Cognitive Biases and Psychology Effects

Entries are listed alphabetically. Cognitive biases are systematic errors in thinking that affect judgements and decisions. Psychology effects are broader empirical phenomena - observed patterns in behaviour or social dynamics - that don't always fit neatly under "bias" but are equally well-documented.

A note on cognitive distortions

Cognitive distortions - Beck's (CBT) term for maladaptive thinking patterns associated with depression and anxiety (catastrophising, all-or-nothing thinking, personalisation, mind-reading, and related constructs) - are sometimes treated as interchangeable with cognitive biases.

The Cognitive bias literature originates in experimental cognitive and social psychology. These are measured under controlled conditions and are largely descriptive and universal - heuristics are not errors in any straightforward sense, but adaptive shortcuts that happen to misfire in specific contexts. The distortions framework are derived primarily from clinical observation within Beck's cognitive model of depression, putting forward the idea of accurate thinking from which disordered cognition deviates.

Alloy and Abramson (1979) found that depressed people sometimes produce more accurate probability estimates than non-depressed people - the depressive realism finding - which complicates the claim that undistorted thinking is simply accurate thinking. That finding is still debated.

Actor-Observer Asymmetry

We tend to explain other people's behaviour by pointing to their character ("she's careless"), while explaining our own behaviour by pointing to circumstances ("I was under pressure"). The direction flips depending on whose actions we're judging.

Jones, E.E., & Nisbett, R.E. (1971). No DOI - book/book chapter.

Authority Bias

We give disproportionate weight to the opinions or instructions of perceived authority figures, even when those instructions conflict with our own judgement or ethical instincts.

Milgram, S. (1963). https://doi.org/10.1037/h0040525

Availability Heuristic

We estimate how likely something is based on how easily an example comes to mind. Vivid or recent events feel more common than they are; abstract or distant ones feel rarer.

Tversky, A., & Kahneman, D. (1973). https://doi.org/10.1016/0010-0285(73)90033-9

Barnum Effect (also: Forer Effect)

We accept vague, generally applicable personality descriptions - horoscopes, personality tests - as uniquely accurate about ourselves. The descriptions feel personal because they're broad enough to fit almost anyone.

Forer, B.R. (1949). https://doi.org/10.1037/h0059240

Meehl, P.E. (1956). https://doi.org/10.1037/h0044164

Bizarreness Effect

Unusual or bizarre information is remembered better than ordinary information. The memory system preferentially encodes what stands out.

McDaniel, M.A., & Einstein, G.O. (1986). https://doi.org/10.1037/0278-7393.12.1.54

Black Sheep Effect ⟨Psychology Effect⟩

We judge a disliked or norm-violating member of our own group more harshly than an equivalent outsider. Ingroup membership raises the standard - defecting from it is perceived as a greater threat than the same behaviour from an outgroup member.

Marques, J.M., Yzerbyt, V.Y., & Leyens, J.P. (1988). https://doi.org/10.1002/ejsp.2420180102

Cheerleader Effect (also: Group Attractiveness Effect)

People appear more attractive when seen as part of a group than when viewed individually. The group context averages out distinctive features, producing a more prototypically appealing impression.

Walker, D., & Vul, E. (2014). https://doi.org/10.1177/0956797613497969

Cinderella Effect ⟨Psychology Effect⟩

Stepchildren face statistically elevated risk of abuse and neglect compared to children living with both biological parents. The effect is interpreted through parental investment theory - genetic relatedness predicts caregiving investment across species, and humans are no exception.

Daly, M., & Wilson, M. (1998). No DOI - book/book chapter.

Confirmation Bias

We seek out, favour, and remember information that confirms what we already believe, and tend to ignore or underweight evidence that challenges it.

Wason, P.C. (1960). https://doi.org/10.1080/17470216008416717

Defensive Attribution

When someone suffers a misfortune, we are more likely to blame them for it if we perceive similarities between ourselves and them. Blaming them reassures us that we are safe - that we would not have made the same mistake.

Shaver, K.G. (1970). https://doi.org/10.1037/h0028777

Egocentric Bias

We overestimate our own contribution to shared outcomes - how much of the work we did, how central our role was.

Ross, M., & Sicoly, F. (1979). https://doi.org/10.1037/0022-3514.37.3.322

False Consensus Effect

We overestimate how many other people share our beliefs, values, and behaviours. Our own position feels like the default.

