When someone is asked a perplexing question, there's a good chance they will spontaneously shift their gaze - either upwards, or to the side.
This seemingly ubiquitous cross-cultural behaviour is currently unexplained.
A research project from 1998 suggested that :
(1) the frequency of gaze aversion is related to the difficulty of cognitive processing,
(2) this behavior cannot be due solely to demand characteristics or embarrassment, and
(3) the behavior is functional"
The research team's broad idea is that averting the gaze to a 'quiet zone' relieves the brain from some high-demand processing power.involved with decoding the complex visual field - allowing it to concentrate instead on the mental task at hand.
See : Averting the gaze disengages the environment and facilitates remembering Memory & Cognition, 26 (4),651-658
So-called Non-Visual Gaze Patterns (NVGPs) are also common when :
Gaze-shifting, however, remains "One of the least understood human cognitive behavioral phenomena." (ref.)
It's notable that research teams with specific interests tend to find explanations relevant to their interests :
For example :
Note: Wikenigma has not been able to confirm when the first formal gaze-shifting research began.