Search Results for “fMRI”

 

fMRI: The New Lie Detector?

A new study, conducted by scientists at Stanford University, claims that machinery can be programmed to detect if a person is being truthful or deceptive.

The article, written by Tommy Sander and published on Monday September 13, 2010 in USC’s Neon Tommy news website, is interesting to say the least .

Machines already control or at least regulate much of our lives as it is today.  Are we ready to hand over, to a machine, determinations of the intimacies of the human mind?

Well, researchers in the psychology department at Stanford are trying to unlock the secrets of the mind.  They have begun working on extracting and understanding memories using functional magnetic resonance imaging (fMRI) of the brain.

Dr. Jesse Rissman and his research colleagues tested their theory in a study where participants were assessed on their ability to accurately recall a certain set of faces.  As the participants responded to the faces scientists simultaneously recorded their brain activity with an fMRI.  They used the scans to identify unique brain patterns which are associated with memory.

Basically, scientists are using a very high tech and expensive MRI for deep brain activity induced by memories.  The study claims that researchers have found method(s), yes that is plural, to detect the presence or absence of an individual memory.  That may sound like an impossible feat but with the pace of technological advances in the 21st century many impossible feats are coming to light as incredible innovations are being created. But does that necessarily equate to improvements?

The article claims that the fMRI scan can be helpful in determining the accuracy of legal testimonies in the future.  The article did not state how far into the future we have to wait until this can be perfected scientific evidence of truth telling.  However, in 2009 lawyers attempted to use fMRI data as evidence in a court of law but eventually withdrew their request.  This year a psychologist in Tennessee obtained evidence from another MRI truth verifying organization and submitted it to a court of law, but the judge refused to admit the evidence.  Judges refuse to admit such evidence for obvious reasons, which have been stated by Dr. Rissman himself.

Rissman acknowledges that the convoluted intricacies of the mind qualify all the data as unreliable.  In effect, the brain scans are only as accurate as a person’s memory.  Therefore, essentially all that was measured was a person’s belief that he/she had seen a particular face.  There are also other drawbacks to testing with fMRIs such as the machines ability to determine and account for the difference in explicit memories and implicit memories.

Is the way of the future to assign machines the ability to detect if a person is being truthful or delusive?  If so, how accurate can a machine be against the most powerful tool in the universe…the human mind?

Image from http://psychcentral.com/blog/archives/2010/03/23/a-psychopaths-brain-on-fmri/

Smelling Feelings?

If something smells awful, it’s because it’s disgusting, right? Maybe, but the truth is a little bit more complicated.

A recent study found that our immediate olfactory reactions to stimuli are heavily influenced by the emotional reactions of other people. This suggests that when we smell something bad, we may be picking up on people’s emotions just as much as the scent of the object. Such a conclusion would fit with previous studies which found a strong relationship between our senses and our emotions.

A team of researchers out of the Ruhr-University Bochum in Germany, examined whether exposure to happy and disgusted faces would affect participants’ reactions to various odors. Participants were shown images of either happy, disgusted, or neutral faces before being exposed to various scents.

Perhaps surprisingly, the participants reacted significantly differently depending on which expression they were exposed to. They rated scents more positively after seeing happy faces, while rating them more negatively after seeing disgusted ones. This held over the majority of scents, despite the odors varying drastically from caramel to human sweat. Only when exposed to the smell of feces did emotion fail to have an impact.

When combining these results with fMRI brain scans, the researchers were even able to identify the section of the brain responsible. They highlighted the role of the piriform cortex, in conditioning our response to a scent, even before we actually smell it.

These results may seem shocking. Don’t our senses simply tell us how the world is around us? Our very empirical skills seem challenged if our sense of smell has more to do with expectation than reality!

However, previous research into other senses has repeatedly found that emotions can influence our sensations, whereas sensations can similarly impact our emotions!

One 2011 study found that tired or overburdened participants actually perceived hills as steeper than those who were energetic or unencumbered. Similarly, happy participants considered their food as actually tasting better than sad ones, while fearful individuals ranked noises as louder and cliffs as higher. In each case, the emotions seemed to profoundly shape perceptions.

This relationship between emotions and sensations works the other direction too: many sensations can trigger certain emotions.

For example, our repeated exposures to certain scents can condition us to react in specific ways. This holds when ardent coffee drinkers immediately feel energetic and upbeat when exposed to the smell of coffee. This can happen even before a drop touches their lips.

After we repeatedly experience pleasure and energy from consuming coffee, our brains become accustomed to associating those feelings with the beverage and are then triggered by the smell, taste, or even sight of it! In a similar, though less uplifting fashion, the mere smell of fire can trigger a fear response in many people, even if they are perfectly safe.

For more information on the relationship between emotion and perception, check out our past blogs here and here!

The Problem of Lie Detection

mri-782459_640Somewhat unsurprisingly, the movies have painted a highly inaccurate picture of the power of polygraphs, or so-called lie-detector tests. While many crime dramas showcase a seemingly miraculous technology for distinguishing truths from lies, this portrayal, itself, is far from true.

However, a new study published in the Journal of Clinical Psychiatry suggests that polygraph tests may yet have a role to play, alongside MRI machines and brain scans.

Subjects were asked to write down numbers and then lie to researchers about what they had written down. While being interrogated, each participant was subjected to both an MRI scan and a polygraph test, and the researchers attempted to evaluate when they were being lied to.

While the MRI test proved to be about 24 percent more effective than the polygraph, both tests employed in tandem were able to determine deception in almost every case: a remarkable achievement.

Previous studies on MRI testing found them to be up to 90 percent accurate, while the accuracy of polygraph tests ranged wildly from perfectly accurate to completely unreliable. Even 90 percent accuracy falls short of being reliable enough for criminal proceedings. However, with this study, the doors have opened towards justifying more research into lie detection testing.

As Dr. Daniel Langleben, a study author, said: “While the jury remains out on whether fMRI will ever become a forensic tool, these data certainly justify further investigation of its potential.”

In order to appreciate the significance of this study, it is important to understand the limitations that both MRI machines and polygraph tests face in detecting deception.

MRI machines generate images of the subjects’ brains. These images allow researchers to see any physical abnormalities or changes in blood flow, revealing which parts of the brain are currently active. Some of the earliest studies on MRIs as lie detectors had subjects select playing cards and then lie about which ones they had picked. This helped narrow down which parts of the brain light up when a person is being deceitful.

However, there may be confounding factors, as these MRI images often just reveal when the subject has to think quickly about how best to respond. While this does detect lies, it may also indicate uncertainty, or it could be easily misled by a well-rehearsed story that took no effort to recite.

Based on this uncertainty, every attempt to introduce MRI-based lie detection as evidence in court proceedings has failed. In fact, they often show false signs of deception, which would be a major flaw in court proceedings.

Polygraph tests, on the other hand, work by tracking the subject’s heart rate, blood pressure, respiration, and other physiological responses. Law enforcement personnel ask “control” questions that are only tangentially related to the investigation at hand, as well as “relevant” questions which probe for details on the subject’s involvement in the crime.

If the subject shows a higher heart rate when asked the “relevant” questions, this indicates that they are attempting to conceal their guilt. However, there are significant underlying problems with this approach. In fact, there is little evidence to show that these physiological responses are even unique to the practice of deception.

Between the theoretical flaws and the fact that polygraphs can be outsmarted, it is understandable that they are currently not admissible in court proceedings.

For more information on polygraph tests, read our blog here. Also, check out this post to learn how you can be a better lie-detector.

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