Abstract: There is a disputation about the effect of working memory (WM) load on the distractor processing between the viewpoints of cognitive control mechanism and specific load mechanism. The former suggests WM has inhibitory action on distractors and the inhibition mechanism is not influenced by WM load types; while the latter claims that resource competition between WM task and selective attention task can cause different interference effects, and this competition is influenced by WM load types. By analyzing the two viewpoints, the authors have found cognitive control mechanism is suitable for representing inhibition processing of distractors and specific load mechanism for representing activation processing of distractors, thus the authors speculate that the primary reason leading to the disputation of the two viewpoints might be caused by their observing respectively only one different stage of distractor processing, and also point out that the two viewpoints were both obtained by adopting interference effect indices only, which is easily to cause confusion. Moreover, the specific load mechanism by Park et al.(2007) has neither been verified whether specific load mechanism is suitable for the distractor interference effect or not in condition that the target stimulus and distractor stimulus of selective attention are of the same attribute, nor does it specifically point out on what resource WM task and selective attention task compete. In this study double indices, both interference effect index and negative priming effect index, were used to divide distractor processing into two stages, the activation processing stage and inhibition processing stage, and to represent the two stages respectively, and experiments were conducted to explore the effect of WM load on the locational distractor processing in order to resolve the disputation of the two viewpoints and to confirm and perfect specific load mechanism viewpoint.
The three experiments were to investigate respectively the effect of spatial WM, object WM and verbal WM load on locational distractor processing. 2×2×2 factorial within-subjects design was used, and the three factors were WM load level (high WM load, low WM load), interference condition (priming interference, priming neutral) and negative priming condition (probing control, probing repetition). The influence of low/high WM load on the interference effect was tested by ANOVA of repeated measures based on WM load factor and interference condition factor, and the negative priming effect was tested by ANOVA of repeated measures based on load condition factor and negative priming condition factor. 42 undergraduates aged from 17 to 23 years participated in the experiments, and E-prime software was used to present experimental stimuli and to collect data.
The test result of negative priming effect showed all three types of WM loads (spatial WM, object WM and verbal WM load) had effect on locational distractor processing, and the effect in low WM load condition was more significant than in high WM load condition, which supported cognitive control mechanism viewpoint. And the test result of interference effect showed only spatial WM load had effect on locational distractor processing, and the effect in low WM load condition was also more than in high WM load condition, which provided the support for specific load mechanism viewpoint.
To sum up, the viewpoint of specific load mechanism was consistent with Park et al’s study when the target stimulus and distractor stimulus were of the same attribute, and the resource WM task and selective attention task competed on was perceptual disposal resource. Second, the influence of WM load on the locational distractor processing could be explained by double mechanisms: cognitive control mechanism and specific load mechanism. So it can be inferred that cognitive control mechanism viewpoint is suitable for representing inhibition processing, and specific load mechanism viewpoint for representing activation processing, and the two viewpoints are integrated and complementary with each other. Previous researchers did not divide the distractor processing into activation processing stage and inhibition processing stage to explore, which caused the disputation between the two viewpoints. Nevertheless, the method of using double indices to analyze in this study can provide reference for related researches on WM and selective attention.

Key words: Key words locational distractor, distractor processing, working memory load, activation processing, inhibition processing