When I was a kid, I liked this poem by Jean Little from her collection, Hey World, Here I Am!:

Our History teacher says, "Be proud you're Canadians."My father says, "You can be proud you're Jewish."My mother says, "Stand up straight, Kate.Be proud you're tall."So I'm proud.But what I want to know is,When did I have the chance to beNorwegian or Buddhist or short?

The poem helped me appreciate that my own characteristics — which felt somehow immutable, even necessary — were highly contingent. Things could have been otherwise.

Now, as an adult and as an experimental psychologist, the poem reminds me that when it comes to our personal narratives about how we came to be the people we are today, we never get a control group. And without a control group, we should be wary of making causal claims — the kinds of claims that so often form the basis for those narratives and for our sense of self.

For instance, was there something about being a woman that led me to pursue a career in cognitive psychology rather than analytic philosophy? Was there something about my upbringing that shaped my current attitudes towards child rearing? I don't know. I don't have a twin in a parallel universe, matched in all respects except these, with whom to compare notes.

It's not that we can't learn about causal relationships in general, when we're studying populations rather than individuals. At the level of populations, we have experimental data when we're lucky, and correlational data when we're not. And it's not that we can't draw inferences about our own case from these data — about which factors, for instance, may have made us more or less likely to pursue particular paths, or to settle on certain beliefs.

The danger arises when it comes to making strong causal claims about the effects of major life experiences in our own case, as individuals. If the control group stems from the imagination — from our imperfect assumptions about that counterfactual twin with whom we're comparing imaginary notes — some extra humility is in order. Most of us can only imagine what it would have been like to be Norwegian or Buddhist or short, and probably not very well.

We may aspire to be scientists about ourselves, and not merely scribes. Unfortunately, the intrinsic limitations of the data we can gather should give us pause. For major life events (the kind that aren't repeatable, the kind that leave their mark), we can't always move beyond the temporal (this happened, and then this) to the causal (this happened, because this). And that — avoiding the pseudoscience of the self — may ultimately require abandoning a common source of personal meaning: the stories we tell ourselves about precisely how we came to be.

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