Love it or loathe it, it’s that time of year again, folks. As the nights draw in, the dinner-party circuit lurches into life. And this time there’s added peril. It’s no longer enough to rock up with a warm bottle of cava and some half-baked outrage about the egregious state of the local primary schools. You need ideas. Big ones. Fashionable ones. You need to be up on your idea porn.

In recent years, bookshops have become littered with intellectual (and, let’s face it, pseudo-intellectual) flotsam. It’s the biggest publishing trend since the misery memoir, with slim volumes such as Blink and The Wisdom of Crowds gaining a vice-like grip on the bestseller lists. Predictably, some writers have become trendy. Malcolm Gladwell, the New Yorker journalist who draws concert-sized crowds to hear his pithy-yet-weighty dissections of cultural and sociological patterns, and Steven Levitt, a professor at the University of Chicago, who uses economics to explain the everyday quirks of life, are the names to drop if you’re a fashionista more used to banging on about Balenciaga. Both Gladwell and Levitt have new tomes out (What the Dog Saw: And Other Adventures and Super-freakonomics) — and they are just the tip of the iceberg.

Fair enough, you might think. Nice to devote more time to your brain than your shoe closet. But while the penchant for vogueish boffinism used to be confined to the coffee tables of more aspirational middle-class homes, suddenly we’re all being judged on how au fait we are with the grooviest new philosophies. Dinner-party conversation has changed. Gone are the days of droning on about nannies and house prices (it was more fun when they weren’t crashing, wasn’t it?). Luckily, idea porn can be every bit as easy to grasp as the fleshpot variety. Here’s a cheat sheet for the books of the season.

On Rumours: How Falsehoods Spread, Why We Believe Them, What Can be Done by Cass Sunstein (Allen Lane £16.99)

Sunstein, a Harvard law professor, has an even more impressive side career as director of the US Office of Information and Regulatory Affairs. He is Obama’s man with the quill (or MacBook), sifting through draft regulations to eradicate injustice. His beef in On Rumours is that a toxic cycle of half-truths gnaws at the foundations of society. He examines how rumours spread — such as whether Sarah Palin really did think Africa was a country (if enough people repeat it, the rest of us soon take it as read) — and is concerned that the problem will worsen in the age of the internet.

Do say “When you think about it, your average political lobbyist and a gossipmonger like Perez Hilton are totally part of the same malaise.”

Don’t say “Is it true Gordon Brown is a bit, you know...”

Catching Fire: How Cooking Made Us Human by Richard Wrangham (Profile £15)

Claptrap, says Wrangham, of the received wisdom that humans should really be nut-munching raw-food eaters. Fire, not hunting, he argues, was the key to our evolution. With unimpressive teeth and tiny mouths (“Mick Jagger’s biggest yawn is nothing compared with a chimpanzee’s”), cooking our food allowed us to wean our young quicker and spend less time chewing (chimpanzees chew for six hours a day), so we could get on with the important business of society building.

Do say “Cooking food may have freed up time for men. But they weren’t the ones doing the cooking.”

Don’t say “Crudités, anyone?”

Wikinomics by Don Tapscott and Anthony Williams (Atlantic £8.99)

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