                 This opinion is subject to revision before final
                      publication in the Pacific Reporter

                                 2015 UT 79


                                    IN THE
       SUPREME COURT OF THE STATE OF UTAH

   COREY AND CAROL NIELSEN, for and in behalf of C.N., a minor,
                          Appellees,
                                       v.
         WADE AND LAURA BELL, on behalf of B.B., a minor
                         Appellants.

                              No. 20131047
                          Filed March 24, 2016

                 On Appeal of Interlocutory Order

                   Third District, Salt Lake Dep’t
                 The Honorable Denise P. Lindberg
                          No. 120903223

                                 Attorneys:
        Daniel F. Bertch, Kevin K. Robson, Darren A. Davis,
          Nathan Langston, Salt Lake City, for appellees
       Peter H. Christensen, Kathryn T. Smith, Salt Lake City,
                           for appellants

   JUSTICE DURHAM authored the opinion of the Court in which
 CHIEF JUSTICE DURRANT, JUSTICE HIMONAS, and JUDGE ROTH joined.
      ASSOCIATE CHIEF JUSTICE LEE filed a dissenting opinion.
    JUSTICE PARRISH did not participate herein. Court of Appeals
                    JUDGE STEPHEN L. ROTH sat.

   JUSTICE DURHAM, opinion of the Court:
                           INTRODUCTION
   ¶1     In this appeal we must decide whether there is a minimum
age below which a child is conclusively deemed incapable of
negligence under Utah’s common law, and if so, what that minimum
age is. We hold that children under the age of five, as a matter of
law, may not be held liable for negligence.
                           NIELSEN v. BELL
                         Opinion of the Court

                          BACKGROUND
   ¶2     Ms. Nielsen was babysitting a boy who was four years and
nine months old. The boy threw a toy rubber dolphin at her, striking
her in the eye. Ms. Nielsen had previously received a cornea
transplant, and, tragically, the impact caused her to lose all vision in
that eye.
    ¶3    Ms. Nielsen sued the boy’s parents for negligent
supervision. She also sued the four-year-old boy for negligence. The
defendants moved for summary judgment, and Ms. Nielsen
conceded that she had no evidence that the boy’s parents had been
negligent. She argued, however, that a dispute of material fact
precluded summary judgment on the negligence claim against the
boy. Ms. Nielsen further asserted that a four-year-old boy could be
liable for negligence under Utah law. The district court agreed,
ruling that it could not find as a matter of law that the boy was
incapable of negligence. The court therefore granted summary
judgment on the negligent supervision claim against the parents and
denied summary judgment on the negligence claim against the child.
   ¶4     We granted a petition for interlocutory review of the
portion of the district court’s order denying summary judgment on
the claim against the child. We review de novo the district court’s
legal determination that a four year old may be held liable for
negligence. See Daniels v. Gamma W. Brachytherapy, LLC, 2009 UT 66,
¶ 46, 221 P.3d 256 (interpretations of the common law reviewed for
correctness).
                             ANALYSIS
    ¶5     State courts have adopted a variety of approaches when
determining whether young children may be held liable for
negligence. Some states reject fixed age limits, resolving the issue of
a child’s capacity to be negligent as a matter of law only where
“reasonable minds could not differ on the matter.” Lester v. Sayles,
850 S.W.2d 858, 866 (Mo. 1993). But “the overwhelming majority of
jurisdictions support the idea of some minimum cutoff age.”
RESTATEMENT (THIRD) OF TORTS: PHYS. & EMOT. HARM § 10 reporters’
note, cmt. d (AM. LAW INST. 2010). Courts in these states have
adopted different cutoff ages for liability, variously holding that
children under seven, six, five, or four may not be negligent as a
matter of law. Id.
    ¶6     In order to determine whether the four-year-old
defendant in this case may be held liable for negligently throwing a
toy at Ms. Nielsen, we assess which of these approaches to the
liability of young children most closely matches this court’s
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precedents. Ms. Nielsen contends that Utah should not recognize a
fixed age cutoff for negligence liability. The four-year-old defendant,
on the other hand, asserts that our precedents hold that children
under the age of seven are conclusively presumed to be incapable of
negligence. Alternatively, the defendant argues that we have
recognized that children under the age of five may not be held liable
for negligence.
   ¶7     We reject the defendant’s contention that this court has
held that children under seven may not be negligent. We agree,
however, with the defendant’s alternative argument that children
under the age of five may not be liable for negligence. We therefore
reverse the district court’s order denying summary judgment on the
negligence claim against the four-year-old defendant.
                        I. THE ILLINOIS RULE
     ¶8     The defendant first contends that Utah has adopted the
Illinois rule regarding the liability of young children for negligence.
Under this rule, children under seven are deemed incapable of
negligence; for children between seven and fourteen, there is a
rebuttable presumption against a child’s capacity for negligence; and
for adolescents fourteen years old and above there is a rebuttable
presumption of capacity for negligence. RESTATEMENT (THIRD) OF
TORTS: PHYS. & EMOT. HARM § 10 cmt. b (AM. LAW INST. 2010). The
Illinois rule is followed in about a dozen states. See id. § 10 reporters’
note, cmt. b.
    ¶9     This court first referenced this rule in Nelson v. Arrowhead
Freight Lines, 104 P.2d 225, 228 (Utah 1940). But although the Nelson
court stated that “[o]rdinarily a child under seven years of age is
conclusively presumed not guilty of contributory negligence,” this
pronouncement was pure dictum. 1 Id. The minor accused of
contributory negligence in that case was sixteen—well above the

   1 While the child accused of negligence in this case is a defendant,
the issue of a child’s capacity to be negligent has most often been
addressed in cases where the defendant has asserted that a child
plaintiff should be charged with contributory negligence. These
contributory negligence cases are relevant to this case because the
capacity for negligence of a child defendant and a child plaintiff is
measured by the same standard. See RESTATEMENT (THIRD) OF TORTS:
PHYS. & EMOT. HARM § 10 cmt. e (AM. LAW INST. 2010); see also Rowe v.
Sisters of the Pallottine Missionary Soc‘y, 560 S.E.2d 491, 498 (W. Va.
2001) (comparative negligence defense requires proof of each of the
elements of negligence).

