Abstract
Inhibiting distractors can decrease interference from these competing distractors. To measure the effect of distractor inhibition, a negative priming paradigm is usually used (Tipper, 1985).
Recently, negative priming was found to be contingent on stimulus repetition (Malley & Strayer, 1995; Strayer & Grison, 1999). That is, a distractor was inhibited only when it was a highly repeated stimulus.
Consider the ecological validity; both repeated and novel distractors exist in daily life. It is critical to examine if distractor inhibition can be applied to both kinds of distractors, or it can be applied to familiar distractors only. The current study was hence conducted.
In the first set of experiments, negative priming for novel stimuli was examined. Response-to-stimuli-interval, word frequency, and location of the probe target were manipulated. No reliable negative priming was found. With the same procedure, negative priming could be observed with repeated stimuli. Therefore, it appeared that only repeated distractors were inhibited.
Two explanations existed for the failure to observe negative priming with novel stimuli. First, novel stimulus might be not inhibited at all, as Strayer and his colleagues suggested. We postulated another. Novel stimuli could not trigger the inhibitory mechanism, but could be inhibited when the inhibitory process was triggered.
To test the hypothesis, an experiment with three items in a trial was conducted. One of these three items was a target while the other two were distractors. Moreover, one distractor was a repeated item while the other distractor was a novel item. The results confirmed our hypothesis. With the presence of a repeated distractor, negative priming for novel distractors could be observed.
In summary, a novel distractor has difficulty in triggering the inhibitory mechanism. However, if the inhibitory process begins due to the presence of other competing distractors, a novel distractor can be inhibited.
We would like to thank the support from the National Science Council to the first author (NSC93-2917-I-002-005).