Positive Affect Facilitates Integration of Information and Decreases Anchoring in Reasoning among Physicians

ORGANIZATIONAL BEHAVIOR AND HUMAN DECISION PROCESSES

Vol. 72, No. 1, October, pp. 117–135, 1997 ARTICLE NO. OB972734

Positive Affect Facilitates Integration of Information and Decreases Anchoring in Reasoning among Physicians Carlos A. Estrada Henry Ford Hospital

Alice M. Isen Cornell University

and Mark J. Young Henry Ford Hospital

The present study investigated the influence of positive affect on clinical reasoning among practicing physicians using a simulated patient protocol. Forty-four internists were randomized to one of three groups; a control group, an affect-induction group, in which they received a small package of candy, or a group that was asked to read humanistic statements regarding the practice of medicine. Physicians “thought aloud” while they solved a case of a patient with liver disease. Two raters reviewed the transcripts to determine how soon the liver disease domain was considered, or at what point it was established, and the degree of anchoring displayed (distortion or inflexibility in thinking). The Affect group initially considered the diagnosis of liver disease significantly earlier in the protocol (20 vs 39%, or 19% earlier; 95% confidence interval; 6 to 32%, p 5 .008) and showed significantly less anchoring than did controls (means of 1.5 vs 3.9, or a difference of 2.4 in a scale of 1 to 10; 95% confidence interval; 0.3 to 4.5, p 5 .031). The Affect and Control groups established the diagnosis at similar points in the protocol. Ancillary analyses The authors thank Mark Chen for his transcription of the protocols. Address reprint requests to Dr. Carlos A. Estrada, East Carolina University, Pitt County Memorial Hospital, Teaching Annex R-389, Greenville, NC 27858-4354. Fax: (919) 816 4688. E-mail: [email protected]. 117

0749-5978/97 $25.00 Copyright q 1997 by Academic Press All rights of reproduction in any form reserved.

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examined questions relevant to the amounts of heuristic processing, premature closure, jumping to a diagnosis without sufficient evidence, or other evidence of superficial or flawed processing. No other differences were found. Physicians in whom positive affect had been induced integrated information earlier (considered liver) and demonstrated less anchoring, but did not show evidence of premature closure or other superficial processing. q 1997 Academic Press

INTRODUCTION

A growing body of research indicates that the induction of positive affect functions to improve integration of information, problem solving, decision making, and cognitive organization in a wide variety of settings. Positive affect has been defined as a pleasant feeling state or good mood. The term “affect” has been used to describe a relatively diffuse feeling state in which people are able to continue to work on ongoing issues or topics, to think about things other than the emotion they are feeling or the object of the emotion. This is in contrast with a more specific emotion—like anger—that focuses attention on itself and its source. In research studies, positive affect has been induced by little things such as receiving a small gift, hearing positive feedback about one’s performance on a task, or seeing 5 min of a comedy film (Deldin & Levin, 1986; Greene & Noice, 1988; Isen, 1987; Isen & Daubman, 1984; Isen, Daubman, & Nowicki, 1987; Isen, Johnson, Mertz, & Robinson, 1985). The induction of positive affect has also been shown to be effective in medical contexts, improving decision making among medical students, and creative problem solving among physicians (Estrada, Isen, & Young, 1994; Isen, Rosenzweig, & Young, 1991). One question that has not yet been explored is whether these kinds of effects of feelings would extend to experts working in their domain of expertise, and if so exactly what form it would take. Thus, the present study examines the impact of positive affect on diagnostic processes among practicing physicians. The problem solving or diagnostic reasoning process among physicians is a matter of interest to the field of decision making and expert decision making generally, as well as more specifically to medical educators and clinicians. The impact of positive affect on the decision processes of experienced experts is also of broad interest. Kassirer and colleagues describe the steps in the diagnostic process as follows: (1) early hypothesis generation, which consists of establishing a small number of hypotheses from initial data about the patient; (2) developing a cognitive representation, or establishing the context to solve the problem; (3) selective data collection, in which, based on the hypotheses generated, data are gathered; (4) hypothesis refinement, during which, the diagnostic categories are revised, rejected, or re-ranked; and the final step, (5) verification or hypothesis confirmation, which consists of arriving at the final