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                        Opinion of the Court

seven-year cutoff age. Id. at 227. Moreover, the sixteen-year-old
plaintiff’s capacity to be negligent was not at issue. Instead, the
plaintiff argued on appeal that she was entitled to an instruction
informing the jury that she should be held to the standard of care of
persons of similar age, capacity, and experience. Id. Therefore, any
rule regarding the age when a child may be held liable for
negligence, or any rule regarding a presumption of either incapacity
or capacity for negligence, was not relevant to the outcome of the
case.
    ¶10 We specifically held that the Nelson court’s articulation of
the Illinois rule was dictum and declined to follow it. In Mann v.
Fairbourn, this court had to decide whether a five-and-a-half-year-old
boy could be contributorily negligent in an accident that caused his
death. 366 P.2d 603, 604, 606 (Utah 1961). We acknowledged our
prior statement in Nelson that children under seven may not be
negligent, but reasoned that “the statement was mere dictum
inasmuch as the plaintiffs in that case were 16 and 20 years at age”
and that “[s]uch a rule of law has not been observed by this court in
other cases.” Id. at 606. The Mann court held that the capacity for
negligence of the five-year-old plaintiff was a factual inquiry to be
resolved by a jury. Id. In subsequent cases we continued to ignore
the Nelson dictum and held that a jury should decide whether a six-
and-a-half year old and a child just under six had the capacity to be
negligent. Donohue v. Rolando, 400 P.2d 12, 13–14 (Utah 1965); Rivas v.
Pac. Fin. Co., 397 P.2d 990, 991–92 (Utah 1964).
   ¶11 Despite this court’s refusal to apply the Illinois rule,
however, we later used at least a portion of that rule. In Kilpack v.
Wignall, we had to determine as a matter of law whether a seven
year old had the capacity to be negligent. 604 P.2d 462, 463, 465–66
(Utah 1979). The Kilpack court ignored our caselaw that either
explicitly rejected or disregarded the Nelson dictum and quoted the
Nelson opinion’s articulation of the Illinois rule. Id. at 466. Because
the child plaintiff in Kilpack was seven, this court then applied a
presumption that he was incapable of contributory negligence. Id.
We held that because no evidence was presented to rebut this
presumption of incapacity, the seven-year-old plaintiff was not
negligent as a matter of law. Id.
    ¶12 The holding of the Kilpack opinion, however, does not
control in this case. In Kilpack, we applied the Illinois rule’s
rebuttable presumption that children between the ages of seven and
fourteen are incapable of negligence. We had no occasion to apply
the rule’s conclusive presumption that children under seven are not
liable for negligence. Indeed, when this court has been presented

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with claims that five and six year olds have been negligent, we have
held that the child’s capacity for negligence was a jury question.
Donohue, 400 P.2d at 13–14 (six-and-a-half-year-old child); Rivas, 397
P.2d at 991–92 (child just under six); Mann, 366 P.2d at 604, 606 (five-
and-a-half-year-old child).
   ¶13 We therefore reject the defendant’s assertion that Utah has
recognized a conclusive presumption that children under seven are
incapable of negligence. 2 Statements we have made to this effect are
dicta, and this court has explicitly refused to follow this rule when
the issue has been squarely presented. Mann, 366 P.2d at 606.
                    II. THE RESTATEMENT RULE
    ¶14 Although this court has never held that children under
seven may not be held liable for negligence, we have recognized that
there is an age at which a child is “so young and immature as to
require the court to judicially know that he is not responsible for his
act.” Donohue v. Rolando, 400 P.2d 12, 14 (Utah 1965). But we have not
yet explicitly held what the cutoff age for negligence liability is. This
court has previously decided this question on an ad hoc basis. An
examination of our caselaw, though, reveals a dividing line between
children under the age of five and children aged five and above.
    ¶15 As noted above, when we have examined the capacity of
five and six year olds to be negligent we have held that it was a jury
question unless reasonable minds could not differ on the issue.
Donohue, 400 P.2d at 13–14; Rivas v. Pac. Fin. Co., 397 P.2d 990, 991–92
(Utah 1964); Mann v. Fairbourn, 366 P.2d 603, 604, 606 (Utah 1961).
We have found only one opinion in which this court has assessed the
capacity of a child under five to be negligent. In Herald v. Smith, a
motorist struck a four-year-and-ten-month-old girl while she was
crossing the street. 190 P. 932, 933 (Utah 1920). The girl sued the
motorist for negligence. Id. at 932. After the trial, the district court
directed a defense verdict after apparently concluding that the
evidence could only support a finding that the child’s negligence

   2 We do not resolve the question of whether Utah recognizes a
rebuttable presumption that children under the age of fourteen are
incapable of negligence. Our caselaw is in conflict on this point. The
Kilpack court applied this presumption in a case involving a seven
year old. But that case appears to contradict earlier cases addressing
a child’s capacity for negligence that rejected the Illinois rule and
resolved this issue without referring to a judicially created
presumption of either incapacity or capacity for negligence. See
Donohue, 400 P.2d at 13–14; Rivas, 397 P.2d at 991–92; Mann, 366 P.2d
at 606.
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                        Opinion of the Court

