As I was leaving the library late at night I spotted a shelf of books by the door with a sign reading “Book Sale, £1 per book, place money in the honesty box”. Intrigued I had a look through the books and guessed that the textbooks on the shelf were worth between ten and twenty times their sale price – bargain. But as I looked up and around the almost empty library I thought, why pay a pound when you could take the book and pay nothing? After all I am studying an MPhil in Economics, and the economic man doesn’t care for honesty or guilt, he just wants to maximise his utility subject to his budget constraints.
What proportion of people finding a book they like on this shelf place the money in the honesty box? Does this figure vary depending on the time of day and the number of people in the library? Could objects in the environment alter behaviour? These are questions I would love to answer experimentally; however, this being one of the smaller libraries at the University of Cambridge I felt spending a few weeks running an experiment would not provide enough data for meaningful analysis. Instead, I discuss the paper “Cues of being watched enhance cooperation in a real-world setting” by Bateson, Nettle and Roberts, 2006. This paper provided the first evidence from a naturalistic setting of the importance of cues of being watched, and hence reputational concerns, on human cooperative behaviour.
The hypothesis tested was that participants contribute more money to an honesty box when the box is placed in the presence of an image of a pair of eyes than when in the presence of a control image of flowers. The experiment took place in a university faculty in the UK, where the system of payment for drinks in the form of an honesty box had been in place for several years. The notice which was located at eye level above the honesty box had a banner below it which alternated between a picture of eyes, and a picture of flowers. A different image was used each week to control for any affects attributable to a single image, and each week the ratio of the total amount of money collected to the volume of milk consumed was recorded.
The findings over the ten weeks were striking; on average people paid 2.76 times as much in the weeks with eyes than with flowers. The figure below shows the ratio over the ten weeks. The transition from flowers to eyes was always met with an increase in contributions, and a decrease was seen when the image changed back to the flowers. A general linear model with factors image type (fixed) and week (covariate) fitted to log-transformed data explained 63.8% of the variance in contributions.
The authors believe that images of eyes motivate cooperative behaviour in an environment where contributions were anonymous because of the induction of the perception that participants were being watched. The human perceptual system contains neurons that respond selectively to stimuli involving faces and eyes, and it is plausible that the images above the honesty box exerted an automatic and unconscious effect on perceptions of being watched. The results therefore support the hypothesis that reputational concerns may be very powerful in motivating cooperative behaviour.
In situations involving the relative generosity of human cooperation, even when interactions are explicitly anonymous and not repeated, it appears the economic man may not always be solely looking after number one..
Until the next time,
Alex.
References
Bateson, Melissa, Daniel Nettle, and Gilbert Roberts (2006), “Cues of Being Watched Enhance Cooperation in a Real-World Setting,” Biology Letters, 2 (June), 412–14
Boundedly Rational 