The Isolation Effect (also known as the Von Restorff Effect) predicts that when multiple similar objects are present, the one that differs from the rest is most likely to be remembered!
This refers to the phenomenon whereby people value a thing differently depending on whether it is placed in isolation and whether it is placed next to an alternative.
In particular, a certain choice can be made to look more attractive if it is placed next to an alternative relative to which it is distinctively better in some respect.
This is also the main reason why all call-to-actions (CTAs) look different from the rest of the action buttons on a site or application!
We want users to be able to differentiate between a simple action button and a CTA, in order for them to have a clear understanding what the CTA does, whilst also remembering it throughout their use of the application or site.
Take this list into consideration:
- Red-headed perfume model
The chance is that you will remember ‘Red-headed perfume model,’ because it stands out by being a noun, longer in word-length and bold in weight. This is an extreme example, but it does highlight the effect.
When the item in question stands out less, the likelihood of it being remembered also decreases.
The Von Restorff effect was recognised by Hedwig von Restorff in 1933. She conducted a set of memory experiments around isolated and distinctive items, concluding that an isolated item, in a list of otherwise similar items, would be better remembered than an item in the same relative position in a list where all items were similar.
There can also be an interesting corollary here. You remember the unique item, but the attention that it grabs from you is removed from other items — thus you may in fact remember less overall.
Hedwig’s work relates to Gestalt, where she related it to the Figure and Ground principles.
Another group of researchers, Taylor & Fiske, found out in 1978 that attention is usually captured by salient, novel, surprising, or distinctive stimuli. These may be used to enhance the Von Restorff effect.
In the ‘attention age’, when the plethora of media around us is constantly battling for a moment of our time, advertisers make much use of this principle, each contesting with the other to stand out from the crowd and hence be remembered by the target audience.
Does a UX designer have to know this one? Of course, because we use Von Restorff all the time. It is used when the ‘selected’ state of a navigation item is different/distinctive from others. And when the ‘special offer’ or a ‘new’ sticker on one item in a product listing stands out. And in the app badge icon to remind us that there is an unread notification.
Every time we design a special state to distinguish an item from similar ones, we rely on this effect.
However, it only works if there are only a few different states to choose from. Otherwise, nothing will stand out. As effective as this might be, it’s important to implement contrast in a way that doesn’t dilute its power. Using the Von Restorff effect intemperately will devalue its presence, may lead to confusion.