had contributed to the accident. Id. at 933. On appeal, we held that
the child could not be charged with contributory negligence: “A
child of that age cannot, as a matter of law, be held to have
appreciated the danger and is not presumed to conduct herself as an
adult person would under similar circumstances.” Id.
    ¶16 Granted, the procedural posture of Herald makes it a less
than ideal signpost for determining the minimum age for negligence
liability under Utah’s common law. The Herald court reversed the
trial court’s legal conclusion that the child plaintiff had been
negligent. Notably, we were not affirming a lower court’s legal
determination that a child had not been negligent. Herald indicates,
however, that this court’s conclusion that the four-year-old plaintiff
was not capable of negligence was arrived at “as a matter of law.” Id.
In line with this legal determination, Herald further held that the
resolution of a factual dispute at trial as to whether the motorist
sounded his horn before the accident would not affect its conclusion
that the child did not have the capacity to be negligent, reasoning
that an “ordinary child of that age could neither appreciate nor
understand the object sought or the reasons for giving such
warning.” Id. at 934. We therefore held that upon remand, the child
plaintiff was entitled to submit to a jury the question of whether the
motorist had negligently caused the accident, further indicating that
the Herald opinion had resolved the contributory negligence issue in
favor of the child plaintiff as a matter of law. Id.
    ¶17 The Herald court’s holding that a girl two months shy of
her fifth birthday could not be negligent marks a dividing line with
subsequent cases holding that five year olds could have the capacity
to be negligent. See Rivas, 397 P.2d at 991–92; Mann, 366 P.2d at 604,
606. This division matches the line drawn by the Restatement (Third)
of Torts, which states: “A child less than five years of age is
incapable of negligence.” RESTATEMENT (THIRD) OF TORTS: PHYS. &
EMOT. HARM § 10(b) (AM. LAW INST. 2010). The restatement rule is
consistent with the rule adopted by the majority of states, which
holds that children under the age of at least five (several states have
a higher age limit) may not be held liable for negligence. Id. § 10
reporters’ note, cmt. d. The restatement authors note that “only in a
tiny handful of states are there actual cases that have permitted
findings of negligence in the conduct of children who are less than
five.” Id.
    ¶18 A number of policy considerations support the
restatement rule. Children under the age of five have a limited
capacity to appreciate how their actions can cause harm to
themselves or others and have an inadequate internal ability to

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control impulses that may lead to injuries. See id. § 10 cmt. d. Absent
an adequate ability to foresee consequences or control their behavior,
“the possibility is slight that the conduct of a child under five is
either deserving of moral criticism or is capable of being deterred by
the application of tort rules.” Id. Moreover, assessing a young child’s
capacity for negligence by placing the child on the witness stand to
answer questions about her individual understanding of cause and
effect, foreseeability, and capacity for impulse control is problematic
to say the least. See id. This is especially true where the trial
examination would likely occur years after the incident when the
child has matured, making it difficult for the child to reclaim her
earlier state of mind. Finally, the restatement rule recognizes that
there is an age below which it is unseemly to subject a child to the
judicial process or to adjudicate a child’s liability for negligence.
    ¶19 Of course, categorical rules are, by their nature, imperfect.
Children develop at different rates, and some four year olds are
undoubtedly more mature than some five year olds. Despite the
inherent drawbacks of age-based rulemaking, however, we must
engage in this line-drawing process to some extent. Legislatures
have done so by setting the age at which individuals can work,
drive, marry, vote, serve in the military, smoke, and drink alcohol, as
well as establishing the age of consent. Courts also make hard, age-
based rules. The Supreme Court has determined that the
Constitution prohibits the execution of an “adolescent” who
commits murder just days before his eighteenth birthday, but
permits the death penalty for an “adult” who commits the same
crime just days after turning eighteen. Roper v. Simmons, 543 U.S. 551,
578 (2005); see also id. at 574 (rejecting objections to drawing a hard
line at eighteen). This court has also created age-based rules as part
of the common law—finding that parent’s waiver of a minor’s
prospective claim for negligence is unenforceable, for example.
Hawkins ex rel. Hawkins v. Peart, 2001 UT 94, ¶ 13, 37 P.3d 1062. And
although statutes now establish the age of majority, determining the
age when individuals assume independent legal rights, such as the
capacity to contract, was a common law function. 42 AM. JUR. 2D
Infants § 4 (2010); RESTATEMENT (SECOND) OF CONTRACTS § 14 cmt. a
(AM. LAW INST. 1981).
   ¶20 In each of these instances the advantages of uniformity,
consistency, and efficiency justify a bright-line rule, despite its
imperfections. Determining the appropriate age at which each of
these rules should be applied on an individualized, case-by-case
basis—e.g., conducting a review process to determine when every
person is mature enough to vote or consent to sexual relations—
would be so inefficient and create such uncertainty as to be
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                         Opinion of the Court

unworkable. Rejecting definitive age-based rulemaking also unduly
impairs policy making concerning the appropriate ages for certain
activities.
    ¶21 We conclude that the instances where it would be
appropriate to hold a child under the age of five liable for negligence
would be rare enough that the social costs of conducting an
individualized inquiry are not justified. Litigants are entitled to some
amount of certainty and consistency. And this court has the duty to
consider the propriety of subjecting children of tender years to tort
liability, or, when they are plaintiffs, denying them recovery for the
negligence of others.
   ¶22 We therefore adopt the restatement rule that children
under the age of five may not be held liable for negligence. The
question of whether a child five or over is capable of negligence is
reserved for the fact-finder, unless a court determines that no
reasonable jury could disagree on the issue. Such a rule conforms
with our precedents and promotes important public policies.
                           CONCLUSION
    ¶23 We reverse the district court’s order denying summary
judgment in favor of the four-year-old defendant. We remand with
instructions to grant summary judgment.




