Lawyers are trained to think logically and analytically. So, if a category ABC includes A, B, and C, one would expect the total, ABC, to be the same as A, B, and C measured separately. But it isn’t always. When human decision-making is factored in, the sum of A, B, and C measured separately will almost certainly be greater than ABC. That is called the “unpacking bias” – when a category is subdivided into parts, then a separate consideration of each of those parts will be greater than the consideration given toward the category when treated as a whole, rather than unpacked.

This bias has implications across several cognitive tasks. Most obviously, it applies to damages: If you give your jury three categories involving different types of noneconomic damages, for example, they will generally award more than they would have awarded if they had been given just the summary category called “noneconomic damages.” This underscores the intuition that more categories will help the plaintiff, while fewer categories (even when those categories are designed to be inclusive) are better for the defendant. The bias also applies to other situations, like assessing risks. In this post, I will take a look at some recent research on the unpacking bias and why it should matter to legal persuaders.

Damages: Defendants Should Pack, Plaintiffs Should Unpack

A single-line figure for damages will net a lower award, and the same damages broken out into categories will net a higher award. The phenomenon is well-known and part of the practical lore of both plaintiffs and defendants, but it has not been extensively studied. One study (Polavin & Wang, 2017), presented at the conference of the American Society of Trial Consultants, does offer some support. Looking at automotive and medical malpractice cases, the researchers found that when the noneconomic damages were unpacked into explicit subcategories — “Loss of enjoyment of life,” “Disfigurement,” “Mental suffering” and “Physical pain” — the total amount awarded was significantly higher than if the award was left in a summary category of “Noneconomic (pain and suffering).”

The researchers also found that inclusion of atypical categories (like “Humiliation”) held awards down. So Plaintiffs don’t want to unpack so much that they’re including categories that jurors might reject. If they do, that can cause a skeptical ripple effect, bringing the averages down in the other categories, as well.

Risk Assessment: Pack to Minimize, Unpack to Maximize

The unpacking effect is most obvious as it relates to damages, but it also plays a role in other cognitive tasks involving addition. In risk perception, we aren’t necessarily objective or analytical (Hoorens, 2020). For example, our perception of risks can be strongly influenced by the number of categories we are given. One recent study (Scherm et al., 2020) demonstrated that “the perceived probability that an event will occur generally increases when the event’s description is unpacked into a dis-junction of sub-events.” Asking investment managers to estimate the probability of a future event, they found that the estimate depends on whether it is described as one event, or as several sub-events. The more it is unpacked, the higher its perceived overall likelihood.

Practically, this suggests that subdividing the ways that risks can occur increases our emotional or intuitive perceptions of these risks. For example, let’s say you want to sensitize your voir dire panel toward the possibility of an accidental injury at work; instead of asking just once about “the chance of accidental injury,” it would be better to ask about each of a number of kinds of workplace injuries, including those related to travel, equipment, desk work, criminal activity, weather events, etcetera.

There are other situations where this bias applies. In distributing responsibility, for example, even as jurors are usually able to get the percentages to add up to 100 percent, it is likely that including a greater number of individuals and entities to that calculation will result in a broader overall sense of liability. That, in turn, is a factor that could result in the perception of greater damages. Jurors will try to approach things rationally, but biases like the unpacking bias provide the reminder that there are extra-logical factors at play as well.