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2002

Judging by Heuristic: Cognitive Illusions in JudicialDecision MakingChris Guthrie

Jeffrey J. RachlinskiCornell Law School

Andrew J. WistrichU.S. District Court, Central District, CA

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Recommended CitationChris Guthrie, Jeffrey J. Rachlinski, and Andrew J. Wistrich, Judging by Heuristic: Cognitive Illusions in Judicial Decision Making, 86Judicature. 44 (2002)Available at: https://scholarship.law.vanderbilt.edu/faculty-publications/713

dedicated judges surely make occa-sional mistakes, but the public ex-pects judges to avoid making system-atic errors that favor particularparties or writing opinions that em-

CHRIS GUTHRIE is a professor atVanderbilt University Law School.

JEFFREY J. RACHLINSKI is a professorat Cornell Law School.

ANDREW J. WISTRICH is a United StatesMagistrate Judge, United States DistrictCourt, Central District of California.

bed these mistakes into the substan-tive law.

Psychological research on humanjudgment, however, suggests that thisexpectation might be unrealistic.This research indicates that people

some circumstances causes people todraw systematically inaccurate infer-ences-in other words, these heuris-tics can create cognitive illusions ofjudgment.

Just as certain patterns of visualstimuli can fool people's eyesight,leading them to see images that arenot really present, certain fact pat-terns can fool people's judgment,leading them to believe things thatare not really true. The systematicnature of the errors that these illu-sions produce can be analogized tothe sort of errors that an expertmarksman makes if his rifle sight isout of alignment: his shots land in atight cluster, but away from thebullseye.

Decades of research indicate thatcognitive illusions affect the way ju-ries decide cases.2 But are judges anybetter? On the one hand, judges are

illusions. On the other hand, re-search on judgment and choice sug-gests that cognitive illusions plaguemany professionals, including doc-tors, real-estate appraisers, engi-neers, accountants, options traders,military leaders, psychologists, andeven lawyers.' Systematic, controlledstudies of judicial decision making

This article is abstracted from Guthrie,Rachlinski & Wistrich, Inside the Judicial Mind, 86CORNrELL L. REv. 777 (2001). The views expressedare solely those of the authors, and not of theFederal Judicial Center, the Administrative Of-fice of the United States Courts, or the JudicialConference of the United States.

1. See Tversky and Kahneman, Judgment UnderUncertainty: Heuristics and Biases, 185 SCIENCE 1124(1974).

2. See MacCoun, Experimental Research on JuryDecision Making, 244 SCIENCE 1046 (1989).

3. See generally, Pious, THE PSYCHOLOGY Or JUDc-MENT AND DECISION MAKING 258 (1993) (observingthat "several studies have found that experts dis-play either roughly the same biases as college stu-dents or the same biases at somewhat reducedlevels").

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are rare, 4 and whetherjudges are sus-ceptible to these cognitive illusionsremains an open empirical question.

To begin to answer this question, weconducted an empirical study to deter-mine whether five common cognitive

4. A few studies have demonstrated the effectsof various cognitive illusions in judges: Anderson,et. al., Evaluation ofAuditorDecisions: Hindsight BiasEffects and the Expectation Gap, 14J. ECON. PSYCHOL.711, 726-727 (1993) (hindsight bias); Eisenberg,Differing Perceptions of Attorney Fees in BankruptcyCases, 72 WASH U. L. Q. 979 (1994) (egocentric bi-ases); Viscusi, How doJudges Think About Risk? 1 Am.L. & ECON. REv. 26 (1999) (over-estimation ofsmall risks, hindsight bias, and ambiguity aver-sion); Robbenolt, Punitive Damage Decision Making:The Decisions of Citizens and Trial Court Judges, 26LAW & HUM. BEHAV. 315 (2002) (various biases inassessment of punitive damages).

illusions-anchoring, framing, hind-sight bias, inverse fallacy, and egocen-tric bias-would influence the decisionmaking of a sample of 167 federal mag-istrate judges. We administered a briefquestionnaire to these judges during ageneral educational conference spon-sored by the Federal Judicial Center.We found that each of these cognitive

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illusions influenced their decision-making processes.

