Three new books reveal how our inner worlds influence our behaviors.

Our unconscious mind is more in control than we might think, argues theoretical physicist Leonard Mlodinow in Subliminal: How Your Unconscious Mind Rules Your Behavior (Pantheon, 2012). Imaging shows that unconscious thought requires substantially more brain activity than conscious reasoning. Our unconscious has evolved to help us act on information quickly. It dictates our choices of friends and forms our biases.

What we eat doesn't just satiate our bellies, it affects our behavior and molds our brains. In The Omnivorous Mind: Our Evolving Relationship with Food (Harvard University Press, 2012), neuroscientist John S. Allen explores why our specific food preferences evolved. For instance, Allen traces our love of crispy foods back to insect-munching primates who lived millions of years ago, suggesting “the appeal of crispy foods is ancient and cognitively deep-seated.”

Getting a poor night's sleep does more than leave you groggy the next morning. Our sleep patterns have a strong influence on our mental and physical health. In Internal Time: Chronotypes, Social Jet Lag, and Why You're So Tired (Harvard University Press, 2012), Till Roenneberg reveals that chronically sleep-deprived people are more likely to smoke, gain weight and become sick. The reason, he explains, is that our largely indoor and sedentary lives confuse our internal clocks. To combat the malaise, he recommends spending more time in the sun by walking to work or eating lunch outdoors.