Rafael Polania is visiting us this week and giving a talk in the SWE colloquium (abstract below). Rafael is a post-doctoral researcher in the group of Christian Ruff at the Economics Department of the University of Zürich.

Perceptual vs. preference-based decisions

Two common types of decisions are particularly prevalent in our daily life: perceptual decisions, where organisms make decisions on the basis of objective states of the world (e.g., melons are bigger than apples), and preference-based decisions, where organisms make decisions on the basis of preferences (e.g., I prefer apples to melons). It has been recently proposed that there must exist some type of computational overlap between these two types of choices, but surprisingly, previous studies have only investigated these two types of decisions in isolation and have used very different experimental paradigms, stimuli, and response options. It therefore remains virtually unknown whether perceptual and value-based decisions are indeed controlled by a unified computational mechanism and whether this mechanism depends on similar or distinct neural processes in the human brain. We developed novel paradigms that allowed us to identify common and distinct neural mechanisms of perceptual and value-based decisions by explicit comparisons of neural activity during both types of decsision taken on identical stimuli and involving the same motor output. The combination of this behavioral paradigm together with fMRI, EEG recordings and computational models of choice offered a uniquely clear view on the neuro-computational processes underlying decision-making by showing that decisions emerge from an integrative evidence accumulation process occuring in parallel across distinct brain regions that process different aspects of the incoming sensory signals. Moreover we showed that these processes are instantiated locally by neural oscillations and are coordinated between different areas via large-scale oscilliatory synchronization.