AnchoringWhen people make estimates (e.g.,the fair market value of a house),they commonly rely on the initialvalue available to them (e.g., the listprice). That initial value tends to "an-

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chor" their final estimates. Relianceon an anchor can be reasonable be-cause an anchor might convey rel-evant information about the actualvalue. Even anchors that do not pro-vide any useful information, however,can affect people's numeric esti-mates.

For example, people asked to esti-mate the average daytime tempera-ture in downtown San Francisco pro-vided higher estimates when firstasked to determine whether the cor-rect answer was greater or less thanthe absurdly high anchor of 558 de-grees Fahrenheit.5 In litigation, an-chors such as statutory damage capsand plaintiffs' attorneys' requests fordamages have been shown to influ-ence the size of damage awards evenwhen they convey no informationabout the extent of the plaintiff's in-jury.

6

We tested for the effect of anchor-ing on the judges in our sample bypresenting them with the followingdescription of a serious personal in-jury suit in which only damages wereat issue:

Suppose that you are presiding over apersonal injury lawsuit that is in federalcourt based on diversity jurisdiction. Thedefendant is a major company in thepackage delivery business. The plaintiffwas badly injured after being struck byone of the defendant's trucks when itsbrakes failed at a traffic light. Subsequentinvestigations revealed that the brakingsystem on the truck was faulty, and thatthe truck had not been properly main-tained by the defendant. The plaintiffwas hospitalized for several months, andhas been in a wheelchair ever since, un-able to use his legs. He had been earninga good living as a free-lance electricianand had built up a steady base of loyalcustomers. The plaintiff has requesteddamages for lost wages, hospitalization,and pain and suffering, but has not speci-fied an amount. Both parties have waivedtheir rights to ajury trial.

We asked half of the judges "howmuch would you award the plaintiffin compensatory damages?" Weasked the other half of the judges thesame question, but only after we firstasked them to rule on a motion filedby the defendant to have the case dis-missed for ostensibly failing to meetthe jurisdictional minimum in a di-

No anchor $1,249, 000 $500,000 $1,000,000 $1,925,000Anchor $882,000 $288,000 $882,000 $1,000,000

versity suit ($75,000). We hypoth-esized that the $75,000 damagethreshold mentioned in the motionwould serve as an anchor, eventhough the motion was frivolous.

Consistent with this hypothesis, wefound that first ruling on the motionhad a dramatic effect on the judges'damage awards, as shown in Table 1.

Those judges who were asked onlyto determine the damage award pro-vided an average estimate of$1,249,000, while those judges whofirst ruled on the motion provided anaverage estimate of only $882,000.Also, three-quarters of the judgeswho ruled on the anchor provideddamage award estimates that werelower than the median award pro-vided in the no anchor condition.Even though the motion was base-less, it forced the judges to considerwhether the case was worth morethan $75,000. In estimating theamount of damages to be awarded,the judges in the anchoring condi-tion began with $75,000 and adjustedupward, albeit inadequately fromthere.

These results are difficult to com-pare with other anchoring studies be-cause we used a low anchor (mostother studies use a high one) and weused a pre-trial motion to introducethe anchor (most studies use a dam-age request by a plaintiff's lawyer).That said, the results of our anchor-ing problem-providing a low an-chor reduced the award by 29 per-cent-are similar to the results of theone mock-jury study (by Malouff andSchutte) that also involved the use ofa low anchor. Although the percent-age reduction in mean awards by thenon-judges in that study exceededthe one we found in judges (46 per-cent versus 29 percent), we found agreater mean reduction in absolute

dollars (roughly $77,000 versus$368,000).

These results likely overstate the ef-fect of an anchor on ajudge decidinga real case. Our materials were neces-sarily brief relative to an actual casein which ajudge would have access tomuch more information, probablyincluding conflicting numeric esti-mates. Although the anchoring ef-fect is real, other factors might alteror diminish its impact in an actualcase.

FramingWhen people make risky or uncer-tain decisions-such as decidingwhether to settle a case or to proceedto trial-they tend to categorize theirdecision options as potential gains orlosses from the status quo.7 This cat-egorization, or "framing," of decisionoptions influences judgment con-cerning the wisdom of incurring risk.People tend to prefer certainty whenchoosing between options that ap-pear to represent gains and to preferrisk when choosing between optionsthat appear to represent losses. Forexample, most people believe that acertain gain of $100 is preferable to a50 percent chance of winning $200but believe that a 50 percent chanceof losing $200 is preferable to a cer-tain $100 loss.

