… the mystery of what ails Limbaugh’s dittoheads and the Tea Party and Fox News listeners and Glenn Beck fans and birthers and the entire alumni body of Liberty University as well as the electorates of Texas, Oklahoma and South Carolina. It turns out that these unfortunates may suffer from frontotemporal dementia, rendering them unable to recognize lies and sarcasm. No cure is in sight, but at least their malady now has a name.
While millions of dollars are being spent on scientific research to find an early detection system for Alzheimer’s disease and other dementias, scientists at the University of California, San Francisco think they have found a simple method. They say senior citizens unable to detect sarcasm and lies are likely victims of dementia.
By asking a group of older adults to analyze videos of other people conversing — some talking truthfully, some insincerely — a group of scientists at the University of California, San Francisco has determined which areas of the brain govern a person’s ability to detect sarcasm and lies.
Some of the adults in the group were healthy, but many of the test subjects had neurodegenerative diseases that cause certain parts of the brain to deteriorate. The UCSF team mapped their brains using magnetic resonance imaging, MRI, which showed associations between the deteriorations of particular parts of the brain and the inability to detect insincere speech…
The ability to detect lies resides in the brain’s frontal lobe. In diseases like frontotemporal dementia, this is one of the areas that progressively degenerates because of the accumulation of damaged proteins known as tau and the death of neurons in those areas.
Because the frontal lobes play a significant role in complex, higher-order human behaviors, losing the ability to detect lies is only one of several ways the disease may manifest. The first signs of the disease may be any number of severe behavioral changes. People sometimes behave in socially inappropriate ways or undergoing fundamental shifts in outlook — switching political affiliations or changing religions, for instance.