Indexing the archive…
Your Universe of Digital Possibilities
Stare at falling water, then at the rocks beside it, and the rocks rise. Here the waterfall is a turning spiral you start yourself; afterwards a still spiral seems to turn the other way. Cancel that motion with real motion, second by second, and the instrument times how fast your motion detectors recover — and whether the effect waits for you in the dark.
Two neighbouring inputs; each is delayed and multiplied with the other, and the two products subtracted. A pattern drifting from 1 to 2 makes the first product win, the opposite drift the second — an opponent motion signal from nothing but timing.
The real motion needed to cancel the aftereffect, t seconds after the adapting motion stops: strength A, falling by a factor e every τ — the time an adapted channel takes to win back its gain.
The probability of one answer as the stimulus x changes: F a sigmoid (logistic or cumulative normal) centred on α, the point of subjective equality, with spread β; γ the guess rate, λ the lapse rate. Every Iris instrument fits it to the visitor’s own trials by maximum likelihood, with the PSE’s error from the profile likelihood.
The fifth percept is a recalibration. Motion is read by channels that compare neighbouring points across a delay; a channel driven for long enough turns its own gain down, so that a world flowing past for minutes stops counting as news. When the flow stops, the tired channel is outvoted by its opposite and the still world drifts back. What a flash beside motion reveals about the timing of that reading is The Lag; what an excitable medium does with a turning spiral of its own is The Spiral; what many moving agents make of their neighbours’ motion is The Flock.