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Comment by tbrownaw | Hacker News Reader

> in response to stimulation of the skin with weak electromagnetic fields that are pulsed with certain frequencies near ½ Hz or 2.4 Hz, such as to excite a sensory resonance

1. As a kid, I remember going to some science museum that had a thing you could touch that could be either warm or cool or quickly switching between them, and that last setting felt surprisingly hot. Is that a similar effect?

2. Aren't flashing lights supposed to be bad for siezures? That's the eyes instead of the skin, but is the mechanism related somehow?

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Flashing lights can cause seizures yes. That's why you'll often see a warning at the start of more visually frenetic videogames.

Famously an old Pokemon episode gave several hundred kids seizures. The wikipedia article contains the scene if you're feeling particularly brave :) https://en.wikipedia.org/wiki/Denn%C5%8D_Senshi_Porygon recommend not watching fullscreen and being ready to click away, as it is a bit intense -- I'm not epilectic but it makes me feel _weird_.

I also remember back in the day learning OpenGL I accidentally wrote a program which would flash between my desktop and a solid color at 60hz. It was literally painful to look at in the few seconds it took to shut it down.

My sister discovered she had photosensitive epilepsy when she passed out on the floor of a broadcasting school while doing editing work.

The Pokémon incident is probably also why Nintendo applies filters to old emulated NES games during rapidly flashing segments including on the NES Classic (such as when Kirby uses the Crash ability in Kirby's Adventure). They're pretty serious about this issue. I don't particularly enjoy adulteration of my old favorites, but my sister is grateful for the feature.

> I remember going to some science museum that had a thing you could touch that could be either warm or cool or quickly switching between them, and that last setting felt surprisingly hot. Is that a similar effect?

What you're describing is a variation of the thermal grill illusion -- in short, activating both heat and cold sensory receptors at the same time is perceived as extreme heat. As far as I'm aware, this phenomenon is specific to the temperature sense, and it has nothing to do with "resonance".

https://en.wikipedia.org/wiki/Thermal_grill_illusion

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