Sharp-edged or smooth flicker (Panitz 2023)
Yes at slower rates. Square-wave flicker gave larger responses than sine-wave at 6 and 8.57 Hz in both laboratories; the difference was weaker at 15 Hz.
The question: Does the shape of the flicker, abrupt or smooth, change the size of the brain's response?
| Type of study | Two-laboratory experiment |
|---|---|
| Who took part | 30 participants across two laboratories |
| What was done | The same patterns were modulated with a square wave or a sine wave at 6, 8.57 and 15 Hz, in two labs with separate analysis pipelines. |
| How much weight it carries | Strong design |
What it found
- Response amplitude fell as the driving rate rose, in both labs.
- Square-wave modulation evoked higher amplitudes at 6 and 8.57 Hz.
- The effect replicated across labs and pipelines; at 15 Hz it was weaker.
Limits
- Eyes-open patterns, not a uniform field through closed eyelids.
- Amplitude of a brain response, not an experience or a benefit.
Where this sits
More in the library on light, flicker and 40 hz. For the wider picture, read 40 Hz, gamma and the brain.
This is our plain-language reading of the paper. It is not medical advice, and one study rarely settles a question.
Sources
- Panitz, C., Gundlach, C., Boylan, M. R., Keil, A., & Müller, M. M. (2023). Higher amplitudes in steady-state visual evoked potentials driven by square-wave versus sine-wave contrast modulation: A dual-laboratory study. Psychophysiology, e14287. doi.org/10.1111/psyp.14287