The isolation effect is our tendency to remember an item that stands out in some way from a set of otherwise similar items—you might easily guess, for example, which name we are more likely to remember from a list of Tom, Terry, Angelica, Theo and Tyler.

When presenting information, the isolation effect is practical if you wish to draw attention to specific items. By standardising the presentation of other items in a list, maybe by muting the colours, making them the same size, or removing features that stand out, you can draw people's attention and improve people's memory of your chosen items.

The isolation effect is standard in web design by using distinctiveness: red notification bubbles on a set of otherwise homogenous apps, a "most popular" plan more prominent than the other options, or a Call-To-Action (CTA) button in a contrasting colour.

The isolation effect is also known as the Von Restorff effect after the German psychiatrist Hedwig von Restorff. See, for example, Hunt, R.R. The subtlety of distinctiveness: What von Restorff really did. Psychonomic Bulletin & Review 2, 105–112 (1995) for a summary of Von Restorff's most cited paper on the effect.

The isolation effect

The Rhyme As Reason Effect suggests that we're more likely to consider something as accurate or truthful when it rhymes. In a lovely study that asked people to consider the accuracy of both rhyming and non-rhyming aphorisms, "Woes unite foes," or "What sobriety conceals, alcohol reveals," for example, were considered more accurate than "Woes unite enemies," or "What sobriety conceals, alcohol unmasks."

A classic example outside of old sayings is OJ Simpson's trial where the defense attorney memorably noted "If the gloves don't fit, you must acquit!"

You can read the study in the delightfully titled paper, Birds of a feather flock conjointly: Rhyme as Reason in Aphorisms (pdf), by Matthew McGlone and Jessica Tofighbakhsh.

In a related note I was always curious how "Beer before wine, you'll feel fine," tallied up with what I heard in the US: "Beer before liquor, never been sicker," or even "Grape or grain but never the twain." It turns out from a neat 2019 study that, whichever way round you rhyme them, they have no effect on your hangover despite how persuasive the Rhyme As Reason effect may be — even after a few beers.

The Rhyme As Reason Effect

The curb-cut effect illustrates how when we design to benefit disadvantaged or vulnerable groups we end up helping society as a whole.

Angela Glover Blackwell explains how campaigning by students with disabilities in Berkeley in the early 1970s led to adding curb cuts to the Berkeley sidewalks to make access easier for those in wheelchairs. Yet it wasn't just people in wheelchairs that it helped. Curb cuts also made life easier for people pushing children in strollers, people using trolleys for deliveries, people pulling a suitcase, those wheeling bikes or on skateboards, and it also helps save lives by guiding people to cross at safe locations.

Another example is adding closed captioning to TV that helps anyone watch in a noisy bar, a waiting room, or watching an airline safety video. Or a classic example of universal design in the OXO Good Grips range originally made to be comfortable for holding a peeler even if you have arthritis.

It's also a useful analogy for "how laws and programs designed to benefit vulnerable groups, such as the disabled or people of color, often end up benefiting all," (PolicyLink) whether that be increasing broadband access, improving public transport or taking cuts out of curbs.

Here's a short, fun video of Gary Karp explaining the curb-cut effect.

Thanks to my patron Quintin Balsdon for sharing it with me.

The curb-cut effect

In much of life we're used to things adding up — got one scoop of ice cream? Two is likely to be better. Buying one thing? Getting another free is probably a good thing. The dilution effect, however, illustrates an interesting action of our brain when evaluating our options. Niro Sivanathan showed that when displaying possible side-effects of drugs, if you were to add another side-effect, a minor one like 'itchy feet', instead of the extra negative side-effect increasing our overall perception of the risk of the drug it actually lowered it. So, people would deem a drug with the side effects heart attack, stroke, and itchy feet, as less risky than one with just heart attack and stroke.

In another clever experiment by Christopher Hsee at the University of Chicago, people were willing to pay less for a new dinnerware set when the set was actually larger but also included some broken items. Even though a set had more intact items the presence of a few broken ones decreased the set's perceived value.

And the same may be true when making an argument to persuade someone to see our point of view. If you have 2 strong points and 1 weaker one, your argument may actually be made weaker by adding the extra point. As Niro Sivanathan, an Associate Professor of Organisational Behaviour at London Business School, explains: Arguments don't add up. They average out.

