An alphabetical list of cognitive biases. Consider it your campaign and communication shopping list!


Adaptive Bias

When there is little information, a decision can be based around the cost of being wrong. The brain has evolved to reason adaptively, in an attempt to reduce the cost of cognitive errors, rather than the number.


Affect Heuristic

A decision making shortcut that relies on emotion over logic.


Ambiguity Aversion

This is the likelihood of choosing a known risk over an unknown risk.



An anchor is a piece of information that precedes a decision and acts as a starting point for the decision, even if the first piece of information is incorrect, illogical or unconnected.


Authority Bias

The tendency to give greater importance to the opinions or statements of those in authority, irrespective of their knowledge, skill or true authority.


Availability Heuristic

When creating a mental projection, people will use things that more easily come to mind, this is often the vivid, emotional or unusual stuff.


Base-Rate Fallacy

The tendency to disregard the 'base' information and instead focus on smaller more specific information.



A well-known term. This is being selective in the information that you choose. Often the best features and ignoring the rest.


Choice Paralysis

When given a challenging selection of choice, it becomes very hard to make any decision at all. Here a short-cut decision is likely to be made.


Clustering Illusion

Overestimating the importance of small patterns in large samples of random data.


Cognitive Dissonance

The state of inconsistent thoughts, beliefs or attitudes, beyond your present knowledge.


Confirmation Bias

Interpreting information in a way that confirms your preconceptions.


Conjunction Fallacy

The assumption that specific conditions are more likely than general ones.


Contrast Effect

The change of perception in relation to contrasting objects.


Costly Signalling

The idea that because a communication strategy costs a lot of money (heavy weighted envelopes, large street ads...), it may increase the potential for the messaging to be a success as there is an assumption that only really good things are worth that amount. The cost can also be in time or energy/effort.


Default Effect

Choice paralysis; when given the choice, people favour the default option.


Effort Justification

The tendency to attribute a higher value to something that has or will take more effort than the truer value of the effort afforded.


Endowment Effect

Considering something to be your own leads to the tendency to create a higher worth for it than you'd give it if you didn't own it.


Extremeness Aversion

This is the propensity to avoid making what could be deemed an extreme choice as this would be of higher risk to your social credentials or safety.


False-Consensus Effect

The tendency to overestimate how much other people agree with them.


Fear of Regret

What it says on the tin, the fear of regretting a decision.


Forer Effect

The tendency to propose a high accuracy to vague descriptions of 'them', that could, in fact, describe anyone. This is the basis of fortune telling and personality tests.



Using the context of information in a way as to create new meaning.


Fundamental Attribution Error

The tendency to overemphasise internal factors, such as personality, taste, emotional status for the reason behind a decision or action, rather than external factors that may indeed have a much greater impact on the decision or action.


Gambler's Fallacy

Ever got stuck on a roulette machine, thinking about your chances of winning next time around? This is the belief that past events have an influence on future probabilities.



The desire for harmony in a group, which leads to dysfunctional decision making.


Halo Effect

The knock-on of one positive impression to another potentially unconnected piece of information.


The Hawthorne Effect / Observer Effect

People act differently when they are being watched. This can obscure test results and experiments. If you want to remove this effect (as best as possible) set up the research as a field or natural experiment.


Hyperbolic Discounting

You can have one sweet now, or the whole bag in 3 months. What do you choose? This is the tendency to prefer immediate payoffs relative to later payoffs.


Ikea Effect

Attaching a higher value to things you have made.


Illusion of Attention

People falsely believe that they are taking in everything that happens in front of them, rather than just the information they are focusing on.


Illusion of Control

The overestimation of your control over external factors.


Illusion of Skill

Overestimating skill over chance.


Illusory Correlation

Seeing a correlation between two unconnected pieces of information.


Illusory Superiority

Overestimating your positive attributes and underestimating your less desirable qualities relative to other people. "I know I'm grumpy, but they're much more grumpy than me..." (says the grumpiest person you know)


Inductive Thinking

Perceiving universal 'truths' from individual observations.


In-Group Out-Group Bias

Favouring members of your own 'group' over members of other 'groups'. The definition of the group can be very arbitrary.


Introspection Illusion

The illusion that you have insight into your own mental states when this is often not true, and treating others introspections with scepticism.


Liking Bias

Being more susceptible to the ideas of someone you like.


Loss Aversion

The pain of giving up an object is greater than the joy of acquiring it.


Measurability Bias

Being biased towards data due it being measurable, rather than it truly being of use. Just because it can be measured doesn't make it useful information. Of course, the opposite is also true.


Motivation Crowding

Outside awards or motivations such as money or punishments can undermine intrinsic motivations.


Neglect of Probability

Disregarding probability when making an uncertain decision.



To be obsessed with the new.


Not-Invented-Here Bias

An aversion to things or information that stems from a place considered 'other'.


Outcome Bias

Judging decisions on the outcome of the decision, rather than the depth and quality of the decision making process.



Peak-End Rule

The tendency to perceive an experience by an average of its climax, rather than on the whole.


Planning Fallacy

The underestimation on how long tasks may take to complete.


Primacy and Recency Effects

In a long list of items, the things at the beginning and end are likely to be remembered most vividly


The Query Effect

People are able to make up an opinion about anything when asked. It doesn't mean that their answer will truly represent their actions, intentions or decision-making processes. This can be the source of useless insight.





Feeling obliged to reciprocate.


Representativeness Heuristic

Judgements that are based on similar issues that are considered known quantities.


Salience Effect

How something stands out from its 'peers'.


Scarcity Error

The assumption that anything scarce is valuable.


Self-Serving Bias

The tendency stake more of a claim to successes than failures.


Social Proof/ Herd Instinct

Baa! This is the tendency to follow the crowd.


Story Bias

The power of a narrative to elevate information.


Subjective Validation

Giving the status of truth to something that is really belief-based thought, this can give meaning to unrelated or coincidental occurrences.


Sunk Cost Fallacy

In investment terms, people tend to justify further investment into something based on having already invested (even though this original investment may have been wrong). In for a penny, in for a pound!


Zeigarnik Effect

This is where-

This is where interrupted or incomplete tasks can be better-

This is where interrupted or incomplete tasks can be better remembered than complete ones, potentially as the status of being incomplete causes tension.




It's a big list, I know. But really, this is just for reference when thinking about the different biases and choice making systems that you might try and tap in to or utilise for your communication advantage.

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