Tonko Zijlstra, M.Sc.

PhD student

Received a bachelor’s degree in Biology in 2016 and a master’s degree in Biology with a focus on behavioural biology in 2018 from Leiden University.

I started in the CoPan lab as a research assistant working on a project that aims to investigate attentional biases towards emotions. Since May 2020 I started my PhD trajectory. An attentional bias towards emotions can be a very useful tool for social animals (like us humans) because it enables us to quickly focus on the most relevant information that is provided by our surroundings. For example, an individual in a social group might be happy because there is access to a new food source, while a fearful group member might be an indication that there are dangerous predators around. Research shows that humans possess such a bias, especially when these emotions are negative emotions, such as fear or anger. One of our close relatives, bonobos, also possess an attentional bias towards emotions. However, in contrast to humans, bonobos have an attentional bias towards positive emotions. So far, this type of attentional bias has not been found in chimpanzees, our other close relatives. Therefore, I am training two chimpanzees in Tierpark Nordhorn (Germany) to participate in an experiment that can measure their attentional bias. This will give insight into when in our evolutionary history an attentional bias towards emotions may have evolved and how different social dynamics may lead to differences within a trait that is shared by different species.

To measure attentional bias in chimpanzees, an emotional dot-probe task is presented on a touchscreen. This task has also been used to measure attention bias in humans and bonobos. An additional goal of this project was to use this task and the experimental setup as enrichment for the chimpanzees, in the hopes of improving their welfare.

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Professor at Leiden University