The ability to control our thoughts and behavior is a fundamental human faculty. However, researchers have yet to pinpoint how the soft tissues and electronic currents that make up the brain dictate our thoughts and influence our actions. Indeed, even neuroscientists still resort to metaphysical theories to explain the connection.
"This is a fundamental 'holy grail' problem in neuroscience and psychology," says cognitive neuroscientist Todd Braver, PhD, "We feel that we are in control of our own behavior, but yet when we try to understand how that control emerges out of the neural components of the brain, the physical tissue, we end up reverting to the idea of a homunculus-that there's this little man in the head who's making the key decisions and doing the most important control operations."
Braver, associate professor and co-director of the cognitive control and psychopathology laboratory at Washington University in St. Louis, has devoted his career to banishing the notion of a homunculus in psychological and neuroscience theories. He aims to discover the neural mechanisms behind cognitive control-the ability to form, maintain and realize internal goals. Braver uses a combination of brain imaging, computational modeling and behavioral studies to investigate how people self-regulate their thoughts and behaviors across a range of tasks involving memory, attention and decision-making.
In recognition of his accumulated research accomplishments, as well as his application of his findings to clinical populations such as aging adults or people with schizophrenia or Alzheimer's disease, in August, the American Psychological Foundation (APF) awarded him the $25,000 APF F.J. McGuigan Young Investigator Research Prize. APF gives the biennial prize to a psychologist less than nine years postdoctorate who conducts psychophysiological research.
It's in the blood
Braver credits his interest in psychology in part to his family heritage: His father, Sanford Braver, PhD, is a social psychology professor at Arizona State University; his mother was a clinical psychologist and social worker; and his grandfather was a psychiatrist. Even with such a strong legacy, though, Braver wasn't initially attracted to psychology as an undergraduate.
"I was somewhat resistant to the idea of being in psychology," he says. "I wanted to be in hard science because I naively thought that psychology was too mushy. I thought I wanted to be a physicist."
Braver began school at the University of California, San Diego (UCSD), and after realizing he wasn't cut out to be a physicist, he was drawn to the field of cognitive science by his interest in quantitative precision and the use of physical principles to understand the mind. UCSD was, he says, an institution doing cutting-edge work in cognitive neuroscience, and biologically based computational modeling of cognition.
Braver went on to receive both his MS and PhD degrees in cognitive neuroscience from Carnegie Mellon University, where he also studied at the Center for the Neural Basis of Cognition (CNBC) before beginning his current post at Washington University in St. Louis in 1998.
Braver was attracted to the CNBC, a joint project between the University of Pittsburgh and Carnegie Mellon University, because of its interdisciplinary approach to cognitive neuroscience. The program combines psychology, neuroscience, computer science and mathematics.
"The CNBC was a wonderful place to learn how to link the mind and the brain from many different perspectives," Braver says, noting that this approach influences his work to this day.
Proactive and reactive control
Much of Braver's current research focuses on his new theory of cognitive control strategy, which he calls the dual mechanisms of control (DMC) model. Braver has found that cognitive control is either proactive or reactive. For example, a person can proactively control a plan to stop at the grocery store during a drive home by keeping in mind the goal of getting to the store before approaching a turnoff that leads to it. Keeping the goal actively in mind could make driving behavior more effective by ensuring that the car is in the correct turning lane before the intersection is reached. However, even if the person forgets the grocery store stop, reactive control can still kick in when the intersection is reached if, for example, the left turn light triggers a reminder of the goal.
Both forms of cognitive control have their benefits, says Braver. Proactive control is generally more effective, but also demands more energy and is more vulnerable to interruptions. Reactive control, though, is more susceptible to interference effects, but is also less demanding than proactive control.
People use both proactive or reactive control, adds Braver, but may have a tendency to favor one form or another depending on the specific situation, or through more trait-like biases.
"We've done a number of experiments that show you can manipulate the tendency of one of these mechanisms or another to be used, and they are not only related to properties of the task, but may also be impacted by stable individual differences that people have," says Braver. "We've been looking at cognitive-related individual differences, as well as personality-related individual differences. Both of these factors may have an important influence on the type of control strategies people use in cognitive situations."
In addition to teasing out different control strategies in healthy populations, Braver is also interested in the clinical applications of his findings in populations such as people with schizophrenia or Alzheimer's disease. He runs a joint Washington University lab with his wife, Deanna Barch, PhD, associate psychology professor and assistant psychiatry professor, who studies the neurobiological mechanisms that contribute to language and cognitive deficits in people with schizophrenia, and other clinical populations.
"Through my interactions with Deanna and her group, I continually get informed and influenced by issues that arise in clinical populations, such as schizophrenia. These issues have enormous implications for our understanding of the normal functioning brain and mind," says Braver. "It's important not only to do basic research, but also to apply what we learn in clinical domains. For example, I'm excited by the prospect that we can use the DMC model to do better cognitive training in groups that have well-known problems with cognitive control, such as older adults and patients with schizophrenia."
Braver says his future plans will perpetuate the multidimensional approach to understanding the brain that he learned at UCSD and CNBC: In collaboration with colleagues domestically and internationally, he aims not only to elaborate on his DMC model and his cognitive training research in older adults and people with schizophrenia, but will also focus more closely on decision-making tasks as another way of understanding cognitive control.
"There is so much good work going on outside of America," notes Braver. "One of the things the McGuigan money is allowing me to do is visit other labs more regularly and start to form collaborations with international colleagues."
For more information, visit the APF F.J. McGuigan Young Investigator Prize Web site.