Framing can have a profound im-pact on the assessment of civil law-

5. Plous, supra n. 3, at 146 (citing to an unpub-lished study by Quattrone and colleagues).

6. See Chapman & Bornstein, The More You AskFor the More You Get: Anchoring in Personal InjuryVerdicts, 10 App. COG. PSYCHol. 519 (1996);Malouff & Schutte, Shaping Juror Attitudes: Effectsof Requesting Different Damage Amounts in PersonalInjury Trials, 129 J. Soc. PSYCHOL. 491 (1989);Robbenolt & Studebaker, Anchoring in the Court-room: The bffects of Caps on Punitive Damages, 23LAw & HuM BEHAV. 353, 358-361 (1999).

7. See Kahneman & Tversky, Choices, Values, andFrames, 30 Am. PSYCHOLOGIST 341 (1984).

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suits because litigation produces anatural frame.' In most lawsuits,plaintiffs choose either to accept asettlement payment from the defen-dant or to gamble that further litiga-tion will produce a larger gain. Mostdefendants, by contrast, choose ei-ther to make a certain settlementpayment to the plaintiff or to gamblethat further litigation will reduce theamount they must pay. Plaintiffs, inother words, often choose betweenoptions that appear to representgains, while defendants often choosebetween options that appear to rep-resent losses.9 Consequently, onemight expect there to be more pres-sure on plaintiffs to accept settle-ment offers than there is on defen-dants to make settlementoffers. Framing effectsmight lead ostensiblyneutral mediators, in-cluding judges, to en-courage plaintiffs to ac-cept settlement offersthat are much lowerthan the expected valueof the lawsuit.

To determine whetherjudges' settlement rec-ommendations might beinfluenced by framing,we presented each of thejudges with a hypothetical fact patternto evaluate:

Imagine that you are presiding over acase in which a plaintiff has sued a defen-dant for $200,000 in a copyright action.Both the plaintiff and the defendant aremid-sized publishing companies with an-nual revenues of about $2.5 million peryear. They are represented by competentattorneys who have not tried cases beforeyou in the past. You believe that the case

8. See Rachlinski, Gains, Losses, and the Psychol-ogy of Litigation, 70 So. CAL. L. REV. 113, 129(1996).

9. Id. But see Guthrie, Framing Frivolous Litiga-tion: A Psychological Theory, 67 U. CHI. L. REV. 163(2000) (explaining that litigants' risk prefer-ences are reversed in frivolous or low-probabilitylitigation).

10. See Korobkin & Guthrie, Psychological Barri-ers to Litigation Settlement: An Experimental Ap_proach; 93 MIcn L. REV. 107, 128-142 (1994);Rachlinski, supra n. 8, at 135-144.

11. See Fischhof, For Those Condemned to Studythe Past: Heuristics and Biases in Hindsight, inKahneman, Slovic & Tversky (eds) JUDMENT UN-DER UNCERTAINTY,; HEURISTICS AND BIASEs. 335,341(1982).

is a simple one, but it presents sometough factual questions. There is no dis-pute as to the amount at stake, only as towhether the defendant's actions in-fringed on the plaintiff's copyright. Youbelieve that the plaintiff has a 50 percentchance of recovering the full $200,000and a 50 percent chance of recovering$0. You expect that should the parties failto settle, each will spend approximately$50,000 at trial in litigation expenses. As-sume that there is no chance that the los-ing party at trial will have to compensatethe winner for these expenses.

We then asked the judges to indi-cate whether they thought the partiesshould settle the case. Half of thejudges reviewed the case from theplaintiff's perspective: "You havelearned that the defendant intends

Judgments that require peophto assess the predictability

of past outcomes arepervasive in the law.

to offer to pay the plaintiff $60,000 tosettle the case. Do you believe thatthe plaintiff should be willing to ac-cept $60,000 to settle the case?" Theother half reviewed the case from thedefendant's perspective: "You havelearned that the plaintiff intends tooffer to accept $140,000 to settle thecase. Do you believe that the defen-dant should be willing to pay$140,000 to settle the case?"

