 Penguin Presents. Blueprint. How DNA Makes Us Who We Are. Written and read by Robert Plowman. Prologue. What would you think if you heard about a new fortune-telling device that's touted to predict psychological traits like depression, schizophrenia, and school achievement? What's more, it can tell your fortune from the moment of your birth, it's completely reliable and unbiased and it costs only 100 pounds. This might sound like yet another pop psychology claim about gimmicks that will change your life, but this one is in fact based on the best science of our times. The fortune teller is DNA. The ability to use DNA to understand who we are and predict who we will become has emerged only in the last three years thanks to the rise of personal genomics. We will see how the DNA revolution has made DNA personal by giving us the power to predict our psychological strengths and weaknesses from birth. This is a game-changer that has far-reaching implications for psychology, for society, and for each and every one of us. This DNA fortune teller is the culmination of a century of genetic research, investigating what makes us who we are. When psychology emerged as a science in the early 20th century, it focused on the environmental causes of behavior. Environmentalism, the view that we are what we learn, dominated psychology for decades. From Freud onwards, the family environment or nurture was assumed to be the key factor in determining who we are. In the 1960s, geneticists began to challenge this view. Psychological traits from mental illness to mental abilities clearly run in families, but there was a gradual recognition that family resemblance could be due to nature, or genetics, rather than nurture alone, because children are 50% similar genetically to their parents. Since the 1960s, scientists conducting long-term studies on special relatives, like twins and adoptees, have built a mountain of evidence showing that genetics contributes importantly to psychological differences between us. The genetic contribution is not just statistically significant, it's massive. Genetics is the most important factor shaping who we are. It explains more of the psychological differences between us than everything else put together. For example, the most important environmental factors, such as our families and schools, account for less than Sample complete. Ready to continue?