initial reaction

• gut feelingInstinctive sense about something
• first impressionInstant assessment of someone
• instinctInnate behavioral tendency
• reflexInvoluntary stimulus response
• spontaneousArising without external cause

knee-jerk · visceral · shock · surprise · startle · flinch · recoil · gasp · double-take · snap judgment · impulse · immediate · automatic · response · trigger · stimulus · alarm · intuition

• first impressionsfirst impression, first impressions, snap judgment, snap judgments, gut feeling
• snap judgmentssnap judgment, snap decision, hasty conclusion, rush to judgment, jumping to conclusions