The Filter Bubble - Eli Pariser [49]
Afterward, Iyengar asked subjects to rank how important issues like pollution, inflation, and defense were to them. The shifts from the surveys they’d filled out before the study were dramatic: “Participants exposed to a steady stream of news about defense or about pollution came to believe that defense or pollution were more consequential problems,” Iyengar wrote. Among the group that saw the clips on pollution, the issue moved from fifth out of six in priority to second.
Drew Westen, a neuropsychologist whose focus is on political persuasion, demonstrates the strength of this priming effect by asking a group of people to memorize a list of words that include moon and ocean. A few minutes later, he changes topics and asks the group which detergent they prefer. Though he hasn’t mentioned the word, the group’s show of hands indicates a strong preference for Tide.
Priming isn’t the only way media shape our identities. We’re also more inclined to believe what we’ve heard before. In a 1977 study by Hasher and Goldstein, participants were asked to read sixty statements and mark whether they were true or false. All of the statements were plausible, but some of them (“French horn players get cash bonuses to stay in the Army”) were true; others (“Divorce is only found in technically advanced societies”) weren’t. Two weeks later, they returned and rated a second batch of statements in which some of the items from the first list had been repeated. By the third time, two weeks after that, the subjects were far more likely to believe the repeated statements. With information as with food, we are what we consume.
All of these are basic psychological mechanisms. But combine them with personalized media, and troubling things start to happen. Your identity shapes your media, and your media then shapes what you believe and what you care about. You click on a link, which signals an interest in something, which means you’re more likely to see articles about that topic in the future, which in turn prime the topic for you. You become trapped in a you loop, and if your identity is misrepresented, strange patterns begin to emerge, like reverb from an amplifier.
If you’re a Facebook user, you’ve probably run into this problem. You look up your old college girlfriend Sally, mildly curious to see what she is up to after all these years. Facebook interprets this as a sign that you’re interested in Sally, and all of a sudden her life is all over your news feed. You’re still mildly curious, so you click through on the new photos she’s posted of her kids and husband and pets, confirming Facebook’s hunch. From Facebook’s perspective, it looks as though you have a relationship with this person, even if you haven’t communicated in years. For months afterward, Sally’s life is far more prominent than your actual relationship would indicate. She’s a “local maximum”: Though there are people whose posts you’re far more interested in, it’s her posts that you see.
In part, this feedback effect is due to what early Facebook employee and venture capitalist Matt Cohler calls the local-maximum problem. Cohler was an early employee at Facebook, and he’s widely considered one of Silicon Valley’s smartest thinkers on the social Web.
The local-maximum problem, he explains to me, shows up any time you’re trying to optimize something. Say you’re trying to write a simple set of instructions to help a blind person who’s lost in the Sierra Nevadas find his way to the highest peak. “Feel around you to see if you’re surrounded by downward-sloping land,” you say. “If you’re not, move in a direction