Jean Twenge

She is also known for her books iGen (2017), Generation Me (2006, updated 2014) and The Narcissism Epidemic (2009, co-authored with W. Keith Campbell). In the September 2017 issue of The Atlantic, Twenge argued that smartphones were the most likely cause behind the sudden increases in mental health issues among teens after 2012. Twenge co-authored a 2017 corpus linguistics analysis that said that George Carlin's "seven dirty words you can't say on television" were used 28 times more frequently in 2008 than in 1950 in the texts at Google Books. Twenge said the increase is due to the dominance of self over social conventions.

In 2017, Twenge wrote an article in The Atlantic asking "Have smartphones destroyed a generation?" which presented findings from her new book iGen. Sarah Rose Cavanagh in Psychology Today disagreed with Twenge's negative view, arguing that Twenge had ignored data supporting positive findings, presented correlation as causation, over-generalized and not taken social contexts into account. Twenge responded to her critics in the same publication, citing a meta-analysis and controlled experiments that showed a negative effect of social media on happiness. She said that her article and book had also highlighted positive trends. She also denied that she was outright opposed to technology: "smartphone or internet use of up to an hour or two a day is not linked with mental health issues or unhappiness... It's two hours a day and beyond that that's the issue."

Writing in The New York Times in 2013, Jeffrey Arnett was critical of her research on narcissism among millennials. He wrote that "I think she is vastly misinterpreting or over-interpreting the data, and I think it’s destructive". His criticisms of her work on narcissism include that she relies on the Narcissistic Personality Inventory (NPI), which he says is inherently flawed at measuring narcissism. Twenge has responded to this criticism by writing that the NPI "...it is employed in 77% of studies of narcissistic traits," and that it "...is also the best self-report predictor of narcissistic traits derived from clinical interviews." She also argues that "Documenting trends in young people’s self-reported traits and attitudes is empirical research, not a complaint or a stereotype."

Jean Marie Twenge (born August 24, 1971) is an American psychologist researching generational differences, including work values, life goals, and speed of development. She is a professor of psychology at San Diego State University, author, consultant, and public speaker. She has examined generational differences in work attitudes, life goals, developmental speed, sexual behavior, and religious commitment.