The Close Talker: Damaged Amygdala?

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Maybe Seinfeld’s close talker was brain damaged…

We all have an invisible circle around us. On the subway, at the airport, in a football stadium, at a bar with friends — if someone comes inside this circle, it freaks us the hell out. Why is that? Or, at least, for where does the radius of that invisible circle come?

Quite possibly: the amygdala.

A new case study published in Nature Neuroscience recounts the case of patient, “S.M.,” a woman with damage to her amygdala — a walnut-shaped part of the brain thought to be involved in emotional processing, particularly of fear — who has no sense of personal space.

Here’s BPS Research Digest, describing some experiments a research team has run:

When asked to indicate the interpersonal distance at which she felt most comfortable as a female experimenter walked towards her, S.M. chose a gap of 34cm [about a foot] – smaller than any of twenty control participants, whose average preferred distance was 64cm [about two feet]. Moreover, when asked to rate her comfort (from one, “perfectly comfortable”, to ten, “extremely uncomfortable”) when an experimenter stood in her face, nose-to-nose with direct eye contact, she scored the situation a “one”. It was a similar story when an accomplice of the researchers stood unnaturally close to S.M. in a situation that she couldn’t have known was part of the experiment. By contrast, the accomplice himself told researchers that he found his proximity to S.M. uncomfortable. S.M. does, however, understand the concept of personal space, and is aware that other people prefer more space than she needs.

In another experiment with a small group of non-amygdala-damaged subjects, the same team found that people’s amygdalae showed more activity when someone was standing near the scanner than when they kept their distance. So, what’s the link between the amygdala and personal space? The researchers hypothesize: “The amygdala may be required to trigger the strong emotional reactions normally following personal space violations, thus regulating interpersonal distance in humans.”

Of course, there are exceptions to our personal space rules. For instance, personal space preferences have been found to vary between cultures (the Japanese, for instance, can get much closer) — though, even with different sized circles, we still have circles. Likewise, in certain situations we get used to regular violations of our personal space — you might be uncomfortable the first time you ride a packed subway, but you get used it. Then, of course, there’s the case of loved ones, whom we want close.

The truth is, we habituate to lots of intrusions on our personal space over time. But the basic concept of personal space seems to come from the fact that we simply don’t trust other people automatically. Even people we’ve known for years, most of the time, we’d prefer keep their distance. And when people don’t, it’s either a sign of hostility or a problem with their brains — both signals that make us want to take a step back.

No one wants to talk to a close talker.