No, that wasn't a typo.

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Are you known among your friends and family as the “Grammar Police”? Do you judge others’ Facebook statuses and Instagram captions on grammar, spelling, and clarity? Well, according to a new study, that dedication to proper English might offer some insight into your personality. Researchers from the University of Michigan have found that personality type could be a predictor of how one responds to errors in e-mails: Extroverts are more likely to ignore typos and grammatical errors, while introverts tend to take it personally, judging the writer negatively.

For the study, published on PLOS ONE, researchers asked 83 people whether or not grammar was important to them. They then had the participants read responses from potential roommates answering an ad. The responses either had no errors, or contained grammar and spelling typos (such as mkae for make or the confusion of it’s and its). Participants then shared their judgments on the writer’s intelligence and friendliness, among other attributes. They also shared information about their own personalities. At the end of the study, they were asked whether they noticed the errors, and if yes, how much the errors affected them.

Not surprisingly, those who said grammar was important at the beginning of the study were more likely to have their day ruined by a grammatical error in the e-mails. Those who were specifically annoyed by grammatical errors were found to be less agreeable overall. And those who were annoyed by typing errors were found to be more conscientious and less open.

Need to brush up on your grammar skills? Make fewer mistakes by checking out these six common grammar mistakes even smart people make. Can’t tell your goose from your geese? (Finally!) find out how to make those 11 tricky words plural. Your introverted friends will thank you.