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or most reasonable diagnosis; during this step, competing hypothesis are eliminated (Kassirer, 1989; Elstein, Shulman, & Sprafka, 1990). For this process to be effective, physicians require a broad fund of knowledge, experience, and an ability to integrate and incorporate information appropriately as new data become available. Identifying interventions that improve these processes among practicing physicians may have major implications in medical decision making. Therefore, one objective of the present study was to determine if the induction of positive affect could influence the diagnostic reasoning process among practicing physicians, and in particular whether such influence would occur at the hypothesis-generation and/or hypothesis confirmation phase. We also examined the impact of positive affect on anchoring, a cognitive style that may lead to errors in diagnostic reasoning because it involves reduced flexibility in thinking (Sox, Blatt, Higgins, & Marton, 1988). Anchoring in reasoning can be related to the Bayesian concept of estimating and adjusting the probability of an event based on some starting point (Sox et al., 1988), in which “anchoring” may be said to occur if an initial evaluation or assessment is over-weighted, or receives too much emphasis, and there is insufficient adjustment to new relevant information. Exploratory analyses were also of interest, to determine effects of feelings on other aspects of clinical decision making, as well. A second focus in this work is theoretical, aimed at addressing issues related to the nature of positive affect and its fundamental influence on thinking. Most of the research literature indicates that positive affect facilitates systematic processing of important or interesting material, leading problem solving to be both more efficient and more thorough than at other times (see for example, Isen, 1993, for review). However, some authors have interpreted the improved creative problem solving found under conditions of positive affect as reflecting heuristic, non-systematic processing, and have suggested that positive affect facilitates only heuristic processing. They argue that positive affect leads to superficial and or non-systematic processing. Some have even suggested that positive affect impairs systematic processing (Mackie & Worth, 1991; Schwarz & Bless, 1991). Thus, one focus of the present study is to examine the influence of positive affect on systematic, careful problem solving, to see if positive affect facilitates or impairs systematic thought processes. If the induction of positive affect leads to earlier hypothesis generation, improved hypothesis confirmation, or to less anchoring among practicing physicians, it may have considerable implication, both practical and theoretical. We predict that positive affect will promote careful and thorough, as well as flexible and open, evaluation and thought about a problem. Thus, we predict facilitated integration of material (earlier recognition of the correct domain of the disease) but reduced anchoring, for the positive affect group, compared with the control group. We do not expect to find that positive affect increases premature closure, distortion of information, or other indication that positive affect impairs systematic, careful, thorough cognitive processing.

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METHODS

Overview We randomly assigned 44 internists, unaware of the hypothesis, to three groups: a control group, an affect-induction group (in which they received a small package of candy, “Affect”), and a condition in which subjects concentrated on statements reflective of the humanistic aspects of medicine (“Statements”). See Fig. 1. Subjects then worked on a creative problem-solving task (results reported elsewhere; Estrada et al., 1994) and then diagnosed a written case of a patient with chronic active hepatitis for this study. Physicians “thought aloud” as they solved the case; sessions were tape recorded and later transcribed for analyses. The framework for analysis is based on the diagnostic reasoning process described by Kassirer (1989) and by Elstein et al. (1990), and on other studies evaluating the impact of affect on decision making. The major dependent measures are generation of the liver domain hypothesis, hypothesis confirmation, and degree of anchoring.

FIG. 1. Study design.

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Subjects Subjects in this study were practicing physicians from the four largest internal medicine clinics of the Henry Ford Health System. We chose to use practicing physicians as subjects because their reasoning process is more complex and representative of expert diagnostic processing than that of medical students. Our procedure also provides data from a setting beyond the research laboratory. Each physician in the clinics received a letter of invitation followed by a telephone call. Physicians were told that the reason for the study was to analyze how an internist solved a clinical case. They were not informed about the hypotheses of the study, nor about the interventions in the other groups. Participation was voluntary, and no payment was provided. We sent letters to 78 board-certified general internists, we were able to contact 67, and 65% of those (44/67) participated in the study. Physicians who declined to participate gave as reasons that they were unable to fit a session into their schedules, were in the process of retirement, or were not interested. Without knowledge of condition, two subjects were excluded prior to rating of the protocols (one subject, from the affect group, was interrupted when somebody entered the room, and the second subject, from the statements group, did not follow the instructions). Procedure The study was carried out at the physicians’ offices, individually, and by appointment. All materials, including instructions, were presented enclosed in a large envelope. From outward appearance, all were identical. After the envelope was handed to the subject, the researcher left the room for the first 7 min so that the subject could open his/her packet, read the instructions, and receive or not receive the affect intervention. After this time the researcher re-entered the room quietly only to remind the subjects from time to time to “think aloud” and to provide patient laboratory test results (if so requested). Subjects were instructed not to talk with the researcher. The design of the study provided for the researcher to be unaware of the subject’s group while interacting with him/her. This was done in order to avoid any possible inadvertent experimenter bias (biased co-interventions) during the session. We tested to see whether this procedure was successful in keeping the researcher unaware of the subject’s group: At the end of each session, the researcher tried to “guess” the group assignment. The researcher was not correct in “guessing” the group assignment, indicating that he could not introduce experimenter bias (k 5 0.03, indicative of poor accuracy). Interventions The control group received a packet of materials with instructions but with no affect or statements intervention. The affect group received, inside the packet of materials, a small package containing five miniature chocolate bars and four hard candies in a transparent

