Priming changes what the mind is ready to notice or recognise before conscious deliberation begins.
The mind does not meet every new object or message from a neutral starting point. Recent words, images, sensations, goals, and social cues can make related material easier to process or bring a particular interpretation closer to the surface.
Priming is the influence of that earlier exposure on a later response. A related word can speed recognition of another word. A cue connected to a goal can make that goal more accessible. The effect can be perceptual, semantic, associative, affective, or behavioural, depending on the relationship between the prime and the later task.
Priming is often described as unconscious influence, but that does not mean it is invisible, unlimited, or irresistible. Effects vary with the stimulus, the task, the interval between exposure and response, and the person’s existing knowledge and goals. Research has also debated how reliably some behavioural priming effects replicate. The strongest use of the concept is precise: prior context can change readiness and interpretation before a person consciously weighs a decision.
Source: Weingarten et al., “Priming Behavior: A Meta-Analysis of the Effects of Behavioral and Nonbehavioral Primes on Overt Behavioral Outcomes,” Personality and Social Psychology Bulletin.