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Professor of Computer Science, MIT; Director, Human Dynamics Lab and the Media Lab Entrepreneurship Program; Author, Social Physics
Computer Scientist, MIT Media Laboratory

Tribal Mind.

What would it be like to be part of a distributed intelligence but still with an individual consciousness? Well for starters, you might expect to see the collective mind 'take over' from time to time, directly guiding the individual minds. In humans, the behavior of angry mobs and frightened crowds seem to qualify as examples of a 'collective mind' in action, with non-linguistic channels of communication usurping the individual capacity for rational behavior.

But as powerful as this sort of group compulsion can be, it is usually regarded as simply a failure of individual rationality, a primitive behavioral safety net for the tribe in times of great stress. Surely this tribal mind doesn't operate in normal day-to-day behavior—or does it? If we imagined that human behavior was in substantial part due to a collective tribal mind, you would expect that non-linguistic social signaling—the type that drives mob behavior—would be predictive of even the most rational and important human interactions. Analogous with the wiggle dance of the honeybee, there ought to be non-linguistic signals that accurately predict important behavioral outcomes.

And that is exactly what I find. Together with my research group I have built a computer system that objectively measures a set of non-linguistic social signals, such as engagement, mirroring, activity, and stress, by looking at 'tone of voice' over one minute time periods. Although people are largely unconscious of this type of behavior, other researchers (Jaffe, Chartrand and Bargh, France, Kagen) have shown that similar measurements are predictive of infant language development, judgments of empathy, depression, and even personality development in children. Working with colleagues, we have found that we can use these measurements of social signaling to automatically predict a wide range of important behavioral outcomes—objective, instrumental, and subjective—with high accuracy, accounting for between 30% and 80% of the total outcome variance.

Examples of objective and instrumental behaviors where we can accurately predict the outcome include salary negotiations, dating decisions, and role in the social network. Examples of subjective predictions include hiring preferences, empathy perceptions, and interest ratings. Even for lengthy interactions, accurate predictions can be made by observing only the initial few minutes of interaction, even though the linguistic content of these 'thin slices' of the behavior seem to have little predictive power.

I find all of this astounding. We are examining some of the most important interactions a human has: finding a mate, getting a job, negotiating a salary, finding your place in your social network. These are activities for which we prepare intellectually and strategically for decades. And yet the largely unconscious social signaling that occurs at the start of the interaction appears to be more predictive than either the contextual facts (is he attractive? is she experienced?) or the linguistic structure (e.g., strategy chosen, arguments employed, etc.).

So what is going on here? One might speculate that the social signaling we are measuring evolved as a method of establishing tribal hierarchy and cohesion, analogous to Dunbar's view that language evolved as grooming behavior. On this view the tribal mind would function as unconscious collective discussion about relationships and resources, risks and rewards, and would interact with the conscious individual minds by filtering ideas by their value relative to the tribe. Our measurements tap into the discussion, and predict outcome by use of social regularities. For instance, in a salary negotiation it is important for the lower-status individual to establish that they are 'team player' by being empathetic, while in a potential dating situation the key variable is the female's level of interest. In our data there seem to be patterns of signaling that reliably lead to these desired states.

One question to ask about this social signaling is whether or not it is an independent channel of communication, e.g., is it causal or do the signals arise from the linguistic structure? We don't have the full answer to that yet, but we do know that similar measurements predict infant language and personality development, that adults can change their signaling by adopting different roles or identities within a conversation, and in our studies the linguistic and factual content seems uncorrelated with the pattern or intensity of social signaling. So even if social signaling turns out to be only an adjunct to normal linguistic structure, it is a very interesting addition: it is a little like having speech annotated with speaker intent!

So here is what I suspect but can not prove: a very large proportion of our behavior is determined by largely unconscious social signaling, which sets the context, risk, and reward structure within which traditional cognitive processes proceed. This conjecture resonates with Pinker's view about brain complexity, and with Kosslyn's thoughts about social prosthetic systems. It is also provides a concrete mechanism for the well-known processes of group polarization ('the risky shift'), groupthink, and the sometimes irrational behaviors of larger groups. In short, it may be useful to starting thinking of humans as having a collective, tribal mind in addition to their personal mind.