Near an honesty box, in which people placed coffee fund contributions, researchers at Newcastle University in the UK alternately displayed images of eyes and of flowers. Each image was displayed for a week at a time. During all the weeks in which eyes were displayed, bigger contributions were made than during the weeks when flowers were displayed. Over the ten weeks of the study, contributions during the ‘eyes weeks’ were almost three times higher than those made during the ‘flowers weeks.’ It was suggested that ‘the evolved psychology of cooperation is highly sensitive to subtle cues of being watched,’ and that the findings may have implications for how to provide effective nudges toward socially beneficial outcomes.