Multiple aspects related to self-awareness and the awareness of others: an electroencephalography study.

The effect of possessive pronouns on the encoding of pronoun-noun associations (e.g., my garden) was investigated using the electroencephalography (EEG). Following an alphabetical, semantic and a contextual encoding instruction depth of noun processing was varied within three separate experiments in order to manipulate the grade of awareness related to verbal information processing. Only for the semantic encoding task (lexical decision) response time was significantly longer for nouns associated with the pronoun "mein" (German for "my") than for nouns associated with the pronoun "ein" (German for "a") although pronouns were not to be consciously processed at all. Following recognition tests related to nouns (without their previously associated pronouns) revealed no significant differences related to the number of correctly identified repeated nouns (hits) depending on the kind of previously associated pronoun. The analysis of neurophysiological data revealed a time range between about 250 ms and 400 ms after stimulus onset within which significant pronoun x electrode interactions occurred. No interaction with depth of word processing was found. Overlaid EEG curves, t maps and low resolution brain electromagnetic tomography (LORETA) demonstrate that in this time range "mein" and "sein" associated conditions elicit similar brain activity, both more negative, compared to the "ein" associated condition over occipital electrodes. On the other hand, at left temporal sites the "mein" condition elicited more negative potentials than both other conditions. It is interpreted that EEG recordings reveal two relevant areas, which are sensitive to the concept of a person (as represented by a personal pronoun) between about 250 ms and 400 ms after stimulus onset. One area is located in the occipital region and can distinguish between personal engagement and a neutral condition and the other area is located in the temporal region and is able to distinguish between oneself and somebody else. Together with our previous MEG results (Walla et al. in Neuropsychologia 45:796-809, 2007) we want to combine the inferences in the frame of the "multiple aspects" hypothesis related to research on self-awareness and the awareness of others.