Semantics, Phonetics and Orienting reaction

With respect to their goal of defining the dynamics and structure of the semantic system, the authors come to two conclusions:
the words are divided into three groups: (1) the nucleus of the semantic complex, to which is related the key word and words in direct semantic proximity to it (they evoke a specific pain reaction); (2) the periphery of the semantic system to which are related words linked less directly with the key word (evoking a non-specific orienting reaction); and (3) neutral words, which in our experiment did not evoke any specific or orienting reactions.
The correlation of these groups at various stages of the experiments may be different, and if at the beginning of the experiment the nucleus of the semantic system has a relatively generalized character, then later it becomes concentrated and only the key word continues to provoke a specific reaction, while the remaining words, which earlier were included in this nucleus, move into the semantic periphery and begin to evoke only a non-specific orienting reaction. ( Luria & Vinogradova, 1959, pp. 99-100)