Lisa Feldman Barrett’s Seven and a Half Lessons About the Brain is a concise yet thought-provoking book that challenges many common assumptions about how the brain works. Barrett, a neuroscientist and psychologist, presents a series of short essays that dismantle popular myths and provide a more nuanced understanding of human cognition and behaviour.
Each lesson explores a fundamental concept about the brain, from its evolutionary origins to how it constructs reality. In this post, we’ll break down each of the book’s main lessons and what they reveal about how our brains function.
Lesson 1: The Brain Is Not for Thinking
One of the most surprising ideas in Barrett’s book is that the brain’s primary purpose is not thinking, feeling, or perceiving—it is regulating the body. She describes the brain as a kind of “body-budgeting” system, constantly working to manage energy, maintain homeostasis, and predictively adjust bodily functions.
Rather than passively responding to the environment, the brain proactively regulates the body to keep it alive and functioning efficiently. This perspective reframes thinking and emotions as secondary functions that emerge from the brain’s core purpose: running the systems of the body.
Lesson 2: Our Brains Are Not Unique
The human brain is often described as the pinnacle of evolution—larger, more complex, and uniquely powerful compared to other species. However, Barrett challenges this notion, arguing that our brains are not as special as we like to think.
Brains evolved in response to environmental pressures, and many of the features we consider uniquely human—such as complex social structures and communication—can be found in other species as well. What sets humans apart is not the size or complexity of the brain alone but how we use it in the context of culture and learning.
Lesson 3: Your Brain Is a Network
Rather than being divided into separate, specialised regions (as often depicted in neuroscience diagrams), the brain operates as a dynamic, interconnected network. Functions like emotion, decision-making, and perception are not localised to specific “modules” but emerge from interactions across multiple areas of the brain.
For example, the amygdala is commonly described as the “fear center” of the brain, but research shows it is involved in a wide variety of functions beyond fear, including processing novelty and uncertainty. Similarly, the idea that the left hemisphere is logical while the right is creative is an oversimplification. The entire brain works together in a constantly shifting network of activity.
Lesson 4: Little Brains Wire Themselves to the World
Unlike many animals that are born with hardwired instincts, human infants have relatively underdeveloped brains that wire themselves based on experience. This plasticity allows humans to adapt to vastly different environments and cultural contexts, making learning and socialisation central to brain development.
Barrett explains that an infant’s brain is not a “blank slate” but a system that expects input from the world to shape its development. The environment plays a crucial role in determining how the brain organizes itself, including everything from sensory processing to emotional regulation.
Lesson 5: Your Brain Predicts (Almost) Everything You Do
One of the most radical ideas in modern neuroscience is that the brain doesn’t passively react to the world—it predicts it. Barrett argues that perception, decision-making, and even emotions are driven by the brain’s constant predictions about what will happen next.
Instead of simply processing sensory input as it arrives, the brain is always anticipating what it expects to happen, filling in gaps and adjusting when reality doesn’t match its predictions. This explains phenomena like optical illusions, where the brain’s predictions override raw sensory data.
This predictive ability is what allows humans to move, think, and react quickly, but it also means that what we perceive is not an objective representation of reality—it’s our brain’s best guess.
Lesson 6: Your Brain Secretly Works with Other Brains
Humans are inherently social creatures, and our brains are wired to function with others. Barrett explains that human survival depends not just on individual intelligence but on our ability to coordinate and regulate each other’s body budgets.
This idea, known as “interoception,” suggests that humans don’t just manage their own physical and emotional states—we also help regulate the states of others through social interaction. This is why a comforting friend can literally calm our nervous system or why social rejection can feel physically painful.
Lesson 7: Brains Make More Than One Kind of Mind
Barrett argues that there is no single “right” way for a brain to function—brains are shaped by culture, experience, and biology, leading to a wide range of mental and emotional experiences. There is no universal blueprint for intelligence, perception, or emotion.
For example, what is considered “rational” in one culture might be seen as illogical in another. The way people think, feel, and behave is heavily influenced by the society they are part of. This means that our understanding of the mind must be flexible enough to account for these variations.
The Half Lesson: Our Brains Can Be Shaped for the Better
In the final “half lesson,” Barrett reminds us that because our brains are so flexible, we have the power to shape them through our habits, environments, and social interactions.
Understanding how the brain works can help us improve mental and physical well-being, reshape our perceptions, and create environments that support better cognitive and emotional health. Since brains wire themselves based on experience, we can take active steps to shape them in positive ways.
Final Thoughts: Rethinking What We Know About the Brain
Seven and a Half Lessons About the Brain offers a fascinating look at the latest neuroscience research, challenging many of the assumptions we take for granted about thinking, perception, and intelligence. Barrett’s insights reveal that our brains are prediction engines, deeply social, and constantly shaped by experience.
Rather than seeing the brain as a fixed, isolated organ that simply processes information, she encourages us to view it as an adaptive, interconnected system—one that is constantly learning, changing, and being shaped by the world around it.
What was the most surprising insight from these lessons for you? Let’s discuss in the comments!
Comments