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plastic bag, tied with a red ribbon. The bag of candy was arranged so that it was flat and therefore not noticeable to the experimenter when he handed the envelope to the subject. A similar method of affect induction has been used in other studies (Isen et al., 1985, 1987; Isen & Daubman, 1984). Instructions enclosed in the envelope indicated that the bag of candies was a small token of appreciation for subjects’ participation and asked them to put the candy away and not let the researcher know that they had received it. None of the participants ate the candy while diagnosing the case. The “Statements” group involved a procedure in which participants were asked to read and think about statements reflective of the humanistic aspects of medical practice. We originally intended to induce positive affect with this intervention; however, upon reflection, we realized that such thoughts might have more complicated effects. Ultimately, data also suggested that this was not a valid way to induce positive affect (Estrada et al., 1994). In our procedure, each subject was asked to read and concentrate for a few seconds on each of 11 phrases related to humanistic sources of practice satisfaction for physicians. Some examples include the following: “Physicians are trusted,” “I can transmit confidence to my patients,” “I can relieve my patients’ anxiety,” and “I care about my patients.”1 Clinical Case The written case described a 45-year-old female who presented with a 6month history of arthralgias, fatigue, dark urine, and “red spots” on both legs. Information on additional history, past medical history, family history, review of systems, and physical exam were covered by easy-to-remove stickers. Subjects removed the stickers as needed to obtain information about the case. Information on patient test results was available from the researcher who was quietly sitting in the room. Written results were handed to the subjects upon their calling for the test. This procedure was used because, otherwise, listing the tests might have cued (or misled) the subjects. Subjects were instructed to review the available information in any order they wanted, and were told they could go back and forth, and could request as many or as few pieces of information, without incentives or penalties. The case was created, modified, and pilot tested with five general internists; see Appendix. We chose this design because it closely reflects the reasoning process among practicing physicians. Transcript Analyses The audio tapes were transcribed, and a physician listened to them again and made corrections. The transcripts were typed verbatim, without any parsing rules. Pauses and interruptions were noted. Transcripts were read multiple 1

We did not include a negative-affect condition in this study. Despite the frequent assumption that “negative” affect is the “opposite” of positive affect and therefore might represent an appropriate control or comparison condition, much of the research literature suggests that the impact of negative affect states such as anger, fear, or sadness is not always opposite to that of positive affect in a simple way (see, for example Isen, 1987; Isen, 1990, for discussion of this issue).