In both instances, the judges wereconfronted with proposed settlementoffers that exceeded the expectedjudgment at trial by $10,000. Never-theless, the plaintiff seemed to bechoosing between gains, while thedefendant seemed to be choosing be-tween losses. We hypothesized thatthe judges evaluating this case fromthe plaintiff's perspective would bemore likely to recommend settle-ment than those judges looking at it

from the defendant's perspective.The results supported this hypoth-

esis. Among the judges evaluatingthe case from the plaintiff's (gains)perspective, 39.8 percent indicatedthat they thought the plaintiff shouldaccept the $60,000 settlement offer,but only 25 percent of the judgesevaluating the case from thedefendant's (losses) perspective indi-cated that they thought the defen-dant should pay the $140,000 settle-ment payment proposed by plaintiff.

Although the frame of the prob-lem influenced the judge's evalua-tions, it had less effect on the judgesthan on laypersons. The judges were15 percentage points more inclinedto say that plaintiff rather than defen-

dant should settle, whileother studies in whichlaw students and under-graduates evaluated simi-lar materials have found14 to 51 percentage-point differences be-tween subjects in the twoconditions."5

Hindsight biasHindsight vision is 20/

20. People overestimatetheir own ability to havepredicted the past and

believe that others should have beenable to predict events better than waspossible.1' Psychologists call this ten-dency "hindsight bias."

Few judgments in ordinary life re-quire people to assess the predictabil-ity of past outcomes, but such judg-ments are pervasive in the law. Forexample, determining whether a de-fendant was negligent requiresjudges and juries to evaluate the rea-sonableness of precautions that thedefendant took against causing anaccident even though they know thatthese precautions failed to preventinjury. Precautions that seem reason-able to people before the fact canseem negligent after the fact.

To test whether judges are suscep-tible to the hindsight bias, we pre-sented each of the judges who partici-pated in our study with ahypothetical fact pattern based on anactual case:

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In 1991, a state prisoner filed a pro se Sec-tion 1983 action in Federal District Courtagainst the Director of the Departmentof Criminal Justice in his state, asserting,among other things, that the prison hadprovided him with negligent medicaltreatment in violation of Section 1983.The district court further found that theplaintiff knew his claims were not action-able because he had made similar claimsseveral years earlier in a case that hadbeen dismissed by the court. Thus, thedistrict court sanctioned the plaintiffpursuant to Rule 11, ordering him to ob-tain the permission of the Chief Judge inthe district before filing any more claims.The plaintiff appealed the district court'sdecision.

We randomly assigned the judges toone of three conditions. Judges ineach condition were told that thecourt of appeals had either: affirmedthe sanction; remanded the case tothe district court for imposition of aless onerous sanction; or vacated thesanction. We then asked all of thejudges: "In light of the facts of thecase, as described in the passageabove, which of the following possibleoutcomes of the appeal was mostlikely to have occurred (assume thatthe three outcomes below are the onlypossible ones) ?" We hypothesized thatthe judges would be unable to escapethe influence of having been given"knowledge" of the outcome when as-sessing which outcome was most likelyto have occurred.

Consistent with this hypothesis, theoutcome significantly influencedjudges' assessments. As shown inTable 2,judges informed of a particu-lar outcome were much more likelyto have identified that outcome asthe most likely to have occurred.

Overall, the sum of the percentageof judges in each of the three condi-tions who selected the outcome thatthey were provided as the "most likelyto have occurred" was 172 percent,whereas it would have been 100 per-cent if learning the outcome had hadno effect on the judges. Thus, thejudges exhibited susceptibility to thehindsight bias.

Prior studies have demonstratedthat the hindsight bias affectsjudges' assessments of negligenceand recklessness. 12 Our study sug-gests that judges are also vulnerable

Affirmed 81.5 7.4 11.1Remanded 40.4 38.6 21.1Vacated 27.8 20.4 51.9

Note: Boldface numbers indicate the percentage of judges identifying the given outcomeas the most likely.

to the bias in procedural contexts,such as judgments regarding:whether Rule 11 sanctions should beimposed (a motion or allegation canseem more frivolous after a judicialruling denying it); and whethercounsel provided ineffective assis-tance (decisions a lawyer makes inthe course of representing a clientcan seem less competent after an un-desirable outcome is obtained).

