Eat poorly, and your body will remember—and possibly pass the consequences onto your kids. In the past several years, mounting evidence has shown that sperm can take note of a father’s lifestyle decisions, and transfer this baggage to offspring. Today, in two complementary studies, scientists tell us how.
The notion of the “biological individual” is crucial to studies of genetics, immunology, evolution,development, anatomy, and physiology. Each of these biological subdisciplines has a specific conception of individuality, which has historically provided conceptual contexts for integrating newly acquired data. During the past decade, nucleic acid analysis, especially genomic sequencing and high-throughput RNA techniques, has challenged each of these disciplinary definitions by finding significant interactions of animals and plants with symbiotic microorganisms that disrupt the boundaries that heretofore had characterized the biological individual. Animals cannot be considered individuals by anatomical or physiological criteria because a diversity of symbionts are both present and functional in completing metabolic pathways and serving other physiological functions. Similarly, these new studies have shown that animal development is incomplete without symbionts. Symbionts also constitute a second mode of genetic inheritance, providing selectable genetic variation for natural selection. The immune system also develops, in part, in dialogue with symbionts and thereby functions as a mechanism for integrating microbes into the animal-cell community. Recognizing the “holobiont”—the multicellular eukaryote plus its colonies of persistent symbionts—as a critically important unit of anatomy, development, physiology, immunology, and evolution opens up new investigative avenues and conceptually challenges the ways in which the biological subdisciplines have heretofore characterized living entities.
From the celebrated neurobiologist and primatologist, a landmark, genre-defining examination of human behavior, both good and bad, and an answer to the question: Why do we do the things we do?
Sapolsky’s storytelling concept is delightful but it also has a powerful intrinsic logic: he starts by looking at the factors that bear on a person’s reaction in the precise moment a behavior occurs, and then hops back in time from there, in stages, ultimately ending up at the deep history of our species and its evolutionary legacy.
And so the first category of explanation is the neurobiological one. A behavior occurs–whether an example of humans at our best, worst, or somewhere in between. What went on in a person’s brain a second before the behavior happened? Then Sapolsky pulls out to a slightly larger field of vision, a little earlier in time: What sight, sound, or smell caused the nervous system to produce that behavior? And then, what hormones acted hours to days earlier to change how responsive that individual is to the stimuli that triggered the nervous system? By now he has increased our field of vision so that we are thinking about neurobiology and the sensory world of our environment and endocrinology in trying to explain what happened.
Sapolsky keeps going: How was that behavior influenced by structural changes in the nervous system over the preceding months, by that person’s adolescence, childhood, fetal life, and then back to his or her genetic makeup? Finally, he expands the view to encompass factors larger than one individual. How did culture shape that individual’s group, what ecological factors millennia old formed that culture? And on and on, back to evolutionary factors millions of years old.
The result is one of the most dazzling tours d’horizon of the science of human behavior ever attempted, a majestic synthesis that harvests cutting-edge research across a range of disciplines to provide a subtle and nuanced perspective on why we ultimately do the things we do…for good and for ill. Sapolsky builds on this understanding to wrestle with some of our deepest and thorniest questions relating to tribalism and xenophobia, hierarchy and competition, morality and free will, and war and peace. Wise, humane, often very funny, Behave is a towering achievement, powerfully humanizing, and downright heroic in its own right.
How can humans be so compassionate and altruistic — and also so brutal and violent? To understand why we do what we do, neuroscientist Robert Sapolsky looks at extreme context, examining actions on timescales from seconds to millions of years before they occurred. In this fascinating talk, he shares his cutting edge research into the biology that drives our worst and best behaviors.