__NOTOC__ Extension neglect is a type of

cognitive bias A cognitive bias is a systematic pattern of deviation from norm or rationality in judgment. Individuals create their own "subjective reality" from their perception of the input. An individual's construction of reality, not the objective input, m ...

which occurs when the

sample size Sample size determination is the act of choosing the number of observations or Replication (statistics), replicates to include in a statistical sample. The sample size is an important feature of any empirical study in which the goal is to make stat ...

is ignored when its

determination Determination is a positive emotional feeling that involves persevering towards a difficult goal in spite of obstacles.Kirby, L.D., Morrow, J., & Yih, J. (2014). The challenge of challenge: Pursuing determination as an emotion. In M. M. Tugade, ...

is relevant. For instance, when reading an article about a scientific study, extension neglect occurs when the reader ignores the number of people involved in the study (sample size) but still makes inferences about a population based on the sample. In reality, if the sample size is too small, the results might risk errors in

statistical hypothesis testing A statistical hypothesis test is a method of statistical inference used to decide whether the data at hand sufficiently support a particular hypothesis. Hypothesis testing allows us to make probabilistic statements about population parameters. ...

. A study based on only a few people may draw invalid conclusions because only one person has exceptionally high or low scores (

outlier In statistics, an outlier is a data point that differs significantly from other observations. An outlier may be due to a variability in the measurement, an indication of novel data, or it may be the result of experimental error; the latter are ...

), and there are not enough people there to correct this via averaging out. But often, the sample size is not prominently displayed in science articles, and the reader in this case might still believe the article's conclusion due to extension neglect. Extension neglect is described as being caused by judgment by prototype, of which the

representativeness heuristic The representativeness heuristic is used when making judgments about the probability of an event under uncertainty. It is one of a group of heuristics (simple rules governing judgment or decision-making) proposed by psychologists Amos Tversky and D ...

is a special case. Forms of extension neglect include: *

base rate neglect The base rate fallacy, also called base rate neglect or base rate bias, is a type of fallacy in which people tend to ignore the base rate (i.e., general prevalence) in favor of the individuating information (i.e., information pertaining only to a ...

insensitivity to sample size Insensitivity to sample size is a cognitive bias that occurs when people judge the probability of obtaining a sample statistic without respect to the sample size. For example, in one study subjects assigned the same probability to the likelihood of ...

scope neglect Scope neglect or scope insensitivity is a cognitive bias that occurs when the valuation of a problem is not valued with a multiplicative relationship to its size. Scope neglect is a specific form of extension neglect. In one study, respondents we ...

duration neglect Duration neglect is the psychological observation that people's judgments of the unpleasantness of painful experiences depend very little on the duration of those experiences. Multiple experiments have found that these judgments tend to be affecte ...

** the

peak–end rule The peak–end rule is a psychological heuristic in which people judge an experience largely based on how they felt at its peak (i.e., its most intense point) and at its end, rather than based on the total sum or average of every moment of the exp ...

* the

conjunction fallacy The conjunction fallacy (also known as the Linda problem) is an inference from an array of particulars, in violation of the laws of probability, that a logical conjunction, conjoint set of two or more conclusions is likelier than any single member ...

* the

less-is-better effect The less-is-better effect is a type of preference reversal that occurs when the lesser or smaller alternative of a proposition is preferred when evaluated separately, but not evaluated together. The term was first proposed by Christopher Hsee. I ...

The extension effect is "neither universal nor absolute". If attention is drawn to set size in an easily interpretable way, an additive extension effect is reported, according to which the valuation of a set is a function of the valuation of a prototypical member of the set ''added'' to set size, rather than ''multiplied''.

See also

Footnotes

Notes

References

Bibliography