PARADIGMS OF ACCIDENT CAUSATION
Before considering the social science research findings and tort cases directly applicable to the
precautionary value of product warnings, it will be useful to consider this issue within the larger
context of how most accidents occur. Two competing behavioral paradigms underlie most of the
academic discussions of product liability issues and, generally, of accident-causing modalities in
tort law.
The Rational Risk Calculator (RRC) Model: People are presumed to be "rational utility
maximizers" who weigh the personal benefits and costs of all risky activities and then choose
which hazards to accept. Under this paradigm, accident victims are viewed as people who
"gamble" on a desired outcome and lose their bet: They choose to minimize expenses by
purchasing lower-cost but riskier products; they decide to expose themselves to some risks
because they enjoy risk taking; or they deliberately devote their attention to some other concern
instead of concentrating on product safety. Proponents of the RRC model believe people would
lack incentives to avoid inefficient losses if they are not required to bear the costs of risky
choices. It may also be unfair to make safe consumers, those who choose to create lower risks or
can otherwise avoid injuries, subsidize compensation for unsafe or unlucky product users.
The Mistake and Momentary Inattention (MMI) Model: People have severe restrictions on
cognitive capacity, attention span, and time that preclude assessing all relevant considerations in
a "rational" manner. Consumers cannot evaluate all dimensions of all product-related risks
because they are subject to these "bounded rationality" constraints, a term devised by Herbert
Simon to denote the presence of intrinsic limitations on people's capacity to make optimal
choices. Under the MMI paradigm, most product-related accidents result from consumer
miscalculations and mistakes, ambiguity, habitual behavior applied in inappropriate settings,
momentary inattention, or other forms of carelessness. Most accidents are truly accidents, not the
results of deliberate gambles that turn out badly. For example, most drivers know how to operate
motor vehicles safely, in the sense that they could pass a test on the subject, but people cannot
remain continuously vigilant and sometimes err when reacting to adverse traffic and road
conditions. It follows from this MMI paradigm that injuries can seldom be deterred by imposing
losses on consumers because most accidents arise from inherent cognitive limitations or
unintended carelessness.
These models represent polar positions on the continuum of accident-causing behavior. Some
accidents undoubtedly result from deliberate and informed risk taking, while others stem from
mistakes and inattention. Yet, judges and legal analysts must decide which characterization best
describes the causes of most accidents, because appropriate legal responses will differ sharply
depending on the paradigm adopted. Advocates of the RRC model prefer risk allocations through
market system choices driven by consumer sovereignty. If people make bad gambles or if good
gambles yield bad results, it would assertedly be efficient and fair to make them bear the
consequences. When consumers lack enough knowledge to use products safely, the proper
solution under this paradigm is information disclosure and education to enable improved
consumer decisions, not coercive imposition of tort liability or regulation.
As one illustration of the RRC mode of analysis, an American Law Institute (ALI) Report on tort
system problems and potential reforms [FN22] adopted the views of two pro-market scholars,
Alan Schwartz and W. Kip Viscusi, that the exculpatory effect of product warnings should be
increased. The ALI Report contends:
The object of a good warning is to provide users with information about risk levels so that users
can harmonize their use preferences with their safety preferences in an informed way, to provide
users with information about safe and dangerous use so that they can choose optimal risk
reduction strategies, or to provide both types of information. The policy goal is not to ensure that
all users always behave in the safest fashion. For example, it is not necessarily irrational to
forego the use of rubber gloves when using household cleaning products: a person could decide
that for him the discomfort costs of gloves outweigh their safety gains. Not only is complete
safety unachievable, but it is inconsistent with a serious interest in warning issues. This interest
presupposes a commitment to individual autonomy--within limits, to letting informed people
decide for themselves what products to buy and how to use products. The central characteristics
of this archetypal RRC analysis are that it emphasizes consumer choice, not consumer safety,
and that it assumes adequate disclosure will enable people to choose whatever risk levels
are consistent with their preferences. Because RRC adherents believe informed product users are
competent decisionmakers who should bear the consequences of their risky choices, these
analysts are likely to support the comment j presumption. For example, Professor Viscusi's
recent book on product liability claims that "if hazard warnings are effective in fully
communicating the risk, then any additional examination of whether a product design is
defective is redundant since the market has already performed such a risk-utility test."
The MMI paradigm presumes that most accidents stem from cognitive imperfections and
inadvertent carelessness, not from reasoned calculations. Under this behavioral characterization,
warnings may achieve some useful precaution in some accident settings but many consumers
cannot use marginal information effectively to avoid injuries. Because manufacturers can employ
specialists in product safety decisionmaking while users generally cannot, strict product liability
and regulation may be necessary to encourage the development of relatively "fool-proof"
products whenever greater safety is feasible.
One example may clarify how the adoption of different behavioral paradigms is likely to
influence the normative choice of legal policies. Some product-related accidents stem primarily
from user fatigue—a problem arising in the contexts of driving, operation of industrial
machinery, use of lawnmowers or other power tools, and many other settings where people must
handle dangerous implements for extended periods of time. Under the RRC paradigm, people are
presumed to understand and accept greater risks in return for the benefits of continuing product
use despite fatigue. If manufacturers need do anything to reduce this source of accidents,
provision of a "good" warning informing consumers about the additional hazards would be
regarded as a satisfactory legal solution because it enables people to make informed
choices on whether to expose themselves to the greater risk.
Under the MMI paradigm, accidents resulting from fatigue would mainly be attributed to errors
in judgment, carelessness, excessive optimism, or other mistakes that do not result from
deliberate risk calculations. In support of this interpretation, a recent research study found that
fatigue not only impairs physical performance but it also degrades judgment; as users become
tired, they are less likely to operate machinery carefully and they also lose some capacity to
recognize their reduced level of competence. If the MMI behavioral paradigm is accepted, it
follows that "good" warnings cannot prevent many accidents caused by fatigue and therefore
should not be treated as legally acceptable substitutes for safer product designs. Manufacturers
should instead be required to incorporate safety devices that can protect tired users whenever
feasible against foreseeable risks from mishandling products. Most academic discussions of
accident-causing behavior reflect the RRC paradigm because torts scholarship in recent decades
has been greatly influenced, if not dominated, by "law and economics" treatments incorporating
the economists' conventional behavioral assumptions.
The RRC model is also compatible with the normatively attractive thesis that people are best
able to pursue their own interests. However, I believe the MMI paradigm offers a far more
realistic explanation of most accident causation. As one prominent scientist noted: "It is a
fundamental premise of cognitive psychology that the amount of attention that can be allocated
to various activities is limited, producing a bottleneck in information processing." The social
science research described in Part II reveals a broad array of cognitive imperfections that are
fundamentally inconsistent with the RRC model.