Turning the corner with the flash-lag illusion.

Area of Science:

• Visual perception
• Motion perception
• Spatial cognition

Background:

• Previous studies on localization bias around L-trajectories yielded conflicting results.
• Some research indicated no bias, while others found biases both inside and outside the path.

Purpose of the Study:

• To investigate localization bias around an L-trajectory.
• To test a predictive model based on the vector sum of motion directions.
• To determine if bias occurs before or after the change in direction.

Main Methods:

• Utilized stimuli facilitating accurate vernier judgments.
• Employed the flash-lag illusion to measure perceived location bias.
• Analyzed data in the context of an L-trajectory with a right-angle turn.

Main Results:

• Observed a 'sideways' bias in perceived position before the turn, in the direction of final motion.
• This finding supports the vector sum model proposed by Eagleman and Sejnowski (2007).
• The bias was detected before the change in direction, not after.

Conclusions:

• The study's findings favor the vector sum model for predicting perceived location bias around L-trajectories.
• Perception is influenced by motion occurring after the point of sampling.
• This research clarifies conflicting previous findings on visual localization bias.