Review of Charan Ranganath’s Why We Remember: Memory as imagination

A neuroscientist examines how the remembrance of things past shapes our present and future. A review of Charan Ranganath’s ‘Why We Remember’

For Marcel Proust, it was the taste of a madeleine dipped in tea that triggered vivid childhood recollections. For Charan Ranganath, it is the aroma of jackfruit that reminds him of walks on the beach with his grandfather in Chennai. Memories are contingent, and in his book Why We Remember, the California-based neuroscientist examines how the remembrance of things past shapes our present and future.

For most of us, forgetting a recent acquaintance’s name while recalling a long-ago lyric are signs of memory’s imperfections. However, Ranganath argues that such processes enable humans to thrive. “The problem isn’t your memory,” he asserts, “it’s that we have the wrong expectations for what memory is for in the first place”. The pertinent question, then, is not “why do we forget?” but “why do we remember?”

Memory, as he illustrates, transcends a mere recollection of the past; it is a lens through which we perceive ourselves and the world, guiding what we say, think and do.

According to Ranganath, we are designed to forget because we need to prioritise information and efficiently use it when necessary. Our memories can be malleable and sometimes inaccurate because our brains evolved to navigate a changing world, and neurons constantly create and recreate connections to improve perception, movement and thinking. To explore the ramifications, Why We Remember takes us on a whistle-stop and sometimes breezy tour of current findings in neuroscience, simplifying concepts without dumbing them down.

In essence, the brain’s prefrontal cortex and hippocampus play a critical, collaborative role in the formation, consolidation, and retrieval of memories. The former absorbs and processes information while the latter organises and retrieves it. Additionally, the amygdala creates emotional connections that influence the strength of memories. Our context and feelings, then, play a large part in how, why, and what we recall.

Broadly speaking, memories can be classified into two types: semantic, which deals with general information, and episodic, which relates to specific events. In Ranganath’s example, you’re using semantic memory when you recall facts about Paris, such as famous landmarks. When you re-experience a trip to the French capital, including sights, sounds, tastes, and emotions, you’re using episodic memory. Both work together, enabling us to pick up information we can rely upon. An everyday example would be taking the optimal route to work while being flexible enough to adapt to circumstances such as using an alternative road when the usual one is closed.

How do mortals accomplish breath-taking feats of memorisation, be it reciting pi to thousands of digits, narrating epics, or keeping a multitude of chess moves in mind? Ranganath discusses some tactics that make this possible. Among them are chunking, which involves grouping large pieces of information into small, manageable units; and using schemas like the memory palace technique that links information with a familiar environment or narrative.