When I was doing my degree it was common knowledge the other psychology lecturers looked down a little on the psychometrics lecturer. And he even admitted it once to us; that psychometrics struggled for recognition as an authentic branch of psychology.
Basically, psychometrics is the attempt of psychologists to quantify behaviour. Without going into too much detail here, one tool we used on each other was the JND - the Just Noticeable Difference. And it involved formulae like this:
We sat for hours with headphones on, trying to distinguish between slightly different pitches and slightly different volumes of sound wavelengths. We tasted different sugar solutions, and smelled different intensities of odours, lifted different weights and looked at pairs of colours that were very similar. Our experiments generated vast quantities of raw data and provided huge volumes of dots for scattergrams and subsequent statistical analysis. But unfortunately didn't tell us much about humans except that the tireder or hungrier or boreder you get the larger has to be the Difference before it's Just Noticed. Not surprising, really.
All this stuff came back to me last night when J. sent me this colour discrimination test/game.
It was much easier than the JND pairing experiments, and actually quite fun. N. got 100%!