No one likes feeling left out, and a new study shows that even being ignored by a stranger hurts.
The study, published in the journal Psychological Science, is based on the idea that people need to feel connected to be happy, and that a person can be negatively affected when even a stranger doesn't acknowledge his or her presence, researchers said.
To test this idea, researchers from Purdue University, Ohio University and the Universidad Nacional de Mar del Plata in Argentina conducted a study that involved making eye contact with passers-by.
They had a research assistant walk past random people at Purdue University, and either made eye contact and smiled, or looked in the same direction as the person but not making eye contact ("looking at them as if they were air," study researcher Eric D. Wesselmann, of Purdue, said in a statement).
Then, another study researcher would stop the person who the research assistant had either looked at or ignored, and ask him or her if they felt disconnected from others. Researchers found that when people were ignored by the research assistant, they felt more disconnected compared with people who made eye contact and received the smile.
"What we find so interesting about this is that now we can further speak to the power of human social connection," Wesselmann said in the statement.
However, social connectedness may also have a dark side -- a study published last year in the Journal of Experimental Social Psychology shows that being socially connected could make us less empathetic to others, TIME reported.
"... That experience of social connection draws a circle around you that defines who is in and who is out. It very clearly delineates who is 'us versus them' and when it is 'us versus them,' people outside appear to be less human," study researcher Adam Waytz, of Northwestern University, told TIME.