Next time you're making your case, consider sticking to your strong arguments.

Hear Niro Sivanathan explain the dilution effect in his 10 min TED talk The counterintuitive way to be more persuasive

The paper: Sivanathan, N., Kakkar, H. The unintended consequences of argument dilution in direct-to-consumer drug advertisements.Nat Hum Behav 1,797–802 (2017).

The dilution effect

There are a lot of reasons why it can make sense to go with the majority. Going with the popular view is a shortcut for taking the time and effort to make our own decisions from scratch. We might reason that if others believe it, then it's probably true. But we can also keenly feel the desire to conform to the majority view because it's uncomfortable to hold a different opinion — the easy choice is so often to go with the flow even if, deep down, you disagree. So we get the bandwagon effect.

The bandwagon effect can lead to the Abilene paradox — where a group can make a decision that no one in the group agrees with. On a night out it may lead to just following the crowd, but in a company it could lead to launching a product that no one thinks is good or, more seriously, in safety critical industries like airlines, if people don't feel comfortable speaking up against the group or authority it could lead to accidents.

The bandwagon effect

The essence of the bystander effect is that in a situation where someone needs help, if others are around who could help then it discourages us as individuals from stepping in.

While there may be many reasons for this, and it has been replicated in lots of different contexts, a recent study of CCTV footage paints a more optimistic picture. In the study they saw that although the likelihood of any individual intervening may be reduced with other bystanders present, the chances of someone coming to help increases the more people are around. In 9 out of 10 public conflicts they studied at least one person and often several came to help. So the lady in the sketch would probably be OK.

Given the bystander effect I remember being taught that if you are in a motor vehicle accident don't assume that someone has called for help already: it could help to choose someone directly and ask them to call for help to avoid everyone thinking everyone else will do it.

It reminds me of the story about four people named Everybody, Somebody, Anybody and Nobody:

There was an important job to be done and Everybody was sure that Somebody would do it. Anybody could have done it, but Nobody did it. Somebody got angry about that, because it was Everybody’s job. Everybody thought Anybody could do it, but Nobody realized that Everybody wouldn’t do it. It ended up that Everybody blamed Somebody when Nobody did what Anybody could have.

The paper referenced is: Philpot, Richard & Liebst, Lasse & Levine, Mark & Bernasco, Wim & Lindegaard, Marie. (2019). Would I be helped? Cross-national CCTV footage shows that intervention is the norm in public conflicts. The American psychologist. 75. 10.1037/amp0000469. (pdf)

The Bystander Effect

Intuitively, we can relate to this: as we get closer to completing a goal we can feel more motivation to complete it. Getting close to the last piece of a puzzle, the last clue of a murder mystery or escape room, the final chapter of your book (perhaps), the final kilometre of a marathon, or as you find you need just one more stamp to get a free coffee, being so close to our goal can give us a motivation lift to get to the end. It has a name:  the goal-gradient effect*.

In the example in the sketch, Oleg Urminksy and coauthors found that as people approached the final stamp towards a free coffee they were more likely to pick up the rate of buying coffees. And when issued with the new card, the coffee buying rate went back down again. They also found that it wasn't so much the absolute 'distance' from a goal, but the perception of distance. So, people who started out on a 12 stamp card with 2 stamps already complete tended to complete the card faster than the people who had a 10 stamp card starting empty even though it was the same number of stamps to the goal.

Read more in Katy Milkman and Kassie Brabaw's Scientific American article, Why Feeling Close to the Finish Line Makes You Push Harder.

Katy Milkman also educated me about the fresh start effect.

*The goal-gradient effect is also known as the goal-gradient hypothesis

The goal-gradient effect

Astronauts returning from space have repeatedly shared experiences like this:

“You develop an instant global consciousness, a people orientation, an intense dissatisfaction with the state of the world, and a compulsion to do something about it. From out there on the moon, international politics look so petty.”— Edgar Mitchell, Apollo 14 astronaut

“When we look down at the earth from space, we see this amazing, indescribably beautiful planet. It looks like a living, breathing organism. But it also, at the same time, looks extremely fragile … Anybody else who’s ever gone to space says the same thing because it really is striking and it’s really sobering to see this paper-thin layer and to realize that that little paper-thin layer is all that protects every living thing on Earth from death, basically. From the harshness of space.”— Shuttle/ISS astronaut Ron Garan

The overview effect, coined by Frank White, is kind of the mother of seeing the forest for the trees. It’s the realisation that we live on a fragile planet, we are all connected, and this is all we’ve got.

