Matt Polly was 36 and overweight, his days as a student of Chinese kickboxing long past. On the precipice of middle age, he took one last shot at glory. He plunged into the bruising sport of mixed martial arts, trained with the pros and eventually tested his skills in an amateur bout, as detailed in his book Tapped Out: An Odyssey in Mixed Martial Arts. Matt and I had a very entertaining conversation about his experiences and about the world of MMA. Matt explains that contrary to its reputation for primal thuggery, MMA is a highly technical sport and even an art.

Robert Trivers is a widely influential evolutionary thinker whose is theories on the genetic trade-offs of altruism, parent-child relationships and other social interactions are a cornerstone of behavioral ecology and evolutionary psychology. His new book, "The Folly of Fools," applies an evolutionary framework to another set of behaviors: deception and especially self-deception. Subjects discussed in our interview include: self-deception in nature, our capacity to simultaneously know and blind ourselves to the truth, the field formerly known as sociobiology, and Robert's own life and career, including his friendship with the late Black Panther leader Huey Newton.

The last time I spoke to John Flansburgh of They Might Be Giants, it was about the group's science album for kids. This time we talked about the whole TMBG phenomenon: their beginnings and ultimate success, aesthetic aims, being taken seriously while also goofing around, and Sleestaks. TMBG turns 30 this year and is about to launch a national tour with some retrospective elements. So this seemed like a good time to look back on their singular career.

Cosmologist Anthony Aguirre and I continue our jaunt through General Relativity. Last week we presented some of the basics. This week, we talk about the evidence, the impacts and implications, including the cosmological constant, the expanding universe, gravity waves, time dilation, black holes, and spacetime singularities.

It was Einstein's greatest idea, and one of the most audacious leaps of scientific imagination ever. Much of what physicists know or think they know about space, time and the cosmos depends on it. But General Relativity is usually brushed over in pop sci accounts, because GR is considered too GD difficult for ordinary brains. Even on this scientifically-minded program, we've given it pretty cursory treatment. But not this time. I'm devoting two whole shows to the subject with physicist Anthony Aguirre. He's taught relativity and applies it in his own cosmological research, and does a yeomanly job here of making some very alien concepts approachable.

They play, they sing and make lovely, original and uncategorizable music. The four women of the Real Vocal String Quartet combine classical backgrounds with influences from across the musical spectrum: pop, folk, jazz and international… In the first part of the program, RVSQ founder and violinist Irene Sazer and violist Dina Maccabee discuss the ensemble's distinctive sound and special chemistry as we listen to tracks from their recent CD. Then, Irene and Dina are joined by the group's other half, violinist Alisa Rose and cellist Jessica Ivry, to perform some new pieces they're working on.

Linguist Guy Deutscher discusses the restless, ever-shifting nature of human languages. Have languages gotten more complex or simpler over the centuries? Does improper usage threaten the integrity of language? How do grammatical systems arise? How much of our linguistic mastery is innate, and how much is acquired through experience?

Yes, people have been fretting that mechanization would render them redundant ever since the early industrial revolution. And though predictions of deep and persistent "technological unemployment" have failed to come true in the past, MIT researchers Erik Brynjolfsson and Andrew McAfee say this time it's for real. In their new book, Race Against the Machine, they argue that the current "jobless recovery" is in large part due to advances in machine intelligence and other technologies. I spoke to Erik Brynjolfsson about the problem and some possible fixes.

Yes, people have been fretting that mechanization would render them redundant ever since the early industrial revolution. And though predictions of deep and persistent "technological unemployment" have failed to come true in the past, MIT researchers Erik Brynjolfsson and Andrew McAfee say this time it's for real. In their new book, Race Against the Machine, they argue that the current "jobless recovery" is in large part due to advances in machine intelligence and other technologies. I spoke to Erik Brynjolfsson about the problem and some possible fixes.

Hany Farid is an expert on photo fakery and develops tools for detecting whether and how much pictures have been ginned up by, say, advertisers hawking beauty products. He's testified about the veracity of photos in court cases, uncovered audacious forgeries, and helped authenticate some iconic images. We had a fascinating conversation about truth and deception in the age of Photoshop: the ways digital retouching has altered our relation to photography, sowed confusion in the legal system, altered our body images, and sparked a race between the technologies of authentication and tools for photo manipulation.