PsychologicalDUAL-USE

Scope Insensitivity

What it is

The failure of valuations, emotions, and willingness to pay to scale with the size of a problem — two thousand, twenty thousand, and two hundred thousand affected can feel, and be valued, almost the same.

How it works

In a 1992 contingent-valuation study, Desvousges and colleagues asked people what they would pay to prevent migratory birds from drowning in uncovered oil ponds; the stated amounts for saving 2,000, 20,000, and 200,000 birds were about 80, 78, and 88 dollars. Kahneman and Knetsch (1992) argued that such answers are not valuations of the birds at all but purchases of moral satisfaction — the respondent pays for the feeling of having helped, and the feeling is produced by a prototype (one oil-soaked bird), not by a quantity. Fetherstonhaugh, Slovic and colleagues (1997) found the same psychophysical numbing for human lives — a program saving a fixed number was valued less when the affected population was larger — and Hsee and Rottenstreich (2004) showed that the more emotionally engaged the judgment, the flatter its relationship to quantity. The bias makes numbers negotiable. Advocates and officials of every stripe present a million and a billion with the same outrage; budget fights fixate on items that are rounding errors while the large lines pass unexamined; charities know a single prototype beats a count; and any pitch that gives you a vivid case without a number is betting that you will not ask.

Real-world examples

  • •Desvousges and colleagues (1992): willingness to pay to save 2,000, 20,000, or 200,000 migratory birds was statistically indistinguishable — a hundredfold difference in scope produced almost no difference in value.
  • •Fetherstonhaugh, Slovic, Johnson and Friedrich (1997): a medical program that would save 4,500 lives was judged more worthwhile when the at-risk population was 11,000 than when it was 250,000; the same lives were worth less as a proportion than as a number.
  • •Public estimates of US foreign aid have for decades placed it near a quarter of the federal budget, against an actual share of about one percent; politicians on both sides have proposed cutting it as if the savings were large, and earmark scandals — the 2005 Alaska “bridge to nowhere”, the 2011 “shrimp on a treadmill” report — drew more outrage than entitlement lines a thousand times larger.
  • •Charity appeals that describe one child or one village raise more than appeals that describe a million, and the research suggests adding the million can lower giving; the sector's reliance on prototypes is a rational response to the bias, and a reason to check the scale yourself.
  • •Insurance for a vivid single risk — flight insurance, a phone screen, an extended warranty — is bought at prices far above expected loss, while coverage for the large, dull, catastrophic risks that would actually ruin the buyer is under-purchased.
  • •A partner's or manager's reaction to a mistake is often sized to how the mistake feels rather than to what it cost; the same insensitivity lets a small vivid failure and a large invisible one draw the same response.

Ethical guidelines

Where the line is

Making a quantity vivid with one example is honest when the quantity is also stated and the example is representative; the line is crossed when a persuader relies on the audience's insensitivity to scale — inflating a trivial sum into an outrage or shrinking an enormous one into a footnote — so that the decision is made on the prototype rather than the number.

  • ●State the number, the base, and the unit — deaths per year, dollars per person, percent of the budget — whenever you ask people to care about a quantity; the prototype is not the argument.
  • ●Do not present a rounding error as a scandal or a major line as a footnote; if the outrage you generate would reverse if the audience saw the proportions, it is manufactured.
  • ●Using a single case to make a large number comprehensible is legitimate; using it to hide the number is not.
  • ●When you sell protection against a vivid risk, disclose the size of the risk next to the price.

How to defend against it

  • ►Ask “how many, out of how many, over what period?” of every alarming or heart-warming figure; then convert it to a per-person or per-year rate you can compare with something familiar.
  • ►Put budget numbers on a common scale — percent of the total — before judging them; a million, a billion, and a trillion are not different flavors of large.
  • ►Decide how much to give or spend by multiplying: what one life or one unit is worth to you, times the number affected; feelings will not do the multiplication for you, and that is the whole problem.
  • ►When a pitch offers a face and no count, ask for the count; when it offers a count and no base, ask for the base.
  • ►Insure against the catastrophic and dull, not the vivid and small; the vividness of a risk is not its size.

References

  1. Desvousges, W. H., Johnson, F. R., Dunford, R. W., Boyle, K. J., Hudson, S. P., & Wilson, K. N. (1992). Measuring nonuse damages using contingent valuation: An experimental evaluation of accuracy. Research Triangle Institute Monograph 92-1
    The migratory-bird study in which willingness to pay did not scale with the number of birds saved.
  2. Kahneman, D., & Knetsch, J. L. (1992). Valuing public goods: The purchase of moral satisfaction. Journal of Environmental Economics and Management, 22(1), 57-70
    The moral-satisfaction account of why stated values ignore scope.
  3. Fetherstonhaugh, D., Slovic, P., Johnson, S. M., & Friedrich, J. (1997). Insensitivity to the value of human life: A study of psychophysical numbing. Journal of Risk and Uncertainty, 14(3), 283-300
    Psychophysical numbing for human lives and the proportion-versus-number finding.
  4. Hsee, C. K., & Rottenstreich, Y. (2004). Music, pandas, and muggers: On the affective psychology of value. Journal of Experimental Psychology: General, 133(1), 23-30 · link
    Evidence that affect-based valuation is nearly flat with respect to quantity.
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