Research

(1) Positive animal welfare, which is the study of positive emotional states in animals and their wider effects on the animals’ biology. We have established a rat-tickling protocol as a standardised approach for inducing positive emotions. We use rats’ ultrasonic vocalisations (USVs) to assess the rats’ emotional response to being tickled and have recently validated our USV data using an independent test of affective state (an affective bias test; Figure below). We have also recent evidence to suggest that rat tickling (as a positive stimulus) may confer resilience to mild behavioural stressors. 

(2) The interface between Health and Welfare with a focus on the impacts of disease states on animals’ mental states including the role of interoception in animal emotions. The focus in animal health is mainly on the physical nature of disease, and there is a lack of work that addresses the effects of infectious disease on animals’ subjective (mental) state. We are interested in how we can assess the effect of signals from the body about pathogenic challenge (or other disease states) on animals’ mental state. We also study non-disease states that confer negative welfare on animals, including intra-uterine growth retardation (IUGR) in piglets, which aims to explore the implications of IUGR on brain health and neurodevelopment. We see important outcomes coming from this work, including a better understanding of the long-term effects of early challenges on health and welfare and the development of health interventions for farm animals which take account of the negative emotional outcomes of disease. 

Rat tickling involves using the human hand to mimic the physical contacts between rats when they are playing; in the standard approach to tickling the rat is contacted on the nape of the neck (B) before being held over the shoulders and flipped on its back (F), where it is ‘pinned’ (C); held down whilst the fingers tickle the belly area. Rats produce ultrasonic vocalisations (USVs) that can be recorded using an ultrasound microphone. The spectrogram shows two 50 kHz USVs; this type of USV is produced in positive emotional contexts including when rats are being tickled. We have argued that rats will vary in whether they prefer to be tickled with pinning1 and have recently provided experimental evidence to support this. Using USVs as our outcome measure, we have shown that juvenile female rats prefer to be tickled with less pinning whilst males show no preference2. We have also provided independent validation of this result using an affective bias test3 providing strong evidence to support the refinement of tickling to reduce pinning events to one per tickling session. 

¹ Bombail, V., Brown, S.M., Hammond, T.J., Meddle, S.L., Nielsen, B.L., Tivey, E.K.L., Lawrence, A.B., 2021. Crying With Laughter: Adapting the Tickling Protocol to Address Individual Differences Among Rats in Their Response to Playful Handling. Frontiers Vet Sci 8, 677872. https://doi.org/10.3389/fvets.2021.677872

² Bombail, V., Brown, S.M., Beyts, C., Martin, J.E., Li, T., Meddle, S.L., Mendl, M., Robinson, E.S., Hammond, T.J., Nielsen, B.L., LaFollette, M.R., Vinuela-Fernandez, I., Tivey, E.K., Lawrence, A.B., 2025. Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats. F1000Research 14, 773. https://doi.org/10.12688/f1000research.166417.1

³ Gonzalez, C., Lawrence, A.B., Mendl, M., Robinson, E., Bombail, V., Brown, S.M., 2026. Sex differences in the enjoyment of enrichment: affective bias testing confirms female rats prefer more playful and less vigorous tickling. Biol. Lett. 22, 20260075. https://doi.org/10.1098/rsbl.2026.0075