I was recently contacted by a startup that is developing a dream-recording app. The startup wants to automatically extract semantic relationships and correlate the narratives that dreamers type into their phones. I assume that the goal is to help the user try to understand their dreams. But why should we assume that dreams are understandable? We now know that waking cognition is unreliable, that meta-cognitive strategies influence decision making, that base rate fallacies are the norm, that perceptions are shaped by apophenia, that framing and language choices dominate decision-making under ambiguity, and that moral judgments are driven by impulse and feeling rather than any rational calculus.

Yet there are some remarkable consistencies about dream content that have led to elaborate theorization down through the ages. Dreams, by being cryptic, want to be explained. But the content of dreams, when sorted out, leads us less to Kerkule’s Rings or to Freud and Jung, and more to asking why there is so much anxiety present in dreams? The Evolutionary Theory of Dreaming by Finnish researcher Revonsuo tries to explain the overrepresentation of threats and fear in dreams by suggesting that the brain is engaged in a process of reliving conflict events as a form of implicit learning. Evidence in support of this theory includes experimental observations that threatening dreams increase in frequency for children who experienced trauma in childhood combined with the cross-cultural persistence of threatening dream content (and likely cross-species as anyone who has watched a cat twitch in deep sleep suspects). To date, however, the question of whether these dream cycles result in learning or improved responses to future conflict remains unanswered.

I turned down consulting for the startup because of time constraints, but the topic of dream anxiety comes back to me every few years when I startle out of one of those recurring dreams where I have not studied for the final exam and am desperately pawing through a sheaf of empty paper trying to find my notes.… Read the rest