Fig. 4: Time-scaling versus distance-scaling of accumulating noise.

a Model comparison using LOOCV between the full model with accumulated error proportional to total travel distance versus total time in trajectory. For both age groups, the full model is better supported by the data. Higher bars indicate poorer model-fit. *** Denotes “very strong” evidence against the model with poorer fit (ΔBIC or ΔLOOCV ≫ 10; see “Methods” section on model comparison, and Supplementary Fig. 7). b Average path integration error at the last stopping point, in trials with and without intermediate stopping points. The path integration error is very similar even though trials with stopping take much more time, indicating that the path integration error mainly scales with distance rather than time. Error bars indicate mean ± SEM (young adults: n = 540 trials without stopping vs. 900 trials with stopping; older adults: n = 468 trials without stopping vs. 780 trials with stopping). c Walking velocity versus path integration error for trials with and without stopping and for both age groups.