Infinite Scroll: The Web’s Slot Machine

A few years ago, everyone was clicking. Today, we’re all scrolling. Twitter, Pinterest, Facebook, Instagram, and Medium – it seems everyone is getting on the infinite scroll bus. What is it about this magical design pattern that has so many consumer web companies using it?

Not too long ago, users were forced to reload pages to progress from one piece of content to the next. Web designers were advised against creating websites with information appearing “below the fold”, the portion of the page underneath what is displayed on the screen. As mobile phones and tablets gained wider adoption, it looked like the swipe might become standard fare. But that’s all changed now. Today, designers are dumping the click and flick and opting for the scroll for one simple reason – it works.

The Endless Search

The infinite scroll is interaction design’s answer to our penchant for endlessly searching for novelty. Certainly, there are technical reasons for the scroll’s increasing ubiquity. The rise of dynamic content, like a new comment entering the feed, necessitated a better solution than pagination built for static content. But to really understand why the scroll works so well requires a brief trip inside the mind and back in time.

Our brains evolved through the millennia into incredible prediction machines, designed to help us make sense of our environment. Our species benefited from our ability to make good decisions based on what we know is likely to happen in the future, thus, keeping us alive long enough to make babies and spread our genes.

To make correct predictions, the brain accesses memories, which allow us to deduce what’s coming next in a nearly instantaneous process of pattern recognition. The ability to learn is simply the conditioning of the brain to recognize cause and (blank).

You were expecting “effect” weren’t you? Of course you were. That’s because your brain has learned that these two words, “cause” and “effect”, tend to go together.

It’s this conditioning that creates cognitive shortcuts and habits, allowing us to process tremendous amounts of information all at once. Our brains move known causal patterns to long-term storage so that our attention can be devoted to learning new things.

And nothing holds our attention better than the unknown. The things that captivate, engross, and entertain us, all have an element of surprise. Our brains can’t get enough of trying to predict what’s next and our dopamine system kicks into high-gear when we’re waiting to know if our team will make the field goal, how the dice will land, or how the movie plot ends. Like a loose slot machine, the infinite scroll gives users fast access to variable rewards.

Interestingly, our brain isn’t wired to seek pleasure alone. In fact, much of our motivation comes from alleviating the pain of desire. Dopamine levels spike when we’re just about to find reward and plummet after we receive it. To get us to do just about anything, evolution uses this chemical cascade to induce anticipation, motivation, and finally pain alleviation. Somehow we call this endless merry-go-round “fun.”