Qu'est-ce que Halo Effect ?

Definition

The halo effect is a cognitive bias first described by psychologist Edward Thorndike in 1920. In recruitment, it occurs when a strong positive impression on one salient dimension — an impressive university, a prestigious employer, fluent English, or physical attractiveness — unconsciously leads the evaluator to rate the candidate positively on unrelated competencies as well.

In practice

A candidate from a top consulting firm may be rated more highly on analytical skills, leadership potential and cultural fit simultaneously — even if the interviewer has only observed one of these directly. The halo effect is particularly powerful when a salient credential aligns with the interviewer's own background (see also affinity bias). The horn effect is the inverse: one negative trait contaminates overall evaluation. Structured assessment methods help: requiring interviewers to score each competency independently, using behavioural evidence rather than impressions, and ensuring multiple independent assessors each evaluate different dimensions.

Key takeaway

One brilliant credential or one poor answer should trigger curiosity, not a verdict — the halo effect converts individual data points into global judgements that have no logical basis.