This Is Your Brain On Parasites: How Tiny Creatures Manipulate Our Behavior and Shape Society

By Kathleen McAuliffe

“Engrossing … [An] expedition through the hidden and sometimes horrifying microbial domain.” —Wall Street Journal

“Fascinating—and full of the kind of factoids you can't wait to share.” —Scientific American
 
Parasites can live only inside another animal and, as Kathleen McAuliffe reveals, these tiny organisms have many evolutionary motives for manipulating the behavior of their hosts. With astonishing precision, parasites can coax rats to approach cats, spiders to transform the patterns of their webs, and fish to draw the attention of birds that then swoop down to feast on them. We humans are hardly immune to their influence. Organisms we pick up from our own pets are strongly suspected of changing our personality traits and contributing to recklessness and impulsivity—even suicide. Germs that cause colds and the flu may alter our behavior even before symptoms become apparent.
 
Parasites influence our species on the cultural level, too. Drawing on a huge body of research, McAuliffe argues that our dread of contamination is an evolved defense against parasites. The horror and revulsion we are programmed to feel when we come in contact with people who appear diseased or dirty helped pave the way for civilization, but may also be the basis for major divisions in societies that persist to this day. This Is Your Brain on Parasites is both a journey into cutting-edge science and a revelatory examination of what it means to be human.
 
“If you’ve ever doubted the power of microbes to shape society and offer us a grander view of life, read on and find yourself duly impressed.” —Heather Havrilesky, Bookforum 

• Language: English
• Publisher: HarperCollins
• Release date: Jun 7, 2016
• ISBN: 9780544193222

Kathleen McAuliffe

KATHLEEN MCAULIFFE is a contributing editor to Discover. Her work has appeared in over a dozen national magazines, including Discover, the New York Times Magazine, Atlantic, and Smithsonian. From 1999 to 2006, she was also a health columnist for More. Her work has been published in Best American Science Writing, and has received several grants and awards, including a science writing fellowship from the Marine Biological Laboratory at Woods Hole. She has appeared numerous times on TV and radio, and was interviewed by To the Point, the nationally syndicated Osgood FIle, and other programs after her 2012 Atlantic feature "How Your Cat Is Making You Crazy" became the second most widely read article in the magazine's history. McAuliffe lives in Miami with her husband—a research physicist—and her two children.

Reviews for This Is Your Brain On Parasites

[steve02476 · Rating: 3 out of 5 stars]

Started out ok, but kind of wandered from the topic (parasites deliberately influencing the hosts behavior) and the last few chapters felt like filler. (In the acknowledgements section she even mentions a few times that she had trouble with her publisher's deadline!) I'd be happy to read a magazine article by her in the future but I'll certainly hesitate to get another of her books.

[sethwilpan · Rating: 4 out of 5 stars]

Among the most momentous revelations in recent years have been those scientific discoveries that undermine the postulation that humans are rational actors. Books like "Thinking Fast and Slow" reveal the we operate from irrational biases that are vestiges of ancestral adaptive behavior. Freakonimcs popularized the quirkiness of the way society operates and acknowledgment of what is called the "second brain" in our guts demonstrates that intelligence is distributed throughout our body. This book brings to light another set of heretofore imperceptible influences on the nature of being human.

I once heard a theory that life was invented by water so that it could move from place to place. It's from that kind of perspective that the author tells the stories of some intricately bizarre ways that parasites have devised to manipulate the behavior of their hosts for the sake of survival. For example, and the first example in the book, is a trematode that invades the brain of an ant causes the ant to cling to a blade of grass so that it can be eaten by a grazing sheep, the gut of which is the only place that the parasite can reproduce.

The narrative wends its way through a series of fascinatingly bizarre examples, ascending from insects to mammals and finally to us humans. Here the scope expands to include not only parasites that directly affect brain processes, but also behavioral adaptations that evolved for the purpose of avoiding infectious diseases. Chief among these adaptations is what has been termed our disgust response, an involuntary impulse to avoid things that are likely to cause disease. The study of this psychological attribute has lain fallow but is starting to gain traction and respectability under the unlikely scientific rubric of disgustology.

The disgust response has far-reaching implications. To take one simple example, our response of disgust at feces causes us, like most other animals, to create separate areas for eating and pooping and to create social pressures to enforce rules to maintain that order, and customs of social order grow eventually lead to ritualistic beliefs, including religion. In fact, the author makes a convincing case that half of the 10 commandments are derived from sanitary laws.

The disgust response influences our attitudes toward other people because many of the cues we take are derived from signals of a person's health. In places where there is a high threat of infectious disease we tend to be more insular. When exposed to influences that arouse disgust we are apt to judge others more harshly. Here is where it starts to intersect with other revelations of the sub rosa biases and suggestibility that we are prone to.

The biological oddities, conveyed skillfully and breezily, are titillating enough, but the real value of the book is its contribution to the evidence that we are not as in control as we once thought we are, so we need to learn how to manage this project of humanity with more humility.

[bness2 · Rating: 4 out of 5 stars]

Fascinating book about the long history of humans and parasites, using many animal examples along the way. We are just beginning to learn the ways that parasites interact with the human brain. Much of the research reviewed in this book is so new that it has yet to have been corroborated by work of multiple researchers, so the conclusions drawn in the book must be taken provisionally. There is no doubt that parasites do affect our brains, the question is by how much.

About the last half of the book looks at the more indirect ways parasites have affected us by focusing on what the author refers to as behavioral immunity, which is the ways we relate to and respond to the world around us that affects the way we behave individually and in groups. Disgust is a the center of behavioral immunity, and it may have shaped human culture and even even human religions. Our human tendencies toward xenophobia and collectivism (and tribalism) may stem from our behavioral immune system. While such theories are somewhat tenuous, they are intriguing to consider.