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                       JUSTICE LEE, dissenting

 ASSOCIATE CHIEF JUSTICE LEE, dissenting:
    ¶24 The court today adopts a categorical rule exempting
children under the age of five from a finding of negligence in tort. It
bases that conclusion on both legal authority and its own
assessments of cognitive psychology. I agree with some of the court’s
premises. I accept the need for a categorical age cutoff at some point.
And I have no doubt that many children under the age of five are
incapable of negligence in some activities. But I respectfully dissent
from the court’s adoption of a categorical cutoff at age five because I
disagree with the conclusion that “the instances where it would be
appropriate to hold a child under the age of five liable for
negligence” are “rare enough that the social costs of conducting an
individualized inquiry” into a child defendant’s mental capacity for
negligence “are not justified.” Supra ¶ 21.
   ¶25 This is not a question for disposition “as a matter of law”
by reference to an aging body of caselaw. It is, at bottom, a question
of social science. The relevant field of social science (cognitive
psychology), moreover, is one that has seen significant advances in
recent years. For that reason it seems perilous to defer too quickly to
the armchair assessments of a child’s analytical capacity made by
judges in decades past.
    ¶26 I would take a fresh look at the age at which a child may
properly be charged with negligence. I would do so based on a
careful assessment of the state of our current understanding of the
field of cognitive psychology. Recent advances in that field undercut
the premises of the standard endorsed by the majority. Cognitive
psychologists do not view all children aged five or older as fully
capable of the kind of thinking necessary to charge them with
negligence; nor do they see all children four or younger as
categorically incapable of that kind of thinking. Instead they
generally agree that children begin to develop cognitive skills like
planning and impulse control at about age three, and continue
developing those skills as they grow older. And although experts in
this field have identified developmental and environmental factors
that explain why different children develop at different rates, they
also generally agree that most children acquire the ability to engage
in planning and impulse control by the age of eight.
   ¶27 With this in mind, I would reject the age five cutoff
adopted by this court and others. I would embrace instead a
framework that would deem all children under the age of three

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                        JUSTICE LEE, dissenting

incapable of negligence and also presume (subject to rebuttal by
expert evidence) that those who are aged three to seven lack that
capacity.
    ¶28 As noted below, I find nothing in the caselaw in this field
that would sustain the cutoff endorsed by the court. The cases
adopting a five-year (or seven-year) cutoff for negligence in other
jurisdictions are based mostly on armchair assessments of cognitive
psychology advanced by judges. To the extent the cases cite any
literature from any relevant fields of expertise, moreover, the
citations are to outdated science. And despite the majority’s
insistence to the contrary, our court has never held “‘as a matter of
law’” that a four-year-old is “not capable of negligence.” Supra ¶ 16
(quoting Herald v. Smith, 190 P. 932, 933 (Utah 1920)).
    ¶29 Even if the cited case could be understood to have
embraced such a holding, I would not be inclined to defer to it on
this appeal. The Herald case is almost a century old. And our
understanding of cognitive psychology has advanced markedly in
the many decades since that decision. A reconsideration of the
question of where to draw the line on an age cutoff for negligence is
past due. I would do so here. And I would adopt a framework that
would deem the four-year-old defendant in this case presumptively
incapable of negligence, subject to rebuttal on remand by expert
testimony to be presented by the plaintiffs.
                                   I
    ¶30 The majority’s approach finds support in judicial decisions
of our sister states. But I cannot agree that this court has held that a
child under the age of five is incapable of negligence as a matter of
law. See supra ¶ 16 (discussing Herald v. Smith, 190 P. 932 (1920)).
And in any event I would not defer to the outdated, unsupported
analysis of this important question in the decades-old caselaw in this
or other jurisdictions.
                                   A
    ¶31 The majority correctly concludes that this court has never
expressly adopted “a conclusive presumption that children under
seven are incapable of negligence.” Supra ¶ 13. And it rightly
concedes that our past cases “have not yet explicitly held what the
cutoff age for negligence liability is,” but have instead “decided this
question on an ad hoc basis.” Supra ¶ 14. Yet the court also asserts
that our cases have implicitly adopted “a dividing line between
children under the age of five and children aged five and above.” Id.
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                        JUSTICE LEE, dissenting

Specifically, the majority views our decision in Herald v. Smith as
concluding “‘as a matter of law’” that a four-year-old is “not capable
of negligence.” Supra ¶ 16 (quoting Herald, 190 P. at 933). And it
insists that Herald “held that upon remand, the child plaintiff” in that
case “was entitled to submit to a jury the question of whether the
motorist had negligently caused the accident, further indicating that
the Herald opinion had resolved” the question of the child’s
contributory negligence “in favor of the child plaintiff as a matter of
law.” Id.
    ¶32 I read Herald differently. The Herald court’s analysis of the
child plaintiff’s capacity for contributory negligence had nothing to
do with establishing a categorical age cutoff as a matter of law. In
fact the court espoused the opposite view—that “[t]he degree of care
required of a child must be graduated to its age, capacity, and
experience, and must be measured by what might ordinarily be
expected from a child of like age, capacity, and experience under
similar conditions.” 190 P. at 933-34 (quoting Gesas v. O.S.L. R.R., 93
P. 274, 279 (Utah 1907)). To the extent Herald was endorsing a
generally applicable rule, then, it was one counter to the age cutoff
adopted by the court today—a rule under which the four-year-old
plaintiff could not “be charged with contributory negligence” “[i]f it
acted as might reasonably be expected of such a child” of her age. Id.
at 934 (citation omitted).
    ¶33 The Herald court’s assessment of the child plaintiff’s
contributory negligence was not based on a categorical analysis of
the cognitive capacity of young children. It was based purely on the
facts and circumstances of that case.
    ¶34 The Herald court’s holding was a rejection of the theory of
contributory negligence advanced by the defendant in the case. That
theory was a stretch—that the defendant driver of a car “had a right
to assume” that the child pedestrian “would not move forward”
“when he blew the horn” on his car, and that the child plaintiff was
therefore negligent because she disregarded the horn. Id. at 933. In
rejecting that theory, the Herald court did not adopt a blanket rule of
immunity. It concluded only that “[t]he defendant’s duty to the
plaintiff cannot be measured by what he might reasonably have
expected to be the conduct of an adult person in such
circumstances.” Id.
   ¶35 In rejecting the defendant’s theory of contributory
negligence, moreover, the court was not assessing the cognitive

