More Doubts Over The Oxytocin And Trust Theory

The claim that the hormone oxytocin promotes trust in humans has drawn a lot of attention. But today, a group of researchers reported that they've been unable to reproduce their own findings concerning that effect. The new paper, in PLoS ONE, is by Anthony Lane and colleagues from Louvain in Belgium. The same team have previously published evidence supporting the link between oxytocin and trust. Back in 2010 they reported that "oxytocin increases trust when confidential information is in the balance". An intranasal spray of oxytocin made volunteers more likely to leave a sensitive personal document lying around in an open envelope, rather than sealing it up, suggesting that they trusted people not to peek at it. However, the authors now say that they failed to replicate the 2010 'envelope task' result in two subsequent studies. Here's the key data. The original 2010 results are at the top, the two replications are below. The bars show the proportion of participants who left the envelope sealed and taped (least trusting), sealed only, or open (most trusting).