I am interested in developing measures of psychological wellbeing in primates and other animals. My research draws on theory and methods used to assess emotion-cognition interaction in humans and assesses the extent to which these may be applied to other species.
People who are anxious or depressed interpret ambiguous information in a more negative way and have a greater expectation of negative future events than do people who are in a more positive emotional state. This negative ‘cognitive bias’ can make the world appear to be more threatening than it is and lead to a downward spiral which, in the extreme, may result in the onset of affective disorders such as clinical anxiety or depression. Our previous work (Bethell et al 2012a, published in the journal Animal Welfare) showed that monkeys who had recently undergone a veterinary check-up showed a more pessimistic interpretation of ambiguous cues than they did on an otherwise normal day. If short term stress can cause monkeys to interpret the (same) ambiguous cues more negatively, are monkeys also at risk of the same downward spiral in mental health that humans are?
Computer-based tasks can be used to capture biases in cognition in humans. For example, when shown a pair of faces, one angry and one neutral, anxious people are faster to look towards the angry face than the neutral face, and do so faster than do non-anxious people. When engaged in an ongoing task, anxious people show more disrupted performance when an angry distractor is presented compared with non-anxious people performing the same task. These tasks may be adapted for use with other species.
My research involves the development of field-based tasks for use with free-ranging primates, and computer-based methods for use with captive animals. This approach should extend our ability to assess good versus poor psychological wellbeing in other species, and further our understanding of the evolution of psychological and affective disorders in humans.
Work with animals:
Behavioural: Observation in field and captive settings (primarily of chimpanzees and macaques);
Cognitive: Experimental design, programming, equipment maintenance and stimulus compilation (attentional and cognitive computer-based paradigms; EPrime; operant training)
Physiological: Enzymeimmunoassay (faecal cortisol metabolite analysis; salivary testosterone - macaques); Luminometer analysis of macaque blood leukocyte activity; genetics
Work with humans:
Electroencephalogram (Event-Related-Potentials of brain wave activity in humans)
Questionnaire adminstration and analysis (online and in person: eg STAI, BDI, Marlow)
Attention bias in rhesus macaques
Post-Doctoral researcher Dr Caralyn Kemp has been running our NC3Rs funded project developing attention bias assessment methods for use with group-housed macaques. These methods will be used to assess (and in the future improve) psychological wellbeing in laboratory macaques. We have been working with experts in human and primate social cognition, as well as eye-tracking technology experts, to develop a new tool that can be used easily and efficiently by staff working with captive rhesus macaques. Through 2012 and 2013 I developed a field-based method for assessing social attention in free-ranging rhesus macaques on the island of Cayo Santiago, Puerto Rico. This work is in collaboration with the research labs of Professor Dario Maestripieri (University of Chicago) and Dr Lauren Brent (Duke University). My field work complements my work with captive rhesus macaques published in PLoS ONE which shows that stressful husbandry procedures can dramatically affect social attention in ways that may have profound implications for wellbeing (Bethell et al 2012b); Using an experimental eye-gaze paradigm, we found monkeys are generally vigilant of angry faces, but become highly avoidant of the same faces when they have recently undergone a statutory - but nevertheless stressful - health check. Avoidance of potentially threatening stimuli may impair ability to deal mentally with subsequent stressors and this can impair wellbeing. In humans, extreme avoidance of even mildly threatening cues is characteristic of affective disorders such as social phobia. The ongoing work with free-ranging macaques on Cayo Santiago will allow us to assess the biological bases and functional significance of attentional biases in a naturalistic social setting.
Cognitive bias in hamsters
I have been working with Dr Nicola Koyama to develop methods that measure the effects of enrichment on wellbeing in the Syrian hamster.
This work has been published in Royal Society Open Science. The hamster welfare Laboratory at Liverpool John Moores University has opportunities for final year student projects. Please contact Dr Bethell or Dr Koyama for further information.
Click on the logos below to see some media coverage of this work:
Photo credits: Male rhesus macaque neutral facial expressions on grey background, experimental stimuli, Emily Bethell; Young male rhesus macaque, Cayo Santiago 2012, Rebecca Smith; Hamsters in hammock, Nicola Koyama