Book Reviewed: Why We Remember: Unlocking Memory's Power to Hold on to What Matters by Charan Ranganath

Biological forces of human memory This is the author’s debut book that reflects on his passion for the neuroscience of human memory. His work is recounted with enthusiasm especially on his interactions with his patients in a clinical setting. Each chapter is a testament to the importance of neurobiological and neuropsychological research that sheds light on how our past shapes our current reality. There are hidden forces of memory behind our perception of the present. There is also a discussion of how memories are integrated with the memory of others. Humans have episodic memory for specific events or experiences, and semantic memory of facts and derived knowledge. Memory is not a unitary process, but it is due to specific regions of brain working together: The hippocampus and surrounding medial temporal lobe structures are primarily responsible for the episodic memory and retrieval. Memory provides us with a storehouse of knowledge and past experiences that we can draw upon to solve problems and navigate new challenges in an ever-changing world. The author also argues that forgetting isn't a failure of memory, but it is a mechanism that allows our brains to prioritize information that helps us navigate and make sense of the world. Thus, making mindful choices in the present to curate a set of memories to move forward into the future. Memory, in its various forms across different organisms, has significant evolutionary implications. The ability to retain and utilize information about past experiences for survival and adaptation in changing environments. In terms of evolution, memory may be a product of natural selection, where organisms that possess memory-related capabilities have a competitive advantage over those that do not. In animals, memory allows for the retention of knowledge about food sources, predators, mating opportunities, social interactions, and communication. This knowledge improves an individual's chances of survival, reproduction, and success of their species. For example, mammals coexisted with dinosaurs for over 150 million years. They evolved from a group of reptiles called therapsids during the Mesozoic Era (225 million years ago): Part of their successful survival is due to the memory capabilities that provided them competitive advantages over dinosaurs. The author could have devoted a separate chapter about the memories in non-human species. Insects with simple nervous systems have demonstrated memory capabilities: Honeybees remember the location of food sources and communicate this information to their hive mates through complex dances. Fruit flies and ants can remember specific routes or locations. Octopuses have advanced nervous systems and complex behaviors. They learn from experience, remember solutions to problems, and recognize individual humans. They have the ability to navigate mazes, solve puzzles, manipulate objects, and use simple tools. They have a single centralized brain located in their head and clusters of neurons known as ganglia distributed throughout their body which perform information processing independently without the participation of brain. The mechanisms of memory formation are an evolutionary process, and it is interesting to relate complex humans’ system with other species. The author is a psychologist who has investigated how individuals acquire, retain, and recall information by examining factors such as attention, perception, and rehearsal strategies. It is rather an insecure feeling for many neurologists and psychologists like him with the emerging field of plant neurobiology that do not have nervous system, but evidence has been presented in peer reviewed journals to demonstrate that plants have a memory. One of the confounding aspects of this book is the title. “Why we remember” rather than “How we remember.” Science can answer the latter, the former is a harder question to answer since that requires the details of evolutionary challenges presented to the species before humans.