August 2, 2010
Here’s the third section of the Chapter 2 draft of my book, Finding the Li: Towards a Democracy of Consciousness. This section discusses theory of mind as a crucial part of what makes us human. It quotes Michael Tomasello on the cognitive differences between humans and chimpanzees, contrasts theory of mind with empathy, and locates it in the medial prefrontal cortex. All constructive comments from readers of my blog are greatly appreciated.
Theory of mind.
In 1978, primate researchers Premack and Woodruff published what was to become a seminal paper entitled “Does the chimpanzee have a theory of mind?”. This was the first time that the phrase “theory of mind” had been used in the scientific literature, which they described as an ability to represent and infer the mental states of others. It “may properly be viewed as a theory,” they stated, “because such states are not directly observable, and the system can be used to make predictions about the behaviors of others.”
More recently, Tomasello has conducted extensive research into how theory of mind differentiates us from other primates. He gives a list of social actions that we take for granted but which nonhuman primates simply don’t do:
In their natural habitats, nonhuman primates:
- Do not point or gesture to outside objects for others;
- Do not hold objects up to show them to others;
- Do not try to bring others to locations so that they can observe things there;
- Do not actively offer objects to other individuals by holding them out;
- Do not intentionally teach other individuals new behaviors.
He believes that they don’t do these things because they “do not understand others as intentional agents in the process of pursuing goals or mental agents in the process of thinking about the world.” In his view, the biological makeup of chimpanzees’ and humans’ brains would be very similar except for the one major difference that we humans “identify” with others of our species “more deeply than do other primates.” It’s from this “one uniquely human, biologically inherited, cognitive capacity,” he believes, that all the other uniquely human traits emerged.
It’s important to understand that, although they’re similar, theory of mind is not the same thing as empathy. As neuroscientist Tania Singer points out, empathy is all about sharing the feelings and emotions of another person. Imagine you’re a volunteer helping out in a foreign country that’s just suffered a natural disaster. You might be sitting with a woman who’s just lost her children, putting your arm around her while she’s sobbing in grief. Perhaps she speaks no English, and you know nothing about her life other than her grief. You would probably feel intense empathy for her, even if you had no idea what thoughts, intentions or beliefs are going through her mind. On the other hand, you can apply your theory of mind on people for whom you have no empathic feelings whatsoever, such as a rival you’re competing against in your profession.
One reason this distinction is important is that empathy and theory of mind are believed to arise from different neural pathways in the brain. Singer, who has reviewed multiple brain imaging studies on the subject, explains that empathy activates the same emotional circuits in our brains and bodies that come alive when we have our own feelings. Here, we can see how those mirror neurons are most likely springing into gear, mirroring not just the actions but the feelings of those we care about. On the other hand, theory of mind activates a different set of brain areas, most notably the pfc.
In fact, it’s a specific area within the pfc called the medial prefrontal cortex that gets activated when we exercise our theory of mind. This is especially interesting because it’s exactly the same part of the pfc that gets activated when we exercise our self-awareness and think about ourselves. In the words of one study, “data indicate that the ability to reflect on one’s own mental states, as well as those of others, might be the result of evolutionary changes in the prefrontal cortex.” In another study, subjects were asked to think about themselves in a wide variety of different states, including pain, tickling, actions and looking at pictures. In all this variety, the one part of the brain that was consistently activated whenever the subjects were thinking about themselves was the medial prefrontal cortex.
The fact that the medial prefrontal cortex is activated when thinking both about yourself and others suggests a fundamental linkage between the evolution of theory of mind and that other uniquely human trait, self-awareness. This linkage can be seen, not just in the actions of our pfc, but also in the developing mind of an infant. A child doesn’t develop a fully fledged theory of mind until she’s reached around 3-5 years of age. But even in the first few months of an infant’s life, Tomasello describes how, in their attempts to understand other people around them, infants “apply what they already experience of themselves,” making the judgment that “others are ‘like me’ and so they should work like me as well.” Tomasello then traces what he calls a “social-cognitive revolution” that occurs in infants at around nine months. Around that age, an infant begins to follow someone else’s gaze and direct other people’s attention to something she cares about. At some point, the infant realizes that the other person’s attention is directed at her! “She now knows she is interacting with an intentional agent who perceives her and intends things toward her.” Before too long, the infant realizes that her actions affect other people’s emotional states. “This new understanding of how others feel about me opens up the possibility for the development of shyness, self-consciousness, and a sense of self-esteem.” The infant has begun to participate in the social universe. Tomasello notes as evidence of this that, around the first birthday, an infant begins to show the “first signs of shyness and coyness in front of other persons and mirrors.”
The key point in this infant’s drama is that it takes an understanding of other people as intentional agents to begin to arrive at an awareness of yourself. And it takes both of these steps together to develop a sense of yourself as a social agent, someone interacting in society. It’s when the hominid brain began to use its theory of mind and self-awareness for social purposes that the evolution towards modern homo sapiens really got going. In fact, over the past thirty years, a powerful theory called the Social Brain Hypothesis has gained increasing acceptance as an explanation for the full development of our unique human cognition.
 Premack, D., & Woodruff, G. (1978). “Does the chimpanzee have a theory of mind?” Behavioral and Brain Sciences, 4, 515–526.
 Cited in Povinelli, D. J., and Preuss, T. M. (1995). “Theory of mind: evolutionary history of a cognitive specialization.” Trends in Neurosciences, 18(9:November 9, 1995), 418-424.
 Tomasello, M. (2000). The Cultural Origins of Human Cognition, Cambridge, Mass.: Harvard University Press, 21.
 Singer, T. (2006). “The neuronal basis and ontogeny of empathy and mind reading: Review of literature and implications for future research.” Neuroscience and Biobehavioral Reviews(30 (2006)), 855-863.
 Povinelli and Preuss, op. cit.
 Frith, C. D., and Frith, U. (1999). “Interacting Minds – A Biological Basis.” Science, 286, 1692-1695.
 Tomasello, op. cit., 89-90.