Seven deadly sins The biology of being human

Humanity's "less savoury tendencies" drive "our survival and success," according to this stimulating treatise from neurologist Leschziner (The Nocturnal Brain). Unpacking this theory through the lens of Dante's seven deadly sins, the author considers how "gluttony" and its "visible signature," obesity, aided human survival by providing extra energy stores in times of famine; how pride "mak us feel that our achievements are under our own control, hence pushing us to persevere"; and how wrath can serve as a valuable "motivator, a drive to continue striving to reach one's objective." According to Leschziner, such personality traits are rooted in a complex constellation of genetic and environmental factors generally outside of one's control. His argument raises complicated questions about free will that he explores in a thought-provoking discussion of whether traditional binaries of good and evil should be used to evaluate moral decision-making if one's choices stem from immutable biological drives (though he stops short of embracing a fully deterministic view). Vivid patient anecdotes appear throughout, including the story of a woman with a syndrome that causes uncontrollable hunger, which Leschziner utilizes to illustrate the complex factors that underlie appetite, making weight loss "rarely so simple" as deciding to eat less and move more. Replete with fascinating forays into neurology, morality, and pathology, this is a captivating glimpse at the mysteries of the mind. (Dec.)

Neurologist Leschziner's (The Man Who Tasted Words) latest work is a fascinating look at how neuroscience can unlock and offer insight into why people act the way they do. He uses the seven deadly sins--gluttony, greed, sloth, pride, envy, lust, and anger--as chapter topics and routes into explaining behavior patterns. Leschziner looks at myriad research fields ranging from epigenetics, which is the contention that generational trauma can be passed down and inherited, to the nature vs. nurture debate as a determiner of human behavior. He argues that the seven sins exist in humankind for evolutionary reasons. They have aided and led humans to become the planet's prime species, but many of these predispositions are no longer useful. One example: members of hunter-gatherer societies once needed to store fat within their bodies for times of caloric shortages. Now that's no longer required due to the abundance of food available to most humans it's led to an alarming rise in obesity rates. Leschziner comes to some striking conclusions, such as that man is ruled by his emotions, which sometimes manifest too strongly and pose a threat. VERDICT A worthy contribution about neuroscience and its importance for understanding human behavior.--Brian Renvall