11 Cognitive Biases Useful in Product Design

Key biases, heuristics and cognitive effects that can be used for designing products.

Most of these are intuitive, and some won’t work everywhere - still, it's useful to be aware.

Fitts’ law 

A predictive model of human movement primarily used in human–computer interactions and ergonomics.

This law states that the time required to rapidly move to a target area is a function of the ratio between the distance to the target and the width of the target.

This is used to place CTAs (Call to Actions) prominently in the interaction space.

Scarcity effect 

This is widely used in ecommerce to convert buyer’s interest to purchase.

The cognitive bias that makes people place a higher value on an object that is scarce and a lower value on one that is available in abundance.

You might have seen this in Amazon where number of items left are shown on Product Details Page (PDP).

Urgency effect 

Ever felt pressured by booking.com's "Only 1 room like this left on our site!" text in red letters?

Used to create sense of urgency in order to drive sales.

Another example is putting a timer on checkout which tends to increase conversions.

Anchoring effect 

This is widely used in discounts where a high base price is shown along with the discounted price.

A form of cognitive bias that causes people to focus on the first piece of available information (the “anchor”) when making decisions.

A high base price gives an anchor of high perceived value to the buyer.

Framing effect

Similar to Anchoring effect:

People make decisions based on the presented options (i.e. limited information.)

Generally the options are presented with positive or negative connotations to influence the buyers. Let’s say a person is given a choice of various wines with different prices mentioned. As price of wine increases, the participant’s report greater enjoyment of the wine.

Endowed Progress Effect 

The effect that leverages our intrinsic goal-oriented behaviour.

The presence of an artificial advancement toward a goal (even if it is artificial) motivates individuals to complete the goal though the goal may not provide any immediate real value.

Completion meter or progress bar in sign up and onboarding flows increases the chance of onboarding and profile completion with more data. Moreover, the closer the users are towards completing the goal, higher is their motivation to complete an additional action and move towards the goal.

IKEA effect 

People value their own effort much more than they value other’s effort.

IKEA has used this to sell unassembled furniture.

Paradox of loss 

We value loss more (overvalue) than we value the gain (in absolute terms).

A person purchasing car spends more if he is given a base price including accessories and then asked to remove accessories (than adding accessories).

Miller’s law 

More choices, more confusion:

The number of objects an average human can hold in his short-term memory is 7 ± 2.

Try to avoid more than 7 actions/choices on any user interface unless absolutely necessary.

Jacob’s law 

Users do not appreciate deviation of expected or industry-standard models.

Users prefer experiences consistent with their existing mental models.

They expect your site or app to work in the same way as others they regularly use.

Occam’s razor 

The more assumptions one has to make, the more unlikely an explanation.

The simplest solution is the best solution.

This is used to simplify the user flows by minimizing the assumptions.

Von Restorff effect / isolation effect 

Simplest examples are the Highlighters and Tags like featured, new that are used on websites/apps to influence user’s preferences.

Predicts that when similar objects are presented, the object which is most distinguishable/different is likely to be remembered the most.

Simplest examples are the Highlighters and Tags like featured, new that are used on websites/apps to influence user’s preferences.

Serial position effect 

Individuals best remember the first and last item in the list.

PMs can use this on search results /listing pages.

Pareto principle 

Finally:

roughly 80% of the effects come from 20% of the causes.

It is widely regarded as a universal truth and used for building MVPs / maximizing output.

Did I miss something? Please share in the comments!

Written by Tarun

Creator & Consultant @ Prodbee
Product Professional @ Lazada, Alibaba group | Magicbricks, Times Group(Ex) | Ola Cabs (Ex)
Enthusiast @ Photography | Arts | Web-designing | Boxing