The Volokh Conspiracy

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Slippery Slope Arguments

Small Change Tolerance Slippery Slopes (Reposted)

[I originally erred in posting this, which kept comments from being available; I've therefore deleted the original and reposted it.]


[This month, I'm serializing my 2003 Harvard Law Review article, The Mechanisms of the Slippery Slope.]

Libertarians often tell the parable of the frog. If a frog is dropped into hot water, it supposedly jumps out. But if a frog is put into cold water that is then heated, the frog doesn't notice the gradual temperature change, and eventually dies. Likewise, the theory goes, with liberty: people resist attempts to take rights away outright, but not if the rights are eroded slowly.

{I have not checked this myself, nor do I intend to. Some sources suggest that real frogs don't behave this way. But consider the discussion as referring to the metaphorical frog—a creature much like the metaphorical ostrich, which (unlike a real ostrich) does bury its head in the sand when danger looms, and which is thus far more useful to us than a real ostrich could ever be.}

The frog doesn't notice the increase because of a sensory failure; it senses not absolute temperature but changes in temperature. Perhaps our decisionmaking skills suffer from an analogous cognitive feature. Maybe we underestimate the importance of gradual changes because our experience teaches us that we needn't worry much about small changes—but unfortunately this trait sometimes leads us to unwisely ignore a sequence of small changes that aggregate to a large one.

This theory suggests that we just don't pay much attention to the small change from 0 to A, the small change from A to B, and so on, even though we would have paid attention to the change from 0 all the way to E. This is not an attitude-altering slippery slope, or a multi- peaked preferences slippery slope: the small shifts don't necessarily persuade people to eventually support the next shift, and don't move the law to a politically unstable position. Rather, people simply don't pay much attention to each shift.

Consider, for instance, the following exchange:

[Peter] Jennings: And the effect of the assault rifle ban in Stockton? The price went up, gun stores sold out and police say that fewer than 20 were turned in. Still, some people in Stockton argue you cannot measure the effect that way. They believe there's value in making a statement that the implements of violence are unacceptable in our culture.

[Stockton, California] Mayor [Barbara] Fass [(a supporter of the ban)]: I think you have to do it a step at a time and I think that is what the NRA is most concerned about, is that it will happen one very small step at a time, so that by the time people have "woken up"—quote—to what's happened, it's gone farther than what they feel the consensus of American citizens would be. But it does have to go one step at a time and the beginning of the banning of semi-assault military weapons, that are military weapons, not "household" weapons, is the first step.

Did Mayor Fass have reason to believe that Americans might indeed take time to wake up to changes that "happen one very small step at a time," or was she mistaken?

Small Change Apathy, Small Change Deference, and Rational Apathy

Let's say a legislator is proposing a ban on .50-caliber rifles. Some kinds of guns are already entirely or mostly banned, while other kinds are allowed. You know that .50-caliber rifles are fairly rare; neither you nor anyone you know owns one. And no one is claiming that the .50-caliber rifle ban will by itself significantly impair gun rights or significantly decrease gun crime. What is your reaction to this proposal?

Most people would probably say "I don't much care" (at least unless they have slippery slope concerns in mind). People have limited time to spend on policy questions; they'd rather invest this time in researching and discussing a few big, radical policy changes than many small, incremental ones. Even if their gut reaction is against the law, they won't feel strongly about it. We might call this small change apathy.

This apathy may be exacerbated by the media's relative lack of interest in small changes. Media outlets want stories that they can tout as big and important. A small change might get little coverage, especially if it's in an already unsexy area of the law, or at the state or local level rather than the federal level.

{Even small changes may sometimes be heavily covered if they touch on a hot issue (such as abortion); there, attempts to change the law in five small steps might draw more aggregate attention than attempts to make the change in one large step. But if the question is less hotly contested, the steps may be small enough that they fall below the media's threshold for serious coverage.}

Media outlets also operate with what one might call subsequent step apathy: they prefer to cover novel changes rather than the latest change in a long progression, partly because it seems more exciting to the journalists, and partly because viewers prefer the novel. Reporters tend to be less likely to cover a story about the sixth or seventh step in the sequence; try pitching such a story to them and see how far you'll get.

