Alignment effects on simple turn decisions in track-up and north-up maps

Turn decisions will be slower and less accurate for misaligned orientations of a map than when the map is aligned with one's heading direction. It is unclear what the size of this effect will be for misalignments within a narrow range around the aligned heading. This series of experiments examined the effect of turn-arrow alignment on accuracy and speed of turn decisions. In the first experiment, participants were presented with a series of maps, each with a turn arrow of a different orientation and heading superimposed over the center. The second experiment added a simulated driving task to increase cognitive load. Results indicate that while error rates and reaction times rise with increased misalignment, a wide range of misaligned headings ±50° around the perfectly aligned heading show error rates and reaction times that are not significantly different from the aligned heading and thus produce little cognitive cost.