Photographs of CNPRC titi monkeys (Plecturocebus cupreus) and rhesus monkeys (Macaca mulatta) [Source]
In a collaboration between the Bales and Bauman Labs, researchers at the California National Primate Research Center (CNPRC) at UC Davis have validated a new method for eye tracking in non-human primates. Eye tracking is when a computer monitor and camera setup uses the reflection of an individual’s eyes to monitor attention to visual stimuli on a screen. This method can be used to understand a variety of topics, such as social attention and cognition, in many different species, including non-human primates. In order to understand where monkeys choose to direct their attention, they monkeys need to sit still while looking at the screen. However, monkeys often do not sit still, and older methods of directly monkeys’ attention to the screen are fairly invasive or involve months of intensive training. The Bales and Bauman labs set out to develop a more humane method that takes animal welfare into consideration. The animals were already familiar with the transport boxes, so the researchers let the animals sit inside the boxes and choose to pay attention to a computer screen through a small viewing window.
Figures 1 and 2 of the testing setup from Ryan et al. 2019 [Figure used with author permission]
The authors found that both rhesus macaques (Macaca mulatta) and coppery titi monkeys (Plecturocebus cupreus) do choose to look at the computer screen when sitting inside familiar transport boxes. For titi monkeys, juveniles looked at the stimuli for a longer overall duration than adults, and in rhesus monkeys, juveniles looked at the stimuli for longer than infants. This method is a turning point for non-invasive primate research and will allow researchers to ask new questions about non-human primate cognition and visual attention in a way that prioritizes animal welfare. This method is comparable to eye tracking studies done in human adults and infants because it provides a more naturalistic view of what animals want to look at when they are given the choice to participate.
For more information:
Ryan, A. M., Freeman, S. M., Murai, T., Lau, A. R.*, Palumbo, M. C., Hogrefe, C. E., Bales, K. L.*, & Bauman, M. D. (2019). Non-invasive eye tracking methods for New World and Old World monkeys. Frontiers in Behavioral Neuroscience, 13, 39. doi: 10.3389/fnbeh.2019.00039
*Denotes an ABGG-affiliated author