What is Cognitive Bias – eCommerce Marketers Should Pay Attention


The truth is, every human has a tendency of being irrational as much as rational. At a first glance, we may be convinced that buying is a simple consequence of evaluating the quality, the price, and the accessibility of a product. The question is if it is that simple. As you may guess, it’s not.

The industry of eCommerce marketing is actually built on refined techniques of persuasion, where two and two may come out as eCommerce marketers fine-tune their content. It is never perfectly rational. In fact, the complex math of making decisions has a lot to do with cognitive bias. 

Cognitive Bias – The (Not So) Secret Ingredient

Understanding well the ways that the human brain works is bringing your art of persuasion to a higher level. The fine lines and nuances that separate rational and irrational are the points where your marketing twists and turns in different directions. In simple words – if you know well how to use cognitive bias, your sales will go skyrocket. 

A cognitive bias is a tendency to think in a particular way, often not very logical, based more on irrational, social, and emotional grounds. Being as such, it may give them leverage in either way – buy or don’t buy.

I’d like to offer some insights into types of cognitive bias that you may find interesting to use in your marketing strategy.

Social Proof

Maybe it is the most obvious example of cognitive bias. People generally tend to have the approval of others by behaving in the same way as their social group or the majority. The point is that an individual will most likely want to buy the product that his or her friends are using or reported to have had a satisfying experience with. 

“Word-to-mouth” marketing is based on this principle and is known as one of the most effective strategies.

When doing business, we all want to increase sales and improve customer satisfaction. One way to do this is to add social proof notifications to your website, for instance, Wiser Notify can help your website visitors build trust in what you offer.

In-group Bias

People feel more trust towards someone whom they see as a member of their group. By group, it is referred to sharing similar interests, from political views to rather particular hobbies or preferences. As a marketer you want to adjust your content to your target audience in a way that they feel you as one of them, understanding their needs perfectly


Any information can be presented in various ways, emphasizing different aspects. Depending on the frame you put in your presentation, you will be more or less persuasive. Naturally, bringing out the most positive traits of the product will make the product more appealing.


When offering two products, you would prefer to sell better one of them. Instead of making a simple comparison, you may introduce the third product into your offer. It will be a decoy to draw attention to the faults of one product, making the other a much better deal.


Making one product look scarce in supply, is having quite an effect on the buyer to want it more. People like to have something that is of limited edition, or it is not so easy to buy. It gives more of a psychological value to the purchase.

Availability Heuristic

Making decisions depends on the latest experience or the news, including the emotional component and creating an opinion based upon it. Once created, the new preference or the new need will direct attention to products or services based on the recent impression, leading to purchase them.

The Barnum Effect

Named after circus artist P.T. Barnum, this kind of cognitive bias is derived from the impression that you are addressing the client one-on-one, knowing exactly who he is and what he needs. The trick is to create content that people will recognize easily as their personal description, yet vague enough to be applied to a great number of people.

Halo Effect

It is a positive bias towards a particular manufacturer that we have a positive experience with. So, if you have already used one product, you will tend to expect other products of the same brand to be satisfying as well.

Backfire Effect

Based on previous beliefs, we are convinced that certain products are valuable. When presented with the argument against these products, we are even more sure of their value, grasping more strongly on the beliefs based on experience.

Ecommerce Marketers

Fear of Missing Out (FOMO)

FOMO, or the fear of missing out, has ground in social proof. In other words, people wouldn’t want to miss out on a social occasion. When used in marketing strategy, it is bringing to the customer a significant number of testimonials of other people, confirming the value of the product.

Hyperbolic Discount

Based on the present-biased decision, hyperbolic discount means that we prefer the immediate reward even though it is smaller than the reward that we would have to wait for.

When asked to choose a dollar today or five dollars next week, people like to get one dollar today. Fast delivery or time-limited offers trigger the present bias, giving the impression of instant gain to a buyer.

Rhyme as Reason

Rhyme is easier to remember and process. Beyond that, the rhyme is conceived as more truthful than the same information presented with no rhyme. 

Using content that rhymes is increasing the trust and reliability of the information given about the product.


The way we present the product on the landing page or the website can affect the perception and decision-making about the product. Cognitive bias is the basis for influencing and directing the decision-making process by framing the information in a precise context.

As you could see, there are many types of cognitive bias, generally categorized and at the same time very individual, giving a marketer a wide variety of use. 

There is no one-size-fits approach, nor strictly defined formula of how and when to deploy the cognitive bias. The products, the target groups, the individual needs of a customer are so versatile that you may have to try out one or more kinds of bias, always being on the edge between crushproof strategy and complete failure.