Schedule of Events | Symposia

Unfamiliar distractors disrupt visual search through a combination of forward and backward masking

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Ryan E.B. Mruczek¹, Michael J. Lesofsky¹, Mariam A. Ayad¹; ¹College of the Holy Cross

Long-term familiarity alters the neural processing of objects and enhances recognition efficiency. For example, both parallel (Mruczek & Sheinberg, 2005) and serial (Manahova et al., 2020) visual search is faster when distractors are familiar, possibly due to sharper neural responses to familiar images (Mruczek & Sheinberg, 2007; Meyer et al., 2014). Here, we test whether the disruptive effects of unfamiliar images during serial visual search are due to forward or backward masking using a multi-day behavioral paradigm. For Days 1-3, participants (n=26) engaged in a visual search task for 1 of 8 familiar targets amongst a consistent set of 20 distractors. We demonstrate familiarity with these distractors on Day 4, which introduced 20 unfamiliar distractors. Consistent with our previous results, participants had lower reaction times and search slopes when searching amongst familiar compared to unfamiliar distractors. On Day 5, participants viewed a rapid serial visual presentation (RSVP) stream of familiar distractors (10 items/s) interspersed with 1 familiar target, and 1 unfamiliar distractor appearing within 300 ms of the target (before or after). Compared to baseline trials without an unfamiliar distractor, participants had lower hit rates (~84.0% vs. 88.1% baseline) and higher miss rates (~12.6% vs. 9.2% baseline) when the target appeared just before (~100 ms) or just after (100-300 ms) the unfamiliar distractor. Our results indicate that the stronger and less-selective neural activity typically evoked by unfamiliar images disrupts prior (backward masking) and, to a greater extent, subsequent (forward masking) object processing.

Topic Area: PERCEPTION & ACTION: Vision