Gob Bluth from the TV show ‘Arrested Development.’ Photo: Netflix

We all know a narcissist or two — the often-annoying colleagues, friends, and family members who seem to be constantly talking about themselves and touting their own achievements. In some ways, these characters are a paradox. They seem to be in love with themselves — and when they’re asked in questionnaires, they claim to have very high self-esteem — but their behavior poses an obvious question: If you were genuinely happy with yourself, why would you feel the need to constantly boast and seek admiration from others?

A new study in Social Cognitive and Affective Neuroscience potentially solves the mystery: Narcissists may talk and act confident, but their brains don’t lie. At a neural level, narcissists are needy.

A research team led by David Chester at the University of Kentucky at Lexington recruited 50 undergrad students and had them complete a standard measure of narcissism. Participants who agreed with statements like “I think I am a special person” were allocated high narcissism scores. Next, the researchers invited the students to lie in a special kind of brain scanner that uses diffusion tensor imaging, a technology that measures the amount of connectivity between different brain areas. Such scans produce beautiful “wiring diagrams” of the brain, in contrast to structural MRI scans that show the brain’s gray matter, and functional MRI scans that measure neural activity — this allows researchers to better understand how much “conversation” there is between the brain’s various functional hubs.

Chester and his colleagues were particularly interested in the density of white matter tracts between a region at the front of the brain known as the medial prefrontal cortex (MPFC) that’s associated with thinking about ourselves, and another, deeper region known as the ventral striatum, which is associated with reward and feeling good. In past research, other neuroscientists have established that higher self-esteem is associated with more dialogue and connectivity between these two areas of the brain, along what’s known as the “fronto-striatal tract” in each hemisphere.

Narcissists may say they have high self-esteem, and their boastful behavior could be interpreted as a sign that they do, but the brain scan evidence suggested otherwise. The more highly students scored on narcissism, the less connectivity they had between the MPFC and ventral striatum. Chester and his colleagues described this as evidence of an “internal deficit in self-reward connectivity” among narcissists. In other words, they may struggle to have rewarding thoughts and feelings about themselves, prompting them to seek out affirmation from other quarters as a kind of compensation for their neural deficit.

This may sound like a bit of a conceptual leap ­— from a structural brain scan to assumptions about the intricacies of a person’s inner emotional life — but it fits with “self-regulatory” theories for narcissism that state these people have difficulty shoring up their own self-concept, and with recent behavioral evidence that narcissists may have low implicit self-esteem (that’s the unconscious kind) underneath their cocky exterior.

The new results also jibe with another recent study in which male teenagers suffered the indignity of social rejection during a computer game — they saw two other virtual participants pass a “cyber ball” back and forth, ignoring the study participant. Those participants scoring higher in narcissism didn’t say they felt the sting of rejection any more than the rest, but their brains again told a different story: In this case, the rejected narcissists showed more brain activity associated with social pain.

It can be tricky to feel much sympathy for vain egoists who are always tooting their own horn. But these brain scan results reveal a vulnerability and neediness beneath their bravado, and could even point to ways to helpfully intervene. As Chester and his colleagues explain, “clinical interventions can readily alter white matter integrity,” which means it could be possible, in theory, to devise therapeutic interventions to help narcissistic people feel better about themselves without resorting to their usual “look at me” methods.

Dr. Christian Jarrett is editor of the British Psychological Society’s Research Digest blog. His latest book is Great Myths of the Brain.