Evaluating faces on trustworthiness after minimal time exposure

Previous studies have shown that trustworthiness judgments from facial appearance approximate general valence evaluation of faces (Oosterhof & Todorov, 2008) and are made after as little as 100 ms exposure to novel faces (Willis & Todorov, 2006). In Experiment 1, using better masking procedures and shorter exposures, we replicate the latter findings. In Experiment 2, we systematically manipulate the exposure to faces and show that a sigmoid function almost perfectly describes how judgments change as a function of time exposure. The agreement of these judgments with timeunconstrained judgments is above chance after 33 ms, improves with additional exposure, and does not improve with exposures longer than 167 ms. In Experiment 3, using a priming paradigm, we show that effects of face trustworthiness are detectable even when the faces are presented below the threshold of objective awareness as measured by a forced choice recognition test of the primes. The findings suggest that people automatically make valence/trustworthiness judgments from facial appearance.