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.