Sunday, April 04, 2010
Other people's motives--How do we judge?
As soon as I learned to drive, my parents instructed me to 'lock your doors' when driving at night or through 'certain neighborhoods.' When I moved to Cleveland for internship, my uncle advised me to forget locking my doors in those riskier parts of that city but rather DO NOT drive through them under any circumstance, night or day.
With such precautions drummed into me at an impressionable age, I remain ever alert to shady pedestrians at downtown intersections. To my son's dismay, I'll lock the doors if I judge a sketchy passerby likely to open the door and grab my purse or, worse yet, to hop in the passenger seat and abscond with me and/or my car (Oh like that would ever really happen Mo-om!).
Call me paranoid or over-sensitive, but never deny that I have a highly trained right temporoparietal lobe aka the temporoparietal junction (TPJ). Scientists now know that this section of our brain, seated just above the right ear, is vice president in charge of judging other people's motives. Here's how they figured this out.
Patients with brain damage to the TPJ are known to have trouble inferring moral intentions. Social scientist Liane Young and colleagues at MIT decided to test normal subjects with their TPJs intact and turned off. Now who on earth would volunteer for an experiment that involves turning off a section of their brain? Perhaps MIT undergrads feel they have neurons to spare.
Anyway, Young and company used "transcranial magnetic stimulation (TMS), a technology that uses a tightly focused magnetic field to temporarily disable individual regions of the brain." Before and after a magnetic zap to their TPJ, the volunteers read scenarios in which subject A accidentally kills subject B or narrowly misses killing the hapless B on purpose. As opposed to their righteous pre-TMS states of mind, the group post-TMS were much more forgiving of attempted murder.
So what? Well, we know that the TPJ continues to mature through adolescence and beyond, so someday my son will 1) be more forgiving of my heightened sense of other people's malevolent motives, 2) will lock his own darn doors, and 3) will make better choices in general (I hope). In addition, the MIT social scientists are now turning their attention to the TPJs of persons with autism spectrum disorders, conditions in which the ability to 'read' other people is seriously impaired.