The following is a summary of “Temporal stability of human heading perception,” published in the February 2023 issue of Ophthalmology by Ali, et al.

In the course of straightforward self-motion, humans can reliably determine their heading from optic flow. Nonetheless, despite the optic flow field’s overall coherence, the eye is constantly in a state of flux due to visual clutter and other realistic circumstances. The visual system must maintain sensitivity to optic flow variations that correlate with actual changes in self-motion and dismiss those that do not accurately determine the heading from optic flow. This presented a challenge that must be solved. 

The heading signals could be stabilized while suppressing transitory fluctuations by integrating the optic flow over time. Yet, sluggishness could be a trade-off for stability. For a study, researchers sought to determine how stable it was for people to perceive their heading after a shift in the simulated self-motion direction. 

They discovered that the beginning heading positively impacted how people perceived the final heading. As the amount of the heading change increased and as the viewing length of the optic flow compatible with the final heading shrunk, bias toward the original heading increased, which is consistent with an evolving heading representation. Later in the trial, intervals of sensory dropout (blackouts) were introduced, raising bias, while an earlier period did not. 

According to simulations of the Competitive Dynamics Model, a neural network, human data was largely captured by a process that generates an evolving heading signal through repeated competitive interactions. The results demonstrated how the visual system strikes a balance between sensitivity to change and stability in heading perception, and they lend credence to the idea that heading perception changes over time.