Lecture 5 the perception of colour and motion. Newton: prisms break up (refract) white light into spectral components (rainbow). Any single component could not be refracted into a different color (monochromatic colors). 2nd prism combining all the colours would re-create white light. We perceive the continuum of wavelengths as qualitatively different phenomena. With colour we per(cid:272)ei(cid:448)e so(cid:373)ethi(cid:374)g that does(cid:374)(cid:859)t e(cid:454)ist. And we are extraordinarily good at it and efficient. Even though the task is actually infinitely ambiguous. Find the faces - without color cues, hard to detect objects. Green filter: nose and stars appear ~equally bright but actually are very different in colour. Problem of univariance: an infinite set of different wavelength-intensity combinations can elicit exactly the same response from a single type of photoreceptor: one type of photoreceptor cannot make colour discriminations based on wavelength responds differently depending on wavelength. Also responds differently depending on light energy. Responses of single photo receptors: the problem of univariance.