I'm not a biologist, and not a member of the Institute of Biology, so I can't access Dr Sigman's article*. But his press release is available on his website, so I've looked at that. Early on in the press release is this graph, presumably excerpted from the article:
I'm not a biologist, neither am I a statistician, but this graph seems to show only that over a period of 20 years, face-to-face social interaction went down from six hours to two hours per day, while over the same two decades use of electronic media went up from four to eight hours per day. So the conclusion seems to be that the four hours that were spent face-to-face in 1987, were in 2007 spent in using electronic media. He seems to be suggesting that face-to-face interaction has gone down because of the increase in use of electronic media. Maybe. Or it could be coincidence. The graph doesn't show what people were doing with the other hours in the day, so on the whole it doesn't tell you very much.
The rest of the press release seems to claim that face-to-face interaction has positive health effects, and this may well be true, but the preponderance of "links" and "associations" suggests that most of these are correlations and not causation. Take this, for example:
It's possible that some women have a small social circle for reasons that are to do with being medically disposed to more serious and life-threatening coronary artery disease - not the other way around. I've not seen Dr Sigman's actual paper (which appears to be a meta-study, and presumably doesn't include any actual clinical research), so I don't know if the causation he ascribes is valid.
"Women who have suspected coronary artery disease (CAD) with a small social
circle exhibit more than twice the death rate of those with a larger social circle."
Valid or not, it makes a good headline, and you can rely on the Daily Mail to pick it up: How using Facebook could raise your risk of cancer.
If the audio expires, download it from RapidShare here:
The paper published in Biologist is now freely available:
Until I get around to reading the paper myself, here's someone who already has:
(via Ben Goldacre's Twitter feed)