Petting pets, inviting immunity

Ig-Nobel-winning work, in some cases, is just one step in pursuing an idea down a long path.

“Effect of Petting a Dog on Immune System Function,” C.J. Charnetski, S. Riggers, and F.X. Brennan, Psychological Reports, vol. 95, no. 3, part 2, December 2004, pp. 1087–91 [AIR 15:4]. Charnetski and Brennan, who shared the 1997 Ig Nobel Medicine Prize for demonstrating that listening to elevator Muzak can help prevent the common cold, explain here that:

“The present study assessed the effect of petting a dog on secretory immunoglobulin A (IgA) levels. 55 college students were randomly assigned to either an experimental group or one of two control groups. Group 1 petted a live dog; Group 2 petted a stuffed dog, while Group 3 simply sat comfortably on a couch. Each participant was exposed to one of the three conditions for 18 min. Pre- and posttreatment salivasamples yielded a significant increase in IgA for Group 1 only.”