Catia Correia‐Caeiro

Facial expressions are a core component of the emotional response of social mammals. In contrast to Darwin's original proposition, expressive facial cues of emotion appear to have evolved to be species-specific. Faces trigger an automatic perceptual process, and so, inter-specific emotion perception is potentially a challenge; since observers should not try to "read" heterospecific facial expressions in the same way that they do conspecific ones. Using dynamic spontaneous facial expression stimu

Facial expressions are subtle cues, central for communication and conveying emotions in mammals. Traditionally, facial expressions have been classified as a whole (e.g. happy, angry, bared-teeth), due to automatic face processing in the human brain, i.e., humans categorise emotions globally, but are not aware of subtle or isolated cues such as an eyebrow raise. Moreover, the same facial configuration (e.g. lip corners pulled backwards exposing teeth) can convey widely different information depen

Dogs have remarkable abilities to synergise their behaviour with that of people, but how dogs read facial and bodily emotional cues in comparison to humans remains unclear. Both species share the same ecological niche, are highly social and expressive, making them an ideal comparative model for intra- and inter-species emotion perception. We compared eye-tracking data from unrestrained humans and dogs when viewing dynamic and naturalistic emotional expressions in humans and dogs. Dogs attended m

Facial expressions are complex and subtle signals, central for communication and emotion in social mammals. Traditionally, facial expressions have been classified as a whole, disregarding small but relevant differences in displays. Even with the same morphological configuration different information can be conveyed depending on the species. Due to a hardwired processing of faces in the human brain, humans are quick to attribute emotion, but have difficulty in registering facial movement units. T

Comparative studies of human-dog cognition have grown exponentially since the 2000's, but the focus on how dogs look at us (as well as other dogs) as social partners is a more recent phenomenon despite its importance to human-dog interactions. Here, we briefly summarise the current state of research in visual perception of emotion cues in dogs and why this area is important; we then critically review its most commonly used methods, by discussing conceptual and methodological challenges and assoc

Children are often surrounded by other humans and companion animals (e.g., dogs, cats); and understanding facial expressions in all these social partners may be critical to successful social interactions. In an eye-tracking study, we examined how children (4-10 years old) view and label facial expressions in adult humans and dogs. We found that children looked more at dogs than humans, and more at negative than positive or neutral human expressions. Their viewing patterns (Proportion of Viewing

Segundo-Ortin & Calvo (S&C) argue for sentience in plants on the basis of several studies of what they describe as "cognitive abilities" in plants. As other commentaries (e.g., Brooks Pribac, 2023; Damasio & Damasio, 2023; ten Cate, 2023) have pointed out, however, there is some misuse of several concepts, and a lack of evidence for sentience. We try to clarify three questions in S&C’s discussion: (1) How is communication defined and conceptualised in animal research? (2) Is plant communication

The Facial Action Coding System (FACS) is a widely recognised coding scheme for analysing human facial behaviour, providing an objective method to quantify discrete movements associated with facial muscles, known as Action Units (AUs), and reducing subjective bias. FACS has been adapted for nine other taxa, including apes, macaques, and domestic animals, but not yet bonobos. To carry out cross species studies of facial behaviours within and beyond apes, it is essential to include bonobos. Hence,

Baker & Winkler (B&W) describe the state of Asian elephant conservation, raising unique issues, and proposing a direction based on rewilding. The long history and socio-biology of elephants and humans has some parallels with the domestication of dogs (and other species). However, markers of domestication seem absent from elephants. The proper use of terms such as “wild” and “domestic” is crucial in defining the best conservation strategies, and, more important, in attending to the welfare needs

Dogs are often used therapeutically (e.g., Pets at Therapy - PAT dogs) to visit elderly residents and those in care to promote social engagement and quality of life. Earlier studies reported that mutual gaze between dogs and owners induces a mutual change in physiology, with the release of oxytocin being a crucial mediator. However, it is not exactly known which types of cues trigger this mechanism, in particular whether these beneficial effects necessarily derive from the direct eye contact whe

Animal emotions have been debated since Darwin's pioneering work on the expression of such states in humans and other animals. Lately, interest in measuring animal emotions has been growing. Hence, a scientific discussion on this topic was needed, which translated into the organisation of the first International Workshop on Research Methods for Animal Emotion Analysis (RM4AEA). The current work aims to provide a concise yet critical examination of the current knowledge and methodological approac

The traditional dissections of the specialized mimetic muscles that produce facial expressions have revealed important insights into the evolution of muscles and their function in human and other mammals' social interactions. However, in small species, the task of manually visualizing and analysing musculature is challenging; even in larger species and muscles, digital anatomy methods, such as DiceCT and MRI-DTI, have been growing in popularity recently, providing detailed new insights into the

Facial expressions are subtle signals, central for communication and emotion in mammals. In humans, facial expressions are automatically classified as a whole (e.g. happy face), i.e., there is a global and emotionally-linked categorisation, but people fail to detect subtle cues (e.g. brow raise). Moreover, the same configuration (e.g. lip corners pulled backwards exposing teeth) can convey widely different information depending on the species (e.g. human: happiness; chimp: fear). The gold standa