We estimate that 24 percent of thejudges in our study made a differentchoice because of the hindsight bias(172 percent minus 100 percent di-vided by 3 conditions). This result iscomparable to data from mock-jurystudies." It is also comparable to theestimate from a statistical review ofstudies of the hindsight bias, whichindicated that the hindsight bias al-ters the decisions of 27 percent ofdecision makers.

14

Inverse fallacyWhen making categorical judg-ments, people tend to discount theimportance of background statistics,such as the general prevalence of aparticular category. 5 In one demon-stration of this phenomenon, medi-cal doctors were asked to estimatethe likelihood that a patient whohad tested positive for a certain raredisease actually had that disease."6

The doctors were told that the testwas 90 percent reliable and that theprevalence of the disease in patientssuch as the one in the example wasone in one thousand. Although theactual likelihood is quite small, 80percent of the doctors indicatedthat it was more likely than not that

the patient had the illness. The doc-tors found the 90 percent reliabilitystatistic compelling, but discountedthe importance of the prevalence ofthe disease.

Psychologists have labeled the spe-cific decision-making problem iden-tified by the aforementioned study asthe "inverse fallacy." 7 The inverse fal-lacy refers to the tendency to treatthe probability of a hypothesis giventhe evidence (for example, the prob-ability that a defendant was negligentgiven that a plaintiff was injured) asthe same as, or close to, the probabil-ity of the evidence given the hypoth-esis (for example, the probabilitythat the plaintiff would be injured ifthe defendant were negligent).

The inverse fallacy can affect theevaluation of probabilistic evidencein the courts. For example, DNA evi-

12. See Anderson, et. al., supra n. 4; Viscusi, su-pra n. 4;Jennings et. al., "Outcome Foreseeabilityand its Effects on Judicial Decisions" (unpub-lished manuscript on file with the authors).

13. Hastie, Schkade & Payne,JurorJudgments inCivil Cases: Hindsight Effects on Judgments of Liabil-ity for Puntitive Damages, 23 LAW & HUM. BEHAV.597, 606 (1999) (24 percent shift); Kamin &Rachlinski, Ex Post (Does Not Equal) Ex Ante: Determining Liability in Hindsight, 19 LAW & HUM.BE-AV. 89, 98 (1995) (34 percent shift); Stallard& Worthington, Reducing the Hindsight Bias: Utiliz-ing Attorney Closing Arguments, 22 LAW & HUM.BEHAV. 671, 679 (1998) (28 percent shift).

14. Christensen-Szalanski & Willham, TheHindsight Bias: A Meta-Analysis, 48 ORGANIZATIONBEHAV. & HUM. DECISION PROCESSES 147, 161

(1991).15. See Kahneman & Tversky, Subjective Probabil-

ity: A Judgment of Representativeness, 3 COGNITIVEPSYCHOL. 430 (1972).

16. Casscells, Schoenberger & Graboy, Interpre-tations by Physicians of Clinical Laboratory Results,299 NEW ENG.J. MEDICINE 999 (1978).

17. See Koehler, Why DNA Likelihood RatiosShould Account for Error (Even When A National Re-search Council Report Says They Should Not), 37JURIMETRIcsJ. 425, 432 (1997).

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dence in a criminal case can providethe probability that a randomly se-lected DNA sample would match theDNA sample from the crime scene(and it typically states this as a tinynumber). Committing the inversefallacy would mean inferring that thelikelihood that the defendant is inno-cent is equivalent to the likelihood ofa random match. This inference,however, would be incorrect, as theprobability that the defendant is in-nocent also depends on the size ofthe population that the suspect'sDNA was drawn from and the reliabil-ity of the DNA test.

To test whether judges in our studywould commit the inverse fallacy, wegave them a problem based looselyon the classic English case, Byrne v.Boadle (1863):

The plaintiff was passing by a warehouseowned by the defendant when he wasstruck by a barrel, resulting in severe in-juries. At the time, the barrel was in thefinal stages of being hoisted from theground and loaded into the warehouse.The defendant's employees are not surehow the barrel broke loose and fell, butthey agree that either the barrel was neg-ligently secured or the rope was faulty.Government safety inspectors conductedan investigation of the warehouse anddetermined that in this warehouse: (1)when barrels are negligently secured,there is a 90% chance that they will breakloose; (2) when barrels are safely se-cured, they break loose only 1% of thetime; (3) workers negligently secure bar-rels only 1 in 1,000 times.

