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.^[1]

In one study, respondents were asked how much they were willing to pay to prevent migrating birds from drowning in uncovered oil ponds by covering the oil ponds with protective nets. Subjects were told that either 2,000, or 20,000, or 200,000 migrating birds were affected annually, for which subjects reported they were willing to pay $80, $78 and $88 respectively.^[2] Other studies of willingness-to-pay to prevent harm have found a logarithmic relationship or no relationship to scope size.^[3]

Daniel Kahneman explains scope neglect in terms of judgment by prototype, a refinement of the representativeness heuristic. "The story [...] probably evokes for many readers a mental representation of a prototypical incident, perhaps an image of an exhausted bird, its feathers soaked in black oil, unable to escape,"^[4] and subjects based their willingness-to-pay mostly on that mental image.

References

1. Kahneman, Daniel (2000). "Evaluation by moments, past and future". In Daniel Kahneman and Amos Tversky (Eds.). Choices, Values and Frames. p. 708.
2. Desvouges, William F.; Johnson, Reed; Dunford, Richard; Boyle, Kevin; Hudson, Sarah; Wilson, K. Nicole (1992). "Measuring Non-Use Damages Using Contingent Valuation: An Experimental Evaluation of Accuracy" (PDF). Research Triangle Institute Monograph 92–1. doi:10.3768/rtipress.2009.bk.0001.1009.
3. Kahneman, Daniel; Ritov, Ilana; Schkade, Daniel (1999). "Economic Preferences or Attitude Expressions?: An Analysis of Dollar Responses to Public Issues" (PDF). Journal of Risk and Uncertainty 19: 203–235. doi:10.1007/978-94-017-1406-8_8.
4. p. 212