Hmmm.....

 

After a two week hiatus, The Gray Area is back with a post describing a study that investigated how the feeling of suspicion is created in our brains. One of my first posts was about researchers have been trying to study how person's brain activity is altered when he/she is telling a lie vs. telling a truth, that is, the neural basis of deception. This current study attempts to describe how brain activity may change when we think someone might be telling a lie, that is, the neural basis for the feeling of suspicion. 

Using the same technique of fMRI, these scientists at Virginia Tech Carilion Research have identified two regions that may be involved in creating the feeling of suspicion- the amygdala and parahippocampal gyrus. The amygdala is involved in processing fear and emotional memories, while the parahippocampal gyrus plays a central role in declarative memory. The task was this: There were 76 pairs of participants, each with a buyer and a seller. Each pair competed in 60 rounds of a bargaining game, while having their brains scanned by the fMRI machine. At the start of each round, the buyer was told the value of a hypothetical widget, and then they were asked to suggest a price to the seller. The seller was then asked to set a selling price; if the seller's price fellow below the stipulated widget, the trade would go through, with the seller receiving the selling price and the buyer receiving any difference between the selling price and the stipulated value. However, if the seller's value exceeded the stipulated price, the trade would not go through, and neither the buyer or seller would receive cash. 

The researchers found that the buyers fell into three categories: 42% were incrementalists, meaning they were actually quite honest about the stipulated value; 37% were conservatives, meaning they tended to withhold information; 21% were strategists, who intentionally deceived the sellers by pretending to be incrementalists (making higher value suggestions when the stipulated value was low, and vice versa). The sellers did have the monetary incentive to correctly predict the stipulated value, but they had no feedback about the buyer's accuracy. The investigators found that the more uncertain the seller was about the buyer's suggested price, the more active his or her amygdala and parahippocampal gyrus became. The activation of the amygdala was not very surprising to the authors, as suspicion is an emotional state. But Read Montague, the lead investigator 

and director of the Human Neuroimaging Laboratory and the Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute, says the activation of the parahippocampal gyrus could be "an inborn lie detector" or a reminder of an untrustworthy person. 

While this study is not a great replication of real life situations in which we may encounter suspicious behaviors or people, it may be important in understanding the neurological basis of increased suspicion and distrust in neuropsychiatric disorders such as anxiety disorders and paranoia.