According to http://www.timesonline.co.uk/tol/life_and_style/health/features/article588739.ece http://www.timesonline.co.uk/tol/life_and_style/health/featu... a

According to http://www.timesonline.co.uk/tol/life_and_style/health/features/article588739.ece http://www.timesonline.co.uk/tol/life_and_style/health/featu... and http://www.bbc.co.uk/pressoffice/pressreleases/stories/2005/12_december/05/slough.shtml http://www.bbc.co.uk/pressoffice/pressreleases/stories/2005/... the people directly involved reported being happier, by more than the experimenters expected. There's no information there about (1) whether the happiness gains lasted or (2) whether they had any effect on other people. Slough's population is ~120k, so I'd be surprised if any "seeding" effect produced measurable results on the population as a whole. I don't see any sign that the BBC has either put the episodes online or offered them for sale.