Luckily our hammers don’t do that — but our digital products often do.
Just take a look at what happened when I simply tried to read an article:
Experiences like this are unfortunately common place. We visit a product for a specific task—only to be interrupted by alerts, banners, & notifications full of unrelated features, dense legal documents, & advertisements.
However, a study by Information Systems Research explains why we should reconsider this approach to product design. Interruptive alerts have a “substantial negative impact in terms of reduced productivity, increased stress, and increased task-completion time”. These are not traits we want associated with our products. At the root of these negative effects is a cognitive limitation called dual-task interference (DTI), in which we experience significant performance loss when we try to complete tasks simultaneously—even if they are simple.
“Even the most well-meaning application has the potential to cause interruption overload.” Adamczyk and Bailey 2004
DTI is easily explained via two cognitive models, capacity-sharing & bottlenecks, which theorize that we share mental capacity among tasks with a limited amount to allocate. Increasing mental capacity for one task will decease the available amount for another, affecting processing time. Attempting multiple tasks at once creates a bottleneck, causing processing time to ballon for at least one task — if not all of them.
Our brains aren’t designed for multi-tasking, nor should our products be.
With this research in mind, we should strive to design products that do not interrupt users but instead find natural pauses in the experience to introduce secondary information. Avoiding DTI not only creates more pleasant & productive experiences, but also increases the likelihood alerts, banners, & notifications will be read because attention is available.
“HCI research on interruptions suggests that the severity of an interruption can be reduced by introducing it at a more opportune moment” Adamczyk and Bailey 2004
Here’s an example we recently implemented in our product at Headliner, a browser based video editor, by repositioning our announcement modal. It initially displayed after log in, interrupting the initial intent of a user’s visit:
By moving the modal from the beginning of the funnel to the end, we utilize the idle time a user encounters while waiting for their video to render:
This placement yields significant conversion without interruption, because it avoids DTI. We call it the “Post-Task Prompt”:
Hammers don’t interrupt, nor should our other products.