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times by two independent raters unaware of a subject’s condition. General agreement was calculated and, as described below, disagreement was resolved by discussion. Physician subjects understood that the goal for the study was to analyze how an internist solves a clinical case. They were instructed to stop when they thought they had reached a reasonable diagnosis. In general, the protocols indicated that subjects found the case more difficult in a way that we had not expected: in particular, after establishing that a chronic liver disorder was the cause of the patient’s problem, subjects seemed to feel obligated to determine the underlying cause of the chronic liver problem (chronic active hepatitis) and an exact etiology (cause of chronic active hepatitis). Some physicians also entertained treatment options for the problem. For this reason, a priori, we decided to focus, not on total length of the protocol, but on measures earlier in the protocol, measures that reflected the basic decision process used to reach the diagnosis itself. Dependent Measures The major dependent measures were generation of the liver domain hypothesis, hypothesis confirmation, and anchoring. These processes, hypothesis generation, hypothesis confirmation, and staying open to disconfirming evidence, are fundamental steps and processes in daily medical decision making. Primary hypotheses. Two independent raters read the transcripts and examined the following aspects of the diagnostic reasoning process: 1. Generation of the liver-domain hypothesis involves recognition that the signs and symptoms of this case could represent a liver disease. This step of the diagnostic reasoning process relates to integration, defined as the ability to associate information appropriately. This was measured as the number of the lines (represented as a percentage) into the transcript at which the physician considered that the diagnosis might involve a liver disorder ([number of lines into the transcript/total number of lines of the transcript]*100). Raters were instructed to score this when the protocol had clearly shown consideration of liver, not just mere mentioning of liver disease. An example of a statement reflecting consideration of the liver domain is the following: Line number Transcript 42 “. . . so, here, ah, I think we can now, at this point, narrow 43 it down to a problem with the liver, it doesn’t necessarily have 44 a liver involvement, I, it sort of narrows my differential diagno45 sis to two major groups, Liver disease and hemolysis . . . 46 ummmm . . . again . . . her father . . . her father had a stroke 47 at age 80 . . . she traveled to Toronto . . . what else is there? . . .” This transcript contained 174 lines, and the score is (43/174) * 100 5 24.7%.

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An example of a statement where liver was just mentioned, but not seriously considered as the domain of the diagnosis is the following: “. . . Um, red spots, I think something like thrombocytopenia, . . . immune hemolysis creating dark urine . . . dark urine makes me, Um, think of a possible hepatic disease, but that doesn’t seem as likely. So the working diagnoses, thrombocytopenia, collagen vascular disease. . . .” 2. Hypothesis confirmation (or verification) relates to the ability to discern among competing hypotheses. This was measured as the percentage of the lines into the transcript at which the physician established that a liver disorder was the cause of the patient’s problem ([number of lines into the transcript/ total number of lines of the transcript]*100). Again, the protocol had to indicate clearly that the physician had concluded that the problem was a liver disease; no other major diagnostic options were allowed after this point. Example: Line number 156 157 158 159 160

Transcript “. . . Umm, lets’ review, jaundice, petechiae, spider angiomata, six months . So she has, definitely had chronic liver disease . . . hemolysis, Um, out of the question, Um Lupus, no, . . Liver disease, Um . . . But from what? . . . one option is that something is damaging the liver . . . alcohol?”

This transcript contained 259 lines, and the measure is (157/259) * 100 5 60.6%. These methods were chosen a priori because we anticipated that some subjects might use the same number of words, even though they might have spent different amounts of time on a given activity. The scoring as described, in terms of the percentage of the protocol, allows adjustment for wordiness and style of processing the information. 3. “Anchoring” in the reasoning process was of central concern to us because it represents insensitivity (or insufficient sensitivity) to potentially disconfirming evidence. If the diagnostic process is to be successful, there must be hypothesis generation, hypothesis confirmation, and openness to potentially disconfirming evidence. We refer to this process as “anchoring” because it can be related to the Bayesian concept of estimating and adjusting the probability of an event based on some starting point (Sox et al., 1988). In that context “anchoring” is said to occur if an initial evaluation or assessment is over-weighted or receives too much emphasis, and there is insufficient adjustment to new relevant information. In our study, we defined “anchoring” as having occurred when a hypothesis was maintained in spite of non-supportive or disconfirming evidence, by distortion or ignoring of the disconfirming evidence. Anchoring would interfere with flexible thinking, since it indicates an inability or unwillingness to change cognitive set, consider new information, and be open to information. While our use of the term is not identical to the Bayesian, in part because it does not explicitly involve probability estimates, the concepts seem

