Why do people talk so much about themselves and Why we 'hear' inner speech in our heads?

Why do people talk so much about themselves?

[Excerpted from:  Scientific American, Mind & Brain, Mind Matters, July 16, 2013]

"The ability to communicate—with almost anyone, about almost anything—has played a central role in our species’ ability to not just survive, but flourish. If you’re like most people, your own thoughts and experiences may be your favorite topic of conversation.  On average, people spend 60 percent of conversations talking about themselves.

Why, in a world full of ideas to discover, develop, and discuss, do people spend the majority of their time talking about themselves? Recent research suggests a simple explanation: because it feels good.

In an initial fMRI experiment, researchers compared neural activation during self-disclosure to activation during other-focused communication. Three neural regions stood out. Self-disclosure resulted in relatively higher levels of activation in areas of the medial prefrontal cortex (MPFC) generally associated with self-related thought. The two 

remaining regions identified by this experiment, however, had never before been associated with thinking about the self: the nucleus accumbens (NAcc) and the ventral tegmental area (VTA), both parts of the mesolimbic dopamine system.

These newly implicated areas of the brain are generally associated with reward, and have been linked to the pleasurable feelings and motivational states associated with stimuli such as sex, cocaine, and good food. Activation of this system when discussing the self suggests that self-disclosure, like other more traditionally recognized stimuli, may be inherently pleasurable—and that people may be motivated to talk about themselves more than other topics.

In a follow up study, answering questions about the self always resulted in greater activation of neural regions associated with motivation and reward (i.e., NAcc, VTA) than answering questions about others, and answering questions publicly always resulted in greater activation of these areas than answering questions privately.  Importantly, these effects were additive; both talking about the self and talking to someone else were associated with reward, and doing both produced greater activation in reward-related neural regions than doing either separately. These results suggest that self-disclosure—revealing personal information to others—produces the highest level of activation in neural regions associated with motivation and reward, but that introspection—thinking or talking about the self, in the absence of an audience—also produces a noticeable surge of neural activity in these regions. Talking about the self is intrinsically rewarding, even if no one is listening.

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Why we 'hear' inner speech in our heads:

[ Excerpted from: Psychological Science, 16 July 2013 ]

Whether you're reading the paper or thinking through your schedule for the day, chances are that you're hearing yourself speak even if you're not saying words out loud. This internal speech — the monologue you "hear" inside your head — is a ubiquitous but largely unexamined phenomenon. A new study looks at a possible brain mechanism that could explain how we hear this inner voice in the absence of actual sound.

In two experiments, researcher Mark Scott of the University of British Columbia found evidence that a brain signal called corollary discharge — a signal that helps us distinguish the sensory experiences we produce ourselves from those produced by external stimuli — plays an important role in our experiences of internal speech.

Corollary discharge is a kind of predictive signal generated by the brain that helps to explain, for example, why other people can tickle us but we can't tickle ourselves. The signal predicts our own movements and effectively cancels out the tickle sensation.

And the same mechanism plays a role in how our auditory system processes speech. When we speak, an internal copy of the sound of our voice is generated in parallel with the external sound we hear.

"We spend a lot of time speaking and that can swamp our auditory system, making it difficult for us to hear other sounds when we are speaking," Scott explains. "By attenuating the impact our own voice has on our hearing — using the 'corollary discharge' prediction — our hearing can remain sensitive to other sounds."