primacy effect
the tendency for facts, impressions, or items that are presented first to be better learned or remembered than material presented later in the sequence. This effect can occur in both formal learning situations and social contexts. For example, it can result in a first-impression bias, in which the first information gained about a person has an inordinate influence on later impressions and evaluations of that person. Also called law (or principle of primacy). Compare recency effect.