Why does touching an item increase the likelihood of purchase? The motivation traces back to what behavioral economists have labeled the "endowment effect." This phenomenon posits that consumers value a product more once they own it. And simply touching that Charmin may increase a shopper's sense of ownership and compel the consumer to buy the product.

"When you touch something, you instantly feel more of a connection to it," says Suzanne Shu, a marketing professor at UCLA's Anderson School of Management and co-author of the study. "That connection stirs up an emotional reaction — 'Yeah, I like the feel of it. This can be mine.' And that emotion can cause you to buy something you never would have bought if you hadn't touched it."

While cash-strapped shoppers might want to start tying their hands behind their backs, retailers should hang signs that say "Feel me."...

...Apple openly invites its customers to fidget with its gadgets, and once you start playing with the iPhone, it's awfully hard to leave the place without one.