We then asked the judges to assess"how likely is it that the barrel that hitthe plaintiff fell due to the negli-gence of one of the workers?" Weprovided the judges with one of fourprobability ranges to select: 0-25 per-cent, 26-50 percent, 51-75 percent, or76-100 percent.

When presented with a problemlike this one, most people committhe inverse fallacy and assume thelikelihood that the defendant wasnegligent is 90 percent, or at least

18. Kaye, Probability Theory Meets Res Ipsa Loqui-tur, 77 MICH L. REv. 1456 (1979).

19. See, e.g., Ross & Sicoly, Egocentric Biases inAvailability and Attribution, 37 J. PERSONALITY &Soc. & Soc. PSYCHOL. 322 (1979) (testing for ego-centric biases in joint activities).

20. 28 U.S.C. §1292(b).

quite high. In fact, however, the ac-tual probability that the defendantwas negligent is only 8.3 percent. Wehypothesized that most of the judgeswould commit the inverse fallacy andselect the "76-100 percent" range.

The judges did relatively well onthis inverse fallacy problem: 40.9 per-cent selected the right answer bychoosing 0-25 percent; 8.8 percentindicated 26-50 percent; 10.1 percentindicated 51-75 percent; and 40.3percent indicated 76-100 percent. Al-though more than 40 percent of thejudges analyzed this problem cor-rectly, a comparable percentagechose the 76-100 percent range, sug-gesting that many of the judges com-mitted the inverse fallacy.

To some extent, judges in thisstudy might have been responding tothe underlying res ipsa loquitur doc-trine that governs cases like the onedescribed in our question. Under thefacts as we describe them, the plain-tiff makes out a clear case for liabilityunder the doctrine. Because the lawdictates that the defendant be liableunder these circumstances, thejudges might have relied on the doc-trine in judging probabilities. Thispossibility, in fact, highlights one ofthe more serious difficulties that canarise from judicial reliance on faultyjudgments, namely, that legal doc-trine might be based on a mistakeninference process. The doctrine ofres ipsa loquitur instructs judges totake no account of the base-rate ofnegligence, thereby cementing theinverse fallacy into important legalprecedent."

In any event, the judges in ourstudy were more attentive than otherexperts to base-rate statistics. Asnoted above, 20 percent of a group ofdoctors-as compared to 40 percentof the judges in our study-provideda correct (or nearly correct) answerto a question using nearly identicalprobabilities.

Egocentric biasesPeople tend to make judgments aboutthemselves and their abilities that are"egocentric" or "self-serving."1" Peopleroutinely estimate, for example, thatthey are above average on a variety of

desirable characteristics, includinghealth, driving, productivity, and thelikelihood that their marriage will suc-ceed. Moreover, people overestimatetheir contribution to joint activities.Following a conversation, for ex-ample, both parties will usually esti-mate that they spoke more than halfthe time. Similarly, when marriedcouples are asked to estimate the per-centage of household tasks they per-form, their estimates typically add upto far more than 100 percent.

Egocentric biases are generally psy-chologically healthy, but they canhave an unfortunate influence on thelitigation process. Due to egocentricbiases, litigants and their lawyersmight overestimate their own abili-ties, the quality of their advocacy, andthe relative merits of their cases.These views, in turn, are likely to un-dermine settlement efforts, as eachside remains too optimistic about itschances of winning at trial.

Like litigants and lawyers, judgesmight also be inclined to interpretinformation in self-serving or ego-centric ways. Egocentric biases mightkeep judges from maintaining anawareness of their limitations, whichcould work to the detriment of liti-gants appearing in their courtrooms.For example, a federal judge cangrant an interlocutory appeal only ifshe is willing to concede that she hasissued a ruling on a matter of law "asto which there is substantial groundfor difference of opinion."2" Thus, alitigant seeking to persuade a judgeto grant an interlocutory appeal mustconvince her that another judgecould easily disagree with her ruling.Egocentric biases may facilitate judi-cial self-confidence and decisiveness,but they also might induce judges tounderestimate the likelihood theywill make mistakes when adjudicat-ing and settling cases.

