Measuring paw preferences in dogs, cats and rats: Design requirements and innovations in methodology

Studying behavioural lateralization in animals holds great potential for answering important questions in laterality research and clinical neuroscience. However, comparative research encounters challenges in reliability and validity, requiring new approaches and innovative designs to overcome. Although validated tests exist for some species, there is yet no standard test to compare lateralized manual behaviours between individuals, populations, and animal species. One of the main reasons is that different fine-motor abilities and postures must be considered for each species. Given that pawedness/handedness is a universal marker for behavioural lateralization across species, this article focuses on three commonly investigated species in laterality research: dogs, cats, and rats. We will present six apparatuses (two for dogs, three for cats, and one for rats) that enable an accurate assessment of paw preference. Design requirements and specifications such as zoometric fit for different body sizes and ages, reliability, robustness of the material, maintenance during and after testing, and animal welfare are extremely important when designing a new apparatus. Given that the study of behavioural lateralization yields crucial insights into animal welfare, laterality research, and clinical neuroscience, we aim to provide a solution to these challenges by presenting design requirements and innovations in methodology across species.

Does owner handedness influence paw preference in dogs?

Handedness has proven to be the most effective and least intrusive measure of laterality in many species. Several studies have investigated paw preference in dogs (Canis familiaris) without considering the potential impact that owner's handedness may have on it, despite dogs being a domesticated species. The aim of this study was to investigate whether owner handedness influences paw preference in their dogs. Sixty-two dogs had their paw preference tested using a Paw Task and a Reach Task in their home over 10 days, recorded by their owners. Interestingly, it was found that left-handed owners were more likely to own a dog with a left paw bias, and right-handed owners were more likely to own a dog with a right paw bias. In the Paw Task, the hand presented to a dog did not significantly predict which paw the dog lifted in response. Furthermore, it was found that females displayed a right paw bias at all age groups. However, males had a left paw bias in puppyhood and right paw bias in older age groups. We conclude that owner handedness influences paw preference in dogs, and it should be considered when suitably pairing dogs to potential owners, especially in assistance work.

Paw preference is associated with behavioural despair and spatial reference memory in male rats

Paw preference, one of the well-studied behavioural markers of asymmetry, has been associated with affective states and pathologies such as behavioural despair, a rodent model of clinical depression. However, a consistent differential effect of paw preference has not been observed for cognitive functions. In order to investigate the affective properties of paw preference together with its potential cognitive effects, we grouped male Wistar rats as left- or right-pawed, and tested them in the forced swim test and Morris water maze for behavioural despair and spatial memory performance, respectively. We found that left-pawed rats were significantly more susceptible to behavioural despair, while spatial learning performance of the two groups were not different over a five-day Morris water maze task. Left-pawed rats, however, displayed a better reference memory than the right-pawed ones on the subsequent probe trial when the hidden platform of the maze was removed. These findings indicate paw preference as a vulnerability factor for behavioural despair and reveal a previously unknown association between left-paw preference and reference memory performance as assessed in the probe trial of the Morris water maze.

Learning is negatively associated with strength of left/right paw preference in wild grey squirrels (Sciurus carolinensis)

Cerebral laterality, via hemispheric specialisation, has been evidenced across the animal kingdom and linked to cognitive performance in a number of species. Previously it has been suggested that cognitive processing is more efficient in brains with stronger hemispheric differences in processing, which may be the key fitness benefit driving the evolution of laterality. However, evidence supporting a positive association between cognitive performance and lateralization is mixed: data from studies of fish and birds show a positive relationship whereas more limited data from studies of mammals suggest a weak or even negative relationship, suggesting the intriguing possibility of a mammal/non-mammal divide in the nature of this relationship. Here, we report an empirical test examining the relationship between lateralization and cognitive performance in wild grey squirrels (Sciurus carolinensis) by measuring left/right paw preference as a behavioural assay of cerebral lateralization and learning speed as an assay of cognitive efficiency. We carried out a motor-based laterality test using a reaching paradigm and measured learning speed on a problem-solving task. In accordance with the suggestion of a mammal/non-mammal divide, we found a negative relationship between strength of paw preference and performance on the learning task. We discuss this finding in light of niche-specific adaptations, task-specific demands and cognitive flexibility.

The relationship between problem-solving ability and laterality in cats

The association between hemispheric asymmetries and cognitive ability is one of the key areas of comparative laterality research. In several animal species, individual limb preferences correlate with perceptual, cognitive, or motor abilities, possibly by increasing dexterity of one limb and minimizing response conflicts between hemispheres. Despite this wealth of research, the association between laterality and cognitive abilities in the cat (Felis catus) is not well understood. Therefore, it was the aim of the present study to investigate the relationship between laterality and problem-solving ability in cats. To this end, strength and direction of paw preferences in 41 cats were measured using two novel food reaching tasks in which the animals needed to open a lid in order to reach the food reward. We found that cats that showed a clear preference for one paw were able to open more lids succesfully than ambilateral animals. Moreover, cats that preferred to interact with the test apparatus with their paw from the beginning, opened more lids than cats the first tried to interact with the test apparatus using their heads. Results also suggested a predictive validity of the first paw usage for general paw usage. It was also shown that the cats' individual paw preferences were stable and task-independent. These results yield further support to the idea that lateralization may enhance cognitive abilities.