond a trained stimulus set. However, it remains unclear which stimuli dogs perceive as the ‘same’ or ‘different’ to others. Understanding this perception would allow the creation of appropriate training aids to improve the performance of working dogs. The aim of this study was to establish whether dogs were capable of same-different concept learning with odours and whether they could generalise this learning to a novel stimulus set. Dogs were presented with two odours simultaneously and trained to give one indication behaviour if the samples were the same, and an alternative indication if they were different. Four of the ten dogs tested were able to meet the learning criteria, indicating that they could learn the task with the training stimuli. However, none were able to generalise the concept to a new stimulus set. The failure of the dogs to generalise the same-different learning to novel stimuli suggests that the procedure used, while showing some promise, may not be the best approach to assess how dogs perceive odours in relation to each other.

Selective breeding for specialized functional roles has resulted in consistent differences among domestic dog breeds in a range of cognitive capacities, as demonstrated by standardized cognitive assessments. What remains uncertain is whether these breed differences extend beyond initial task performance to influence how dogs adjust their behaviour or improve their performance when they are re-tested on the same tasks. In the present study, we used a structured hand-touch learning task to examine changes in Discrimination, Reversal learning, and resistance to Extinction performances across two testing sessions in 105 dogs representing five breed clades. Statistical analyses accounted for demographic variables, reward responsiveness, impulsivity, and training history. Dogs showed limited changes in learning performance across sessions, with statistically significant improvement observed only in Reversal learning from Test 1 to Test 2. Most breed-clade differences in average performance found during the initial test were no longer evident at Test 2. There was also limited evidence that breed clades differed in the extent of their performance change over time. Taken together, these results suggest that initial performance differences across breed clades likely reflect breed-specific cognitive profiles that shape how dogs engage with novel learning tasks. Following re-exposure to the task, average performance tends to improve and potentially mask the initial between-clade differences, although the magnitude of improvement appears broadly similar across breed clades. These findings highlight the importance of considering both initial performance and prior experience when interpreting breed differences in learning and cognitive capacities.

For optimal decision-making, social animals can benefit from evaluating others’ behaviours. Some species seemingly consider the skills of others when deciding who to interact with in different contexts. Yet, whether and how nonhuman animals form impressions about others’ competence is still unclear. In this study, we investigated whether Tonkean macaques (Macaca tonkeana) and brown capuchins (Sapajus apella) can evaluate the skilfulness of others. Subjects observed two human actors (one skilful, one unskilled) trying to open several food containers. Only the skilful actor successfully opened the containers and released food so the experimenter could give it to the subjects. Our results revealed that subjects did not choose the skilful actor significantly more frequently than the unskilled one. Their choices for the skilful actor did not increase through trials nor were they based on the outcomes experienced in previous trials. However, when we considered their initial preferences for the human actors, we observed a significant shift in preference for the skilful actor. Our subjects also looked preferentially at the skilful over the unskilled actor when both simultaneously manipulated a container. While the underlying cognitive mechanisms (impression formation vs. outcome-based process) are still unclear, our findings indicate that Tonkean macaques and brown capuchins may have used social information about the actors’ skills to inform their decisions and raise questions about which behavioural measures best capture social evaluation in nonhuman species.

Exaggerated prosody directed toward dogs has multiple functions, including attention getting and maintaining as well as expressing positive emotions toward the canine partner. However, the role of prosody in owner-dog familiarity remains unclear. To address this gap, we examined the effect of familiarity on the acoustic and visual prosodic features of dog-directed speech. To this end, we analyzed the prosodic features of female speakers when interacting with their own dogs vs. an unfamiliar dog of the same breed during three different situations: Attention-getting, Task-solving, and Nursery rhymes. Interestingly, only the mean pitch was affected by familiarity as speakers used a higher pitch when interacting with the unfamiliar dog compared to their own dog. Meanwhile, pitch range and the intensity of ‘happy’ facial expressions were affected by the dog’s size: speakers used a wider pitch range and more intense ‘happy’ expressions when interacting with smaller dogs. The Nursery rhymes situation evoked the most intense visual prosody, perhaps due to the use of nursery rhymes when interacting with infants. Our results suggest that a heightened overall pitch may serve as a way to appear friendly toward an unfamiliar being, acting as a universal engaging mechanism in human-dog communication. In contrast, the ‘happy’ facial expression and pitch range seem to be less sensitive to the familiarity with a dog, being more influenced by the specific situation and size of the canine partner which is likely related to the ‘cuteness factor’ and/or the baby schema in female speakers.