The sketch is based on the image of earth from the moon taken on the Apollo 11 mission.

The overview effect

The story goes something like this. Back in colonial India the top Brit in charge decided there were too many cobras around Delhi. To reduce the population they put in place a cash reward, or bounty, for anyone who brought in a dead cobra. The intention was clear. Legend has it that people did bring in the cobras reliably because some enterprising souls had started breeding cobras for the very purpose of getting the bounty. When the authorities realised this they scrapped the scheme, the cobra farms closed and the bred cobras were released into the wild significantly increasing the cobra population by a few orders of magnitude. Hence, the cobra effect: when a well-intentioned measure can have the opposite effect to that desired.

It’s not clear how true this story is, but the cobra effect has been demonstrated many times. The Freakonomics podcast on the cobra effect discusses some excellent examples (with references), including:

A bounty on rats in French colonial Hanoi — where the bounty was earned by bringing in a rat tail — which went the same way as the cobra story

Removing wild pigs at Fort Benning, Georgia, at $40 a pigs tail that didn’t make a dent. It could be the hunters would bait the pigs with all sorts of tempting scraps. Many pigs learned to avoid the hunters and instead bred like crazy while well-fed on scraps.

The capital of Colombia, Bogotá, tried to reduce traffic congestion by restricting each car from driving one day during the week. The result: people started buying more than 1 car and did more driving on weekends.

Publication of proposed areas of habitat to be protected for endangered species meant land developers responded by building in those areas before the land was protected.

People are smart. Incentives work, in the sense that you tend to get what you incentivise. So be careful what you are incentivising.

Also see: Goodhart’s Law and What gets measured gets better.

The cobra effect

There’s something about being out in Nature for 3 days or more that resets us and improves our mood, our wellbeing, and how well our brain is working. Observed by river rafting guide Ken Sanders who used to see a marked change in the groups he led on the 3rd day of being out on the river, it’s known as the 3-day effect. Since then, David Strayer and his group at the University of Utah have conducted studies that measured a real change in our calmness and even our creative problem solving after 3 or more days in Nature.

“I think it takes the first two days and nights to wash away whatever veneer of civilization you have brought with you. The new reality begins on that third day.”

More about the 3 day effect at National Geograhic: This is your brain on Nature and REI: The Nature Fix.

No doubt similar things at work to the magic of forest bathing.

The 3-day effect

Coined after the French philosopher Denis Diderot’s remarkably titled essay “Regrets on Parting with My Old Dressing Gown”.

The gist of the effect is that we generally surround ourselves with objects that fit our current sense of identity. If we get something that doesn’t fit that identity we may find ourselves replacing the rest to match the new identity.

Poor Diderot was given a fancy new dressing gown and ended up replacing most of his possessions and ultimately living in poverty, to paraphrase a little.

The Diderot Effect was introduced by Grant McCracken, and I learned about it, once again, from Atomic Habits. Diderot also played a key role in the development of the encyclopedia as I learned from Seth Godin’s podcast, Akimbo,

The Diderot Effect

The name given to situations where people can give mutually contradictory versions of the same event. Named after the 1950’s Japanese film Rashomon which hinges on four conflicting descriptions of the same incident. Also commonly seen on the football field.

The Rashomon effect

I like this one because it basically shows that most of us can just relax a bit and not stress about what other people think — because they’re probably not thinking about us, they’re probably thinking about themselves.

I probably only remember it because of the effect effect.

The spotlight effect

It’s named Streisand after Barbara Streisand tried to have an aerial photo of her house removed from a set of California coastline photos intended to document coastal erosion. Views of the photo apparently went from 6 to 420,000.

The Effect Effect

Nature’s greatest snow machine, where crazy amounts of snow can fall in huge snowstorms on the downwind — leeward — side of a lake. Where the effect is pronounced, such as on the East of some of the Great Lakes in the US, it can generate regions known as snow belts because of the amount of snow they receive.

