Copyright 1965, American Law Institute

Division Two - Negligence
Chapter 12 - General Principles
Topic 2 - The Standard By Which Negligence is Determined


 Unless the actor is a child, his insanity or other mental deficiency does not relieve the actor from liability for conduct which does not conform to the standard of a reasonable man under like circumstances.


a.  If the actor is a child, his mental deficiency is taken into account. See § 283 A.

b.  The rule that a mentally deficient adult is liable for his torts is an old one, dating back at least to 1616, at a time when the action for trespass rested upon the older basis of strict liability, without regard to any fault of the individual. Apart from mere historical survival, its persistence in modern law has been explained on a number of different grounds. These are as follows:

1. The difficulty of drawing any satisfactory line between mental deficiency and those variations of temperament, intellect, and emotional balance which cannot, as a practical matter, be taken into account in imposing liability for damage done.

2. The unsatisfactory character of the evidence of mental deficiency in many cases, together with the ease with which it can be feigned, the difficulties which the triers of fact must encounter in determining its existence, nature, degree, and effect; and some fear of introducing into the law of torts the confusion which has surrounded such a defense in the criminal law. Although this factor may be of decreasing importance with the continued development of medical and psychiatric science, it remains at the present time a major obstacle to any allowance for mental deficiency.

3. The feeling that if mental defectives are to live in the world they should pay for the damage they do, and that it is better that their wealth, if any, should be used to compensate innocent victims than that it should remain in their hands.

4. The belief that their liability will mean that those who have charge of them or their estates will be stimulated to look after them, keep them in order, and see that they do not do harm.

c.  Insane persons are commonly held liable for their intentional torts. While there are very few cases, the same rule has been applied to their negligence. As to mental deficiency falling short of insanity, as in the case of stupidity, lack of intelligence, excitability, or proneness to accident, no allowance is made, and the actor is held to the standard of conduct of a reasonable man who is not mentally deficient, even though it is in fact beyond his capacity to conform to it.

REPORTERS NOTES:  This Section has been added to the first Restatement, which contained, in § 283, an exception as to insane persons, followed by a Caveat stating that the Institute expressed no opinion as to their liability. In the 1948 Supplement, this exception and the Caveat were stricken out. This Section is now added to complete the change.

The 1948 Supplement contained a lengthy Note by the Reporter, discussing and explaining the change. Without repeating it here, reference may be made to the following cases:

As to mental deficiency falling short of insanity, the following hold that the negligent conduct is not excused: Bessemer Land & Improvement Co. v. Campbell, 121 Ala. 50, 25 So. 793, 77 Am. St. Rep. 17 (1898), excitable temperament; Worthington v. Mencer, 96 Ala. 310, 11 So. 72, 17 L.R.A. 407 (1892), "dull mind"; Georgia Cotton Oil Co. v. Jackson, 112 Ga. 620, 37 S.E. 873 (1901), stupidity; Deisenrieter v. Kraus-Merkel Malting Co., 97 Wis. 279, 72 N.W. 735 (1897), lack of intelligence.

See, however, Seattle Electric Co. v. Hovden, 190 F. 7 (9 Cir. 1911), affirming Hovden v. Seattle Electric Co., 180 F. 487 (W.D. Wash. 1910), and Noel v. McCaig, 174 Kan. 677, 258 P.2d 234 (1953), both holding that the plaintiff's low intelligence must be taken into account in determining his contributory negligence. Also the dictum in Riesbeck Drug Co. v. Way, 111 Ind. App. 467, 39 N.E. 2d 776, 11 N.C.C.A. N.S. 752 (1942).

As to insanity, it was held in Williams v. Hays, 143 N.Y. 442, 38 N.E. 449, 26 L.R.A. 153, 42 Am. St. Rep. 743 (1894); Sforza v. Green Bus Lines, 150 Misc. 180, 268 N.Y. Supp. 446 (1934); Johnson v. Lambotte, 147 Colo. 203, 363 P.2d 165 (1961); and Shapiro v. Tchernowitz, 3 Misc. 2d 617, 155 N.Y.S.2d 1011 (1956), that an insane person was liable for harm caused by his negligence. There are, in addition, general statements in a number of cases that insane persons are liable for negligent conduct, which are in the nature of dicta. See Ellis v. Fixico, 174 Okla. 116, 50 P.2d 162 (1935), insane person liable for negligence of his chauffeur in driving a car; Parke v. Dennard, 218 Ala. 209, 213, 118 So. 396 (1928); Leary v. Oates, 84 S.W.2d 486 (Tex. Civ. App. 1935), error dismissed; In re Meyer's Guardianship, 218 Wis. 381, 261 N.W. 211 (1935).

On the other hand, in Buckley & Toronto Transp. Commission v. Smith Transport, Ltd., [1946] Ont. Rep. 798, 4 Dom. L. Rep. 721, it was held that insanity, which prevented the defendant's driver from understanding his duty of care, or rendered him incapable of performing it, prevented liability for negligence.

There are a good many cases involving intentional torts, which contain general statements that an insane person is liable for all his torts. See for example Seals v. Snow, 123 Kan. 88, 254 P. 348, 51 A.L.R. 829 (1927); Hackenberger v. Travelers Mut. Cas. Co., 144 Kan. 607, 62 P.2d 545, 547 (1936); Toepffer v. Toepffer, 151 Kan. 924, 101 P.2d 904 (1940); Roberts v. Hayes, 284 Ill. App. 275, 1 N.E.2d 711 (1936); Phillips' Committee v. Ward's Adm'r, 241 Ky. 25, 43 S.W.2d 331 (1931); Yancey v. Maestri, 155 So. 509 (La. App. 1934); McGuire v. Almy, 297 Mass. 323, 8 N.E.2d 760 (1937); Bryant v. Carrier, 214 N.C. 191, 198 S.E. 619 (1938); Sweeney v. Carter, 24 Tenn. App. 6, 137 S.W. 2d 892 (1939); Shedrick v. Lathrop, 106 Vt 311, 172 A. 630 (1934).

See, generally, as to the tort liability of insane persons: Hornblower, Insanity and the Law of Negligence, 5 Colum. L. Rev. 278 (1905); Bohlen, Liability in Tort of Infants and Insane Persons, 23 Mich. L. Rev. 9 (1924); Cook, Mental Deficiency in Relation to Tort, 21 Colum. L. Rev. 333 (1921); Ague, The Liability of Insane Persons in Tort Actions, 60 Dick. L. Rev. 211 (1956); Wilkinson, Mental Deficiency as a Defense to Tort Liability, 17 Rocky Mt. L. Rev. 38 (1944).