Testing for Behavioral and EEG Correlates of Forward and Backward Priming
Mareike Wilson,¹,²,³ Marc Wittmann,¹ & Jürgen Kornmeier1,²,³
¹Institute for Frontier Areas of Psychology and Mental Health
²Department of Psychiatry and Psychotherapy, Medical Center, University of Freiburg, Germany
³Faculty of Medicine, University of Freiburg, Germany
Background: In a classical priming task, a priming stimulus is presented first followed by a task-relevant target stimulus. The target stimulus is either related to the prime (congruent condition), or it is unrelated (incongruent condition). In the congruent condition, the prime typically pre-activates the neural representation of the target, resulting in faster reaction times of the target stimulus. The backward priming experiment, first introduced by Bem, is a variant of this paradigm, where the order of prime and target stimulus is inverted. The aim of Bem’s study was to investigate whether a prime, presented after the target stimulus and its corresponding response, could influence the reaction time to the target. Participants were asked to class a target image presented on a computer screen as negative or positive via button press. The prime following the target and the target-related button press was a word that was either negative or positive. In a congruent trial, the target and the prime were the same (either positive/positive or negative/negative), and in an incongruent trial, the target and prime were different (positive/negative or negative/positive). Bem found significant faster reaction times in congruent compared to incongruent trials. These findings are interpreted to constitute a precognition effect.
To date, the mechanisms underlying precognition and the brain areas that are potentially involved are unknown. Moreover, due to the lack of empirical evidence, it is not possible to predefine (hypothesis based) spatial (brain regions) and temporal regions of interest (ROIs) for the analysis of physiological (EEG) data. In the present study, we replicated Bem’s precognitive priming task (hypothesis-driven study part) and measured concurrently the EEG of the participants (exploratory study part) to test whether certain EEG activity correlates with behavioral forward or backward priming effects. Given the absence of a pre-defined spatio-temporal ROIs, we decided to use Artificial Neural Networks (ANNs) as analysis tools because they do not require predefined spatial and temporal ROIs.
It is further unclear whether the population contains few precognitively gifted individuals among a majority of ungifted individuals or whether precognitive abilities are normally distributed in the population. It is also unclear whether precognitive abilities are state variables that occur only if a person is in a certain mental state or whether they can be regarded as trait variables. As a consequence, we use our ANN approach to execute statistical analyses both on the group level and at the level of individual participants.
The present study focused on the following hypotheses:
If precognitive effects exist,
1. They are correlated with specific brain activity of the person that shows the precognitive effects.
2. They are not normally distributed in the population but instead restricted to individual gifted participants during specific mental states.
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Dr. Jürgen Kornmeier studied biology and mathematics at the Albert-Ludwig University in Freiburg, Germany. In 2012, he earned his Ph.D. in Neurobiology and in 2013, Habilitation, both at the Albert-Ludwig University in Freiburg, Germany. Since July 2022, he has been the Director of the Institute for Frontier Areas of Psychology and Mental Health in Freiburg, Germany.
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Program chaired by Jacob W. Glazier. Download the Abstracts at https://parapsych.org/uploaded_files/pdfs/00/00/00/01/26/2023_pa_abstracts_of_presented_papers.pdf
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Published on December 23, 2024
