Once upon a time, three groups of subjects were asked how much they would pay to save 2,000 / 20,000 / 200,000 migrating birds from drowning in uncovered oil ponds. The groups respectively answered $80, $78, and $88.1 This is scope insensitivity or scope neglect: the number of birds saved—the scope of the altruistic action—had little effect on willingness to pay.
Similar experiments showed that Toronto residents would pay little more to clean up all polluted lakes in Ontario than polluted lakes in a particular region of Ontario, or that residents of four western US states would pay only 28% more to protect all 57 wilderness areas in those states than to protect a single area.2 People visualize “a single exhausted bird, its feathers soaked in black oil, unable to escape.”3 This image, or prototype, calls forth some level of emotional arousal that is primarily responsible for willingness-to-pay—and the image is the same in all cases. As for scope, it gets tossed out the window—no human can visualize 2,000 birds at once, let alone 200,000. The usual finding is that exponential increases in scope create linear increases in willingness-to-pay—perhaps corresponding to the linear time for our eyes to glaze over the zeroes; this small amount of affect is added, not multiplied, with the prototype affect. This hypothesis is known as “valuation by prototype.”
An alternative hypothesis is “purchase of moral satisfaction.” People spend enough money to create a warm glow in themselves, a sense of having done their duty. The level of spending needed to purchase a warm glow depends on personality and financial situation, but it certainly has nothing to do with the number of birds.
We are insensitive to scope even when human lives are at stake: Increasing the alleged risk of chlorinated drinking water from 0.004 to 2.43 annual deaths per 1,000—a factor of 600—increased willingness-to-pay from $3.78 to $15.23.4 Baron and Greene found no effect from varying lives saved by a factor of 10.5
A paper entitled “Insensitivity to the value of human life: A study of psychophysical numbing” collected evidence that our perception of human deaths follows Weber’s Law—obeys a logarithmic scale where the “just noticeable difference” is a constant fraction of the whole. A proposed health program to save the lives of Rwandan refugees garnered far higher support when it promised to save 4,500 lives in a camp of 11,000 refugees, rather than 4,500 in a camp of 250,000. A potential disease cure had to promise to save far more lives in order to be judged worthy of funding, if the disease was originally stated to have killed 290,000 rather than 160,000 or 15,000 people per year.6
The moral: If you want to be an effective altruist, you have to think it through with the part of your brain that processes those unexciting inky zeroes on paper, not just the part that gets real worked up about that poor struggling oil-soaked bird.
1 William H. Desvousges et al., Measuring Nonuse Damages Using Contingent Valuation: An Experimental Evaluation of Accuracy, technical report (Research Triangle Park, NC: RTI International, 2010).
2 Daniel Kahneman, “Comments by Professor Daniel Kahneman,” in Valuing Environmental Goods: An Assessment of the Contingent Valuation Method, ed. Ronald G. Cummings, David S. Brookshire, and William D. Schulze, vol. 1.B, Experimental Methods for Assessing Environmental Benefits (Totowa, NJ: Rowman & Allanheld, 1986), 226–235; Daniel L. McFadden and Gregory K. Leonard, “Issues in the Contingent Valuation of Environmental Goods: Methodologies for Data Collection and Analysis,” in Contingent Valuation: A Critical Assessment, ed. Jerry A. Hausman, Contributions to Economic Analysis 220 (New York: North-Holland, 1993), 165–215.
3 Daniel Kahneman, Ilana Ritov, and David Schkade, “Economic Preferences or Attitude Expressions?: An Analysis of Dollar Responses to Public Issues,” Journal of Risk and Uncertainty 19, nos. 1–3 (1999): 203–235.
4 Richard T. Carson and Robert Cameron Mitchell, “Sequencing and Nesting in Contingent Valuation Surveys,” Journal of Environmental Economics and Management 28, no. 2 (1995): 155–173.
5 Jonathan Baron and Joshua D. Greene, “Determinants of Insensitivity to Quantity in Valuation of Public Goods: Contribution, Warm Glow, Budget Constraints, Availability, and Prominence,” Journal of Experimental Psychology: Applied 2, no. 2 (1996): 107–125.
6 David Fetherstonhaugh et al., “Insensitivity to the Value of Human Life: A Study of Psychophysical Numbing,” Journal of Risk and Uncertainty 14, no. 3 (1997): 283–300.
I read the part of the cited press release that regarded the migratory waterfowl problem. To use this study as evidence of the existence of what you are calling scope insensitivity is a perfunctory maneuver. In the section, no mention is made of the framing of the question, the population from which participants were sampled, how they were assigned to their respective groups, and so forth. Were they informed that there would be a linear relationship between the amount of money spent and the extent of relief provided to the waterfowl, as is often the case in similar conundrums involving pedestrian quantities? Factors outside the scope of experimental design can be reasonably assumed to influence the answers of the participants as well. I see that the authors included attempts to attribute significance to explanatory variables but left out some possible variables that should be obvious. Do these people care at all about migratory waterfowl? How much money do they think a single waterfowl’s life is worth? Do they think saving migratory waterfowl will have a significantly positive effect on anything other than migratory waterfowl? What is the most valuable collection of cash they’ve ever seen or possessed in a single instance? Are they aware this is just an experimental survey, and their answers will have no influence on actual migratory waterfowl populations? I could devise 10,000 more questions relevant to this scenario that could drive these peoples' decisions towards apparent insensitivity that are not based on innate, indiscriminate insensitivity. Indeed, I’d wager that if a stranger approached me and asked, “if you had to, how much money would you spend to save 5,000 chickens in Whocaresville?”, my answer would probably not change whether it was 5,000 chickens or 5 trillion chickens. Not because I’m insensitive to the magnitudes being presented to me, but because I do not particularly care about chickens (especially those that have no tangible relationship to me), nor have I ever seen more than about $1,000 in cash that belongs to me (thus my internal scale of salient monetary values would inevitably stint my upper-limit on spending, regardless of the amount of chickens), nor do I have any idea how much money I should spend per chicken even if I did care, and most of all, I would likely realize that the question is entirely fantastical. My answer would likely change if I was asked how much money I’d spend on funding varying amounts of gene therapy research labs, for instance. The questions and arguments I’ve posed here equally apply to the Toronto study, and even the human life studies. One must realize that I have not claimed that so-called scope insensitivity does not exist, but that these studies provide tenuous evidence at best of its existence because of the lack of defensible generalizability of their results. If the claim being made was that people are insensitive to the magnitude of imagined results (such is the case in all these studies that posit made-up scenarios) that they have no personal reason to care about, then I would agree based on the presented evidence. Paradoxically, your concluding statement addresses effective altruists; scope insensitivity would be least likely to betide this group of people, since effective altruists are spending real money in the real world and causing real changes that they ostensibly care about. At the very least, we have little reason to assume it’d betide them off the basis of the aforementioned studies because the studies meet none of the conditions in the previous sentence.
A tangential rant on your comment regarding visualizing things: A specious statement has been made here, but I must admit you’re not the first to claim this nor will you be the last, and it’s probably not your fault that you think this. What law precludes every member of Homo sapiens from visualizing large quantities of objects? If you can visualize yourself flying in a helicopter over a football field blanketed by a single layer of individually visible chickens, you have successfully “visualized” roughly 57,000 chickens. Mind you, this asks a different question than those asking of the abstract interpretation of such quantities, which I believe to be a more important and useful question; this is what you may have been getting at, but you have not made it easy to infer that if that is the case. Regardless of this small digression, I see what you’re insinuating with this point. I wonder then if there has been a study investigating the effect of participants being exposed to visuals of gargantuan quantities prior to answering questions of spending.
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