To test whether judges are proneto egocentric biases, we asked thoseparticipating in our study to respondto a simple question: "United Statesmagistrate judges are rarely over-turned on appeal, but it does occur.If we were to rank all of the magis-trate judges currently in this room ac-cording to the rate at which their de-

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Anchoring effects Estimated damages with No difference between Anchor reduced awards Comparableand without a low anchor conditions by 29%

Hindsight bias Percent identifying known Total percent of judges Percentage identifying Comparableoutcome as most likely identifying known outcome known outcome summedoutcome (across 3 conditions) sums to 172%

-^ - 1t~o

cisions have been overturned duringtheir careers, [what] would your ratebe?" We then asked the judges toplace themselves into the quartilecorresponding to their respective re-versal rates: highest (i.e., >75 per-cent), second-highest (>50 percent),third-highest (>25 percent), or low-est (lowest 25 percent).

The judges exhibited an egocentricbias. Overall, 56.1 percent of thejudges reported that their appeal rateplaced them in the lowest quartile;31.6 percent placed themselves in thesecond-lowest quartile; 7.7 percent inthe second-highest quartile, and 4.5percent in the highest quartile. Inother words, nearly 87.7 percent ofthe judges believed that at least half oftheir peers had higher reversal rateson appeal. This pattern of results dif-fers significantly from what one wouldexpect if judges were unbiased. Evenassuming that the 56.1 percent of thejudges in the lowest quartile hadnever been overturned on appeal (anunlikely possibility, but one that wouldmake their assessments reasonable),the remaining distribution ofjudges isskewed significantly towards the lowerquartiles.

The magnitude of the egocentricbias exhibited by the judges in thisstudy was similar to that reported in

other studies of the bias. Judges inour sample were comparable to auto-mobile drivers (87.5 percent claim tobe safer than the average driver),slightly more modest than universityfaculty (94 percent claim to be betterteachers than average), and muchmore modest than couples about tobe married (99 percent claim to beless likely than the average couple toget divorced).21

Judges are humanJudges, it seems, are human. Theyappear to fall prey to the same cogni-tive illusions that psychologists haveidentified among lay persons andother professionals. Table 3 summa-rizes our results and compares themto the results of studies onnonjudicial decision makers.

Although the judges in our studywere less susceptible to framing ef-fects and the inverse fallacy thanother decision makers faced withsimilar situations, they proved to bejust as susceptible as other expertsand laypersons to the influence ofanchoring effects, the hindsight bias,and the egocentric bias.

Overall, our results indicate that,like the rest of us, judges use heuristicsthat can produce systematic errors injudgment. Even if judges are free

from prejudice against either litigant,fully understand the relevant law,know all of the relevant facts, and canput their personal politics aside, theymight still make systematically errone-ous decisions because of the waythey-like all human beings-think.

Unlike the rest of us, however,judges' judgments can compromisethe quality of justice that the courtsdeliver. In the law review article fromwhich this article was abstracted, wehave identified several things thatjudges can do to minimize the effectsof cognitive illusions, including con-sidering multiple perspectives andseeking out decision-making meth-ods or standards that are less likely tobe influenced by misleading heuris-tics.22 A deeper understanding ofhow people think, including an ap-preciation of the power of heuristics,is the first step toward crafting soundsolutions. Vi

21. See Svenson, Are We All Less Risky and MoreSkillful Than Our Fellow Drivers? 47 ACTAPSYCHOLOGICA 143, 145-146 (1981) (driving);Cross, Not Can, But Will College Teaching Be Im-proved? 17 NEw DIRECTIONS FOR HIGHER EDUCATION

1, 5-6 (1977) (college professors); and Baker andEmery, When Every Relationship is Above Average:Perceptions and Expectations of Divorce at the Time ofMarriage, 17 LAw & HUM. BEHAV. 439 (1993) (en-gaged couples).

22. Guthrie, Rachlinski & Wistrich, Inside theJudicial Mind, 86 CORNELL L. Rrv. 777 (2001).

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