GSR is one of the most sensitive markers for measuring physiological arousal. It relies on micro sweat production caused by shifts in emotion.

• The Biology: Our palms and feet are densely packed with eccrine sweat glands. Controlled exclusively by the sympathetic nervous system (fight or flight response). These glands react almost instantly to emotional stimuli.

  
  

• The Physics: Water conducts electricity. A GSR sensor passes an unnoticeable electrical current between two fingers. When a participant is emotionally aroused, their sweat ducts fill, the current flows faster, and the sensor registers a spike.

  
  

• The Benefit: Because this pathway is entirely autonomic, it measures a pure emotional response that participants cannot alter or suppress.

Marketing Applications

• Video Ads & Trailer Testing: Find out if your key plot points, punchlines, or brand reveals are generating the intended emotional hooks. By pinpointing exactly where engagement spikes or drops, you can optimize your edit for maximum impact.

  
  

• Website & App UX Testing: Traditional post-test surveys often miss fleeting moments of frustration. GSR uncovers hidden friction points, like a confusing checkout page or a buried menu, by catching the exact millisecond a user experiences stress.

*Note: GSR measures emotional intensity, not direction. It tells us how much someone is feeling, but not what they are feeling. To get the full picture, we usually pair GSR with facial coding (to see the specific emotion) and eye tracking (to see exactly where they are looking).