[mickronome]

I completely agree, a quarter of a second is absolutely not instantaneous.

Especially not to oddballs like me that has some kind of perceptive 'bug', it's like I lack a 'motion filter'. One effect being that movement in computer games doesn't feel completely fluid until the refresh rate is close to 200Hz.

Before internet and slow loading web pages might have lowered peoples expectations, I remember Human-computer interaction guidelines stating that < 0.1 was experienced as instantaneous in almost all cases. Above 1s without feedback started to cause measurable stress in test subjects.

Since this was before computers were ubiquitous, it's probably a good measure for how we react on a more basal, subconscious level. Anything measured today is likely to be include learned expectations, so a quarter of a second seems like reasonable learned expectation of the perception of instantaneous in that particular context.