Lattices of neurons are linked by pathways forged, then continually revised, by experience. So intimate is this feedback that there is no way to separate the brain's neural structure from the influence of the world that surrounds it.
"We think there are branded brains," Asp said.
The Caltech experiment, funded with a $1-million grant from the David and Lucille Packard Foundation, seemed to detect a part of the brain susceptible to such influences.
After analyzing test data from 21 men and women, Quartz and Asp discovered that consumer products triggered distinctive brain patterns that allowed them to classify people in broad psychological categories.
At one extreme were people whose brains responded intensely to "cool" products and celebrities with bursts of activity in Brodmann's area 10 — but reacted not at all to the "uncool" displays.
The scientists dubbed these people "cool fools," likely to be impulsive or compulsive shoppers.
At the other extreme were people whose brains reacted only to the unstylish items, a pattern that fits well with people who tend to be anxious, apprehensive or neurotic, Quartz said.
The reaction in both sets of brains was intense. The brains reflexively sought to fulfill desires or avoid humiliation.
Asp, a Swedish researcher who once studied aspects of industrial design, volunteered for the fMRI probe. The scanner revealed a personality quite at odds with her own sense of self.
She searched the scanner's images for the excited neurons in her prefrontal cortex that would reflect her enthusiasm for Prada and other high-fashion goods. Instead, the scanner detected the agitation in brain areas associated with anxiety and pain, suggesting she found it embarrassing to be seen in something insufficiently stylish.
It was fear, not admiration, that motivated her fashion sense.
"I thought I would be a cool fool," she said. "I was very uncool."
Inside the brain of the 54-year-old male volunteer, the sight of a desirable product triggered an involuntary surge of synapses in the motor cerebellum that ordinarily orchestrate the movement of a hand.
Without his mind being aware of it, his brain had started to reach out.
Deconstructing the anatomy of choice, the researchers are also probing the pliable neural circuits of reasoning and problem-solving — the last of the brain's regions to evolve, the last to mature during childhood, and the most susceptible to outside influences.
They have begun to obtain the first direct glimpses of how marketing can affect the structures of the brain.
Consider something as simple as a choice of soft drink.