Flicker made of colour changes instead of on and off (Henney 2024)

Yes, and the size of the response depends on the pair of colours: amber-red was strongest, and pairs that included blue or red were consistently stronger than those without.

A plain-language summary from binaural's reading notes, edited by Jude Mc. Last updated 10 November 2026. Not medical advice.

The question: Can a light that alternates between two colours, which looks far less flickery, still drive a 40 Hz response?

What it found

• The amber-red combination evoked the highest response.
• Combinations including blue and/or red consistently evoked higher responses than those without.
• The work is motivated by the discomfort of stroboscopic 40 Hz light.
• A related study from the same group found a near-invisible spectral flicker produced a 40 Hz response, though smaller than a strobe's (Agger 2022).

Limits

• A response measure in healthy young adults; no outcome was tested.
• Purpose-built multi-colour LEDs, not a phone display.

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.