Visual search asymmetry: The influence of stimulus familiarity and low-level features

Wang, Cavanagh, and Green (1994) demonstrated a pop-out effect in searching for an unfamiliar target among familiar distracters (U-F search) and argued for the importance of a familiarity difference between the target and the distracters in determining search efficiency. In four experiments, we explored the generality of that finding. Experiment 1 compared search efficiency across a variety of target-distracter pairs. In Experiments 2, 3, and 4, we used Chinese characters and their transforms as targets and distracters and compared search performance between Chinese and non-Chinese participants. We demonstrated that search asymmetry and search efficiency in the U-F condition are influenced by the presence of low-level feature differences between the familiar and the unfamiliar stimuli. Our findings suggest that the familiarity of the distracters, rather than the familiarity difference between the target and the distracters, determines search efficiency. We also documented a counterintuitive familiarity-inferiority effect, suggesting that knowledge of search stimuli may, sometimes, be detrimental to search performance.