EEG correlates of found remote and nearby associates
Shemyakina N.V., Nagornova Zh.V.
IHB RAS, St.Petersburg, Russia, shemyakina_n@,mail.ru Within testing the theory of creative thinking of S. Mednik (1962) we developed the task (Shemyakina, Nagornova, 2010) on RAT (remote associative test) basis . Subjects (55 total, 18 men, middle age - 26±5 years) had to be original and were asked to find definitions (adjectives) uniting two nouns (frequency occurrence > 10 ipm).
The suggested task (were presented 444 pairs of nouns) initiated remote associative search. At the same time, the number of possible decisions wasn't limited to the only correct answer for one pair of nouns: even asked to be original the person could find, both the remote association, and trivial. Simultaneously with task performance monopolar registration of EEG (10-20) from 19 sites was carried out. Subjects were to press the button while the decision was found, afterwards they pronounced the answer. When the task was over, answers of subjects were devided into two groups with help of expert assessment (participated – the philologist, psychologists). They were divided into definitions focused on search: of remote associations between nouns (original, according to the theory S. Mednick) and semantic close (nearby). The first were focused on definition of implicit signs of concepts (exp: use of figurative sense), the second - on their literal characteristics (color, the size, the invoice, a form, etc.). Experts decisions were checked on coherence (Alpha Cronbach showed > 0.8). Further we carried synchronization/desynchronization EEG analysis be means of wavelet. Distinctions of the synchronization/desynchronization connected with an event were investigated in the range of EEG frequencies (2-7.5 Hz) with a 0.5 Hz step in three 500-millisecond intervals (1500-1000 ms; 1000-500 ms; 500-0 ms) before pressing the button. The choice of range of frequencies was caused by ideas of interrelation of associative search processes and long-term memory. The statistical data analysis was carried out with t-test. We obtained: finding of the remote associations was accompanied by higher level of a low-frequency EEG event-related synchronization (4Гц, 3Гц, 3.5. Hz) in front, middle temporal sites of the left hemisphere of a brain, and also in the front central site correspondingly. It doesn't exclude existence of possible changes in other frequency ranges, but stresses the importance of low-frequency EEG synchronization for brain ensuring processes of associative search and the related conditions.