If voters are generally apathetic about small changes, they may support the law just because they know that some influential opinion leaders—politicians, the media, or reputable interest groups—support it. Voters might not defer to expert judgment on big debates (for instance, should dozens of varieties of guns, owned by 20% of the population, be banned all at once?), but for small changes, they might prefer to follow the experts rather than investing the time and effort into arriving at an independent conclusion.

We might call this decisionmaking process the small change deference heuristic—if a change seems small enough, defer to elite institutions, so long as you think the institutions are right on most issues most of the time. Like most heuristics, this one stems from rational ignorance (or rational apathy): when there seems to be little at stake in a decision, and the cost of making the decision thus exceeds the benefit of independent investigation, deferring to others makes sense, even if their views don't always perfectly match your own.

Of course, any investment of effort by typical voters may be irrational if their only goal is simply bettering their own lives—the chances of any vote affecting the result are too slight to outweigh the costs of learning about the issues. But many voters also enjoy feeling informed about important political matters and being able to discuss such matters intelligently with friends. These voters likely get less utility from feeling educated about the proposed small changes than from feeling educated about the big ones; they are thus more willing to remain rationally ignorant and rationally apathetic, and to defer to authorities, on the small proposals. And this is doubly true for potential volunteers and contributors, who'd rather spend their time and money on big issues than on small ones.

Voters' small change deference heuristic may also carry over to legislators: when voters care little about a proposal, legislators will tend to care little about it as well (though other factors, such as interest group pressures, party discipline, and political friendships and enmities, may counteract or reinforce this tendency). But beyond this, legislators may themselves be rationally ignorant or apathetic about certain proposals, and may often defer to elite opinion or the views of fellow legislators and the party leadership. Lawmakers and their staffs have more time to devote to policy questions than voters do, but they also have more questions to deal with. A state legislator facing a budget battle, education reform, and a .50-caliber rifle ban might understandably defer to others' views on the last question—or, as discussed below, might be willing to compromise on this issue to get something valuable on some other issue.

This small change deference heuristic doesn't itself favor all small changes; rationally ignorant voters may defer to others' opposition to the changes as well as to others' support of them. But the heuristic does favor small changes that are supported by elite institutions. Thus, for instance, gun rights supporters in a state where the media favors gun control more than the public does might worry that their gun rights may be eroded in small steps unless mildly pro-gun-rights voters are made aware of the slippery slope risk.

Small change apathy likewise favors small changes that are backed by intense supporters. In politics, a strongly committed minority may often prevail if the majority on the other side is less concerned about the issue. Thus, in a state where pro-life voters are better organized and on average more committed than pro-choice voters, abortion rights supporters might worry that abortion rights may be gradually eroded by a sequence of small pro-life victories, unless the mildly pro-choice voters block each small change.

{Of course, people might also pay more attention—and express more opposition—to all the small changes in the aggregate than to one sharp shock. For instance, if some people strongly oppose any tax increase, no matter how small, it might be easier for supporters of higher taxes to increase the tax rate from 20% to 40% in one big political fight, rather than fighting ten battles over ten 2% increases. The same may apply if people oppose even tiny new burdens on abortion rights, gun rights, privacy rights, free speech rights, or economic freedom, perhaps precisely because they worry about the small change tolerance slippery slope; I will discuss this possibility in more detail below, in section IV.A. Furthermore, people may sometimes get disillusioned with a sequence of small changes when each change has little effect, and may therefore lose enthusiasm for small changes of that sort. For now I just want to claim that, at least in some situations, the aggregate opposition to a series of small changes might be less than the opposition to one large one.}