The concept of “simulation” is a useful theoretical concept for dream research. It unifies definitions and descriptions of the basic nature of dreaming, and helps to formulate testable theories of the function of dreaming. Applying this concept to the social reality of dreams means that we start to describe the persons and social interactions in dreams as simulations of their counterparts in real life. Consequently, we can ask: How does the simulated social reality relate to the actual social reality in the same person’s waking life? Is it plausible to hypothesize that the avatars in the dreaming brain might in fact be there in order to force us to maintain and practise various evolutionarily important functions of social perception and social bonding?
In this paper we made an attempt to clarify what it means to put forward the theoretical statement that “dreaming is a social simulation”, especially when this claim is offered as an expression of a theory of the function of dreaming. The SST can be formulated in a testable manner, and a number of testable predictions can be derived from it. Some of those predictions, concerning basic social perception and mindreading abilities, already receive rather strong support from the published literature. Many more hypotheses remain to be tested. To achieve theoretically-informative results and to directly contrast the predictions of different theories, future studies have to be designed in a strictly theory-driven and hypothesis driven manner—which, unfortunately, is not a common approach in dream research.
If the SST, or some parts of it, prove successful, we have to be able to show that the SST predicts the nature and the occurrence of social simulations in dreams more accurately than its main competitors, the CH and the TST. To fare better than the CH, the data would have to show that the most important social contents are actively selected for incorporation in dreams as social simulations, and therefore rehearsed in an exaggerated quantity or form in dreams. To show that the CH is on the right track, the data would have to show that dream simulations merely reflect, both quantitatively and qualitatively, whatever experiences waking life has recently presented to the same person. To go beyond what the TST predicts and explains, the data supporting the SST would have to show that dreaming over-represents and actively runs positive or neutral social simulations in dreams that strengthen the skills of social perception and bonding, but that have nothing specifically to do with threat-perception and avoidance.
At this point, we are not yet sure how strong the empirical case for SST is going to be, and whether the evidence will mostly turn out to be for or against it. We shall wait for the kind of studies that directly test SST and set it against other theories’ predictions. However, what we are confident about is that SST is an empirically testable theory, and that dream research would in general gain much if dream content studies were rigorously designed to test the predictions derived from opposing theories, and if dream data were in general collected and analysed in a manner that provides us with strong tests of different theoretical hypotheses rather than just producing more and more purely descriptive data of dream content (and then presenting vague, post-hoc theoretical interpretations of them). In that way, dream research would be able to find and test new, promising theoretical ideas, perhaps derived from cognitive and social neuroscience and from evolutionary psychological considerations. New theoretically-guided studies would help leave behind old ideas if they did not generate any clear and testable predictions or if such predictions did not gain sufficient empirical support.
Even if we will at some point be able to explain some of the functions of social simulation in our dreams, we might not be able to explain the underlying mechanisms that generate the simulations. The fundamental metaphysical nature of the simulated persons inhabiting our dreaming brain might after all be almost equally mysterious as the immaterial nature of a Cartesian ghost, because, like everything we experience in our dreams, the avatars in our dreams are built out of features that have no objective, physically observable, or measurable substance. Instead, they consist of subjectively-experienced phenomenal features, and at least at the present state of consciousness science, the only way for us to get any empirically-based data about them is through the introspective reports carefully collected from the dreamers. How the sleeping brain produces vivid, dynamic, complex phenomenality and organizes it into subjective spatiotemporal hallucinations, inhabited by avatars and social simulations, still remains beyond any current theoretical explanations of dreaming and consciousness. Any plausible explanation of the actual brain mechanisms that do the trick would have to solve the hard problem of consciousness (Chalmers 1996) and cross the explanatory gap (Levine 1983) between the objective neural mechanisms in the brain and the subjective experiential realities going on in subjective consciousness. We are not quite there yet.
Acknowledgements
This research was supported by the Academy of Finland, Research program HUMAN MIND, project number 266434.