It’s not exactly clear why people with British accents sound smarter to Americans, but several studies show that Americans who have not lived outside of the United States tend to rate British English speakers as having higher intelligence and social status than non-British English speakers. Americans who have lived outside the U.S. for at least three months tend to rate British English speakers as lower in intelligence than either Middle Easterners or people from Latin America. What is clear is that people’s accents play a large role in how others perceive them. In fact, a study from the Friedrich Schiller University at Jena in Germany found that study participants categorized people almost exclusively based on their accent.
More facts about accent:
Imitating a conversation partner’s foreign accent appears to help people understand each other better. A Dutch study found that participants who tried to imitate an unfamiliar accent had a much higher level of understanding and comprehension in conversations than those who did not.
Foreign accents can sometimes make people seem less truthful. This is apparently because accents can make it more difficult for people to understand what others are saying, which is often perceived as untruthfulness.
Even regional accents have a significant effect on how people view others. For instance, people who speak with a Southern U.S. accent might be viewed as intellectually inferior to those from other regions. The region of the U.S. where the local accent is closest to standard American English is southern Iowa, parts of western Illinois and parts of eastern Nebraska