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                        JUSTICE LEE, dissenting

capacity of children in general; it was rejecting the defendant’s
theory of contributory negligence under the facts of that case. The
court’s analysis was as follows:
     Under the circumstances and facts of this case it is
     immaterial whether such alarm [the defendant’s horn]
     was given or not. The plaintiff was a little girl not yet five
     years of age. The ordinary child of that age could neither
     appreciate nor understand the object sought or the
     reasons for giving such warning. If it made any
     impression at all upon her mind, she probably accepted it
     as for her amusement rather than anything else; in other
     words, we regard the fact as to whether defendant
     sounded the horn as immaterial. It would in no way
     relieve the defendant of the charge of negligence, if he
     was negligent in going forward after he observed the
     child crossing the street, nor would it charge the plaintiff
     with contributory negligence.
Id. at 934.
    ¶36 I find no basis in the above for the conclusion that the
Herald court in any way established a “signpost for determining the
minimum age for negligence liability under Utah’s common law.”
Supra ¶ 16. Its only “signpost” was the proposition that a child is
held to a standard “‘graduated to its age, capacity, and experience,”
to be “measured by what might ordinarily be expected from a child
of like age, capacity, and experience under similar conditions.”
Herald, 190 P. at 933-34 (citation omitted). And its holding that the
child plaintiff in that case was not negligent “as a matter of law” was
based on the court’s analysis of the facts of that case, not an
assessment of the cognitive capacity of four-year-olds in general.
    ¶37 In all events the Herald case is almost a century old. Even if
it could be read to establish a hard age cutoff on the basis of the
court’s understanding of cognitive psychology, that question would
surely be ripe for reconsideration in light of advances in our
understanding in this field in recent decades.
                                   B
    ¶38 As the majority indicates, the Restatement (Third) of Torts
concludes that “[a] child less than five years of age is incapable of
negligence.” Supra ¶ 17 (quoting RESTATEMENT (THIRD) OF TORTS:
PHYS. & EMOT. HARM § 10(b) (AM. LAW INST. 2010)). And a “majority
of states” has embraced an age cutoff along these lines. Id. Some set
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                         JUSTICE LEE, dissenting

the cutoff at five, and others at age seven. But most state courts agree
that children in this age range are categorically incapable of
negligence. Only a “handful” deem children under the age of five
capable of the kind of thinking that would render them eligible for a
finding of negligence. Supra ¶ 17 (quoting RESTATEMENT (THIRD) OF
TORTS: PHYS. & EMOT. HARM § 10 reporters’ note, cmt. d). 1
    ¶39 In my view, however, the number of these decisions far
exceeds the depth of their analysis. The widespread notion of a
young child’s incapacity for negligence is rooted more in judicial
tradition than cognitive science. Many courts have alluded to what
they see as “common knowledge of the mental development of . . .
children.” 2 They view the cognitive capacity of a child as a matter of
judicial notice, asserting (without citation to expert authority or
literature) that children under the age of five (or sometimes seven)
have not “developed the mental capacity for foreseeing the
possibilities of their inadvertent conduct which would rationally
support a finding” of negligence. 3
   ¶40 Occasionally our judges have cloaked these conclusions in
the legal-sounding garb of Latin phrases—deeming young children
“non sui juris” (not their own master), 4 or described by the maxim
“quaedam personœ sui juris sunt, quaedam olicuo juri subjectœ” (some



   1 But see Beggs v. Wilson, 272 A.2d 713, 714 (Del. 1970) (rejecting an
age cutoff because “[i]n growing up, each child is physically unique,
and the law should recognize this uniqueness”); Lester v. Sayles, 850
S.W.2d 858, 867 (Mo. 1993) (concluding that “[p]ositing a
predetermined age at which negligence or fault can occur has little
basis in reason or logic”).
   2  Christian v. Goodwin, 10 Cal. Rptr. 507, 509 (Cal. Ct. App. 1961)
(citation omitted).
   3 Id. (citation omitted) (holding that a child under the age of five
is incapable of negligence); see also Cox v. Hugo, 329 P.2d 467, 469
(Wash.1958) (asserting, without reliance on any expert or scientific
authority, that a child under the age of six “is a creature of impulse
and impetuosity” and “has no habits of deliberation and
forethought” (citation omitted)); Swindell v. Hellkamp, 242 So. 2d 708,
710 (Fla. 1970) (opining that children under six are “conclusively
presumed to be incapable of committing contributory negligence”).
   4   Graham v. Rolandson, 435 P.2d 263, 278 (Mont. 1967).
                                   13
                             NIELSEN v. BELL
                          JUSTICE LEE, dissenting

persons are independent, and some are subject to another). 5 But
legal-sounding words cannot turn this question into a matter for
legal analysis; the premise of the age cutoff for young children is a
scientific question of cognitive psychology, not a proper subject of
legal analysis or judicial notice.
    ¶41 Still, courts have long resisted challenges to the judicial
prerogative of fixing a lower bound on a child’s capacity for
negligence. Some acknowledge “the arbitrary nature” of a hard
cutoff at age five or seven, yet fall back on the notion that such cutoff
“has been the law” for many decades. 6 Another went so far as to
“agree . . . that the arbitrariness of the rule supports its
abandonment,” while “reluctantly conclud[ing] that the principle of
stare decisis require[d] th[e] court” to retain it. Appelhans v. McFall,
757 N.E.2d 987, 991 (Ill. Ct. App. 2001).
    ¶42 To their credit, some courts have looked to the cognitive
psychology literature in fixing an age cutoff for negligence. To the
extent they have done so, they have relied principally on the
research and publications of psychologist Jean Piaget. 7 Piaget
grouped children into four rigid developmental categories; he placed
children under seven in a category of children deemed “incapable of
understanding the physical world” and “unable to foresee the
consequences of action.” 8 Piaget’s analysis was respected in its day.9


