Correct me if I'm wrong, studies have shown that external events cannot affect our happiness. What we're talking about here is about internally derived change though. It's not about the job you choose, rather it's about the fact that you've made a choice. This is different from a random event that happened in which you had no control over, like suddenly winning the lottery. I'm not aware of any studies that addressed happiness relating to self-directed change.
No, you are correct. It's how our choices are made that seems to have the largest influence. The semi-choice is dangerous because it kinds of leaves other choices open, both in the future and in the past.
The problem with self-directed change is that "change" implies "options". It's a total lack of options that works. Yes, we can control this, but "self directed change" for happiness means that Grayscale should literally give everything up, take up his job, burn his bridges and never ever think about the alternatives.
Not many people think that way, and it's tough to say that's what people mean when they say "self directed change". However, people can do other things to help themselves. They can fully invest themselves in what they do. Identify with it. This causes less options to be available.
The only problem here is if this is really under our control. It may be as simple as people who do this are happy, but they need to be pre-programmed to be "happy" (via being programmed to not consider alternatives.)
Most common examples:
* Going through brochures of vacations makes you less happy with the choice of vacation you take. Yet, some people would realise this and do it, then complain that they could of gotten a better vacation if they had shopped around. It's not cut and dry - both statements can be true, if the biological influence is the root cause.
* Meeting with "other potential mates" (exes, etc) makes you less happy with your current mate - maybe. Again, depends on the perspective of "options". On the flip side, being forced into a marriage (ie: arranged) or just getting married removes choice (for most - those that it doesn't aren't as happy... which way does the causation train run?) makes you happier with the marriage. Yet some people will always regret getting married because it cuts off their possibilities. Can someone really just resign themselves and create happiness? Those that resign themselves can, but maybe that is biological too.
So I'm inbetween. I agree, and yet... I don't see much evidence that it is under our control. The mechanisms describe what we do, but the general level of happiness still remains unchanged almost all the time. That is, from the TED presentation, just because we like the one we own more, doesn't mean we are happier with our marriage. Perhaps someone can show that applying the principles everywhere will truly make us happier - affect our brain chemistry sufficiently to make us content with everything we have - but... I have my doubts.