Researchers at Harvard University in the United States studied a group of elderly patients and their responses to the facial expressions of health - care providers.
अमरीका के हार्वर्ड विश्‍वविद्यालय में खोजकर्ताओं ने कुछ बुज़ुर्ग मरीज़ों पर अध्ययन किया ।