Selective nontarget inhibition in Multiple Object Tracking

Abstract

We previously reported that in the Multiple Object Tracking (MOT) task, which requires tracking several identical targets moving unpredictably among identical nontargets, the nontargets appear to be inhibited, as measured by a probe-dot detection method. The inhibition appears to be local to nontargets and does not extend to the space between objects—dropping off very rapidly away from targets and nontargets. In the present three experiments we show that (1) nontargets that are identical to targets but remain in a fixed location are not inhibited and (2) moving objects that have a different shape from targets are inhibited as much as same-shape nontargets, and (3) nontargets that are on a different depth plane and so are easily filtered out are not inhibited. This is consistent with a task-dependent view of item inhibition wherein nontargets are inhibited if (and only if) they are likely to be mistaken for targets.

Keywords:

• Tracking
• Multiple object tracking
• Nontarget inhibition
• Probe-dot detection
• Segregation by depth
• Visual attention

Acknowledgements

This research was supported by NIH Grant 1R01 MH60924. The authors are grateful to Jeremy Wolfe and Andrew Hollingworth for their comments as reviewers of an earlier version of this manuscript.