Availability Bias Explained: How Easy Memories Trick Your Judgment

We constantly process the stimuli from the world, make judgements, and respond. However, the process is not as calculating and perfect as we tend to believe. We employ a variety of cognitive heuristics to speed processing. Consequently, our speedy responses sometimes fail in accuracy. One of these cognitive heuristics is availability bias. This heuristic is a cognitive bias that affects how we make decisions and assess the probability of events based on the ease with which examples or instances come to mind. This bias leads us to overestimate the likelihood of events that are easily remembered or readily available in our memory.

Behavior economics examines psychological mechanisms, such as availability bias, that interfere with our ability to accurately evaluate the frequency and probability of events. Availability bias exerts tremendous influence over decision making. For example, during the COVID-19 epidemic, since the virus was ever-present on everybody’s minds, doctors quickly diagnosed an ill patient with COVID-19, while other, possibly more dangerous, possibilities were overlooked. In makes sense, since most respiratory problems during the time were COVID-19, a quick diagnosis, allowed treatment to begin.

However, most of these decisions weren’t a conscious, deliberated diagnosis. Other symptoms, not associated with the corona virus were overlooked, and opportunity for proper treatment delayed. Doctors, like everyone else, are subject to the thinking errors common to humanity. We make decisions based on what information is presently available in our limited workstation of our mind. Basically, it is impossible to evaluate decision on every bit of data we know. Accordingly, we pull the most easily accessed criteria into working memory and from there make a decision.

How Availability Bias Influences Decision Making

When we make decisions, our minds tend to rely on information that is easily accessible and readily available in our memory. This information could include recent events, vivid experiences, personal anecdotes, or even information that is frequently highlighted in the media. For example, after the release of the movie Sybil in 1976, there was a rush of new cases of a rare form of dissociative disorder. Patients complained of similar ‘Sybil’ like symptoms and professionals followed suit at diagnosed multiple personality disorder diagnosed.

Amos Tversky and Daniel Kahneman, the pioneers of behavior economics, proposed that “when faced with the difficult task of judging probability or frequency, people employ a limited number of heuristics which reduce these judgments to simpler ones” (Tversky & Kahneman, 1973).

Frequency and Probability

Typically, we predict probability based on frequency of past occurrences. Basically, how things happened before are likely to continue to occur in the future. However, recency of memories blurs our ability to establish frequency. Accordingly, events that have happened recently appear, at least in the unconscious mind, to occur more frequently. Studies reveal that “at any level of actual frequency, items that were better recalled were judged more frequent” (Tversky & Kahneman, 1973).

Leonard Mlodinow explains, “we give unwarranted importance to memories that are most vivid and hence most available for retrieval. The nasty thing about the availability bias is that it insidiously distorts our view of the world by distorting our perception of past events and our environment” (Mlodinow, 2008).

Reid Hastie and Robyn M. Dawes explain that “many of the judgments we make are memory-based in the sense that we don’t have the ‘data’ necessary to make the judgment right in front of us, but we have learned information in the past, now stored in long-term memory, that is relevant to the judgments. This simple form of associative thinking is called the availability heuristic by researchers, and we rely on ease of retrieval to make a remarkable variety of judgments” (Hastie & Dawes, 2009).

Ease of Recalling Examples

Evaluating probability of an event is strongly influenced by the ease in which we can recall past examples. Strong emotional events are imprinted on our mind and are more salient when making decisions. Scott Plous explains that “the availability heuristic is a rule of thumb in which decision makers assess the frequency of a class or the probability of an event by the ease with which instances or occurrences can be brought to mind” (Plous, 1993. p. 121).

Casino owners love this phenomenon. The gambler distinctively remembers the four hundred dollar win (emotional memory), however, conveniently overlooks the five hundred one dollar losses. The lucky risk taker feels like a winner after losing one hundred dollars at the slots.

How Availability Bias Influences Decision Making

Availability bias can influence our decision-making process in several ways:

• Selective Perception: Availability bias causes us to focus on information that supports our existing beliefs or biases. We may overlook or dismiss contradicting evidence simply because it is not prominent or readily available in our memory.
• Overestimating Probability: When vivid or memorable events come to mind easily, we tend to overestimate their likelihood of occurrence. For example, if we frequently hear news stories about plane crashes, we might become more fearful of flying even though statistically it is a safe mode of transportation.
• Neglecting Statistical Data: Availability bias often leads us to neglect statistical data and rely more on examples from memory. This can lead to inaccurate assessments of risk and probability. For instance, people may avoid swimming in the ocean after hearing about a shark attack, despite the fact that the chances of being attacked by a shark are extremely low.
• Impact on Decision-Making: Availability bias can have a significant impact on decision-making, both in personal and professional contexts. It can affect choices related to investments, career decisions, purchasing decisions, and even medical diagnoses (Kyere, et al., 2022).

