Most studies investigating the influence of primes on the processing of subsequent targets involve a main task in which responses are made to the targets, and a task that tests prime awareness. If the participant is not aware of the prime location/identity but an influence of the prime is observed in the main task, researchers conclude that this influence can be ascribed to unconscious processing of the prime. This implies the assumption that the prime's influence is independent of task instructions: a prime consciously perceived in the prime task is consciously perceived in the main task. In the metacontrast-masking study, we compared motor- and attention-related electroencephalographic (EEG) components in three tasks with the same stimuli but different instructions and showed that early posterior contralateral negativities (PCNs) and lateralized readiness potentials (LRPs) were smaller when primes were task-relevant than when targets were task-relevant. This suggests that early components may depend on task instruction and are not purely prime-related.