Why we remember Unlocking memory's power to hold on to what matters

Ranganath, a psychology professor at the University of California Davis, debuts with a riveting overview of how memory works. He explains that the prefrontal cortex helps coordinate brain activity and direct attention, influencing what details are remembered or forgotten, and that the hippocampus enables recall by reactivating the neuronal connections that were active at the moment a memory formed. Discussing memory's fallibility, the author describes how in the 1990s psychologist Elizabeth Loftus presented study subjects with a list of memories, three real and one made-up, assembled by a "trusted close relative" and found that, after repeated questioning, the participants began to "remember" and embellish the fake event. A contributing factor to false memories, he suggests, is that information about "what's happening at the time you are trying to reconstruct the experience" gets incorporated into the original memory during recall, so that "every time you recall the event, the memory updates a little bit more." Ranganath has a knack for describing neuroanatomy in accessible terms, and the science consistently surprises, as when he reports on research showing how individuals often have worse recall when working in groups because listening to the recollections of others can crowd out one's own memories, producing a "homogenizing" effect in which information that's not shared is more readily forgotten. Approachable and enlightening, this is worth seeking out. Agent: Rachel Neumann, Idea Architects. (Feb.)

A professor of neuroscience and psychology delivers a wide-ranging study of how memories make us who and what we are. Memory is a quirky thing, writes Ranganath, director of the Dynamic Memory Lab at the University of California, Davis. We can remember song lyrics from 20 years ago, but we can also forget what we ate yesterday. The author has been trying to understand memory for decades, and he admits that a huge amount still remains a puzzle. He explains the mechanisms of memory in the brain and the different types and levels of memory, as well as the evolutionary reasons for it. Many theories have been posed about how memories develop, but the current thinking involves "a phenomenon called error-driven learning," where memory is a constant process of reworking experiences to fit our larger mental picture. Memory failures have been linked to depression, poor sleep, and other ailments. Ranganath explains how fake "memories" can be inserted by repeated suggestion, to the point that people have "remembered" and confessed to crimes they didn't commit. Some memories, especially those of traumatic events, break into our consciousness unbidden. The author suggests that they can be kept under control by persistent and intentional rejection, although it takes effort. He also offers tips on how to not forget routine things (phone, keys) by connecting their image to something else. It's useful advice, but much of the book is devoted to Ranganath's examination of theories of memory and the new generation of testing. Anyone expecting a simple how-to guide on improving their memory may be disappointed. The author's research is undeniably intriguing, but the book will appeal to specialists more than general readers. A well-informed tour of a mysterious and crucial part of the brain, promising greater self-awareness and mental clarity. Copyright (c) Kirkus Reviews, used with permission.