Examining associative learning effects on accuracy in free and serial word recall and neural oscillations in young adults (Hebrew)

Free and serial recall of verbal memories is an important skill that we need in everyday life in various fields, and especially in learning processes, where it is necessary to remember a lot of verbal information. Verbal information represents many different fields of knowledge and affects various cognitive processes. Retention and understanding of information are largely related to learning processes that allow access to retrieve specific information more efficiently (Hooper, 2002). The ability to retain and retrieve memories freely or serially from semantic and episodic networks is significantly related to working memory capacity and brain activity in prefrontal cortical networks (Oberauer et al., 2018).

In the present study, we sought to examine whether free and serial recall of verbal memories can be improved in young adults, using a cognitive manipulation that incorporates associative learning, which allows for the association of newly learned verbal information with existing information already stored in long-term memory. In addition, we examined whether the behavioral improvement in different recall states would demonstrate significant changes or differences in electrical brain activity (such as alpha wave power mean) under frontal-temporal and occipital target electrodes. The test in the current study was conducted using the Hopkins test, which tests verbal working memory, immediate recall, and long-term memory in delayed recall (Brandt, 1991). The associative learning manipulation was given to the experimental group through the Chunking strategy, which links words by creating semantic associations (Oberauer et al., 2018). This was compared to the participants in the control group who learned the same words without cognitive manipulation. In addition, and as an innovation in the current study, we measured the electrical brain activity during free and serial recall in order to examine the relationship between electrical brain activity and the various recall states. The test was performed using EEG (electroencephalography) to quantitatively characterize electrical brain activity in different brain frequency ranges according to changes in brain waves (neural oscillations) theta, alpha, and gamma. We also examined whether the cognitive manipulation in the experimental group compared to the control group significantly affected brain activity at different brain frequencies during immediate and delayed recall, and whether these changes were related to the level of accuracy in free or serial recall. The comparison was performed in each frequency range with respect to the average amplitude size (wave intensity) between the groups. In examining behavioral activity, we found that participants in the experimental group significantly improved accuracy in serial recall after the associative learning manipulation, compared to the control group, in which no changes in recall accuracy were observed between the experimental stages. In examining brain activity, changes were found in the intensity of theta waves, which are linked according to previous studies with serial information encoding, alpha waves, which are linked to the inhibition of irrelevant information, and gamma waves, which are linked to the preservation and retention of information in working memory (Roux & Uhlhaas, 2014). In the present study, we found that the intensity of theta, alpha, and gamma wave activity during the delayed serial recall phase after the associative learning manipulation was lower in

the experimental group compared to the control group. This is because no differences were found between the groups in the intensity of the three frequency ranges (theta, alpha, and gamma) in the resting-state EEG test. A negative relationship was also found, whereby in both groups, the higher the accuracy score in the delayed serial recall, the lower the intensity of theta wave activity was found at this stage. In addition, we found a positive relationship only in the experimental group, whereby the higher the accuracy score in the delayed serial recall after the manipulation, the higher the intensity of alpha wave activity in the experimental group during the free recall phase after the manipulation. The changes in the intensity of brain frequency activity, as observed in the current study, may indicate a connection between the manipulation of associative learning and the neural oscillations involved in improving accuracy in various recall situations and open a window for the future integration of associative learning intervention programs with the aim of improving memory performance.