Self Selection in Wonderland

Thursday, January 23rd, 2014

Ability levels vary by degree, as this figure demonstrates:

Ability Level vs. Academic Degree

Verbal (V), spatial (S), and mathematical (M) z-scores vary across academic areas of study — from education and business to physical science and engineering — and degree attained.


  1. James James says:

    I understand that Verbal, Spatial and Mathematical abilities are separate (even if correlated), so it’s a bit weird that this chart shows everyone’s Mathematical ability as higher than their Spatial. Shouldn’t they be scaled to have the same average? Or not joined by lines, or just put on separate graphs.

  2. Isegoria says:

    Those scores are z-scores, so they are all normalized to have a mean of zero and a standard deviation of one. College entrance exams explicitly test verbal and mathematical ability, and different majors emphasize one over the other, while spatial ability seems to come along for the ride.

  3. James James says:

    So the reason everyone’s M is shown as higher than S is because non-graduates are not included? If so, that would imply that non-graduates have higher S than M, which seems reasonable.

  4. Isegoria says:

    Right — and not just non-graduates, but also anyone who didn’t go to college in the first place.

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