   5Mangum v. Brooklyn City R.R. Co., 38 N.Y. 455, 459 (N.Y. 1868)
(Mason, J.).
   6   Graham, 435 P.2d at 267.
   7 See generally BÄRBEL INHELDER & JEAN PIAGET, THE GROWTH OF
LOGICAL THINKING FROM CHILDHOOD TO ADOLESCENCE (1958); Lisa
Perrochet & Ugo Colella, What A Difference A Day Makes: Age
Presumptions, Child Psychology, and the Standard of Care Required of
Children, 24 PAC. L.J. 1323, 1351 (1993) (“The view among courts that
young children are incapable of caring for their own well-being
probably emerged from the influence of the developmental portrait
painted by Piaget.”); see also Tyler v. Weed, 280 N.W. 827, 832 (Mich.
1938) (relying on the research of Piaget and others, which “brought a
new light upon the mysterious mind of the child”).
   8   Perrochet & Colella, supra note 7, at 1335–36.
   9Perrochet & Colella, supra note 7, at 1334 (noting that “[p]rior to
the 1970s, the work of Swiss Psychologist Jean Piaget was the
dominant paradigm among developmental psychologists”).
                                    14
                           Cite as: 2016 UT 79
                         JUSTICE LEE, dissenting

But cognitive psychology, not surprisingly, has seen substantial
developments in the past few decades. And for decades Piaget’s
approach has been viewed as rooted in outdated notions of rigid,
universal phases of child development. 10
    ¶43 For these reasons I would not base a decision in this case
on existing caselaw. However widely accepted, the notion of a hard
age cutoff at age five finds no reasoned basis in the caselaw. I would
therefore take a fresh look at the question of a child’s cognitive
capacity for negligence by examining the relevant literature in the
field of cognitive psychology.
                                    II
    ¶44 The majority seeks to root its age cutoff in assertions about
cognitive psychology. It claims that “[c]hildren under the age of five
have a limited capacity to appreciate how their actions can cause
harm to themselves or others and have an inadequate internal ability
to control impulses that may lead to injuries.” Supra ¶ 18. And it
insists that “[a]bsent an adequate ability to foresee consequences or
control their behavior, ‘the possibility is slight that the conduct of a
child under five is either deserving of moral criticism or is capable of
being deterred by the application of tort rules.’” Id. (quoting
RESTATEMENT (THIRD) OF TORTS: PHYS. & EMOT. HARM § 10 cmt. d
(assuming, without citing support in social science literature, that
“by the time children reach the age of five, moral rules are becoming
internalized, rather than being controlled by external sources”)). 11




   10  Id. at 1336 (explaining that “Piaget’s views have been
challenged by cognitive psychologists”).
   11    The Restatement asserts that “modern developmental
psychology tends to divide the years before adulthood into several
phases”—birth to two, two to six, six to eleven, and eleven to
eighteen. Id. § 10 cmt. b. But there is very little that is “modern”
about the Restatement’s notions of cognitive psychology. Its
“phases” are based on the outmoded thinking of Piaget, who
adopted similar age cutoffs. See Perrochet & Colella, supra note 7, at
1335–36. So the Restatement seems suspect for reasons identified
herein. See infra ¶¶ 46–50. And it also seems problematic for another
reason: It adopts a cutoff at an age (five) that falls in the middle of one
of its listed phases of development. RESTATEMENT (THIRD) OF TORTS:
PHYS. & EMOT. HARM § 10 cmt. b.
                                    15
                             NIELSEN v. BELL
                          JUSTICE LEE, dissenting

    ¶45 I do not doubt that the majority’s premises hold for many
children under the age of five in some circumstances. But I cannot
agree that most all such children are incapable of the kind of
thinking required to sustain a finding of negligence—or that so
many of them lack that capacity that we should endorse a hard five-
year cutoff as a matter of law.
    ¶46 In recent decades cognitive psychologists have repudiated
the notion that children become capable of the kind of thinking
necessary to sustain a finding of negligence only at the age of five.
Experts in this field have come to understand that “children vary
widely in their mental development and do not move magically
from one developmental stage to another simply because they have
celebrated a birthday.” 12 Importantly, cognitive psychologists have
identified an age younger than five at which some young children
begin to acquire the mental attributes necessary to be held morally
culpable and to be deterred from such behavior. They generally
agree that some children acquire those attributes as early as age
three. 13 And they have identified factors that affect the rate of
development of such attributes in individual children—such as the
physical development of the brain and the social environment that
shapes cognitive human responses. 14
   ¶47 To merit attribution of fault, children must be able to
foresee the consequences of their actions and avoid them by
controlling their impulses. This involves the ability to plan—to
“understand and anticipate the causal connection between actions
and outcomes.” 15 In order to plan, children “must (1) have the ability
to understand cause and effect relationships in the physical world;


   12   Perrochet & Colella, supra note 7, at 1337.
   13  See, e.g., Rochel Gellman, Cognitive Development, in 2
D.L. STEVENS’ HANDBOOK OF EXPERIMENTAL PSYCHOLOGY 533, 537540
(3rd ed. 2002) (compiling studies showing increasing awareness of
cognitive ability in children at age three or even earlier); John R. Best
& Patricia H. Miller, A Developmental Perspective on Executive
Function, 81 CHILD DEV. 1641, 1643-52 (2010) (discussing recent
studies measuring inhibition in young children).
   14 Perrochet & Colella, supra note 7, at 134850; see also generally
Tracey Fay-Stammbach et al., Parenting Influences on Executive
Function in Early Childhood: A Review, 8 CHILD DEV. PERSP. 258 (2014).
   15   Perrochet & Colella, supra note 7, at 1339 (citations omitted).
                                     16
                            Cite as: 2016 UT 79
                          JUSTICE LEE, dissenting

