Expressly Human

Conventional advice says clear communication should be calm, reasoned, and free of feeling, with emotions treated as noise to be filtered out. Changizi and Barber ask whether this has it backwards. Perhaps the emotional colouring of our speech carries the real message, and the logical wording is mostly packaging.

Over billions of years, animals grew more complex and more aware, and along the way they developed emotions that helped them survive difficult situations. Those feelings began as private states. Eventually, social animals started displaying them, often in striking ways. A display may faithfully reveal what someone feels, or it may conceal it, as when a grin hides fury from a boss. The book asks why creatures that once kept impassive faces became so expressive, and why that expressiveness is what makes us who we are.

Evolutionary neurobiologist Mark Changizi and mathematician Tim Barber argue that emotional expression is humanity's oldest and most important language, one that lets social beings carry out intricate exchanges and bargaining. The book proposes an original theory, built up from basic principles, that explains how the full range of emotional displays evolved, and it offers a guide for decoding human communication.

The authors apply this framework to everyday moments, such as deciding who gets the last slice of pizza, and to high-stakes deals worth millions. Readers may come away seeing every social interaction differently and rethinking what it means to be human.