Right. I think these are all fair, and I’ve tried to take them into account and be pretty conservative in not underestimating the risk. There are obviously a bunch of balancing forces on the opposite side from those you’ve laid out—eg the tipping point effect balances against the “you never notice” effect, otherwise you’re double-counting. In general, I’m trying to find a coherent picture that takes into account the negatives while not overcounting them—it seems very easy to overcount given that all good things correlate and all bad things correlate, but small affects don’t actually send one into a spiral.
To sanity-check my calculations, let’s consider what it would do to increase the amount of weighting to IQ by a factor of 3. I had estimated a .15-point loss in IQ is .5% of your life-equivalent lost, so tripling this would mean 1.5%. Then losing 1 IQ point would be equivalent to 10% of your life, and every fifth of a standard deviation would be a third of your life-equivalent. This would mean at your margins, exercising like two half-hour amounts in a week would cause your life to get 20% better. I think that stretches the bounds of credulity. Even a factor of 2 increase seems to stretch things, unless you’re very comfortable counting 70% of your life’s value as coming from that small edge of intelligence that differentiates eg a better-than-average grad student from an average grad student (maybe IQ 140 vs IQ 130).
Re “this”, I think I meant productivity but had changed the sentence. I’ll edit to fix.
Right. I think these are all fair, and I’ve tried to take them into account and be pretty conservative in not underestimating the risk. There are obviously a bunch of balancing forces on the opposite side from those you’ve laid out—eg the tipping point effect balances against the “you never notice” effect, otherwise you’re double-counting. In general, I’m trying to find a coherent picture that takes into account the negatives while not overcounting them—it seems very easy to overcount given that all good things correlate and all bad things correlate, but small affects don’t actually send one into a spiral.
To sanity-check my calculations, let’s consider what it would do to increase the amount of weighting to IQ by a factor of 3. I had estimated a .15-point loss in IQ is .5% of your life-equivalent lost, so tripling this would mean 1.5%. Then losing 1 IQ point would be equivalent to 10% of your life, and every fifth of a standard deviation would be a third of your life-equivalent. This would mean at your margins, exercising like two half-hour amounts in a week would cause your life to get 20% better. I think that stretches the bounds of credulity. Even a factor of 2 increase seems to stretch things, unless you’re very comfortable counting 70% of your life’s value as coming from that small edge of intelligence that differentiates eg a better-than-average grad student from an average grad student (maybe IQ 140 vs IQ 130).
Re “this”, I think I meant productivity but had changed the sentence. I’ll edit to fix.