Human factors research

For a piece of code I’m writing, I need to break the angle of a turn down into “continue”, “bear left (or right)”, and “turn left (or right)”. The program takes a topological map of points within a building and converts a path through the building into spoken directions. Intuitively, it seems to me, there is some small range of angles that are effectively “continue forwards” or “straight ahead”, some range of angles to the left and right of that that are “bearing” without being “turning”, and some range of angles to the left and right of that range that are “turning”.

Before I go any further, I should point out that this isn’t a study. Anything with n=7 and a population consisting of exclusively white male computer science students in their 20s is not exactly an unbiased sample. It’s a guess, based on the opinions of the people who happened to be standing around at the time.

My procedure was to show the participant a protractor, and ask them to imagine a person standing at the origin and facing the 90° mark. I then asked them what ranges, in degrees, constituted “straight forward”, “bear left/right” and “turn left/right”.

The results:

Participant "Straight"  "Bear"      "Turn"
p1          70-110      L 100-140   L 140-180
R 80-40     R 40-0

p2          80-100      L 130-150   L 130-180
R 50-30     R 50-0

p3          60-120      L 130-150   L 130-180
R 50-30     R 50-0

p4          75-115      L 115-125   L 140-180
R 75-50     R 40-0

p5          70-110      L 110-130   L 160-180
R 70-50     R 20-0

p6          88-92       L 92-112    L 160-180
R 88-68     R 20-0

p7          75-105      L 105-125   L 125-180
R 75-55     R 55-0

Based on this, I’m going to say that “straight” corresponds to about 70-110 degrees, “bear” is about 110-130 on the left and 70-50 on the right, and anything outside of that is a “turn”. This is nothing more than a stupid rule of thumb, but if anyone complains, it’s easy enough to change the code.

I could complicate it further and add “bear slightly L/R” and “turn hard L/R”, but I’m not sure the gain in resolution translates to any gain for indoor navigation. Changing how the questions are presented or whether or not the user gets to refer to a protractor would probably also change the answers.