Case Order Effects in Legal Decision-Making

Does justice depend on the order in which cases are presented?

In a perfect legal system, justice should be consistent. We expect judges and juries to apply the same rules and values to each case, regardless of whether it is the first or last case they have seen that month. However, research suggests that legal outcomes may be influenced by the order in which cases are presented. This is known as the power of case order effects.

Psychologists have investigated how the order of cases affects moral judgment using the well-known “trolley problem.” This research examines how people’s intuitions may change depending on what they are shown first. For example, people may be more likely to choose a “utilitarian” option, such as switching a track to save five lives at the cost of one, when that option is presented first. However, they may become more disapproving of that same type of reasoning if they have just judged a more emotionally difficult scenario, such as pushing someone off a bridge to save others.

The research discussed in this article shows that these biases can leak into the justice system, which has important implications for both civil and criminal law.

Study 1: Life, Death, and Civil Law

The first study investigated a civil law scenario involving assisted suicide for the purpose of organ donation. Participants were presented with two cases:

1. A patient with multiple sclerosis, or MS, who wanted to end their life and donate their organs.

2. A patient diagnosed with long-term depression who also wanted to end their life and donate their organs.

When the cases were judged separately and in isolation, the MS case received higher approval, with a 58% acceptability rate. The depression case, on the other hand, was largely rejected, with only a 33% acceptability rate.

However, when participants were given the depression case first, their opinion of the MS case changed. Approval for the MS case dropped to 43%. In other words, the first case created a reference point. After judging the depression case, participants seemed to view the MS case as less acceptable than they otherwise would have.

Studies 2 and 3: The “Shipwreck” Cases

The researchers also looked at a more criminal-law-based scenario. In these studies, participants were asked to act as jurors in a case based on the historical trial of R v. Dudley and Stephens, which involved sailors who resorted to cannibalism after a shipwreck.

Participants considered two versions of the case:

1. The “Apprentice” case, where two sailors killed a young apprentice without his knowledge or consent.

2. The “Captain” case, where the crew drew lots, the captain lost, and he sacrificed his life.

   
   

The results showed a different kind of order effect. The “Captain” case remained relatively stable, but the “Apprentice” case was more changeable. When participants saw the captain’s sacrifice first, they viewed it as more “fair,” which made them more likely to convict in the apprentice case. Because the cases were similar but morally different, the “fair” case made the “unfair” case seem even worse. As a result, participants’ judgments diverged further.

Why Do These Effects Happen?

The researchers tested two theories to explain these shifts.

The first theory is individual consistency. This is the idea that people care about appearing consistent and unbiased. As a result, they may try to make their second decision match their first, even when the facts of the second case differ. 

The second theory is a salience-based explanation. This is the idea that the first case brings certain facts or moral issues to the decision-maker’s attention. Once those facts become more noticeable, they may influence how the person evaluates the next case.

For example, the MS/depression study seemed to favor the consistency explanation. Participants appeared to adjust their later judgment so that it fit with their earlier judgment. The shipwreck studies, however, seemed to support the salience explanation. Judging the fairer “captain” case made the unfairness of the apprentice case stand out more clearly.

Other studies also showed that simply telling people about a fairer method, such as drawing lots, did not change their decisions as much as having them actually judge a case involving that method. This suggests that actively making a decision may be more psychologically powerful than simply receiving information.

Stare Decisis and the Danger of Order Effects

One of the most concerning implications of this research involves stare decisis, the legal principle of “letting the decision stand.” Courts often rely on precedent to ensure consistency and predictability in the law. However, if a decision is influenced by the arbitrary order in which cases appear, that effect does not stop with a single person or case.

Instead, the impact may spread throughout the legal system. A decision shaped by the order of cases could become precedent, which could then influence future cases in the same area of law. In this way, a seemingly small psychological bias could create a larger legal consequence.

The order in which courts receive cases is often random. Because of this, the foundation of predictable justice may be more vulnerable to the luck of the draw than we previously thought.