Methods matter: An examination of factors that moderate predictions of the capability model concerning the relationship of frontal asymmetry to trait measures.

The capability model of anterior asymmetry integrates trait-related and state-related frontal asymmetry research by proposing that frontal asymmetry is dependent on relevant traits if they are activated by a situation. However, differences in experimental design and EEG recording methods haven't been fully explored. We investigated 56 participants under three different situational paradigms (virtual T-maze, mental imagery, movies), varying the stimulus and type of measurement concerning frontal asymmetry. We predicted that "strong" situational manipulations (virtual T-maze, frontal asymmetry measured as event-related desynchronization) would eclipse relationships between frontal asymmetry and relevant traits, whereas "weaker" task manipulations, measured during longer time periods, would enhance relationships to relevant traits compared to frontal asymmetry at rest. The results confirmed these expectations, stressing the importance of stimulus characteristics, trait measures and recording methods with respect to the capability model. Additionally, a revision of the capability model to an inverse U-shaped quadratic relationship might be appropriate.