By Elizabeth Landau, CNN
June 13, 2013 -- Updated 1756 GMT (0156 HKT)

Philadelphia (CNN) -- Martha Farah is leaning forward, furiously typing on her thin laptop in her spacious office at the University of Pennsylvania. Awards, paintings and posters lean against the walls on the floor as she puts the final touches on a grant proposal.

"I hate it, but I love it!" she exclaims, in a voice that often rises melodically to stress words with enthusiasm. "The adrenaline!"
Farah, 57, built a career that has taken many exciting turns. The scope of her work in the field is impressive: She has studied vision, brain-enhancing drugs and socioeconomic influences on the brain, among other topics. Currently, she is the founding director for Penn's Center for Neuroscience and Society.
"One of the things that really drew me to her was her interest in applying the tools and insights of cognitive neuroscience to socially relevant questions," said Andrea Heberlein, a former postdoctoral fellow in Farah's lab and current lecturer at Boston College. "How can we make the world better, using these tools?"

A revolution in the works
After completing her undergraduate education at Massachusetts Institute of Technology, Farah studied experimental psychology in the 1970s and '80s at Harvard University, where she earned her Ph.D.

The prevailing idea among scientists at the time was that the mind is like computer software and the brain is like the hardware; software would explain "cognitive" phenomena such as memory, problem-solving and information processing.
It wasn't clear in these early days whether the field of cognitive neuroscience -- which looks for the basis for those functions in the brain itself -- was going to be very fruitful or productive, Farah said.

"As a result, I feel like I had a ringside seat for, really, a scientific revolution," Farah said.

Farah herself wrote a landmark book, published in 1990, called "Visual Agnosia," which laid out a comprehensive analysis of how cognitive neuroscience can study visual recognition disorders.

One patient in her work on vision and memory made a big impression on her. Farah visited him in western Ontario. He had suffered a motorcycle accident, resulting in brain damage that left him unable to recognize faces he had encountered after his brain injury but still remembered the faces that were familiar to him from before the accident -- an extremely rare phenomenon.
The face of his own wife, whom he had met after his accident, failed to stick in his mind. He could never recognize her either, Farah said.

Farah tested his impairment by showing him images of a single person who had undergone a dramatic shift in appearance after the man's accident: Michael Jackson.

Sure enough, the man had no idea who Jackson was in a photo after Jackson's transformation, but he easily recognized the singer from an earlier photo. This is distinct from prosopagnosia or "face blindness," a condition which neurologist Oliver Sacks has that results in a lack of recognition of all faces.
With regard to the man in the motorcycle accident, it's unclear exactly where in his brain was the lesion resulting in his unusual condition, Farah said.

"We would hypothesize that it's essentially a disconnection between the parts of the brain that recognize faces that are damaged, like in the Oliver Sacks-type cases, and the parts of the brain that learn," she said.

Socioeconomics and the brain
For much of her career, Farah continued studying vision and memory. That subject is far more controlled and better understood than what she's doing now, which involves looking at the brain's response to circumstances of social class.
She got interested in questions of the brain and social class when she started hiring baby sitters for her daughter, now 17. Among the women she hired to take care of her daughter were single mothers on welfare who were making extra money by baby-sitting. In the scientific literature, they would be called "low SES" -- in other words, low socioeconomic status.
Farah watched over time how the lives of the baby sitters and their children were different from her own.
"I actually became pretty obsessed with social class, this major dimension of variation in the human race and certainly in American society," Farah said.

As sociological studies have corroborated, it seemed to Farah that child-rearing and children's early experience was very different depending on social class.

Poor children don't get as much exposure to language as their wealthier counterparts, research has found, and they tend to get more negative feedback. What they do hear is not as grammatically complex, with a narrower range of vocabulary. There is less understanding of how children develop and what they need for cognitive development, Farah said.
Stress is another huge factor in these disparities.
Parents of low socioeconomic status have uncertainty about having basic needs met, dangerous neighborhoods, crowding and other factors, causing stress for children and their parents. Stressed parents are less patient and affectionate, further stressing their children, according to Farah.
Farah wanted to investigate the huge differences she saw.
"We're so segregated by class, we don't even realize we're segregated because we don't even know what life is like just two miles north of here," she said.

Farah and colleagues have conducted research suggesting that high-stress childhoods, which include less warm parenting, are correlated with changes in stress physiology and stress regulation.

One study, published in March in the journal PLOS One, involved African American adolescents who came from households of low socioeconomic status. At age 4, their parents' responsivity (warmth and supportiveness) was evaluated. Then, 11 to 14 years later, the same participants took a stress test: Giving a talk in front of an unfriendly audience.

Volunteers gave saliva samples so that researchers could analyze it for the stress hormone cortisol. Researchers found that cortisol reactivity was related to parental responsivity, and the less parental responsivity, the less of a normal stress response the volunteers had.

"You might say, 'Well, of course life is more stressful in lower socioeconomic strata,' " she said. "But the degree of magnitude of the stress that they live with is just unbelievable."

Such research points to the idea that stress leads to a stunting of brain development in children of low socioeconomic backgrounds. It is unknown whether that stunting can be reversed, but you shouldn't assume that it's unchangeable, Farah said.

In animal models, researchers have found that later enriching experiences can at least partially compensate for the effects of early life stress on the hippocampus -- a seahorse-shaped structure in the brain vital for memory and stress reactivity -- and other brain areas. It's not that the initial effects of the stress are reversed, though; it appears that different pathways are enabled to compensate.

"If you're interested in child policy and stuff, the important bottom line is: You never want to say, 'Oh, damaged goods, so there's nothing we can do now,' " she said.

Farah is quick to add that middle-class parents aren't perfect either. Eagerly watching children for every small advance in development, and showering children with praise, isn't necessarily helpful either.

"But I am also willing to make a value judgment: Smacking young children, saying a lot of negative things to them, not talking to them very much, is bad." She hits the table. "Let's just say it."

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