The von Restorff isolation effect (sometimes called the von Restorff effect or the isolation effect) is a cognitive bias that causes people to remember things better when they stand out from other things that they’re next to. For example, the von Restorff isolation effect means that people who are shown a color photo in a group of black-and-white photos will likely remember the color photo better, because it stands out from the others.
The von Restorff isolation effect can play an important role in many situations, so it’s beneficial to understand it. As such, in the following article you will learn more about this effect, and see how you can use it yourself, as well as how you can account for its use by others.
Examples of the von Restorff isolation effect
An example of the von Restorff isolation effect is that in the list of colors “red, GREEN, yellow, blue”, the word “GREEN” is emphasized through capitalization, which makes people more likely to remember it, compared to the other words. A similar effect could be achieved in other ways, like italicizing, underlining, or bolding key items in the list, to make them visually stand out compared to others. In the context of learning an education, this means that visually highlighting a key sentence or section in a textbook can lead people to focus on it and remember it better.
In addition, this effect can also apply to things other than written text. For example, in user interface design, it’s possible to highlight important buttons, by making them a different shape and color from the others, in order to help users remember the buttons’ location and function.
This effect can also be created by making something different from the other stimuli based on some attribute that doesn’t have to do with perceptual salience (i.e., with how it looks). For example, in the list “bird, dog, apple, cat, mouse”, the word “apple” stands out from the other items based on its meaning, because it refers to a fruit, whereas the other items refer to animals. Similarly, an advertisement that stands out because it’s humorous and shown at the same event as non-humorous ads, will also likely be remembered better due to this effect.
Overall, examples of the von Restorff isolation appear when it comes to various stimuli, like individual words, educational material, slogans, events, and faces, and this effect can be achieved in various ways, such as making a certain stimulus stand out perceptually (e.g., by being a different color) or conceptually (e.g., by belonging to a different semantic category). As one study notes:
“The unusual, bizarre, or distinctive event seems inherently more memorable than common, everyday occurrences… The effects of distinctiveness on memory are exploited in textbooks in which major concepts are printed in bold print, and in virtually every form of advertising in which loud music, bright colors, or other distinctive stimuli scream for our attention.”
— From “Can we have a distinctive theory of memory?” (Schmidt, 1991)
Note: This effect is sometimes also classified as a novelty effect, and is considered to be the best-known example of the distinctiveness effect, whereby unusual information is remembered better.
Psychology and causes of the von Restorff isolation effect
The von Restorff isolation effect has been attributed to various causes. These include the Gestalt explanation, which states that similar stimuli are aggregated while isolated items stand out against them, the interference explanation, which states that isolation aids memory because it reduces interference from other stimuli, and the attention explanation, which states that isolated items receive more attention than other stimuli.
These explanations can be categorized into two main types:
- Explanations which state that isolated items benefit from improved processing and encoding, due to the highlighted similarities and differences between them and background stimuli during the initial interaction.
- Explanations which state that isolated items benefit from improved retrieval, due to the relationships between cues, targets, and competitors during retrieval of information.
Some studies argue that the van Restorff isolation effect occurs primarily due to facilitated retrieval, by showing that this effect can occur even without influencing processing at the encoding stage. For example, such studies show that isolating items early can enhance memory to a similar degree as isolating them later, even though no context has been established in which the isolated stimuli are incongruent (i.e., before the isolated stimuli stand out). Furthermore, similar findings have been used to rule out the theory that surprise is exclusively responsible for this effect.
However, salience at the processing and encoding stage can still sometimes cause this effect to some degree, for example by increasing the time and effort spent engaging with the isolated stimuli. Furthermore, the order of presentation of information (sometimes referred to as serial position) can matter in some cases, where presenting isolated stimuli early reduces or eliminates the isolation effect. Accordingly, and given the general evidence regarding the role that encoding can play in causing this effect, its role cannot be ruled out entirely, and it’s likely that both improved encoding and improved retrieval can play a role in causing the van Restorff isolation effect.
In addition, this effect may be influenced by various other factors. These include, for example, factors pertaining to the stimuli, like how they were isolated, and factors pertaining to the individuals who are engaging with the stimuli, like age.
In this regard, note that the von Restorff isolation effect may not aid all types of memory. For example, some studies suggest that it aids the free recall of information, but not its recognition. Similarly, some studies suggest that people experience a stronger effect when they memorize things in a rote manner (through simple repetition), compared to when they memorize things using elaborative strategies, such as organizing the stimuli or using mnemonic devices.
Overall, the von Restorff isolation effect can be attributed to multiple causes, which may play a role in different combinations in different situations; these include explanations pertaining to the processing and encoding of information, as well as ones pertaining to its retrieval. Furthermore, many factors can influence whether and how this effect occurs; these include the type of stimuli being remembered and the age of the person doing the remembering.
