Lunch at a restaurant with friends reduces cognitive control more than lunch eaten alone at a desk does, according to research published July 31 in the open access journal PLOS ONE by Werner Sommer from the Humboldt University at Berlin, Germany, and colleagues from other institutions.
Participants in the study either ate a solitary meal alone at their desk in a restricted amount of time, or took a short walk to a restaurant for an hour-long lunch with a friend. All meals were identical in the kind and amounts of food consumed. After the meal, people who had a restaurant lunch were calmer and less wakeful than those who ate at their desks. They also fared more poorly on performance tests of cognitive control, and neurophysiological measurements indicated decreased cognitive control of performance and error monitoring processes. Since the meals differed in many ways including the presence of a friend, environment and lack of time restrictions, the authors explain "It is impossible to specify at this point, which of the variables above are crucial for the effects observed in our study."
They add, "Reduced cognitive control is a disadvantage when close self-monitoring of performance and detailed attention to errors is required, such as in numerical processing. In other situations, an attenuation of cognitive control may be advantageous, such as when social harmony or creativity is desired."