Overcoming Availability Bias

Being aware of availability bias is the first step towards overcoming its influence on decision-making. Here are some strategies to help mitigate the effects of availability bias:

• Seek Diverse Perspectives: Actively seek out diverse opinions and viewpoints. Consider alternatives and different sources of information before making a decision. This helps broaden your perspective and reduces the reliance on easily available information.
• Rely on Statistical Data: When making decisions, rely on objective and statistical data rather than personal anecdotes or vivid examples. Look for reliable sources of information that present a comprehensive view of the topic at hand.
• Take Time for Reflection: Slow down the decision-making process and take time for reflection. Analyze the situation carefully, weigh the pros and cons, and consider all relevant factors before reaching a conclusion.
• Challenge Your Assumptions: Question your own biases and assumptions while making decisions. Ask yourself if you are basing your judgement on solid evidence or if availability bias is influencing your decision. This self-reflection helps to make more rational and well-informed choices.

Associated Concepts

• Rational Thought: This style of thought integrates diverse information sources to derive meaning. It’s hindered by biases and emotions, which can lead to irrational beliefs and behaviors. Mindfulness can enhance rational thinking by promoting critical reflection and decoupling from biases and emotions.
• Selective Attention: This refers to a vital cognitive process that allows us to focus on specific stimuli while filtering out distractions. It helps optimize our cognitive abilities, manage information overload, and make better decisions. Understanding its principles provides practical insights for enhancing focus and productivity in daily life.
• Heuristics and Biases: This concept explores how people often use mental shortcuts in decision-making, which can lead to systematic errors or biases.
• Attentional Control Theory: This theory provides a psychological framework that examines the influence of anxiety on an individual’s ability to maintain attention on tasks. It posits that anxiety can disrupt the balance between two types of attentional systems: the goal-directed system, which is under voluntary control, and the stimulus-driven system, which is automatic and reactive to external stimuli.
• Cognitive Load: Cognitive load refers to the demand of current cognitive tasks on limited cognitive resources.
• Hostile Media Effect (HME): This is a bias where individuals perceive media coverage as skewed against their own views. This phenomenon arises due to cognitive distortions, selective information processing, and subjective perceptions, impacting societal polarization and media influence on behavior and perception.

A Few Words by Psychology Fanatic

By understanding and actively working against availability bias, we can significantly enhance our capacity to make informed and rational decisions. This cognitive heuristic often leads us astray, causing us to rely on readily available information rather than considering the broader spectrum of relevant data. Acknowledging its presence in our decision-making processes is crucial; it allows us to step back from impulsive judgments and engage in more thoughtful analyses. While we may never completely eliminate these biases from our thinking—nor would we necessarily want to, as they serve a purpose in streamlining our cognitive load—we can adopt strategies that promote critical reflection. By challenging ourselves to question the information at hand, we pave the way for better decision-making outcomes.

Moreover, actively mitigating the effects of availability bias not only empowers us as individuals but also fosters an environment of collaborative learning and growth within groups and organizations. When teams prioritize diverse perspectives and statistical evidence over anecdotal experiences, they cultivate a culture where sound judgment prevails over instinctive errors. Such mindfulness enables all members involved to contribute their unique insights without fear of disregarded viewpoints. As we strive for clarity in our decision-making processes, let’s remember that by consciously confronting availability bias together, we can elevate the quality of decisions made collectively—ultimately steering towards successful resolutions while avoiding potential pitfalls along the way.

Last Update: July 19, 2025

References:

Hastie, Reid; Dawes, Robyn M. (2009). ‎Rational Choice in an Uncertain World: The Psychology of Judgment and Decision Making. SAGE Publications, Inc; Second edition.
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Kyere, K.; Aremu, T.; Ajibola, O. (2022). Availability Bias and the COVID-19 Pandemic: A Case Study of Legionella Pneumonia. Cureus. DOI: 10.7759/cureus.25846
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Mlodinow, Leonard (2008). The Drunkard’s Walk: How Randomness Rules Our Lives. Vintage.
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Plous, Scott (1993). The Psychology of Judgment and Decision Making. McGraw-Hill; First Edition.
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Tversky, Amos; Kahneman, Daniel (1973). Availability: A heuristic for judging frequency and probability. Cognitive Psychology, 5(2), 207-232. DOI: 10.1016/0010-0285(73)90033-9
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