Chimpanzees master VR to find hidden fruit

A chimpanzee sits in a tree at a zoo

Chimpanzees can find their way through a computerised world to find virtual fruit, new research led by the University of St Andrews has found.

Using touchscreen technology, six primates at Leipzig Zoo, Germany, learned to navigate towards a distant virtual tree with different types of fruit underneath it, even working out how to find the landmark from different starting locations.

Led by Dr Matthias Allritz and Dr Josep Call from the School of Biology at the University of St Andrews and Dr Francine Dolins at the University of Michigan-Dearborn, the work is the first empirical study of how chimpanzees navigate an open-field, naturalistic, virtual environment and demonstrates that chimpanzee manoeuvres in the virtual world share several key features with real-life navigation.

The results also suggest that virtual environment technology can be used to address longstanding questions in the study of primate spatial and other forms of cognition.

Dr Matthias Allritz, postdoctoral researcher at the University of St Andrews and the Max Planck Institute for Evolutionary Anthropology, said: “Almost all animals navigate their environment to find food, shelter and mates. Because of the space restrictions in zoos, studying the spatial cognition of nonhuman primates experimentally is notoriously difficult. Using virtual environments allows researchers to create large-scale, controllable environments for primate participants to navigate, including completely novel environments.

“Beyond the clear goal-orientation in the chimpanzees’ spatial learning, one thing that stood out to us was the remarkable speed at which the chimpanzees learned to control the virtual agent and to complete the spatial tasks. It required less training than I originally thought it would, and certainly less than many of the more traditional touchscreen tasks designed for animals.”

Three adult male and three adult female chimpanzees from the Wolfgang Köhler Primate Research Center (WKPRC) at Leipzig Zoo, Germany, participated in the study. All six chimpanzees had prior experience with using touchscreens, and five of them had limited experience with 3D video games at the time the study began. All participation was voluntary, and all testing was conducted in the apes’ familiar testing areas at WKPRC, where they are given access to touchscreen tasks regularly.

A new custom virtual reality (VR) application – APExplorer 3D – was created for the study, presenting the primates with a virtual environment through which an invisible, first-person character could be steered to explore and interact with objects in a three-dimensional cartoon style.

Using a touchscreen monitor, the chimpanzees guided the virtual agent through an open space containing grassy hills, trees, rocks and other obstacles. Over a month, the chimpanzees were presented with progressively more challenging navigation tasks, exhibiting several cognitive processes and behavioural signatures within the virtual environment that have been predicted to guide navigation in the wild, such as learning to recognise and search for distinct landmarks and to optimise route efficiency.

Dr Francine Dolins, principal investigator and associate Professor at the University of Michigan-Dearborn, said: “Tracking primate navigation in the wild has many challenges, including not knowing what landmark information they use as the basis for making spatial decisions. Virtual reality affords greater control over what landmarks are presented and where they are in relation to the virtual foraging sites, for example, a fruiting tree.

Professor Josep Call, co-principal investigator, added: “Our study illustrates that non-invasive experiments in open space virtual environments have great potential to study primate spatial cognition. The chimpanzees in our study learned the basic game mechanics quickly and soon exhibited learning and decision-making patterns that resembled real-life navigation. They learned to recognise certain objects as landmarks and to orient and search for these when they could not see them. And they flexibly adapted when food availability became less predictable – though some of them were clearly faster than others.

“Provided that future studies can replicate and extend these findings to other primate species, naturalistic virtual environments may become a powerful tool to address longstanding questions in the evolution and development of primate navigation that had previously been difficult to study in captive environments and in the wild.”

Dr Allritz added: “Chimpanzees are the closest living relatives of humans, so understanding how they make travel decisions and how they recognise, remember and reason about travel routes does not only help us to better understand them, it is also critical for understanding the evolution of navigational abilities in our own species.”

From a welfare perspective, the chimpanzees may also benefit from the cognitive enrichment that virtual environment games may provide, given their creative problem-solving and innovative abilities.

To facilitate wider adoption of Virtual Reality (VR) research, the team plans to make a version of the APExplorer 3D app available on the Open Science Framework, allowing other researchers to directly replicate these methods and adapt them for related research questions.

The research was supported by the Templeton World Charity Foundation, the University of Michigan-Dearborn and the University of St Andrews.

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