Dustin may be right, but his argument in support of his conclusion is hardly persuasive on the basis of its logical structure!
Firstly, the article is a typically poor piece of journalism. It is poorly argued, and belittles the subject with unnecessary “humorous” words like “noggin” instead of head. The actual factual content is thin, and is obscured by the poor writing.
As a survey, I would call it “technological” rather than scientific. He has a lot of data, but the data were not derived from a proper scientific experiment. There is no “control” and no “blind” for example.
Perhaps the researcher felt safer in the helmet, and rode further out from the kerb. The car drivers kept their usual distance from t e kerb, and were therefore nearer to the cyclist. The explanation fits the facts, and requires only one person to change his behaviour instead of many.
Perhaps he had a point to prove, and (unwittingly) moved a little closer to the cars. When I’m in a bad mood, all the other drivers drive worse. When he feels the drivers are more dangerous, perhaps he subconsciously exposes himself to more risk to “prove” it.
The “long wig” effect may well be true. Most drivers are male. Most males notice attractive women and behave towards them in a manner somewhere along the spectrum from “chivalrous” to “patronising”. Anywhere on that scale would involve givng the attractive woman more room to ride.
The helmet effect is less likely to be real. It implies that the driver sees the male cyclist, carefully assesses his vulnerability, taking into account the helmet, and reacts accordingly - disregarding the risk of damage to the car, or to the cyclist’s legs, torso and arms.
My relevant experience is 35 years cycling (including tandeming and unicycling), 25 years driving, sometimes up to 35 000 miles a year, 15 years motorcycling or scootering, and 25 years working in insurance claims - including investigating motor accidents, reading police and Coroner’s reports, interviewing drivers and witnesses, visiting accident scenes and attending civil court cases.
Most drivers out there have little or nothing in the way of hazard perception skills or hazard management skills. But men always notice pretty girls.