The use of an intermittent schedule of reinforcement to evaluate detection dogs’ generalization from smokeless-powder

Abstract

Odor generalization is essential for detection dogs. Regardless of its importance, limited research is available on detection dog odor generalization. The objectives of this study were (1) evaluate the use of an intermittent schedule of reinforcement to assess generalization in dogs and (2) evaluate olfactory generalization from a single exemplar of smokeless powder (SP). Dogs (N = 5) were trained to detect SP in an automated olfactometer under an intermittent schedule of reinforcement where only 60% of correct responses were reinforced. After training, eight non-reinforced probe trials were inserted within a session. A total of 15 testing odors were evaluated across 15 consecutive sessions (one odor/session). Six of the testing odors were control and the remaining testing odors were objects indirectly exposed to SP, objects that contained or were directly exposed to SP, single-base SP and diphenylamine (the main volatile present in the headspace of SP). Dogs’ response rate to all testing odors except for the cotton gauzes and t-shirt cloths exposed to the headspace of SP, the simulated IED, and Getxent tubes exposed to direct contact with SP were statistically lower than their response rate of actual SP. The response rate to SP was not different across all 15 testing sessions suggesting that the intermittent schedule of reinforcement, maintained dog motivation and performance. Data show that the outlined method is a good approach to study generalization in detection dogs. These results also highlight dog generalization to SP varieties and associated odors.

Cognitive bias in animal behavior science: a philosophical perspective

Abstract

Emotional states of animals influence their cognitive processes as well as their behavior. Assessing emotional states is important for animal welfare science as well as for many fields of neuroscience, behavior science, and biomedicine. This can be done in different ways, e.g. through assessing animals’ physiological states or interpreting their behaviors. This paper focuses on the so-called cognitive judgment bias test, which has gained special attention in the last 2 decades and has become a highly important tool for measuring emotional states in non-human animals. However, less attention has been given to the epistemology of the cognitive judgment bias test and to disentangling the relevance of different steps in the underlying cognitive mechanisms. This paper sheds some light on both the epistemology of the methods and the architecture of the underlying cognitive abilities of the tested animals. Based on this reconstruction, we propose a scheme for classifying and assessing different cognitive abilities involved in cognitive judgment bias tests.

Chasing perception in domestic cats and dogs

Abstract

Chasing motion is often used to study the perception of inanimate objects as animate. When chasing interaction and independent motions between two agents are displayed simultaneously on a screen, we expect observers to quickly perceive and recognise the chasing pattern (because of its familiarity) and turn their attention to the independent motion (novelty effect). In case of isosceles triangles as moving figures, dogs and humans both display this behaviour, but dogs initially preferred to look at the chasing pattern whereas humans started to increase their gaze towards the independent motion earlier. Here, we compared whether family cats perceive moving inanimate objects as animate and whether their looking behaviour is similar to that of small family dogs. We displayed a chasing and independent motion side by side on a screen in two consecutive trials and assessed subjects’ looking behaviour towards the motions. Similarly to previous studies, we found that dogs eventually looked longer at the independent motion, but cats preferred to look at the independent motion at the beginning of the video display and only later shifted their attention to the chasing motion. No difference was found in the frequency of gaze alternation of the two species. Thus, although cats discriminate between the chasing and independent motions, it is not clear whether this discrimination is controlled by animate motion cues. The difference may originate from their ecological situation and/or may be explained by specific perceptual mechanisms.

Nest sanitation as an effective defence against brood parasitism

Abstract

Egg rejection is a crucial defence strategy against brood parasitism that requires the host to correctly recognise the foreign egg. Rejection behaviour has, thus, evolved in many hosts, facilitated by the visual differences between the parasitic and host eggs, and driving hosts to rely on colour and pattern cues. On the other hand, the need to recognise non-egg-shaped objects to carry out nest sanitation led birds to evolve the ability to discriminate and eject objects using mainly shape cues. However, little is known regarding the evolutionary significance of rejection behaviour in general and the cognitive processes underlying it. Here, we investigated the response of the barn swallow (Hirundo rustica) during pre-laying and laying stages to four objects types that differed in shape (eggs vs stars) and colour/pattern (mimetic vs non-mimetic) to investigate (1) what cognitive mechanisms are involved in object discrimination and (2) whether egg rejection is a direct defence against brood parasitism, or simply a product of nest sanitation. We found that swallows ejected stars more often than eggs in both stages, indicating that swallows possess a template for the shape of their eggs. Since the effect of colour/pattern on ejection decisions was minor, we suggest that barn swallows have not evolved a direct defence against brood parasitism but instead, egg ejection might be a product of their well-developed nest sanitation behaviour. Nonetheless, the fact that mimetic eggs were ejected especially in the pre-laying stage shows that nest sanitation could be an effective defence against poorly timed brood parasitism.

