On Mon, Apr 9, 2018 at 11:35 PM, Stephen J. Turnbull <turnbull.stephen.fw@u.tsukuba.ac.jp> wrote:

Tim Peters writes:

> "Sum reduction" and "running-sum accumulation" are primitives in
> many peoples' brains.

I wonder what Kahneman would say about that. He goes to some length
to explain that people are quite good (as human abilities go) at
perceiving averages over sets but terrible at summing the same. Maybe
they substitute the abstraction of summation for the ability to
perform the operation?

[OT] How is that human ability tested? I am a visual learner and I would propose that if you have a set of numbers, you can graph it in different ways to make it easier to perceive one or the other (or maybe both):

- to emphasize the average, draw a line graph -- in my mind I draw a line through the average (getting the trend for free)

- to emphasize the sum, draw a histogram -- in my mind I add up the sizes of the bars

--Guido van Rossum (python.org/~guido)