How much do we have in common with our children and grandchildren? Less than our parents had in common with us—or at least that’s the theory animating Jean M. Twenge’s new book, Generations. Twenge, a psychologist at San Diego State University, is most widely known for iGen, which chronicled how the rise of the smartphone should be held responsible for a significant decline in mental health among adolescent girls. In Generations, Twenge again examines the surpassing role of technology in the lives of Americans over the past 75 years.

“Contrary to past theories,” she writes, “generations did not become who they are by experiencing major events at impressionable ages. Instead, generations differ because technology has radically changed daily life and culture, both directly and through technology’s daughters, individualism and a slower life.” The advent of social media has produced enormous changes in a few short years. But Twenge argues that the technology behind the birth-control pill, television, the microwave, and other innovations led to unexpected and massive social changes—in sexual behavior, gender roles, family formation, and fertility—that have made younger generations much different from older ones.

Twenge is the rare scholar who seems to play it down the middle. Her book, which contains complete portraits of all six generations living today, is based on 24 data sets that include a total of 39 million people. This nationally representative information allows Twenge to write about the characteristics of each generation in cultural, economic, and political terms that are, for once, justified by the sheer scope of the evidence. And there are some surprises.

Contrary to the popular notion that generational differences in political affiliation are really the result of age—the familiar theory that the older you get, the more conservative you become—Twenge notes that different generations have different political leanings. Age is only one factor.

“Boomers were the first group of 56–74-year-olds to be majority Republican since the survey began in 1952,” she writes. “Thus, Boomers are more Republican than previous generations were at the same age. It’s a stunning evolution for a generation that was very liberal in their youth, and it creates a sizable generation gap between Boomers and the more liberal Millennials and Gen Z’ers.”

There are other startling revelations about the Boomer generation, namely their very low levels of mental health. Twenge describes how the “deaths of despair” we have been hearing so much about lately “are actually a story about Boomers, especially white Boomers.” These included a huge increase in deaths that were the result of drug overdoses: “While young adults were once slightly more likely to overdose than older adults, older adults 55–64 were more likely to overdose starting in 2007, with the gap widening by 2020.”

So what was it about being born between the years 1946 and 1964 (the trends she describes were particularly prevalent among those born between 1955 and 1964) that produced these results? Twenge speculates that higher levels of drug usage when Boomers were younger may have made them more comfortable using depressive drugs when they were older. But she also blames “individualism and technology.” She writes that “individualistic societies can feel disconnected and lonely.… As Janice Joplin sang, ‘Freedom’s just another word for nothing left to lose.’” Twenge’s cleverness in finding cultural references for each generation helps to break up what can be a tedious undertaking.

Also, though Boomers are often blamed for perpetuating income inequality, Twenge argues that “they were its first casualties.” It was not just a widening class divide, but also the fact that the link between happiness and wealth has actually grown stronger. There was not a large gap in happiness between higher-income and lower-income white Americans in the 1970s, but by the 2010s, “five times as many whites in the lowest fifth for income were unhappy compared to those in the top fifth.” Happiness levels for blacks increased as well among the upper classes, while lower-income happiness rates among blacks stayed steady. So the gap increased there as well, but only lower-income whites actually became less happy. “A nation in which one social class is increasingly unhappy while another is content is a nation divided,” writes Twenge.

From an economic perspective, Twenge argues that many people who think they’re not prospering actually are. Gen X’ers ended up with a “higher median household income than Boomers and Silents at the same age in 2004 and 1987 respectively.” While it may have initially seemed as if they were not doing as well on measures like home ownership, it turns out that was merely a factor of the economic cycle. Fewer people of all generations owned homes in the 1990s, but that trend swung back in the other direction. Why would people think they were poorer?

Millennials, to judge from social media, are the most put-upon generation. Indeed, when experts note the falling fertility rate among Millennials, the common response is something like: “No one is getting paid enough, there’s not adequate maternity leave, no one can afford hospital bills, most of us can’t afford a house—like, what did you think would happen?” But Twenge argues that this is simply not true: “The median Millennial household made about $9,000 more than Gen X’ers at the same age, and about $10,000 more than Boomers. So Millennials were actually doing better than their parents’ generation, not worse.” And since they are not having kids at the same rate, they are making more money and supporting fewer people.

Unfortunately, as she points out, “feeling well-off is relative.” She notes that Boomers may have had “unrealistically high expectations” as a result of what they saw on tele-vision as they were growing up. In 2001, David Brooks argued that one of the big differences between Red and Blue America was that the denizens of Red America are not constantly faced with things they could never in a million years afford. Restaurants where they live make it hard to spend more than $25 per person. But a middle-class person in Blue America is regularly confronted with cars and homes and private schools and clothing and food that are not affordable in their wildest dreams.

Social media has made us all residents of Blue America now. Twenge argues that it “showcase[s] those at the very top of the income distribution, giving a skewed view of others’ income. The result is what’s called relative deprivation.”

Generations is a useful corrective to many popular narratives, including some on the right. Despite articles that purport to describe a religious resurgence among the young, Twenge correctly notes that this new explosion of faith does not seem to have materialized. Neither belief in God nor religious attendance has returned to levels seen in the first half of the 20th century. Even when they married and had children, Millennials and those who have followed them are not coming back to religion. “Why is religion less popular with Millennials?” Twenge asks. “In short because it is not compatible with individualism—and individualism is Millennials’ core value above all else.”

Twenge is not a doomsayer, but she is a realist. The trends she describes are sobering. While she is humble enough to know that no one knows what the future holds, it is clear that technology is accelerating some of the most depressing trends in American society—making us less likely to invest in families, friends, and religious communities, and more likely to be sad and alone.