Sunk cost is a "rule of thumb", or heuristic, that social psychology suggests people all too often use. How does social psychology's research into our thinking help transsexuals? Consider when people say, "It's too late for me to transition."
Do you say things to yourself like, "It's too late for me to transition", "I'm too old", or "If only I could go back to (some earlier point in my life) then I would transition." If you say things like that you might consider the possibility you're making a classic reasoning error called the fallacy of sunk cost.
A fallacy is an illogical way of thinking that's very appealing to almost everybody almost all the time. It doesn't say anything bad about you if you make the error. Most very 'educated' people make it including those who study it! Sunk cost is a concept from decision theory, a branch of psychology combined with a branch of mathematics. It's applied to many fields but most notably economics.
It's very hard to clearly explain this fallacy. So I'm going to quote the first page of Robyn Dawes "Rational Choice in an Uncertain World." It's a phenomenal and easy to read book on decision theory. So, if you're intrigued by this essay, you might want to get it.
Would you rather pay $100 to be where you wanted to be or where you didn't want to be? The answer to this question seems obvious. Now let's rephrase the question.
You and your companion have driven half-way to a resort. Responding to a reduced-rate advertisement, you have made a non-refundable $100 deposit to spend the weekend there. Both you and your companion feel slightly bad physically and out of sorts psuchologically. Your assessment of the situation is that you and your companion would have a much more pleasurable weekend at home. Your companion says it's "too bad" you have reserved the room because you both would much rather spend the time at home, but you can't afford to waste $100. You agree. Further, you both agree that given the way you feel now, it is extraordinarily unlikely you will have a better time at the resort than you would at home. Do you drive on or turn back? If you drive on, you are behaving as if you prefer paying $100 to be where you don't want to be than to be where you want to be.
Look at the problem another way. The moment you paid $100 your net assets decreased by $100. That decrease occured several days before you drive half-way to the resort. Is the fact that your net assets have decreased by $100 sufficient reason for deciding to spend the weekend at a place you don't want to be?
The point is, you reiterate, that if you turn back you will have wasted the $100. ...
If the $100 could be refunded, you would certainly return home; otherwise you must remain a slave to [your purchase]. What does that imply? Once the deposit was made, you had a certain net asset level. Now if you could only get a refund and therby increase your net assests by $100, you would be willing to do what you prefer to do - otherwise not. That's rational?
The $100 you have already paid is technically termed a sunk cost. Rationally, sunk costs should not effect decisions about the future.
I always think about this book when I hear other transsexuals make the "too late for me" argument. It's very easy to fall into the fallacy of sunk cost. Now I'll try to make the issue as explicit as possible:
A 30 year old transsexual who still hasn't transitioned thinks:
This 30 year old transsexual concludes it's not worth transitioning now. I should have transitioned back then, but I didn't. If I transition now, I'm accepting that I've wasted all these years.
Of course, if the person could have those years back (just like if the travellers in Dawes example could have the money back), then the transsexual would transition.
The question, "Should I transition?" has nothing to do with your past. The question is about your future. Would you rather transition now and be happy for your remaining years or would you rather not transition now and remain unhappy for your remaining years.
When you make your decision I hope you'll consider only the present (what you have to loose in the actual present) and the future. It doesn't matter how the past brought you here.