Recency Bias

Recency Bias


Recent events and trends are easier to remember and discern than either events in the distant past or unknown events that will occur in the future. Rather than studying the past or accepting the fact that, despite our best efforts, we are often useless at predicting future events (both require effort), we fall prey to Recency Bias.

Recency Bias (or, Recency Effect Bias): the tendency to weigh recent events more heavily than earlier events. Often classified as one of many different decision-making errors, or biases, and closely related to the human tendency towards Cognitive Ease, i.e. the preference for readily accessible cognitive information (memory, pattern-matching, explanation, interpretation etc.) over the less accessible cognitions only available through the hard work of “thinking, analysing and deciding”[1].

At a more specific level, a particular example of Recency Bias can be demonstrated by limitations in human memory capacity, as shown by the Recency Effect.

Recency Effect: people are much more able to remember the final numbers/digits/objects of a string of numbers/digits/objects, whether presented visually or audibly[2]. This effect becomes more likely as the string of numbers/digits/objects increases beyond our short-term memory capacity[3].

Perhaps the difference between Recency Bias and Recency Effect is that the former is dictated by habitual laziness, and the latter by limitation. We have a choice in the first case, but no choice in the second.


Recency Bias can manifest itself in many different ways, and is closely linked, or conflated with several other cognitive errors and biases, such as Familiarity Bias, Continuation BiasExpectation Bias and Confirmation Bias. Like these other cognitive biases (or, decision-making errors) Recency Bias is most likely to occur when under time stress; basically, because it relieves cognitive capacity for activities considered as higher priority. Some example situations are provided below.

  • Repetition, habit and/or familiarity: if an air traffic controller is repeatedly issuing the same instructions to different aircraft, one after the other, e.g. contact Centre on 118.425 then he/she is more likely to make an error, by repeating the familiar, when required to issue a different instruction, say, contact Area on 118.45.
  • Evaluation: a pilot, when faced with abnormal engine parameters, or responses, may diagnose the fault incorrectly, because he/she had a similar (but not exactly the same) experience recently, and in that case the chosen diagnosis was correct. Rather than fully investigate the uniqueness of the current problem, decision-makers can opt for the familiar; and, the most recent events are given greater importance as they are more easily recalled.
  • Expectation: this concerns our tendency to predict that performances, trends and patterns we have observed in the recent past will continue in the future. Anyone who has tried predicting stock market activity from recent results will know the folly of this tendency. This may concern our own performance e.g. if our last landing at Kolndorf runway 27L at night with a crosswind lead to a near excursion, we may expect the same to happen again when the conditions are similar. Of course, with this example, this bias may result in additional awareness and application of skill, thereby improving safety; however, the stress and anxiety may lead to a reduction in performance and a reinforcing of negative expectations in the future. This may also concern the performance of others (e.g. expecting late deceleration permission from ATC, or expecting poor cross-monitoring from Captain), and even equipment (e.g. not trusting the heaters in a de-icing vehicle, or over trusting the ability of a surface movement radar to detect vehicles).


The points made below are not exclusive nor comprehensive, but should be considered as points for discussion when trying to explain how Recency Bias (and other biases) can be mitigated against, in practice.

  • Training: Raising awareness of Recency Bias (and others) through crew resource management (CRM), team resource management (TRM), and human factors training is a necessary first step. Part of this process should include discussion and review of occasions (preferably personal experiences) where Recency Bias may have contributed to a reduction in safety.
  • CRM: when time stress is low, requiring team leaders (e.g. Captains) to involve teams, and crews, in the decision-making process, and encourage production of many options for action, giving each equal weight, regardless of who offered the suggestion, or which suggestions came first or last. Note: seemingly in contradiction to Recency Bias, Primacy Bias gives greater importance to solutions that present themselves first, i.e. which come easily to mind. However, such easily forthcoming solutions may well be as a result of Recency Bias!
  • Checklists/Procedures: following standard checklists and procedures (even decision making and memory aids) can reduce the chances of subjective thoughts and feelings over-ruling a more rational appraisal of the situation.
  • Data: seek as much data, facts and contextual information as possible before making decisions.
  • Expect Randomness: (at least sometimes), avoid the need to try and explain every single situation by joining the dots. Some things do happen at random, or as one-off unique events, and often we do not have too many relevant dots to join.

Related Articles


  1. ^ Kahneman, D., 2011. Thinking Fast and Slow. London. Penguin Books.
  2. ^ Reason, J., 1990. Human Error. Cambridge, UK. Cambridge University Press.
  3. ^ Memory in ATC

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