The Scientific American Book of Love, Sex and the Brain / Who's in Charge? / Connectome

If you’ve ever wondered how your brain does what it does, look no further than this Triple Featured Selection. Judith Horstman compiles insights on how our brains handle desire, Michael Gazzaniga clarifies the links between mind and brain, and Sebastian Seung shows how our individual identities are forged by our neural wiring.

The Scientific American Book of Love, Sex, and the Brain

Can neuroscience explain how, why and who we love? In The Scientific American Book of Love, Sex, and the Brain, Judith Horstman shows the answer is yes. Showcasing insights first appearing in Scientific American and Scientific American Mind, she tours the brain and the forms of love it expresses: parental love, erotic love, and the love of companionship, animals, God, and more.

You will learn, for example, why we crave the companionship of others, and how social isolation is so bad for your brain that solitary confinement could be considered torture. Horstman shows why the loss of a mate sometimes leads to sudden death, and how becoming a parent actually makes Mom and Dad’s brains bigger. How do your genes contribute to your love life, from your sexual orientation to how likely you are to dabble in one-night stands. Why does it only take one-fifth of a second for your brain to decide if someone is physically attractive, but requires months to get over rejection? Why is smell perhaps our most erotic sense, and how does the hormone oxytocin prompt love? Science’s current best answers are discussed here.

The Scientific American Book of Love, Sex, and the Brain offers a cornucopia of insights on the neuroscience of love.

Who’s in Charge?

Apart from love, free will is a thorny topic in neuroscience. Most researchers think physical laws drive brains and consciousness. In contrast, Michael Gazzaniga claims that the mind “constrains” the brain’s operation, much as cars are constrained by traffic they create. As a result, we’re responsible for our actions to an extent dismissed by many in the field.

In Who’s in Charge? Gazzaniga explores his view and its consequences. He acknowledges the classic idea of “free will” is wrong; in fact, our sensation of freedom of choice is generated by a brain module he dubs “the interpreter.” There is no ghost in the machine. But this doesn’t mean that we are wholly programmed to act in specific ways. The fact is, he says, that life’s experiences affect our emergent mental system. How we interact with others is governed as much by high-level choices as what lies “under the hood.” We aren’t robots solely driven by “bottom-up” causality; we absorb external information, and this information modifies what we get from our physical brains in shaping how we should act in a given situation. “My brain made me do it” is an invalid defense when we act badly.

Who’s in Charge? counters the claim that our lives are wholly determined by physical processes we can’t control.

Connectome

One factor that does shape minds is the specific connections between our 100 billion neurons—a network known as the connectome. In Connectome, Sebastian Seung argues that minds differ because connectomes differ, and shares insights on how we can map these connections neuron by neuron. It is a monumental effort—but if successful, it could uncover the basis of personality, identity, intelligence, memory, and perhaps autism and schizophrenia.

Seung first shows how brain researchers historically viewed the brain’s sections as specializing in specific tasks. He then chronicles the rise of connectionism, which views these regions not as units but as networks of neurons, and shows how their organization is shaped by genetics. We explore the techniques that connectome researchers have developed to delve into the complexity of these connections and decode what is written in them, compare them, and see ho