Skip to comments.Caltech Neuroscientists Find Brain Region Responsible for Our Sense of Personal Space
Posted on 08/30/2009 5:54:01 PM PDT by neverdem
Pasadena, Calif.—In a finding that sheds new light on the neural mechanisms involved in social behavior, neuroscientists at the California Institute of Technology (Caltech) have pinpointed the brain structure responsible for our sense of personal space.
The discovery, described in the August 30 issue of the journal Nature Neuroscience, could offer insight into autism and other disorders where social distance is an issue.
The structure, the amygdala—a pair of almond-shaped regions located in the medial temporal lobes—was previously known to process strong negative emotions, such as anger and fear, and is considered the seat of emotion in the brain. However, it had never been linked rigorously to real-life human social interaction.
The scientists, led by Ralph Adolphs, Bren Professor of Psychology and Neuroscience and professor of biology and postdoctoral scholar Daniel P. Kennedy, were able to make this link with the help of a unique patient, a 42-year-old woman known as SM, who has extensive damage to the amygdala on both sides of her brain.
"SM is unique, because she is one of only a handful of individuals in the world with such a clear bilateral lesion of the amygdala, which gives us an opportunity to study the role of the amygdala in humans," says Kennedy, the lead author of the new report.
SM has difficulty recognizing fear in the faces of others, and in judging the trustworthiness of someone, two consequences of amygdala lesions that Adolphs and colleagues published in prior studies.
During his years of studying her, Adolphs also noticed that the very outgoing SM is almost too friendly, to the point of "violating" what others might perceive as their own personal space. "She is extremely friendly, and she wants to approach people more than normal. It's something that immediately becomes apparent as you interact with her,” says Kennedy.
Previous studies of humans never had revealed an association between the amygdala and personal space. From their knowledge of the literature, however, the researchers knew that monkeys with amygdala lesions preferred to stay in closer proximity to other monkeys and humans than did healthy monkeys.
Intrigued by SM's unusual social behavior, Adolphs, Kennedy, and their colleagues devised a simple experiment to quantify and compare her sense of personal space with that of healthy volunteers.
The experiment used what is known as the stop-distance technique. Briefly, the subject (SM or one of 20 other volunteers, representing a cross-section of ages, ethnicities, educations, and genders) stands a predetermined distance from an experimenter, then walks toward the experimenter and stops at the point where they feel most comfortable. The chin-to-chin distance between the subject and the experimenter is determined with a digital laser measurer.
Among the 20 other subjects, the average preferred distance was .64 meters—roughly two feet. SM's preferred distance was just .34 meters, or about one foot. Unlike other subjects, who reported feelings of discomfort when the experimenter went closer than their preferred distance, there was no point at which SM became uncomfortable; even nose-to-nose, she was at ease. Furthermore, her preferred distance didn't change based on who the experimenter was and how well she knew them.
"Respecting someone's space is a critical aspect of human social interaction, and something we do automatically and effortlessly," Kennedy says. "These findings suggest that the amygdala, because it is necessary for the strong feelings of discomfort that help to repel people from one another, plays a central role in this process. They also help to expand our understanding of the role of the amygdala in real-world social interactions."
Adolphs and colleagues then used a functional magnetic resonance imaging (fMRI) scanner to examine the activation of the amygdala in a separate group of healthy subjects who were told when an experimenter was either in close proximity or far away from them. When in the fMRI scanner, subjects could not see, feel, or hear the experimenter; nevertheless, their amygdalae lit up when they believed the experimenter to be close by. No activity was detected when subjects thought the experimenter was on the other side of the room.
"It was just the idea of another person being there, or not, that triggered the amygdala," Kennedy says. The study shows, he says, that "the amygdala is involved in regulating social distance, independent of the specific sensory cues that are typically present when someone is standing close, like sounds, sights, and smells."
The researchers believe that interpersonal distance is not something we consciously think about, although, unlike SM, we become acutely aware when our space is violated. Kennedy recounts his own experience with having his personal space violated during a wedding: "I felt really uncomfortable, and almost fell over a chair while backing up to get some space.
Across cultures, accepted interpersonal distances can vary dramatically, with individuals who live in cultures where space is at a premium (say, China or Japan) seemingly tolerant of much closer distances than individuals in, say, the United States. (Meanwhile, our preferred personal distance can vary depending on our situation, making us far more willing to accept less space in a crowded subway car than we would be at the office.)
One explanation for this variation, Kennedy says, is that cultural preferences and experiences affect the brain over time and how it responds in particular situations. "If you're in a culture where standing close to someone is the norm, you'd learn that was acceptable and your personal space would vary accordingly," he says. "Even then, if you violate the accepted cultural distance, it will make people uncomfortable, and the amygdala will drive that feeling."
