Ambiguity and rationality

Recently, several theories of decision making and probability judgment have been proposed that take into account ambiguity (Einhorn and Hogarth, 1985; Gardenfors and Sahlin, 1982). However, none of these theories explains exactly what the psychological causes of ambiguity are or addresses the issue of whether ambiguity effects are rational. In this paper, we define ambiguity as the subjective experience of missing information relevant to a prediction. We show how this definition can explain why ambiguity affects decisions in the ways it does. We argue that there are a variety of rational reasons ambiguity affects probability judgments and choices in the ways it does. However, we argue that the ambiguity effect does not cast doubt on the claim that utility theory is a standard of rational choice. Rather, we suggest that the effect of ambiguity on decisions highlights the fact that utility theory, like any normative model of decision making only prescribes the optimal decision, given what one knows.     

Medical hermeneutics: Where is the “text” we are interpreting?

The present paper is a commentary on an article by Drew Leder [1]. Leder identifies a series of texts in the clinical encounter, emphasizes the central role of interpretation in making sense of each of these texts, and articulates ordering principles to guide the interpretive work.The metaphor of clinical work as textual explication, however, creates the expectation that there is a text somewhere to be found. Such an expectation invites doctors and patients to search for the text and runs the risk of conceptualizing patients as more static than they are. If one is to use the textual metaphor, one must appreciate the radical extent to which the clinical encounter is a mutually produced and shifting entity. The qualities of mutuality and indeterminacy are not those one usually associates with texts. One might ultimately be better served by a different metaphor based more directly on uncertainty.     

Interviewers’ Moods and Evaluations of Job Applicants: The Role of Applicant Qualifications1

Participants were induced to experience positive affect, negative affect, or no shift in current affect. Then they conducted a simulated job interview with an applicant (actually an assistant) who appeared to be highly qualified, ambiguously qualified, or unqualified for the job in question. It was predicted that interviewers’ moods would exert the strongest influence on ratings of the applicant when this person's qualifications were ambiguous. Results offered partial support for this hypothesis. When the applicant's qualifications were ambiguous, participants induced to experience positive affect rated this person higher on several dimensions than participants induced to experience negative affect. When the applicant appeared to be highly qualified for the job, in contrast, interviewers’ moods had no significant effect on their ratings of this person. Contrary to expectations, however, interviewers’ moods significantly influenced ratings of the applicant when this person appeared to be unqualified for the job in question. In this condition, participants induced to experience positive affect actually rated the applicant lower than those induced to experience negative affect. Several mechanisms that may have contributed to these results (e. g., tendencies toward mood maintenance, adoption of a positive-test strategy) are examined. In addition, practical implications of these findings for conducting job interviews and for the use of various impression-management techniques by applicants are discussed.     

Social support and immune function among spouses of cancer patients

This study investigated whether social support was related to immune function among spouses of cancer patients. Effects of depression and negative life events were examined as potential mediators. Results showed evidence of greater immunocompetence on 2 of 3 dynamic measures: natural killer cytotoxicity and proliferation response to phytohemagglutinin among spouses who reported high levels of social support. All six components of social support assessed by the Social Provisions Scale (Cutrona & Russell, 1987) were strongly related to these indices of immune function. No evidence was found for mediation by either life events or depression.     

A Whiff of Reality: Empirical Evidence Concerning the Effects of Pleasant Fragrances on Work-Related Behavior1

Two studies were conducted to investigate the potential effects on workrelated behavior of one environmental variable: pleasant fragrances. In Study 1, participants performed a word construction task under low or high stress while in the presence or absence of pleasant fragrances. Performance was significantly enhanced by fragrance in both stress conditions. In addition, exposure to pleasant fragrances significantly increased performance on an additional task (decoding written messages) completed by participants following exposure to stress. In Study 2, both exposure to pleasant fragrances and receipt of a small gift increased performance on the same word construction task used in Study 1. In addition, fragrance and a gift increased participants' willingness to engage in both immediate and delayed helping. Together, the results of these studies offer support for the view that pleasant fragrances can influence work-related behavior, and that such effects may be mediated, at least in part, by increments in positive affect.     

Effects of a variable-ratio conditioning history on sensitivity to fixed-interval contingencies in rats.

We investigated the possibility that human-like fixed-interval performances would appear in rats given a variable-ratio history (Wanchisen, Tatham, & Mooney, 1989). Nine rats were trained under single or compound variable-ratio schedules and then under a fixed-interval 30-s schedule. The histories produced high fixed-interval rates that declined slowly over 90 sessions; differences as a function of the particular history were absent. Nine control animals given only fixed-interval training responded at lower levels initially, but rates increased with training. Despite differences in absolute rates, rates within the intervals and postreinforcement pauses indicated equivalent development of the accelerated response patterns suggestive of sensitivity to fixed-interval contingencies. The finding that the histories elevated rates without retarding development of differentiated patterns suggests that the effective response unit was a burst of several lever presses and that the fixed-interval contingencies acted on these units in the same way as for single responses. Regardless of history, the rats did not manifest the persistent, undifferentiated responding reported for humans under comparable schedules. We concluded that the shortcomings of animal models of human fixed-interval performances cannot be easily remedied by including a variable-ratio conditioning history within the model.     

Psychological determinants of decision attitude

Decision attitude — an analog of risk attitude — is the propensity to make (or avoid making) a decision: in decision aversion, a person finds it more desirable to receive through fiat the better of two options than to have a choice between them; in decision seeking, the choice is more desirable, even though it can lead to nothing better than the best option. Both decision aversion and decision seeking were found in hypothetical scenarios. Experimental manipulations and subjects' justifications point to anticipated regret, fear of blame for poor outcomes, and desire for equitable distributions as sources of decision aversion. One source of decision seeking (for self) and decision aversion (when deciding for others) appears to be the desire for the self-determination of the affected parties. We consider the implications of our results for personal choice and public policy decisions.