Logical Fallacies In Design Critiques
- A design critique is a session to evaluate a set of design solutions.
- A logical fallacy is a violation of logical reasoning.
- Journalists, politicians and lawyers are trained to identify and avoid logical fallacies. Designers, traditionally, are not!
Designers have to continuously shift mental gear as they move through a design process. Periods of idea generation require creative or ‘divergent’ thinking. And periods of testing or evaluation require more logical or ‘convergent’ thinking. Excelling in both these modes of thinking is incredibly hard, most design schools and agencies focus more on the creative thinking side. To help designers, or anyone who works in a design process, understand and spot logical fallacies, I’ve started a list of common logical fallacies and how they are found in design critiques. Here are the first three:
Appeal to Authority Fallacy
An appeal to authority is a false claim that something must be true because an authority on the subject believes it to be true. It is possible for an expert to be wrong, we need to understand their reasoning or research before we appeal to their findings. In a design meeting you might hear something like this:
“Amazon is a successful website. Amazon has orange buttons. So orange buttons are the best.”
Feel free to switch out ‘Amazon’ and ‘orange buttons’ for anything you want; you get an equally week argument. We could argue back that Amazon is surviving on past success and that larger company are often hard to innovate so shouldn’t be used as a design influence. We could point out that Jeff Bezos has a reputation for micro-managing and ignoring the evidence provided by usability experts he has hired. As a result, we could point out that Amazon is possibly successful in spite of its design not because of it. But the words ‘often’, ‘reputation’ and ‘possibly’ make all these arguments equally week and full of fallacies.
When we counter any logical fallacy, we want to do it as cleanly as possible. In the above example, we only need to point out that many successful websites don’t have orange buttons and many unsuccessful sites do have orange buttons. Then we can move away from the matter entirely unless there is some research or reason available to explain the authorities decision.
Ad Hominem Fallacy
We try to devalue a person or organisation to make their decisions look less valid. Office politics leaves loads of scope for people to use this technique, you can’t trust anything that the stupid department decides! I made an Ad Hominem in the last section so let’s use that example:
“Jeff Bezos likes orange buttons. Jeff Bezos ignores user research. so orange buttons are bad.”
There is some relevance to the argument, as the attack on Jeff’s character does relate to his ability to make design decisions. However, the attack on his character is also hearsay and a generalisation. If this exact example came up, we could use it to suggest doing user research into button colours as that would be hugely useful to our design critique and the other person agrees that user research is important.
An Ad Hominem is easy to counter but hard to bring the other person around. If you’re debating with someone who feels the need to attack someone’s character to make a point, they may not be open to logical debate. The ‘even a stuck clock is right twice a day’ argument can work in the short term. To simply point out that they could be correct about the person’s character, but that person may accidentally be correct this time.
Straw Man Fallacy
With this fallacy, we simplify the other person argument and then counter the simplified version. Fundamentally change the argument to make it easy for us to knock down. An example of a straw man fallacy might look like this:
“Using A/B testing with a sample size of 10,000 users we had a 35% higher conversion rate with the orange sign-up button over the blue one.”
“I know you like orange buttons, but most of us like the blue buttons. So we should use the blue buttons.”
In this example, the second person has reduced the argument made by the first person to ‘you like…’ which was not the claim they made. The ‘you like’ claim is incredibly easy to counter. The actual argument made by the first person is substantial and can not be knocked down by the second argument.
We often see a straw man used when the person who made the argument is not present to defend it. You can spot this when an opinion or argument is brought up in a design critique and the author of the argument is not there. If their argument is effortlessly knocked down, make sure you follow up with that person afterwards to ensure their argument remained intact.
Please let me know if you’d like to see a few more logical fallacies and how they apply to design meetings.
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