Are you an introvert or an extrovert? Open to new experiences, or comforted by routine? Shy or the life of the party? Figuring out what makes us tick is an important part of understanding how we function within our families, communities, and workplaces. Thousands of tests online promise to assess your personality — but what are they actually measuring? Where does personality come from, how does it form, and where does it live? On this episode, we explore the science behind how we become who we are. We hear stories about what makes for a healthy personality, how our brains betray who we are, and why we change depending on who we’re with.

Also heard on this week’s episode:

• Reporter Jad Sleiman explores how advances in brain imaging are bolstering the science behind personality research — including the famous “Big Five” personality test. Neuroscientists Colin DeYoung and Emily Finn talk test scores and brain mapping.
• Countless self-help books promise to turn us into the kind of people we want to be. But what exactly is a healthy personality — and is it even possible to change? To find out, Alan Yu talks with Kristen Meinzer about what she’s learned from years of living by self-help books, along with psychologists Wiebke Bleidorn, Rodica Damian, and Brent Roberts about what science has to say about personality change.
• Science historian Jonny Bunning discusses how humans have thought about personality across the ages, and how we’ve tried to measure it. We also explore how much of our personality comes from within, and how much is shaped by outside influences.
• Science journalist Olga Khazan from The Atlantic talks about her new book “Weird: The Power of Being an Outsider in an Insider World.”