Concept · Cognitive Bias: Memory biases and distortions
Leveling and sharpening
Origin: Allport & Postman, 1947
Biological Parallel
Stories transmitted through primate groups lose details (leveling) while dramatic elements amplify (sharpening)—this is information compression for efficient transmission. Memory naturally filters: routine details decay while distinctive features strengthen because unusual elements carry more predictive value. Leveling and sharpening is lossy compression: the brain sacrifices fidelity for transmissibility, keeping patterns that matter most for future prediction.