The short answer
Rejection sensitivity is a well-documented pattern where a person anxiously expects rejection, readily perceives it in ambiguous situations, and reacts to it more intensely than the situation objectively calls for. It was first measured as its own distinct trait in the 1990s, separate from general anxiety or self-esteem.
The research
Rejection sensitivity was first measured as its own distinct psychological trait, separate from general anxiety or low self-esteem, using a dedicated questionnaire developed to capture the pattern specifically.
— Downey & Feldman, Rejection Sensitivity Questionnaire, 1996
Why it feels so automatic
For someone high in rejection sensitivity, an ambiguous signal — a short text, a flat tone, a delayed reply — doesn't feel ambiguous at all. It feels like confirmed evidence of rejection, almost instantly. That speed is the defining feature: the interpretation happens before there's time to weigh other, more neutral explanations.
Where it tends to come from
Researchers link rejection sensitivity to early experiences of inconsistent or conditional acceptance — situations where love or belonging felt uncertain or contingent. The nervous system essentially learns to scan for rejection early and often, as a form of protection, even after the original situation is long gone.
Want to see this pattern in your own thinking, not just in the research?