When should we ascribe sentience to animals? A commentary on “Hermit crabs, shells and sentience” (Elwood 2022)

Abstract

In a new review article, experiments on hermit crab behaviour are discussed in the context of possible animal sentience. Sentience can be defined as the ability to experience feelings such as pleasure or pain but there are also broader definitions that include elements of awareness. Here I suggest that of the different levels of awareness described as components of sentience, only the higher levels (assessment and executive awareness) seem distinct from the basic non-sentient cognitive tasks of gathering, processing and storing information, which are demonstrated by most animals. Studies that attempt to differentiate between basic cognitive functions and higher levels of awareness are rare for most animal taxa, including hermit crabs. Therefore, while results such as those obtained from studies of hermit crab behaviour are compatible with sentience they cannot yet be distinguished from simpler explanations based on basic cognitive functions, which we should prefer for the time-being. Nevertheless, hermit crabs are promising model systems for investigating awareness in animals.

Comments on “Intra- and interspecific variation in self-control capacities of parrots in a delay of gratification task”

Abstract

Brucks (Anim Cogn 25(2):473–491, 2021) have published an intriguing paper on the differing abilities of various species of parrots to succeed in a delay of gratification task. I find their interspecies comparisons of considerable interest but take exception to their misrepresentation of prior research on delayed gratification from our laboratory in Koepke (J Comp Psychol 129:339–346, 2015). Contrary to their claims, our subject was never trained on the task; rather, one might argue instead that all their subjects received considerable training or at least forms of pre-exposure that could affect their overall claims. I also briefly discuss other design features that may have affected their results.

Behavioral evidence for two distinct memory systems in rats

Abstract

Serial reaction time tasks, in which subjects have to match a target to a cue, are used to explore whether non-human animals have multiple memory systems. Predictable sub-sequences embedded in the sequence of cues are responded to faster, demonstrating incidental learning, often considered implicit. Here, we used the serial implicit learning task (SILT) to determine whether rats’ memory shows similar effects. In SILT, subjects must nose-poke into a sequence of two lit apertures, S1 and S2. Some S1 are always followed by the same S2, creating predictable sequences (PS). Across groups, we varied the proportion of PS trials, from 10 to 80%, and show that rats with more PS experience do better on them than on unpredictable sequences, and better than rats with less experience. We then introduced test trials in which no S2 was cued. Rats with more PS experience did better on test trials. Finally, we reversed some sequences (from predictable to unpredictable and vice versa) and changed others. We find that rats with more PS experience perseverate on old (now incorrect) responses more than those with less PS experience. Overall, we find a discontinuity in performance as the proportion of PS increases, suggesting a switch in behavioral strategies or memory systems, which we confirm using a Process Dissociation Procedure analysis. Our data suggest that rats have at least two distinct memory systems, one of which appears to be analogous to human implicit memory and is differentially activated by varying the proportion of PS in our task.

Azure-winged Magpies would rather avoid losses than strive for benefits based on reciprocal altruism

Abstract

It is no doubt that the reciprocal altruism of humans is unparalleled in the animal world. However, how strong altruistic behavior in the non-human animal is still very controversial. Almost all previous researches allowed only one individual in the dyad for action or dyad to accomplish tasks and obtain rewards simultaneously. Here, we designed current study based on the prisoner’s dilemma to investigate reciprocal altruism under interactions of Azure-winged Magpies (Cyanopica cyanus), which is direct reciprocity of allowing subjects obtain rewards, respectively. The results suggest that Azure-winged Magpies failed to show continuously altruistic behavior due to the empiricism that stemmed from interactions, that is, avoiding losses. Meanwhile, the resource exchange game paradigm, which is designed in our study, is worthwhile to study the evolution of cooperation in more species in the future.

Mother–pup recognition mechanisms in Australia sea lion (Neophoca cinerea) using uni- and multi-modal approaches

Abstract

Communication is the process by which one emitter conveys information to one or several receivers to induce a response (behavioral or physiological) by the receiver. Communication plays a major role in various biological functions and may involve signals and cues from different sensory modalities. Traditionally, investigations of animal communication focused on a single sensory modality, yet communication is often multimodal. As these different processes may be quite complex and therefore difficult to disentangle, one approach is to first study each sensorial modality separately. With this refined understanding of individual senses, revealing how they interact becomes possible as the characteristics and properties of each modality can be accounted for, making a multimodal approach feasible. Using this framework, researchers undertook systematic, experimental investigations on mother–pup recognition processes in a colonial pinniped species, the Australian sea lion Neophoca cinerea. The research first assessed the abilities of mothers and pups to identify each other by their voice using playback experiments. Second, they assessed whether visual cues are used by both mothers and pups to distinguish them from conspecifics, and/or whether females discriminate the odor of their filial pup from those from non-filial pups. Finally, to understand if the information transmitted by different sensory modalities is analyzed synergistically or if there is a hierarchy among the sensory modalities, experiments were performed involving different sensory cues simultaneously. These findings are discussed with regards to the active space of each sensory cue, and of the potential enhancements that may arise by assessing information from different modalities.