My Credentials?- On the subject of helmets- none. I have laymen's knowledge, informed but a laymen's knowledge.

On the subject of human behavior- it's my field, it's what I teach and I work in the field of human behavior. While I've worked with a variety of populations from people in locked facilities to persons with mental and physical handicaps and communication disorders I currently teach undergraduates primarily and some private workshops and classes. I am not a clinician, a statistician nor a theorist. My work, and that of my mentors and colleagues is more likely to be used as source material by others like Malcolm Gladwell, Carol Gilligan, and Antonio Damasio. I confer and am in dialogue with behavioral theorists, psychologists and neurologists frequently in order to stay current in my field. Occasionally, I am fortunate enough to have experts in those areas take one of my classes and am inspired by the dialogue.

I am particularly interested in the work being done by neuroscientists and am fortunate enough to live in Boston, where I occasionally get to work and/or associate with true experts in that field. What you may be reading as a "bug up my ass" is that I've developed a healthy appreciation for the value and vulnerability of the human brain. And wearing a helmet in the appropriate circumstances is something I do see as valuable.

With regards my 'insult' when I said you had less than a laymen's understanding of risk compensation behavior my intention was not to insult but to simply be honest- you do.

Without launching into a dissertation on behavioral science and how incredibly inexact it can be and how sensitively such theories are applied in the field before anything remotely resembling a conclusion is drawn.I'll address a couple of points.

#1- More than likely risk compensation is learned behavior. In other words, risk compensation studies, like the one done on children in playgrounds. Have them play without protective equipment then give them helmets, gloves, knee pads, elbow pads and send them out to play and they engage in riskier playground behavior. Why? Because they were told the equipment would make them safer? Nope. Because they fell for a second on their knee and it didn't get scraped, they jammed their finger and it didn't get hurt, they bumped their head and they didn't cry. Oooh, guess what? suddenly they start taking more risks, pushing the envelope. It's because they learned the limits had changed.

#2 The ABS study you cite is even more problematic. A car without ABS brakes behaves differently than a car with ABS brakes. While risk compensation behavioral theory has as one of it's parameters that the subject be aware of the change (i.e. the car now has better, more sophisticated brakes) the body mind connection that operates the car actually feels the difference. Suddenly the driver starts driving too close to the car in front of them, applying the brakes later as they approach a stop light. They appear "less cautious" because they have learned "kinesthetically" that the limits have changed.

People push the envelope in learned behavior situations. For example, there have been tremendous advances made in the area of skydiving. Technically, it should be a safer sport. But statistically the fatality rate is not substantially changed. Well, here's where risk compensation theory is applicable. Sky divers tend to be risk oriented individuals. They engage in the sport for the thrill- the risk is part of attraction to the sport. As improvements are made the risk becomes less so in order to maximize the thrill they cliff jump, wait longer to deploy the shoot, do more daring stunts etc.

Certain bicyclists: extreme downhill cyclists, trick riders, MTB'ers that do extremely technical trails may fall into a similar category as sky divers. But again, these are learned behaviors altered by the equipment. In learning to do extreme sports of this kind there is a learning curve. You will fall, you will have crashes- it's how you learn. When you fall and survive because you had on shin guards or knee pads or a helmet your body learns it as much as your mind. And, yes, in these cases risk compensation theory may have some application.

However, it is most often cited in BF's as to how it applies to all cyclists. This is where the risk compensation theory loses it's grip. The way it is oft applied as a challenge to helmet efficacy is that once a person puts a helmet on their head they will now take more risks. But neuroscience tells us that is not how the brain works. The decision making for this kind of behavior is not made by a piece of information about helmets that sits in the frontal lobes. It's far more complex. The body has to receive signals, and usually several that it is indeed safer. Basically, the body is smarter than that. It needs to get a light bump on the head or good slam to the ground to learn and feel the difference. That's why the kids in playground learn quickly they can be more audacious in their behavior with safety equipment, it's why hockey and football players do the same thing. The person with the ABS brakes can feel the change in the way the car behaves. The skydiver can feel the equipment can be pushed to a further limit- they feel it in their body.

For risk compensation theory to apply to a helmet wearing commuting cyclist they would have to have a couple of bumps, falls, crashes for the complex series of neuropathways that engage when you run a red light, weave through, traffic or descend a hill at high speed and even then unless they are seeking the thrill those bumps, falls and crashes may just as likely make them be more careful helmet or not.

So, maybe, just maybe, risk compensation and bicycle helmets works to some degree for the thrill seeking cyclists. The cyclists who see commuting as an extreme sport.(<<<----for the humorously challenged that's a joke) And the "study" that you say links bicycle helmets and risk compensation- is it the one done by the guy in England that concludes motorists behave differently when passing helmeted cyclists? First off, that study has never been duplicated and secondly, where's the evidence in the change in a bicyclist's behavior?

For the overwhelming number of people who simply just ride their bikes for fun, participating in what I know you consider a relatively safe activity, risk compensation theory makes barely a blip on the radar of the topic of helmet efficacy.