Associative learning is one of the most important forms of human learning. New associations are frequently formed incidentally, based on repeated co-occurrence. Hence, episodic principles are considered the primary factors in associative learning. However, within the framework of our previous collaboration supported by GIF, we demonstrated that incidentally formed associations are considerably facilitated by semantic factors. In particular, we found that associations formed between two words during repeated co-appearance of stronger if 1) the orientation task requires access to their meaning than if the orientation task is shallow; 2) the words are exemplars of the same semantic category than if they are semantically unrelated; or 3) they appear in a sentential context than as a context-free, isolated pair. Furthermore, recording magneto-encephalographic brain activity we found evidence for semantic categorization in the brain. This pattern was most evident in the posterior temporal regions of the right hemisphere starting at 150 ms post-stimulus onset, and in anterior temporal regions of the left hemisphere later on, up to about 450 ms post stimulus onset. <B>The major goal of the presently proposed study is to unveil the cognitive mechanism of the semantic influence on the formation of episodic associations and explore the dynamics and neuroanatomy of the brain activity related to this effect.</b> The following questions illustrate our specific objectives: 1) Is semantic integration of binding mechanism that facilitates the formation of new associations? 2) Do newly formed episodic associations affect the semantic network? 3) How are new phonological items assigned to meanings and integrated in the semantic categorical structure? 4) What is the mechanism of enhanced and diffused semantiv priming in schizophrenia? 5)How are semantic categories represented in the schizophrenic brain? 6)How much attention the process of incidental learning of associations needs?
We hope to achieve this goal by using elaborated cognitive designs, and recording human performance as well as event-related potentials (ERP) and magnetoencephalographic (MEG) measures of brain activity. The basic learning paradigms will be developed in Jerusalem, whereas MEG recordings will be done in Konstanz. Multi-channel ERP recordings and brain mapping will be performed in both laboratories.
Whereas in real life associations are mostly formed without intention and the associated events are usually part of a larger semantic context, psychological research, particularly within the behaviourist tradition, focused particularly on intentional learning of paired associates. Our present attempt to understand the role of semantic factors in incidental formation of new associations is novel in this respect, and better revealing the natural process. Furthermore, the assessment of brain activity time-locked to the associative process should provide a better insight into the time course and functional neuroanatomy of cognitive process of forming new associations.