This blog is a place where I will translate interesting findings in biomedical and basic science research from scientific jargon to plain old English. The bottom line: You don't need a PhD to understand science!

Saturday, May 8, 2010

Moral Judgment Mind Control

A man steals candy from a baby. Whether or not the baby cries, most would argue that the man acted immorally. It seems that humans have an innate ability to judge if an act is moral or not, regardless of the act’s outcome or consequences.

How we judge whether actions are moral or not is a subject that some people attribute to human spirituality, while others simply chalk it up to the mysterious inner workings of the human mind. A study recently published in the Proceedings of the National Academy of Sciences by Dr. Liane Young and colleagues from the Massachusetts Institute of Technology may just bring us one step closer to understanding how the brain controls our moral judgments.

When judging the morality of another person’s actions, we usually analyze the person’s intent. For example, if the man who stole candy from the baby did so to protect the baby from a closely swarming bee, his actions might be considered permissible. This conclusion requires our ability to infer the mental state of another person. Dr. Young hypothesized that an area of the brain involved in mental state reasoning, called the right temporoparietal junction (RTPJ), would be required for making moral judgments.

To test this hypothesis, Young’s group disrupted the RTPJ using transcranial magnetic stimulation (TMS), a noninvasive technique that uses focused magnetic fields to disrupt neural activity in a specific area of the brain. Volunteers were then asked to make moral judgments about fictitious scenes.

The experiment included four scenarios. Each scenario consisted of either a neutral act or negative act combined with a neutral outcome or negative outcome. When the volunteers received TMS on a control area of the brain (in other words, the RTPJ was functioning), most of the participants indicated that a negative act was less permissive, whether or not the outcome was neutral or negative. However, when the RTPJ was disrupted, the volunteers indicated that the negative act was more permissible if the outcome was neutral. 

This suggests that with the RTPJ disrupted the volunteers based their judgments on the outcome, rather than the act itself.
In the man and baby scenario, this study implies that a disrupted RTPJ would lead a person to conclude that stealing candy from a baby is permissible as long as the baby doesn’t cry.

The Bottom Line: The right temporoparietal junction of our brains helps correlate intentions and outcomes when making decisions about the permissiveness (morality) of another person’s activities.

So, cultural exposures aside, it’s interesting to think about friends who seem more comfortable with—what some might consider—immoral acts, as long as there isn’t a bad outcome…

Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):6753-8.

Sunday, April 25, 2010

Yet another amazing feat by the human brain

Every day the human brain commits vast amounts of information to memory. No single man-made machine can match the immense storage capacity contained within the brain’s approximate 100-billion neurons. How our most complex organ sifts through a steady stream of sensory input—deciding what is important versus what is trivial—is an area of intense scientific investigation.

In a study recently published in the journal Plos Genetics, scientists report that memory formation is enhanced by attention-demanding tasks. A group from the University of Washington, led by Dr. Jeffrey Y. Lin, presents a set of experiments that test participants’ memory during image recall.

In each experiment, participants are shown a series of urban and rural scenes and asked to correctly indicate if an image has been presented in the set of pictures. A fifty-percent correct answer rate, or that which could be achieved by simple guessing, would indicate little to no memory is formed. In the first experiment, Lin reports that participants are correct fifty-one percent of the time, indicating a lack of memory formation. However, in a subsequent test, Lin’s team pairs the scenery images with a black or white letter and asks participants to remember which letter is white. Surprisingly, even though the participants are not specifically asked to memorize the scenery in the images, the participants are able to correctly recall the scene with the white letter sixty-seven percent of the time, indicating a statistically significant result.

This finding suggests that the act of performing an attention-demanding task causes the brain to enhance the memory of what surrounds the target of focus (i.e. the urban and rural scenes surrounding the letter). Lin’s team finds a similar result when the scenery images are paired with two auditory tones, with participants correctly remembering the image paired with the target tone almost sixty-five percent of the time.

To verify that memory is enhanced by the focused task, and not by the presentation of a novel stimulus, (in this case a newly colored letter), participants are shown the images with letters again, but are told not to take note of the white letter. In this case, no memory enhancement is observed, suggesting that the attention-demanding task itself enhances memory.

The Bottom Line: The brain can automatically perceive and encode visual stimuli in attention-demanding settings, suggesting that our brains are wired to involuntarily remember more about our environment when we are presented with a situation that requires focused attention.

Reference: Lin JY, Pype AD, Murray SO, Boynton GM. (2010). Enhanced Memory for Scenes Presented at Behaviorally Relevant Points in Time. PLoS Biol. Mar 16;8(3):e1000337

Plos Biology is an open-access journal. This research article can be downloaded at: