›abbreviation for et alia: and others. It is used in formal writing instead of giving a longlist of names of people who have written something together: The method is described in an article by Feynman et al.
According to sociologists (=people who study the relationships between people living in groups), we are good at lying. As a species, we have developed a remarkable ability to deceive each other (= persuade each other that something false is true). Being able to say things that are not true can help with