Tom Gilovich finds it fun to study the whys and wherefores of how human beings make sense of the information delivered by the world around them. And why not, he explains to interviewer David Edmonds in this Social Science Bites podcast. "We're dynamic, very complicated creatures who do all sorts of things and sometimes make you go, 'Huh?' That's interesting."

He adds, "At the same time, some of the things that people do have great consequences," which means understanding how understandings come about also has great import.

"A lot of the research on judgment and decision making is that there's a schism between the rational choice and the psychologically compelling choice," Gilovich continues, "and that has provided fertile ground for psychologists like me to explore it: "OK, this is what the rational analysis suggests. Why don't we do that?" And there's often some interesting psychological answers to that. Doesn't make logical sense, but it makes lots of psychological sense."

In that spirit, Edmonds and Gilovich, the Irene Blecker Rosenfeld Professor of Psychology in the Department of Psychology at Cornell University, run through what Edmonds calls "the greatest hits" of Gilovich's research findings. These include the "spotlight effect," which posits that individuals often assume others pay more attention to them than they are, and its cousin, "the illusion of transparency," in which people assume others recognize their feelings and emotions accurately. They also look at regret, bias blind spots, and why third-place finishers are happier than second-place ones.

Gilovich is the co-director of the Cornell Center for Behavioral Economics and Decision Research. He's written or co-written several books, ranging from the academic (the textbook Social Psychology written with Dacher Keitner, Serena Chen and Richard Nisbett), titles that bridge academia and the general public (2002's The psychology of intuitive judgment: Heuristic and biases written alongside Dale Griffin and Daniel Kahneman), and books that bring psychological insights directly to the public (such as 1999's Why smart people make big money mistakes—and how to correct them: Lessons from the new science of behavioral economics with Gary Belsky and 2015's The wisest in the room: How you can benefit from social psychology's most powerful insights with Lee Ross).

This Social Science Bites podcast offers a dollop of good news and heaping helping of bad. The good news is that since the end of American Civil War the economic condition of Back Americans has improved, using as a comparison the presumed status quo population of white Americans. According to Princeton University economist Ellora Derenoncourt, this "wealth gap" has fallen from 60-to-one to six-to-one in the intervening 160 years.

While that's heartening, as Derenoncourt details for interviewer David Edmonds, that six-to-one gap hasn't budged since the 1950s. The academic, the founder and faculty director for Princeton's Program for Research on Inequality, breaks down that stall using historical data, parsing out differences between classes and also discussing the difference between income and assets.

"Income," she notes, "has its own growth process, and income between the two groups has been converging over the last 150 years, and savings from income helped Black Americans accumulate some wealth, driving the racial wealth gap down." But as incomes came closer, accumulated assets and the wealth derived from that have only inched closer, driven in part by generational wealth, especially in housing.

"[F]or most Americans, housing is their wealth," she explains. "And we can keep going down the distribution to ask, '"'When is it the case that white Americans at this point in the distribution are mostly renters versus homeowners?'"' That's where we're going to start to see these dynamics of the wealth gap shift.

Derenoncourt closes with some policy ideas that could accelerate closing the gap, including the politically hot topic of slavery reparations.

There is a value to shared knowledge that tends to go unrecognized because it's so ubiquitous. Nonetheless, experimental psychologist Steven Pinker explains in this Social Science Bites podcast, common knowledge underlies things like paper money, governance, and even coral reefs.

And common knowledge, he makes clear to host David Edmonds, "does not have its ordinary sense of conventional wisdom or an open secret or something that everyone knows, but rather something that everyone knows that everyone knows, and everyone knows that, and everyone knows that, and so on, ad infinitum."

Possing that shared knowledge – and the knowledge that others share that knowledge – creates the conditions for coordination, and thus action beyond what an individual could achieve. That's the reason, he says, "that autocrats fear common knowledge of the regime's shortcomings is that no regime has the firepower to intimidate every last citizen."

Pinker, the Johnstone Professor of Psychology at Harvard University, details his understanding of the virtues and vices of common knowledge in his most recent book, When Everyone Knows That Everyone Knows...: Common Knowledge and the Mysteries of Money, Power, and Everyday Life. The book, his 13th, continues his streak as one of the most publicly recognized of public intellectuals, including recognition as one of Foreign Policy's "World's Top 100 Public Intellectuals" and Time's "100 Most Influential People in the World Today." He is also only the second (so far) returning guest to Social Science Bites, having addressed violence and human nature in a 2012 podcast.