The study, published today in the online journal Biology Letters, made use of a long-running kitty arrangement in a common room used by about 48 staff members, so there was no reason for workers to suspect that an experiment was being run. The journal is published by The Royal Society, Great Britain's scientific academy.
The lone change to the setup was a poster placed above the cash box listing prices of tea, coffee and milk, with an image banner across the top that alternated each week between different pictures of flowers or images that featured eyes looking directly down on the serving table.
The eye pictures varied in the gender and head orientation of the face, but all were chosen so that the eyes seemed to look directly at the observer.