The use of gaze to study cognition: limitations, solutions, and applications to animal welfare

Looking out for danger: Theoretical and empirical issues in translating human attention bias tasks to assess animal affective states

Understanding animal emotional (affective) state is highly relevant to various disciplines (e.g., animal welfare, neuroscience, comparative psychology), and has been significantly advanced by translating affect-induced cognitive bias paradigms rooted in human psychology to non-human animal studies. Attention bias (i.e., preferential attention allocation, AB) tests are increasingly used as more practical substitutes to commonly used judgement bias tests. Yet, evidence that AB reflects affective valence in animals is still limited. We review in-depth the concept of attention and AB described in humans and discuss utilising human-derived AB paradigms for measuring animal affective states. We describe key concepts and functions of attention in humans, before concentrating on the relationship between AB to threat detection and human anxiety. We critically review animal AB studies, discuss methodological discrepancies in such studies, and highlight the need for further experimental refinements. This includes identifying appropriate species-specific test designs and stimuli, modes of presentation (e.g., real-life vs. artificial stimuli), and consideration of subject-related factors (e.g., personality, age). We conclude that experimental limitations currently hamper the validity of AB as a proxy of animal affect and hope that the knowledge gaps highlighted in our review will encourage further research.

The ability of teleost fishes to recognize individual faces suggests an early evolutionary origin in vertebrates

The face is the most important area on the human body for visually differentiating between individuals. When encountering another person, humans initially gaze at and perceive the face holistically, utilizing first-order relational information and specific neural systems. Information such as identity and emotional state are then obtained from the face by distinguishing between small inter-individual differences, i.e., second-order relational information. Similar patterns and mechanisms underlying individual face recognition have been documented in primates, other social mammals, birds, and more recently in some fishes. Like humans, fish are capable of rapidly (<0.5 s) and accurately recognizing multiple familiar conspecifics by individual-specific variation in the face. Fish can also recognize faces from various distances and angles, providing evidence for mental representation of faces in this large and diverse vertebrate group. One species, the cleaner fish, has even demonstrated mirror self-recognition (MSR) via self-face recognition, strengthening the claim that non-human animals are capable of having mental images and concepts of faces. Here, we review the evidence for individual face recognition in fishes and speculate that face identification neural networks are both similar and widespread across vertebrates. Furthermore, we hypothesize that first-and second-order face recognition in vertebrates originated in bony fishes in the Paleozoic era ~450 Mya, when social systems first evolved, increasing the importance of individual recognition.

The Royal Zoological Society of Scotland's Approach to Assessing and Promoting Animal Welfare in Collaboration with Universities

Good zoos have four aims-to conserve species, educate the public, engage in research, and provide recreation-all of which can only be achieved when underpinned by high animal welfare standards. In this paper, we share the approach that The Royal Zoological Society of Scotland's (RZSS) Edinburgh Zoo and Highland Wildlife Park take to animal welfare. We highlight the role that animal welfare research, in collaboration with universities, has had in enabling the zoo to take an evidence-based approach to welfare and to put findings into practice. We share the collaborative process through which we developed and piloted the current animal welfare assessment tools, how they were validated, and how they were tested for reliability as part of a long-term collaboration between the Royal Zoological Society of Scotland and the University of Stirling: (1) the RZSS Welfare Assessment Tool, a 50-question animal welfare assessment adapted from the British and Irish Association of Zoos and Aquariums (BIAZA) Toolkit; and (2) the Stirling Toolkit, a package of evidence-based resources for behavioural-data collection. Our aim is to facilitate standardised, evidence-based approaches to assessing animal welfare which, when finalised, can be used collaboratively across zoos.

Does the primate face cue personality?

When looking at others, primates primarily focus on the face - detecting the face first and looking at it longer than other parts of the body. This is because primate faces, even without expression, convey trait information crucial for navigating social relationships. Recent studies on primates, including humans, have linked facial features, specifically facial width-to-height ratio (fWHR), to rank and Dominance-related personality traits, suggesting these links' potential role in social decisions. However, studies on the association between dominance and fWHR report contradictory results in humans and variable patterns in nonhuman primates. It is also not clear whether and how nonhuman primates perceive different facial cues to personality traits and whether these may have evolved as social signals. This review summarises the variable facial-personality links, their underlying proximate and evolutionary mechanisms and their perception across primates. We emphasise the importance of employing comparative research, including various primate species and human populations, to disentangle phylogeny from socio-ecological drivers and to understand the selection pressures driving the facial-personality links in humans. Finally, we encourage researchers to move away from single facial measures and towards holistic measures and to complement perception studies using neuroscientific methods.