Should I use surveys and self-report or the Immersion SDK to measure emotional response in my app?
Ask the user how they felt. No legal obligations. A scientific limit. The Immersion SDK measures the body's response to what the brain is doing, on the device, with no biometric identifier, no health data leaving the device, and no emotion-recognition system.
| Surveys and self-report | Immersion SDK | |
|---|---|---|
| What it measures | What people are willing and able to say, after the fact. | Neurochemical signatures in cardiac rhythm, decoded into Value and Psychological Safety (0–100). |
| What it collects | Ordinary personal data; no biometrics. | Nothing from the user. Your app passes sensor samples in; the Immersion SDK scores them in memory and discards them. It requires no HealthKit or Health Connect permission of its own. One activation call carrying your app credentials. No PII. |
| Passive | No | Yes |
| Timing | Minutes to days after the moment. | Instant. |
| Biometric identifier | No | No |
| Health data leaves device | No | No |
| Emotion-recognition system | No | No |
| Predicts behavior | Weak. Self-report is biased by memory, social desirability, and the question itself. | Strong. Value predicts memory and behavior with 85–98% accuracy in published work. |
No legal obligations. A scientific limit.
Surveys are lawful and simple. They’re also late, thin, and biased, which is usually why a developer is asking this question in the first place. Response rates fall as apps mature, and the people who answer aren’t the people who left the event.
In practice: Cheap to build, hard to trust, and impossible to act on in the moment.
A prediction engine, not an emotion-recognition system.
No biometric identifier, so BIPA and its cousins don’t apply. No health data stored or transmitted, so nothing crosses a border that Apple, Google, or GDPR Article 9 would care about. No named emotions inferred, so it’s not an emotion-recognition system under the EU AI Act. It calculates from whatever sensor your app already reads and computes two behavioral predictors inside your app: a prediction engine that draws no inference from a face, a voiceprint, or a brain scan.
In practice: The Immersion SDK asks your users for nothing. It requires no HealthKit or Health Connect permission and no entitlement of its own: your app hands it samples from whatever source it already has (a BLE fitness sensor, a watch, a file) and it hands back Value and Safety. A BLE fitness strap feeding fitness data into your app needs no health permission at all. If your app reads heart rate through HealthKit or Health Connect, that permission is your app's requirement, not the Immersion SDK's. No biometric consent, no emotion-recognition disclosure, no health data leaving the device.
Where surveys and self-report persists, and why that doesn’t help
You’ll keep using surveys for the things a survey is for: what a person consciously prefers, what they remember choosing, what they say they want next. None of that is ground truth for how much the experience actually mattered to them. Ground truth is a direct, unfakeable response measured while the moment is happening, which is what the Immersion SDK reads from the heart. A survey can’t calibrate it; a survey is the thing it replaces.
Regulatory summaries are for orientation, not legal advice. Confirm classification for your own app with counsel.
Related
All guides- Why would heart rate tell you anything about the brain?The oxytocin → vagus nerve → cardiac rhythm mechanism, with citations.
- Heart rate vs HRV vs ImmersionWhat each metric can and can’t tell you, with five worked moments.
- How do I measure emotion in my app?Five ways to do it. Four make you liable for something. One doesn’t.
- Immersion vs facial codingBiometric identifier plus emotion recognition.
- Immersion vs voice prosodyVoiceprint plus emotion recognition.
- Immersion vs HRVHealth data plus emotion recognition, without the science.