%A Samuele Centorrino %A Elodie Djemaï %A Astrid Hopfensitz %A Manfred Milinski %A Paul Seabright %J Adaptive Human Behavior and Physiology %T A model of smiling as a costly signal of cooperation opportunities %K Smiling %K Costly signaling %K Experiment %K Trust game %P 325-340 %V vol. 1 %D 2015 %R 10.1007/s40750-015-0026-4 %I Springer International Publishing %L publications16892