Mechanisms for the object-based negative compatibility effect: voluntary versus involuntary inhibition

This study investigates whether the object-based negative compatibility effect (NCE) originates from involuntary or voluntary inhibition. We hypothesised that both supraliminally presented primes (the prime is a mug with its handle pointing either left or right) and experimental instructions (i.e., ignoring the prime) in previous studies might induce participants to develop a voluntarily inhibitory strategy that is responsible for the object-based NCE. To test this hypothesis, we conducted 3 experiments. Experiment 1 confirmed a suitable paradigm. Experiment 2 altered participants' strategies by varying the frequency of compatible trials across blocks. The results revealed a significant NCE for the low-frequency condition, which suggested that voluntary strategy might be primarily responsible for the object-based NCE. Experiment 3 combined a free-choice target with an object-based NCE paradigm. The results showed equivalent frequencies and mean response times between the free-choice responses that corresponded to or were opposite from the orientations of the mug handle. Combined with the results of response time quartiles, which revealed NCEs in fast responses (Q1-Q3) but no compatibility effect in slow (Q4) responses, we concluded that the object-based NCE might be primarily based on voluntary inhibition. Moreover, this inhibition might take effect earlier than that of the arrow-based NCE.