Before the era of data mining that's now everywhere, University of California, Berkeley scientists in the 1960s began a first-of-its-kind longitudinal study to find out how personalities are formed - by observing and conducting experiments on a group of preschoolers. In her memoir, " Data Baby: My Life in a Psychological Experiment," former test subject and journalist Susannah Breslin goes back in search of that data, hoping it will reveal something about her.