The researchers, led by Dr. Eric Krause in the department of psychiatry and behavioral neuroscience, gave rats sodium chloride to dehydrate them. It turns out that the same hormones that help the kidneys respond to dehydration also regulate the brain's response to stress and social anxiety.
When compared to a control group, the rats that received the sodium chloride secreted fewer stress hormones when presented with a stressor and were more interactive and less socially anxious when placed in pairs. Their blood pressure and heart rate also showed less of a spike and more quickly returned to normal levels.
According to Dr. Krause, the team is calling this the "Watering Hole Effect." He explains, "When you're thirsty, you have to overcome some amount of fear and anxiety to approach a communal water source. And you want to facilitate those interactions—that way everyone can get to the water source."
This research has implications both for social anxiety disorder and autism, whose suffers have problems with social impairment.