The revelation that Facebook was attempting to manipulate the emotions of some users by altering the status updates that appear in their newsfeeds triggered a wave of anger from users and researchers alike.

But the world’s largest social network is hardly the only company to study its customers. Every business selling a major consumer product — snacks, cars, newspapers, smartphones, and, yes, social networks — tests changes or new features on some customers before releasing them to the masses.

What separates acceptable tests from those that shake the entire Internet?

Steve Wendel, the principal scientist at District-based software company HelloWallet, penned a book last November called “Designing for Behavior Change,” which outlines standards for corporations to conduct ethical behavior testing.

HelloWallet, which was bought by Morningstar in May, regularly conducts experiments on its customers with the goal of helping them to save money and pay off debt. And each test must meet a certain threshold.

Steve Wendel is the principal scientist at District-based HelloWallet. (Photo courtesy of HelloWallet)

Wendel cautions that the use of behavioral psychology in product testing, particularly technology products, is a relatively new field. As a result, mistakes are bound to happen and the dialogue that the Facebook backlash has prompted is ultimately beneficial.

“In the end there are some things that are OK and good for the user, and some things that clearly aren’t,” Wendel said. “We need room to discuss as a community what falls into each category.”

The user should know what you’re doing. This may sound obvious in the wake of the Facebook study, but the right degree of disclosure is often difficult for researchers. Give the user too much information, for example, and it can skew the authenticity of the results. HelloWallet makes it clear to customers that its trying to improve their spending habits, then tests new features based on that premise. “What Facebook did was different,” Wendel said. “I don’t think that was about improving your product.”

Don’t hide behind your terms and conditions. The reality is that many, if not most, users won’t read a lengthy document full of legalese before using a product. Thus, it’s wrong for a company to only disclose its testing there, Wendel said. “You need to make sure what you’re doing is ethical, regardless of what your terms and conditions are,” he said.

Put yourself in the customer’s position. It’s a simple role play scenario: Would you want to be studied in that manner? It’s a question a company should ask its employees before proceeding with a study. “Your own product team is going to be a certain selected population, but if it doesn’t get passed your own folks, then that’s a problem,” Wendel said.

Then, ask an outsider. At dispute in the Facebook incident, for instance, is whether the company or its academic partners fully vetted the study with peers. At HelloWallet, all product testing has to be cleared by an independent chief privacy officer, who ensures the test meets the company’s ethical, legal and security guidelines. If the test is conducted in concert with academics, it must clear an external institutional review board.

Don’t harm the user. One of the heaviest criticisms of the Facebook study was that toying with customers’ emotions can be dangerous, especially if someone already suffers from depression or another disorder. But Wendel says the harm companies must avoid can be less obvious than that. Providing a user with a lesser quality product, for example, can be harmful in its own way. “We want to make sure every version [of our product] we give we have faith in,” he said.