A new study of people with early dementia suggestions that one early symptom of the brain disease might be the inability to tell when someone is lying or being sarcastic.
The brain researchers used MRIs to study a variety of people while they were being lied to and found that those who believed the liar (or failed to recognize sarcasm) had deterioration of the frontal lobes.
The frontal lobes are the part of the brain used to detect lies and sarcasm, among other things.
Here's a summary of the study:
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