In the lexical decision paradigm, the stimuli are presented sequentially and the subjects are instructed to respond by depressing a key, indicating that each stimulus is either a ‘word’ or a ‘non-word’. This paradigm is primarily said to measure automatic spreading activation, in other words the association strength (Hutchison, 2003), and to reduce post-lexical strategies on the semantic priming effect (Silva-Pereyra et al., 1999; Timothy et al., 1988). However, the current study had a long SOA of 1750 ms. The stimuli studied included antonym-pairs, which by their very nature had a high degree of relatedness, the proportion of related-pairs was thirty-three percent, and there were high rates of non-words (fifty-percent). This suggests that the N400 in the current study possibly reflects relatively more controlled mechanisms/post-lexical strategies and less automatic spreading activation. Within the controlled mechanism, the more active process would be ‘semantic expectancy’, where upon presentation of the first word of the antonym pair, subjects tend to generate the expectation for the second word of the pair. Therefore, the lack of N400 attenuation observed in alcoholics in the current study
