Does subliminal priming of free response choices depend on task set or automatic response activation?

In a task requiring speeded bidirectional responses to arrow symbols (≪,≫), "free choice" responses to interspersed bidirectional stimuli (<>) are influenced by masked directional primes (e.g., Schlaghecken & Eimer, 2004). By varying stimulus-response (S-R) compatibility, we tested whether this priming effect is mediated by the conscious instructional set, or instead by pre-existing directional associations to the symbols. In two experiments, one group of participants was instructed to respond with the hand consistent with the implied direction of the arrow symbols, while another group was instructed to make the spatially opposite responses. Both groups showed priming of "free choice" responses. However, such priming was always biased according to the instructional set rather than pre-existing associations. Subliminal priming of "free choice" responses therefore depends on conscious task goals.