It works kind of like this: cold air blows over a lake. As the cold air passes over the warmer lake it picks up water vapour from the lake and it warms. This causes it to rise and in turn cool, such that when it reaches the downwind side of the lake it is now a lot of cold moist air which can cause some incredible snowstorms, like 2–3 inches of snow per hour. Satellite pictures like these show it in action pretty clearly. If the land rises after the lake the air can cool faster and increase the effect — and also cause a rain shadow — and if there’s a whole lot of convection and the air is rising fast you can get what’s called thundersnow — a thunderstorm in a snowstorm. I know.

Find weather interesting? Me too. You might also be interested in: Dirty thunderstorms, thunderclouds, yesterday’s weather (applying weather forecasting to software engineering), rain shadow, lenticular clouds, know your cirrostratus from your altocumulus, and British weather.

Lake-effect snow

A term coined by Mike Masnick, for what happens when you try and censor or suppress information: it draws attention to it.

The Streisand Effect

Related to psychic numbing, the singularity effect is the name to how we care disproportionately about an individual as compared to a group. Think, Saving Private Ryan, where an enormous effort is launched to save a single soldier in the second world war. It turns out that even as you add a second person there’s some justification for something known as compassion fade. The addition of more people doesn’t increase our willingness to help proportionally — our compassion fades as more people are involved.

The singularity effect

The nocebo effect is how the expectation of pain or negative effects of a treatment increases the chances people will feel them — even if they're aren't any. So, tell someone that a treatment will hurt or have side-effects and they're now more likely to feel that pain or find something wrong.

Taken together with the placebo effect I guess we might do well, for normal affairs, to let people know that what they will get will probably help them and not raise unnecessary expectations that something might hurt.

The nocebo effect

The remarkable, yet commonplace fact, that when people expect a treatment to help it can, even if the treatment doesn't actually do anything.

The placebo effect

The simple fact that the start of something, pretty much anything, means we’re more likely to try something new. Be it your birthday, your next house, a new day or a new country, these turn out to be great mental triggers for us to get started.

For more, you could do much worse than listen to Katherine Milkman, an assistant professor at The Wharton School of the University of Pennsylvania, on the Freaknomics podcast: When Willpower Isn’t Enough.

The fresh start effect

We love it more if we made it. Or, more scientifically perhaps, the IKEA effect is ‘the increase in valuation of self-made products,’ when we have put more effort into it. 

Turns out, if we’ve put effort in ourselves we’re also likely to think that others will like it even more just as we do—usually not the case. But for us at least, more effort = more love.

Watch Dan Ariely do a great job explaining some experiments that lead to this conclusion, or read the full paper, The “IKEA effect”: When Labor Leads to Love (pdf), Norton, Mochon, Ariely HBS working paper, 2011.

Dan points out that kids are the ultimate expression of the IKEA effect: they’re very hard, they don’t come with instructions and they take a lot of effort.

Also see The Betty Crocker Effect, or ‘the egg theory.’

The IKEA effect

Where “all the children are above average.” From the intro by Garrison Keillor to the News from Lake Wobegon on the radio show A Prairie Home Companion. Also known as illusory superiority. From the popular studies where, for example, 80% of people think they are above average drivers, when asked to estimate the % of chores done in the household it adds up to more than 100%, and we overestimate our input to project work and it’s impact on its success. For the best treatment I’ve read, and references, see Thinking Fast and Slow by Dan Kahneman.

The Lake Wobegon Effect

When cliques, of people, with a lot of time to chat, start to believe in things that would seem crazy to the wider population. So named after an observation of firemen who would spend a lot of time talking between fires.

My intro to this was from Fooled by Randomness by Nassim Nicholas Taleb.

The Firehouse Effect

The Betty Crocker effect refers to how, in the world of instant cake mixes, when something is too easy it reduces the value. The legend goes that instant cake mixtures that just needed water didn't sell nearly as well as when you needed to add an egg. Adding the egg yourself gives investment in the process of making the cake so we appreciate it more, and the extra effort demonstrates the act of love that is baking a cake.

Also easy to understand as the IKEA effect. As is so often the case, Dan Ariely explains it well. 20mins well spent watching Dan Ariely's TED talk What makes us feel good about our work?. You can jump straight to it around 12mins 50s.

Sketchplanations tagged with effect