Thesis Defense Johannes Algermissen (Donders Series 600)

3 April 2023

Promotor: prof. dr. W.P. Medendorp
Copromotor: dr. H.E.M. den Ouden

On the Origin and Control over Pavlovian Biases in Learning and Decision Making

Many of our every-life decisions do not follow from conscious deliberation, but seemingly from a mental “auto-pilot”. For example, sitting on the couch with a bowl of chips, we often mindlessly eat too many of them. At work, when our boss scolds our office mate, we often stay silent rather than standing up for them. More generally, the mere presence of rewarding objects tends to invigorate our behavior, while the presence of threats makes us freeze and inhibit any behavior.
These automatic action tendencies are called Pavlovian biases. They are even seen in animals and likely underlie several psychiatric disorders. However, little is known about how they arise in the brain. Neither is it clear how these biases interact with other decision-making systems, especially whether a synergy of multiple systems could improve decision-making.
In his thesis, Johannes Algermissen mapped the neural circuits that underlie these biases. Also, he found that humans are not merely passive subjects, but active users of these biases: they strategically expose themselves to reward or punishment information when they need to invigorate or inhibit behavior. In sum, his thesis sheds new light on the neural origin of Pavlovian biases and their strategic use in decision-making.