Medical College Admission Test (MCAT) Psychological, Social, and Biological Foundations of Behavior (Psych/Soc) Practice Exam 2026 - Free MCAT Psych/Soc Practice Questions and Study Guide

Primacy bias is a cognitive bias that highlights how the first information we receive about a person or situation tends to have a disproportionate influence on our perception and judgments of that individual or circumstance. This effect underscores the critical role that first impressions play in shaping our opinions and expectations. When we encounter someone for the first time, our initial assessments often set the tone for how we view them going forward, making subsequent information less impactful.

In this context, while recent experiences and subsequent information can influence our judgments, the emphasis of primacy bias specifically lies with the information we encounter first. Consequently, it illustrates why early encounters can have lasting effects on our perceptions, framing the individual in a particular light that can be hard to shift, regardless of later interactions or information. This makes the concept of first impressions central to understanding primacy bias.