(2) believe that actions produce outcomes in the physical world; and
(3) have the ability to exercise self-regulation.” 16 Young children
vary widely in their capacity for this kind of thinking because they
develop cognitive abilities at different rates.17
   ¶48 Core executive functions, including working memory,
inhibitory control, and cognitive flexibility, are key components in
brain development during preschool years. 18 “Executive
functions . . . make possible [skills such as] mentally playing with
ideas; taking the time to think before acting; meeting novel,
unanticipated challenges; resisting temptations; and staying
focused.” 19 Individual components of executive function emerge
before the age of three. 20 Primitive signs of working memory and
inhibition can be observed in infancy, and experts have identified
substantial variability in the development of this attribute among
young children. 21 From age three and on, children typically undergo
the most significant period of executive function development.22
   ¶49 Of particular relevance to a child’s capability for
negligence is the development of inhibition: “[I]nhibition is a
necessary precursor to the forward-planning, self-regulating, goal-


   16   Id.
   17 Perrochet & Colella, supra note 7, at 1337 (“[C]hildren vary
widely in their mental development and do not move magically
from one developmental stage to another simply because they have
celebrated a birthday.”).
   18 See generally Adele Diamond, Executive Functions, 64 ANN. REV.
PSYCHOL. 135 (2013); Nancy Garon et al., Executive Function in
Preschoolers: A Review Using an Integrative Framework, 134 PSYCHOL.
BULL. 31 (2008).
   19   Diamond, supra note 18, at 135.
   20   Garon at al., supra note 18.
   21 See generally Peter J. Anderson & Natalie Reidy, Assessing
Executive Functions in Preschoolers, 22 NEUROPSYCHOL. REV. 345, 355
(2012).
   22 See, e.g., HARV. UNIV. CTR. on the Developing Child, In Brief:
Executive Function (2012), https://perma.cc/G3E8-G782 (noting that
“executive function skills . . . begin to develop shortly after birth,
with ages 3 to 5 a window of opportunity for dramatic growth in
these skills”).
                                       17
                             NIELSEN v. BELL
                          JUSTICE LEE, dissenting

directed, higher processes that integrated executive functions
engender.” 23 Studies show that there is rapid change in developing
inhibitory control between the ages of three and five. 24 Most children
are able to demonstrate inhibitory control by the age of five, 25 and a
child’s capacity for inhibition improves markedly through the age of
seven. 26 So the ages identified in the caselaw are not entirely
arbitrary. But the cognitive psychology literature does not support
the notion that most all children under the age of five are incapable
of inhibition. At least some children at younger ages have that
capacity.
    ¶50 A child aged three or four may well possess sufficient
capacity for executive functions like planning and inhibition to be
held responsible for at least some kinds of basic life activities. And
for me that is a sufficient ground for rejecting the five-year cutoff
advanced by the majority. Our tort law, after all, is not just aimed at
protecting the interests of defendants; it must also account for the
interest of providing compensation to injured plaintiffs.
    ¶51 With the above in mind, I would adopt a tiered framework
for assessing the negligence of children: (a) children under the age of
three would be categorically immune from a finding of negligence;
(b) children between the ages of three and seven would be subject to
a presumption of incapacity for negligence—a presumption that
could be rebutted by expert testimony establishing the individual
child’s capacity for the kind of executive functions (planning and
inhibition) necessary to hold them responsible for the actions in
question; and (c) children aged eight or older would be held to a
standard of a reasonable child of like age, capacity, and experience
under similar conditions. This framework seems to me to follow
from the premises of cognitive psychology outlined above.


   23  Jacqui A. Macdonald et al., Age-Related Differences in
Inhibitory Control in the Early School Years, 20 CHILD
NEUROPSYCHOL. 509, 510 (2014).
   24 HARV. UNIV. CTR., supra note 22; see also generally Philip David
Zelazo et al., The Development of Executive Function in Early Childhood,
68(3)in Monographs of the SOC’Y for Res. in Child Dev. 68(3) (2003).
   25 Macdonald et al., supra note 23, at 509; see also Anderson &
Reidy, supra note 21; Livia Freier et al., Preschool Children’s Control of
Action Outcomes, DEV. SCI., Oct. 28 2015, at 13.
   26   Macdonald et al., supra note 23, at 509.
                                     18
                          Cite as: 2016 UT 79
                        JUSTICE LEE, dissenting

    ¶52 This framework would lead to an affirmance of the district
court’s decision in this case. Because the child defendant in this case
was four years old, he should be entitled to a presumption that he is
incapable of negligence; but the plaintiffs should also be entitled to
present evidence aimed at rebutting that presumption. I would
affirm and remand to give the plaintiffs a chance to present evidence
of the defendant’s capacity for the kind of thinking necessary to hold
him responsible for the injury he caused by throwing a toy at his
babysitter.
    ¶53 That act was a fairly simple one. At least some four-year-
olds seem capable of anticipating the consequence of the basic act of
throwing something at another person, and of controlling their
impulse to do so. In any event I would leave such questions for case-
by-case disposition by the court on the basis of expert testimony
instead of foreclosing the possibility as a matter of law.
    ¶54 I acknowledge the complication introduced by the likely
gap between the date of the tort and the time when the child’s
cognitive capacity is assessed by the court. See supra ¶ 18. But the
majority overstates the problem. Under my framework the child’s
capacity would not be judged on the basis of trial testimony from the
child as to “her individual understanding of cause and effect,
foreseeability, and capacity for impulse control.” Id. It would be
judged on the basis of expert testimony. And that testimony could
often be judged as a matter of law on pretrial motions.
    ¶55 Expert analysis of a child’s capacity for negligence would
be complicated by the noted time gap between the tort and the
decision by the trial judge. But the complication is hardly intractable.
A cognitive psychologist could inquire into the child’s history and
experience and offer an opinion on the child’s likely ability to engage
in the sort of planning and inhibition necessary to be responsible at
the time of the activity in question. And ultimately the presumption
would go against allowing a suit to go forward. So if the time
problem identified by the majority becomes too difficult, it will count
against a determination of a child party’s capacity for negligence.
   ¶56 The timing problem, moreover, is hardly evaded by the
majority’s approach. The problem remains for the children aged five
or older left open to a finding of negligence by the court. So the
question presented in this case should not be resolved on the basis of
the timing problem identified by the majority. It must be resolved by
our careful assessment of the age below which most all children are