Ross, L., Greene, D., & House, P. (1977). https://doi.org/10.1016/0022-1031(77)90049-X

Fading Affect Bias

The emotional charge attached to negative memories fades faster than the emotional charge attached to positive ones. Bad memories don't disappear - but the unpleasant feeling connected to them weakens more quickly over time than the good feeling connected to good memories.

Walker, W.R., Vogl, R.J., & Thompson, C.P. (1997). https://doi.org/10.1002/(SICI)...

Fundamental Attribution Error

When explaining others' behaviour, we overemphasise personal traits and underestimate situational factors. We assume people act as they do because of who they are, not because of the context they're in.

Ross, L. (1977). https://doi.org/10.1016/S0065-2601(08)60357-3

Group Attribution Error

We assume that individual group members personally endorse the outcomes or decisions produced by their group - even when those outcomes emerged from group processes, majority votes, or external constraints.

Hindsight Bias

After an event, we believe we would have predicted it - that the outcome was obvious all along. This distorts how we learn from experience.

Fischhoff, B. (1975). https://doi.org/10.1037/0096-1523.1.3.288

Illusion of Asymmetric Insight

We feel we understand others better than they understand us, and better than they understand themselves. We perceive our own inner life as rich and complex; others' behaviour appears more transparent.

Pronin, E., Kruger, J., Savitsky, K., & Ross, L. (2001). https://doi.org/10.1037/0022-3514.81.4.639

Mood-Congruent Memory Bias

We are more likely to recall memories that match our current emotional state. Feeling low makes negative memories more accessible; positive moods prime positive recollections.

Bower, G.H. (1981). https://doi.org/10.1037/0003-066X.36.2.129

Rosy Retrospection

We remember past experiences - holidays, events, relationships - as more positive than we rated them at the time. Memory edits out the discomforts.

Mitchell, T.R., Thompson, L., Peterson, E., & Cronk, R. (1997). https://doi.org/10.1006/jesp.1997.1333

Self-Serving Attributional Bias

We attribute our successes to our own abilities and effort, and our failures to bad luck, other people, or circumstance. The attribution flips depending on the outcome.

Zuckerman, M. (1979). https://doi.org/10.1111/j.1467-6494.1979.tb00202.x

Self-Serving Bias

More broadly: we perceive and evaluate ourselves in ways that protect and enhance our self-image.

Greenwald, A.G. (1980). https://doi.org/10.1037/0003-066X.35.7.603

Source Confusion (also: Source Monitoring Error)

We misremember where a piece of information came from - confusing something we read with something we witnessed, or something we imagined with something that actually happened.

Schacter, D.L. (1996). No DOI - book/book chapter.

Spacing Effect

Information is retained better when study is spread across multiple sessions rather than concentrated in one. Distributed practice consistently outperforms massed practice.

Ebbinghaus, H. (1885). No DOI - book/book chapter.

Suggestibility

Misleading information encountered after an event can alter our memory of that event. Memory is reconstructive, not a fixed recording - it is vulnerable to post-hoc contamination.

Loftus, E.F., & Palmer, J.C. (1974). https://doi.org/10.1016/S0022-5371(74)80011-3

Telescoping Effect

We misjudge when past events occurred. Recent events tend to feel further away than they are (forward telescoping); distant events tend to feel closer (backward telescoping).

Rubin, D.C., & Baddeley, A.D. (1989). https://doi.org/10.3758/BF03202626

Testing Effect (also: Retrieval Practice Effect)

Actively retrieving information from memory - through testing or self-quizzing - produces more durable learning than re-reading the same material.

Roediger, H.L., & Karpicke, J.D. (2006). https://doi.org/10.1111/j.1467-9280.2006.01693.x

Ultimate Attribution Error

An extension of the fundamental attribution error to entire groups. Negative behaviour by outgroup members is attributed to their character; positive behaviour is explained away as luck or exception. The same logic is applied in reverse to ingroup members.

Pettigrew, T.F. (1979). https://doi.org/10.1177/014616727900500407

Von Restorff Effect (also: Isolation Effect)

An item that stands out from its surroundings - by colour, size, position, or novelty - is remembered significantly better than comparable items that blend in.

Von Restorff, H. (1933). No DOI - predates DOIs.

Women are Wonderful Effect ⟨Psychology Effect⟩

Both men and women tend to evaluate women more positively than men on measures of attitude and evaluative stereotype content - the female stereotype carries a more favourable evaluative tone than the male stereotype. The effect is considered a form of benevolent bias: superficially positive attitudes toward women that can coexist with, and reinforce, broader patterns of gender prejudice.

Eagly, A.H., & Mladinic, A. (1994). https://doi.org/10.1080/14792779543000002

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