The findings may have relevance to studies of autism, a complex neurodevelopmental disorder that affects an individual's ability to interact socially and communicate with others. "We are really interested in looking at personal space in people with autism, especially given findings of amygdala dysfunction in autism. We know that some people with autism do have problems with personal space and have to be taught what it is and why it’s important," Kennedy says.
He also adds a word of caution: "It's clear that amygdala dysfunction cannot account for all the social impairments in autism, but likely contributes to some of them and is definitely something that needs to be studied further."
Other coauthors of the paper, "Personal Space Regulation by the Human Amygdala," are postdoctoral scholar Jan Gläscher and J. Michael Tyszka, the associate director of the Caltech Brain Imaging Center and director of Magnetic Resonance Physics. The work was funded by the National Institute of Mental Health, the Simons Foundation, the Della Martin Foundation, and a global Center of Excellence grant from Japan.
There’s something ironic about poking around in a person’s brain to learn about their sense of personal space...
I agreed, now i hope they will leave me alone.
My sense of personal space is about one planet.
Looks like another case of nature versus nurture, to me.
“Personal space” is largely cultural, and therefore learned, in my experience.
When I first moved to the outer ‘burbs down here, I’d get annoyed in the local stores, because I honestly could not distinguish, between people standing around shooting the breeze, and people who were standing in line for the cash register.
It’s still hard to tell, but I’ve learned if they’re facing the register, they’re probably in line, even though they’re spread out with three feet or more between them. They’ll line up to the back of the store, to maintain this spacing. It’s really sort of odd, but I’ve gotten accustomed.
Shanghai, China people must have a different kind of brain then.
A guy I knew in college was from pre-rev Iran. We about touched noses when he talked. Freaked me out at first. Are their brains different or is it just cultural. He appeared to have NO personal space.
My grandson went to NYC in March, I asked him what the most memorable thing was and he said that it was walking shoulder to shoulder with people you don’t even know.
NYC is great for a few days at a time, but beyond that, I start feeling like throwing elbows myself, lol.
There is a lot more to our “personal space” area than meets the eye.
That is, in some traditional cultures, personal space defines an area within an energetic “shell” that surrounds living organisms. This shell is vital, because it protects our internal energies from the “energy at large” that surrounds the shell. In short, when the shell is ripped open, we are severely traumatized, and unless we can repair it, we die.
Such shells tend to interfere with each other, as two people approach each other, and many people can “feel” them contacting, followed by the mild discomfort of someone in your personal space. The shells can also be deformed, by injury, illness, or incapacity.
There are all sorts of attributions assigned to these shells in different cultures. But unlike the active energy within our bodies, the shells are rather dull containers, imagine a large inflated ball of plastic wrap.
It is my understanding that the tendency toward liberalism has also been located. It is found in the part of the brain known as the rectal lobe.
I’ve been actively researching this for almost 20 years. I’ve done several demonstrations for medical professionals, even in university settings. It freaks them out when I demonstrate this.
Many times, in public forums, I will have volunteers from the audience come down and I will have them close their eyes, I say nothing, and do not touch them in any way. I walk back fifteen feet and by moving my finger slightly (stimulating consciousness fields), and move their physical body to the point it often knocks them off their feet. I then repeat the process and tell them what the event was that happened in their life that has caused their consciousness patterns to develop the way they did(personality formation). They never say a word, not even their names. I have completely bypassed their sensory stimulation and thus their critical thinking. I figured out exactly where memories are stored and how they are processed and retreived. Freaks people out. The personal space stuff is child’s play as it is so easy to do and simple to understand.
I did this at a Harvard Mind Body Institute program a few years ago and the faculty members could not believe what they saw with their own eyes. Same was true at Duke University. Karl Pribram at Stanford University was correct in his theories concerning memories being stored as holograms and I can prove it by reading the stored memories in a subject. It’s not mysticism, it’s science and is easily explained. The amygdala only interacts with one aspect of the consciousness field, the emotional aspect of the stored memory. When I stimulate the memory, a person’s physical body responds as though they have a vestibular disfunction.
Did the same presentation in the Naval Intelligence Building, Arlington VA, for a small group a few years ago. Their response, “The public is not ready for this yet. They want to think that their thoughts are private!”
Autism is a super masculine consciousness that limits the interaction with the emotional aspects of consciousness at the base level. In virtually every person I tested with autism or aspergers syndrome, the change occurred in the third month of pregnancy that created the disconnect in processing. You could say it is the process of intellectualizing emotions at the base level of development.
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How did you learn to do that?
So is BamaKennedy a 'natural-born', Constitutionally qualified CIC?
People from India do not seem to respect anothers personal space. They will invade your space like it’s nothing.