In a recent interview with Barron’s, Nobel laureate Robert Shiller talks about his new book, Narrative Economics and shared insights on the markets and investor behavior.

Here are some highlights:

Cyclically adjusted price/earnings metric (CAPE): When asked for evidence to support today’s high valuations, Shiller responded that after the financial crisis the market was “tentative”, and that the recovery involved “forgetting the fear.” He added that “the Trump narrative encourages optimism about the stock market, not through rational reflection on corporate taxes, but a sense of where we are in history.”

The dot com bubble: In the early 2000s, according to Shiller, people mistrusted stocks and financial professionals and favored “hard” assets.

On “viral” stories: Shiller said “things go viral because they’re a usable story that people can retell,” citing the example of the Laffer Curve—which presents the amount of tax revenue collected at different tax rates. “The Laffer Curve,” Shiller argued, “is useful to people who advocate tax cuts.”

Robots replacing humans: Shiller admits to having become a “bit more ambivalent” than he was several years ago on the degree to which computers will displace workers. He explains, “I’m basically excited about the computer revolution. I can’t predict all that’s going to come from it.”

On the impetus behind his book, Shiller said that he wanted to “nudge people,” adding, “There’s a tendency in academia to get too compartmentalized, and too focused on extending the literature rather than thinking about inconvenient truths that don’t mesh with the theory—but that’s what we should be doing.”