Beyond Reaction Times: Incorporating Mouse-Tracking Measures into the Implicit Association Test to Examine its Underlying Process

Although the Implicit Association Test (IAT) has been widely used as an implicit measure over the past decade, research into its underlying mechanism remains woefully insufficient, partly due to the limitation of reaction time measures it uses. In two experiments, we modified the procedures of flower-insect IAT and two implicit self-esteem IATs by instructing participants to respond with a computer mouse instead of pressing keys. Analysis of motor trajectories showed that, although participants chose the correct response button in most of the trials, their mouse movement was continuously attracted toward the alternative response button, suggesting that both response representations are partially and simultaneously activated during the process. Furthermore, analysis of velocity profiles indicated that mouse movements toward the correct response button were slower in incompatible trials than in compatible trials, especially for attribute stimuli. Theoretical and methodological implications of these results are discussed.