The influence of complex distractors in the remote distractor effect paradigm

Abstract

This thesis reports six experiments that examine the influence of complex distractors in the Remote Distractor Paradigm. Experiment 1 examined whether linguistic distractors modulated the RDE in any systematic way under bilateral target presentation. This was found not to be the case, but all types of linguistic distractors produced prolonged saccades for central versus peripheral distractor location. Non-linguistic distractors produced equivalent saccade onset latencies for central and peripheral presentation and these were significantly shorter than those produced for all types of linguistic distractors. This unexpected finding was investigated in Experiment 2, which showed that repeated presentation of a distractor resulted in shorter saccade latencies at central presentation, compared to those distractors that changed on every trial. This was termed the 'constancy' effect. Experiments 3 and 4 employed only repeated non-linguistic distractors under different target presentation conditions. Under bilateral target presentation peripheral distractors produced longer saccade latencies and greater RDE magnitudes compared to central distractors. Under unilateral target presentation RDE magnitudes for peripheral distractors were of a similar order to those produced by Walker et al, (1997). This replicated for linguistic and non-linguistic distractors, and for repeated and changing distractors in Experiment 5. Thus repeated distractors result in shorter saccade onset latencies compared to changing distractors at central presentation, and RDE magnitudes of a similar order to those obtained for central and peripheral distractors in the Walker et al., (1997) study only occur under unilateral target presentation, hi Experiment 6 a difference was obtained between two different types of linguistic distractors for saccade onset latencies and RDE magnitudes at an intermediate dish-actor location, and the 'constancy' effect was reproduced for same category repeated and changing distractors. Taken together the findings show that saccade onset latencies and RDE magnitudes can, under some circumstances be modulated by higher-level cognitive factors.