From 2001 to 2005, a team of social scientists studied 32 middle-class families in Los Angeles, a project documenting every wiggle of life at home. The study was generated by the U.C.L.A. Center on the Everyday Lives of Families to understand how people handled what anthropologists call material culture — what we call stuff. These were dual-earner households in a range of ethnic groups, neighborhoods, incomes and occupations, with at least two children between the ages of 7 and 12 — in other words, households smack in the weeds of family life.

What the researchers gleaned was an unflinching view of the American family, with all its stresses and joys on display. They’ve organized their findings into a book, scheduled to be available next week, called “Life at Home in the 21st Century.” It’s full of intriguing data points about the number of possessions the families owned (literally, thousands), much of it children’s toys. Women’s stress-hormone levels spiked when confronted with family clutter; the men’s, not so much. Finally, there was a direct relationship between the amount of magnets on refrigerators and the amount of stuff in a household.

One of the authors, Anthony P. Graesch, 38, an assistant professor of anthropology at Connecticut College, was a newly married, childless graduate student when the study was conducted (his co-authors are Jeanne E. Arnold, Enzo Ragazzini and Elinor Ochs). What Dr. Graesch witnessed as a lead researcher deeply imprinted his behavior as a husband and father, he said, in a recent interview.