Is the startle reaction an emotion?
Level 4 - case-series / case-control
Laboratory experimental physiological study examining facial muscular responses across conditions without a randomized controlled trial design.
PubMed 4078682 · doi:10.1037//0022-3514.49.5.1416
What was done
Researchers measured facial muscular actions during acoustic startle reactions induced by a blank pistol fired under predictable and unpredictable conditions. Participants were also instructed to voluntarily suppress their startle response or simulate a startle response in the absence of a gunshot.
What was found
The abstract provides no numerical data, statistics, or effect sizes. It reports that facial muscular measurements supported previous findings by Landis and Hunt (1939) and suggested that startle should be classified as a reflex rather than an emotion.
Why it matters
This study provides empirical evidence separating basic physiological reflexes from complex emotional states, contributing to theoretical debates regarding cognitive appraisal in emotion.
Limits
The abstract does not report sample size, participant demographics, exact methods of measurement, or quantitative outcomes. Findings are constrained to laboratory acoustic startle paradigms.