This mechanism is said to be influenced by the instructions and the proportions of prime-target pairs (den Heyer et al., 1983; Neely and Keefe, 1989; Silva-Pereyra et al., 1999). In general, semantic matching is also referred to as a post-lexical priming mechanism. It refers to the strategy, where after the lexical and semantic access and activation of prime and target pair, but before the subject’s decision and response to the target is completed, the subject may match the target with the prime that preceded it. If it is related, a ‘word’ decision/response bias ensues, thereby facilitating responses to related word target; if it is unrelated, a ‘non-word’ decision/response bias follows (Neely and Keefe, 1989; Silva-Pereyra et al., 1999). The latter two mechanisms are referred to as controlled priming mechanisms. The relatively recent body of research suggests that the controlled priming mechanisms are generally believed to act more effectively at relatively long stimulus onset asynchrony (SOA) of greater than 500 ms, whereas automatic spreading activation is thought to be the mechanism that influences the priming effect at short SOAs (De Groot et al., 1986; Neely, 1991).
