Toothless but Still Superior: Grins aren't required for happiness superiority effect in multi-target face search

Previous research (Thirkettle & Wilson, 2024) demonstrated a happiness superiority effect in a novel visual search task, where participants more efficiently identified happy faces than angry ones amongst arrays of randomly assorted emotional expressions. However, prior studies (e.g., Savage et al., 2013) have raised concerns that low-level visual artifacts-particularly in classic one-target search paradigms-may confound such effects. While our task mitigates many of these issues through multiple, distinct, targets and including trial-by-trial randomisation of all array images, one potential confound remains: the bright visual cue created by exposed teeth in toothy smiles. To isolate this factor, we compared search performance using closed-mouth smiles versus toothy-grinned happy faces as targets. Results revealed that the happiness superiority effect persisted with closed-mouth smiles, though it was attenuated. This suggests that while low-level features like visible teeth may enhance detection, the effect is not solely driven by them. Our findings align with Becker et al. (2011), supporting the robustness of the happiness superiority effect and pointing to underlying mechanisms beyond mere visual salience.