Daniel Kahneman Nobel Lecture

Shafir (1993) presented respondents with problems in which they played

the role of a judge in adjudicating the custody of a child between divorcing

parents. Each parent was described by a list of attributes. One of the descrip-

tions was richer than the other: it contained more negative and more positive

attributes. The framing of the instruction was varied. Some respondents were

asked which custody request should be accepted, others decided which re-

quest should be rejected. The rich description was favored under both in-

structions, presumably because the respondents attended to its many advan-

tages in deciding which custody request to accept, and to its many

disadvantages in deciding about rejection. 

A large-scale study by LeBoeuf and Shafir (in press) examined an earlier

claim that framing effects are reduced, in a between-subjects design, for par-

ticipants with high scores on ‘need for cognition’ (Smith & Levin, 1996). The

original effect was not replicated in the more extensive study. However,

LeBoeuf, and Shafir (2003) showed that more thoughtful individuals do show

greater consistency in a within-subject design, where each respondent en-

counters both versions of each problem. This result is consistent with the pre-

sent analysis. Respondents characterized by an active System 2 are more like-

ly than others to notice the relationship between the two versions and to

ensure the consistency of the responses to them. Thoughtfulness confers no

advantage in the absence of a relevant cue, and is therefore irrelevant to per-

formance in the between-subjects design. 

Framing effects are not restricted to decision-making: Simon and Hayes

(1976) documented an analogous observation in the domain of problem

solving. They constructed a collection of transformation puzzles, all formally

identical to the tower of Hanoi problem, and found that these ‘problem iso-

morphs’ varied greatly in difficulty. For example, the initial state and the tar-

get state were described in two of the versions as three monsters holding balls

of different colors. The state transitions were described in one version as

changes in the color of the balls, and in the other as balls being passed from

one monster to another. The puzzle was solved much more easily when

framed in terms of motion. The authors commented that “It would be possi-

ble for a subject to seek that representation which is simplest, according to

some criterion, or to translate all such problems into the same, canonical,

representation…” but “subjects will not employ such alternative strategies,

even though they are available, but will adopt the representation that consti-

tutes the most straightforward translation…” (Simon & Hayes, 1976, p 183). 

Passive adoption of the formulation given appears to be a general princi-

ple, which applies as well to these puzzles, to the displays of Figure 2, and to

the standard framing effects. People do not spontaneously compute the

height of a tower that could be built from an array of blocks, and they do

not spontaneously transform the representation of puzzles or decision

problems. It is of interest, however, that some specialized perceptual and

cognitive systems exhibit a limited ability to generate canonical representa-

tions for particular types of stimuli. Having seen a face once from a particu-

lar angle, for example, observers will recognize it from another angle, and

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they will also identify a black and white picture of it, or even a contour draw-

ing. But even the versatile face-recognition module has its limitations: its

performance is quite poor in recognizing familiar faces that are shown up-

side down. The brain mechanisms that support the comprehension of lan-

guage also have a substantial ability to strip the surface details and get to the

gist of meaning in an utterance, but this ability is limited as well. Few of us

are able to recognize ‘137 x 24’ and ‘3,288’ as ‘the same’ number without

going through some elaborate computations. Invariance cannot be

achieved by a finite mind.

The impossibility of invariance raises significant doubts about the descrip-

tive realism of rational-choice models (Tversky & Kahneman, 1986). Absent a

system that reliably generates appropriate canonical representations, intuitive

decisions will be shaped by the factors that determine the accessibility of dif-

ferent features of the situation. Highly accessible features will influence deci-

sions, while features of low accessibility will be largely ignored. Unfortunately,

there is no reason to believe that the most accessible features are also the

most relevant to a good decision.

3. CHANGES OR STATES: PROSPECT THEORY

A general property of perceptual systems is that they are designed to enhance

the accessibility of changes and differences (Palmer, 1999). Perception is ref-

erence-dependent: the perceived attributes of a focal stimulus reflect the contrast

between that stimulus and a context of prior and concurrent stimuli. Figure 5

illustrates reference dependence in vision. The two enclosed squares have the

same luminance, but they do not appear equally bright. The point of the

demonstration is that the brightness of an area is not a single-parameter func-

tion of the light energy that reaches the eye from that area. An account of

perceived brightness also requires a parameter for a reference value (often

called adaptation level), which is influenced by the luminance of neighboring

areas.

Figure 5.

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