Here is each word's surprise against the time it takes to read it. The same cloud, a straight line fitted over it. Switch the vertical ruler — milliseconds or their logarithm — and turn the surprise's exponent: watch the cloud straighten or bend without a single datum having changed.
For each ruler there's an exponent that makes the cloud look straightest — where the fit's R² is highest. Only it isn't the same exponent for both: the millisecond ruler asks for one, the log ruler for another. Slide k and watch the two peaks refuse to line up.