There are two kinds of test. There are the ones which you do to prove how hard and well you've been working, or which they make you do to find out how hard and well you've been working. And there are the kind which you do simply to find out what sort of person you are, or because someone else wants to find out what sort of person you are. I've been reading more of Robert Waterman's book Frontiers of Excellence (already mentioned here before in connection with Theory X and Theory Y) and he refers to all those psychological tests that Career Counselling experts unleash, provided all concerned have a bit of time and money to spend.

The tests give clues to how you prefer to interact with others, and the kinds of people you interact with best. They show whether you have a strong need to lead in some fashion or prefer to let others do so. The tests might suggest that one person performs best in chaos, while another person needs a logical orderly environment. When someone naturally suited to detail and follow-up work is placed in a job that demands developing broad strategies, then you've got a fish crawling across the prairie. That these complex but fairly distinct personality traits influence happiness at work, and most especially job performance, is to me highly obvious.

To me also. Waterman mentions various acronyms like FIRO-B, MBTI, 16PF, SIMA, and so on. I am an amateur career counseller myself, and ask questions designed to tease out, on an informal basis, just such an understanding of what makes my customers tick, or not tick and get miserable. I keep meaning to try to learn more about these tests, or "instruments" as the psychology people apparently prefer to call them. Clearly googling can teach me a lot.

But Question: How soon does it make any sense for a child to take such test? Assuming that a child is eager or at least willing to learn or to allow others to learn about how he functions most happily and effectively, at what age are the broad outlines of a child's personality, in this sort of sense, established?

You can see what kind of personality I am: better at asking good questions than answering them with good answers, and better at "broad strategy" than detail. So, people, help me with the details here?

I don't have any children myself, but the anecdotal evidence I get from all parents I've ever talked with about such things who have more than one child is that children are very distinct in their personalities pretty much from year zero. On the other hand I also hear that children change a lot over the years, especially the early years.

What follows from the answers to such questions is extremely controversial, but what I am interested in here is the simple factual question. Assuming these tests do tell us things about adults, do they also discover truths about younger people? Or don't they work under a certain age? Perhaps they can identify how a person might best set about learning things for the next couple of years, but not what strategies are likely to work for that same person in later life?

One can imagine such truths, if discoverable, to be used to unleash all manner of horrors and premature decisions on children, and in general to fill the world with yet more self-fulfilling prophecies about what this or that child is capable of achieving. Much the same point is made about claims concerning the alleged intellectual differences between different racial groups. Such objections to the pyschological testing of children are not empty. But all that is quite beside the point I'm asking about here, which is simply that I'd like to know the truth about this. Once I've learned the truth, I promise not to jump to any logically imperfect conclusions from it. Anyone?

The two people who spring to mind as likely to have helpful input on this are John Ray and Michael Jennings, the former because he is an academic psychologist, and the latter because if you ask him any question on just about any technical type subject he seems to be able to come back at you with a useful answer within about two hours. Example: portable phones in the London Underground. Seriously, Jennings is a great learning resource, a sort of super-intelligent search engine in humanoid form. I wonder what the psycho-testers would make of him? And I wonder what he was like when he was three?