                                  19
                           NIELSEN v. BELL
                        JUSTICE LEE, dissenting

incapable of the kind of thinking required to sustain a determination
of negligence.
   ¶57 The answer to that question is a difficult one. Our current
understanding of cognitive psychology suggests that the answer is
age three. It also indicates that many children between the age of
three and seven are similarly incapable. I would adopt a legal
framework that reflects this understanding.
                                  III
    ¶58 Few young children are likely to engage in the kind of
risky activity that will often result in significant harm to others. And
when they do, many would-be claimants are likely to cut them some
slack for one reason or another—in recognition, for example, of their
minimal capacity for culpability, or their limited resources (absent
insurance) for payment of damages. In the rare case when a young
child is brought to bar, however, our law should reflect the current
understanding of cognitive psychology. The framework that I
propose would accomplish that objective.
     ¶59 It would not, however, open any floodgates for child tort
litigation. My framework would impose a presumption that sweeps
more broadly than the majority’s age cutoff. It would hold children
aged three through seven presumptively incapable of negligence,
subject to rebuttal by expert testimony.
    ¶60 For many children and many activities, this presumption
would be difficult to rebut. But at least some young children are
likely to be shown capable of understanding the likely consequences
of the kind of basic activity at issue in this case—of throwing a toy at
another person’s face—and of controlling their impulses in such acts.
I would not foreclose the possibility of such a determination as a
matter of law.
    ¶61 I dissent from the majority’s adoption of a cutoff at age
five because I find no basis for it in the caselaw or in the relevant
field of science. I also find the majority’s focus short-sighted. Its
analysis of the relevant policy considerations is focused exclusively
on the question of a defendant’s capacity for moral missteps. Yet tort
suits are a two-way street. They are aimed not only at deterrence of
unreasonable conduct but also at compensation for the injuries that
are caused thereby. I would also consider the claimant’s interest in
compensation before we decide to cut off an entire category of
claims. And because at least some children between the ages of three
and seven are capable of planning and impulse control, I would
                                  20
                          Cite as: 2016 UT 79
                        JUSTICE LEE, dissenting

leave the door open to the possibility of compensating a plaintiff
who is both injured by a child defendant and who can prove by
expert testimony that the child is capable of negligence.
    ¶62 The majority’s decision is also short-sighted in a second
respect: It ignores the effect of its decision in cases initiated by child
plaintiffs. If young children are mentally or morally incapable of
negligence, they will not only be immune from suit as defendants;
they will also be deemed incapable of fault when they initiate suit as
plaintiffs. 27 That prospect raises the stakes for our decision today. I
suspect that more children file suit as plaintiffs than are named in
suits as defendants. If so, the predominant effect of today’s decision
will not be to restrict liability in suits involving children but to
expand it. If no young plaintiff will ever have any fault attributed to
him in a negligence suit, the defendant in such a suit will be left with
full responsibility in every case no matter how minimal his degree of
actual relative fault.
    ¶63 Consider a (presumably common) case involving a child
pedestrian plaintiff and a somewhat older driver defendant. The
driver defendant will be deemed 100 percent at fault in 100 percent
of the cases—even if the defendant is barely negligent and the
plaintiff is borderline reckless. So a driver who exceeds the speed
limit by one mile per-hour will be 100 percent at fault even in a case
filed by a plaintiff who recklessly darted into the roadway in full
view of an oncoming car. 28 So long as the plaintiff is under the age of
five, he can never have any fault attributed to him under the
standard adopted today.


   27 See RESTATEMENT (THIRD) OF TORTS: PHYS. & EMOT. HARM § 10
cmt. e. (“The rules relating to children and negligence apply also to
children and contributory negligence.”); Benallo v. Bare, 427 P.2d 323,
325 (Colo. 1967) (finding children under six incapable of contributory
negligence); Swindell v. Hellkamp, 242 So. 2d 708, 710 (Fla. 1970)
(holding that children under seven are “conclusively presumed to be
incapable of committing contributory negligence”).
   28 Swindell, 242 So. 2d at 710 (concluding that a nearly five- year-
old girl who darted into traffic could not be held contributorily
negligent); Benallo, 427 P.2d at 325 (finding that six-year-old who
darted across the street could not be held contributorily negligent);
Baker v. Alt, 132 N.W.2d 614, 620 (Mich. 1965) (holding that a six-
year-old who rode his bike against traffic at an excessive speed could
not be held contributorily negligent).
                                   21
                           NIELSEN v. BELL
                        JUSTICE LEE, dissenting

    ¶64 That will hold for any plaintiff so long as the defendant is
at least five years old. Thus, the prospect of full fault for the barely
negligent defendant would hold if the hypothetical involves not an
adult driver of a vehicle but a five-year-old operator of a bicycle or a
motorized scooter. The five-year-old is 100 percent at fault as a
matter of law even if his conduct is only barely unreasonable and the
pedestrian’s acts border on reckless.
    ¶65 I find these prospects troubling. And I see no legal or
scientific basis for adopting the age five cutoff that will lead us down
this path. I respectfully dissent.




                                  22
