Item

Abstract

Magic violates deeply held prior beliefs about the world and is hence uniquely positioned
to examine neural mechanisms of predictive coding at different levels of the brain’s
hierarchy. Yet, only a handful prior studies examined corresponding effects in the brain.
Most previous studies investigating violations of expectations focused on responses to
artificial stimuli based on newly stablished associations or simple violation of sequences
(e.g., oddball-paradigm) and only few investigated the neural correlates of high-level
prediction errors using ecologically valid stimuli (e.g., something disappearing). In this
functional magnetic resonance imaging (fMRI) experiment, we aimed to investigate neural
responses to violations of different deeply held beliefs using magic tricks and the role of
prior knowledge in the perception thereof. We created and validated a set of stimuli
showing either magic, control actions or surprising events. The magic videos consisted of
three effects (appear, change and vanish), performed with three simple objects and
presented with and without knowledge about the underlying method behind the shown
magic tricks.
Univariate whole brain analyses revealed two types of responses: the first were specific to
the three effects, the second were generic across all tricks. These results were obtained by
comparing responses to magic videos with and without prior knowledge about the
underlying method. Specially the anterior cingulate cortex, an area involved in signaling
unexpected outcomes, was active in all tricks. Effect-specific contrasts revealed distinct
regions in posterior sensory processing regions. Moreover, multivariate cross-
classification analyses revealed that specific prediction errors (i.e., effects) were preferentially decodable in posterior regions and less so in prefrontal areas, revealing an
exclusive encoding of violations of specific expectations in sensory areas. Together, these
results suggest a generic representation of violation of high-level expectations in the
prefrontal cortex with concurrent effect-specific representations in sensory areas involved
in the processing of the expected information.