Note: Evidence of the von Restorff isolation effect has been found not only in humans but also in animals.
How to use the von Restorff isolation effect
It can sometimes be beneficial to actively use the von Restorff isolation effect, both when it comes to improving your own memory and when it comes to improving other people’s memory.
The key to doing this is to present whatever you want people to remember in a way that makes it stand out against a homogeneous background. For example, to help yourself remember key parts of a textbook, you can highlight them, in order to make them stand out visually. Similarly, to make people remember your presentation out of many others that they see, you can use a unique style (e.g., humor), in order to make it stand out.
You can make things stand out in various ways, based on both perceptual attributes (e.g., color) and conceptual ones (e.g., type of item). In general, the more similar the background stimuli are to each other, and the greater the difference between them and the key items that you want people to notice and remember, the stronger the isolation effect will be.
In addition, you can isolate more than a single thing, for example by making multiple parts of a text stand out. However, the more things you try to make stand out, the less they will generally stand out overall, and the weaker the isolation effect will be.
Finally, accounting for the von Restorff isolation effect can be beneficial when you’re not using it yourself. For example, this can help you predict what details in a presentation people are likely to remember, and what they’re likely to forget. Alternatively, this can help you identify cases where a salesperson is trying to make an offer appear better than it actually is, by emphasizing certain parts of it over others.
Caveats about the von Restorff isolation effect
There are two important caveats that you should keep in mind about the von Restorff isolation effect, especially if you plan to use it.
First, the effect improves memory for the stimuli that stand out compared to the stimuli that don’t. Furthermore, it generally also improves memory for key stimuli compared to how they would be remembered if they didn’t stand out. However, this effect doesn’t necessarily lead to better memory for the key stimuli than if they were presented alone, so it can sometimes be better to eliminate background stimuli instead, if possible.
Second, the improved memory for the stimuli that stands out can come at the expense of worse memory for the background stimuli (a phenomenon sometimes referred to as induced amnesia). This can be especially likely for stimuli that appear immediately before and after the isolated stimuli, though it’s not always a problem, and there are even situations where such material benefits from being near the unique stimuli.
The fact that homogeneous stimuli tend to not be remembered as well as stimuli that stand out can be either problematic or beneficial. Notably, it can be problematic when you want people to remember those stimuli too. Conversely, it can be beneficial when you want to distract people from something, in which case you can hide it by making it more similar to other things, and by also presenting it next to isolated stimuli that stand out and that people are likely to remember better.
Additional information
History of the von Restorff isolation effect
The von Restorff isolation effect is attributed to Hedwig von Restorff, who published her work on it in the 1933 paper “Über die Wirkung von Bereichsbildung im Spurenfeld [On the effects of the formation of a structure in the trace field]”, in Psychologische Forschung (volume 18, pages 299–342).
Von Restorff (1906–1962) was a German psychology researcher at the time, who obtained her PhD under the supervision of Gestalt psychologist Wolfgang Köhler in 1933, and who later became a medical doctor and a family physician.
Note that some research on the topic has also been conducted beforehand, such as in Mary Whiton Calkins’s 1896 work on the associated effects of vividness.
Related effects
There are various effects that are associated with the von Restorff isolation effect, and which can be beneficial to use in addition to or instead of the isolation effect. They include the following:
- Contrast effect– a cognitive bias that distorts our perception of something when we compare it to something else, by enhancing the differences between them.
- Humor effect– a psychological phenomenon that causes people to remember information better when they perceive that information as humorous.
- Verbatim effect– a cognitive bias that causes people to remember the gist of information, which is its general meaning, better than they remember its exact form, which is the way the information was presented and the minor details that it involved.
- Zeigarnik effect– a psychological phenomenon that causes people to remember interrupted tasks better than completed ones.
Summary and conclusions
- The von Restorff isolation effect is a cognitive bias that causes people to remember things better when they stand out from other things that they’re next to.
- For example, the von Restorff isolation effect means that people who are shown a color photo in a group of black-and-white photos will likely remember the color photo better, because it stands out from the others.
- The isolation effect can be involved in various stimuli, like texts and events, and can be achieved in various ways, like making something stand out perceptually (e.g., by being a different color) or conceptually (e.g., by being of a different type of stimulus).
- To use this effect, present your key stimuli in a way that makes them stand out against a homogeneous background; the more homogeneous the background, and the more different it is from the key stimuli, the stronger the isolation effect will be.
- This effect doesn’t necessarily help people remember the key stimuli better than if it was presented by itself, and can make people struggle to remember the background stimuli.