The Elephant in the Brain: Hidden Motives in Everyday Life

by Kevin Simler

If we return to the backpack analogy, we can see why relevance is so important. If you’re interested primarily in trading, you might ask, “What do you have in your backpack that could be useful to me?” And if your partner produces a tool that you’ve never seen, you’ll be grateful to have it (and you’ll try to return the favor). But anyone can produce a curiosity or two. The real test is whether your ally can consistently produce tools that are both new to you and relevant to the situations you face. “I’m building a birdhouse,” you mention. “Oh, great,” he responds, “here’s a saw for cutting wood,” much to your delight. “But how will I fix the wood together?” you ask. “Don’t worry, I also have wood glue.” Awesome! “But now I need something to hold birdseed,” you say hopefully. Your ally thinks for a minute, rummaging through his backpack, and finally produces the perfect plastic feeding trough. Now you’re seriously impressed. He seems to have all the tools you need, right when you need them. His backpack, you infer, must be chock-full of useful stuff. And while you could—and will—continue to engage him in useful acts of trading, you’re far more eager to team up with him, to get continued access to that truly impressive backpack of his.29 We want allies who have an entire Walmart in their backpacks, not just a handful of trinkets.30