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meaningfully similar, as they relate to insufficient adjustment from a starting point, and the potential for distortion of the factors that that involves. Our measure of anchoring involved a global assessment, on a scale from 1 to 10, of the degree to which anchoring characterized the subject’s reasoning style, rather than a notation of specific places in the transcript at which this occurred. The mere presence of one anchored statement did not result in the entire reasoning style being characterized as anchored. Raters assigned a number between 1 and 10, with a lower score indicating less anchoring, and a higher score more anchoring. An example of a protocol that would receive a higher score would be one in which a subject continued to consider hemolytic anemia after having found that the patient had jaundice, spider angiomata, and elevated liver function tests. In this example, a liver problem should be apparent, in view of the new pieces of information; however, the subject is “anchored” on hemolytic anemia and does not adjust his/her diagnostic testing. Exploratory analyses. One rater, unaware of subjects’ condition, read the protocols to determine the following measures: number and cost of tests ordered, evidence of premature closure (scored if a subject concluded that a liver disease explained the patient’s problem without enough evidence for that), number of pieces of information relevant to liver disease requested (jaundice, spider angiomata, laboratory tests, such as liver function tests, hepatitis serology, prothrombin time, partial thromboplastin time, urinalysis, bleeding time, or imaging studies such as ultrasound or scans of the abdomen). Cost of tests was determined by reference to the 1994 Medicare reimbursement rates for the state of Alabama. We also examined deterministic reasoning (association based on compiled knowledge in the form of routine rules) (Kassirer, 1989). For example, if the patient was jaundiced, then a liver disease or hemolysis could come to mind. Predetermined deterministic examples were jaundice (for liver disease or hemolysis), history of blood transfusion (for liver disease), spider angiomata (for liver disease), antinuclear antibody results (for lupus), aspartate aminotransferase/ alanine aminotransferase (AST/ALT) ratio of 2:1 (for alcoholic liver disease), and anti-mitochondrial antibody titer (for primary biliary cirrhosis). Protocols were also read to determine if a consult had been obtained or if the diagnosis of chronic active hepatitis was reached. The number of diagnoses was also recorded. Statistical Analyses Even though the study randomized subjects to three groups, we did not plan to do an overall analysis including all groups simultaneously; rather, we performed pairwise comparisons (a priori) between the Affect and Control group, and between the Statements and Control group. This was done for three reasons. First, the objective of the study was to determine if the Affect group would be different from the control group (and not whether the three groups differed). Second, the study was exploratory regarding whether the third intervention (Statements) would be a possible inducer of affect. And finally, the

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results of the creative problem solving segment of the study, which we were using as a kind of manipulation check on the induction of affect, showed that the Statements group did not differ from the control group (Estrada et al., 1994). The methods of analyses for these pairwise comparisons were the t test or Fisher’s exact test. The significance level for the primary hypothesis was p 5 .05. A significance level of p 5 .003 was chosen for the exploratory analyses (Bonferroni’s correction, 15 comparisons). Confidence intervals (95%) were included to demonstrate the range of values that is likely to cover the true but unknown value. Systat 5.1 software was used for data analyses (Evanston, Illinois). Our findings did not change even when the three groups were compared simultaneously. Two raters read and scored the protocols independently, without knowledge of the subject’s experimental condition. Agreement was said to occur if the line number in the protocol identified by each rater was within two lines (for the hypothesis generation and hypothesis confirmation task), or if the anchoring score was within 2 points. The overall agreement measure for each group is defined as how frequently the raters agreed. Disagreement was resolved by discussion, still without knowledge of the subject’s experimental condition. This research was approved by The Human Rights Committee at Henry Ford Hospital. Oral informed consent was obtained, and no identifiers were attached to any protocol. Data was collected between December 1992 and March 1993. RESULTS

The Affect, Control, and Statements group subjects were similar in the number of years from graduation (14.7 6 10, 14.7 6 11, 13.8 6 8, respectively), in gender distribution (percentage of males: 57, 60, and 62%, respectively), number of interactions with the experimenter (2.6 6 2.7, 2.7 6 1.8, 2.9 6 2.4, respectively), number of lines in the transcripts (242 6 137, 204 6 87, 286 6 158), and time spent on the entire protocol (39 6 16 min, 40 6 10 min, 46 6 17 min, respectively) (all numbers are means 6 SD), all p . .4. The interrater agreement levels were 60% for generation of the liver domain hypothesis, 74% for hypothesis confirmation (or verification), and 69% for the degree of anchoring. After discussion without knowledge of experimental condition of individual protocols, disagreement was resolved in all cases. As shown in Fig. 2, people in the positive-affect condition generated the correct hypothesis and began to consider the possibility of a liver diagnosis significantly earlier than did those in the control condition. The liver domain hypothesis was generated at, on average, 20% of the protocol in the Affect group, 39% in the Control group, and 36% in the Statements group, meaning that the Affect group began considering liver disease as a cause of the patient’s problem significantly earlier in the protocol than did controls (19% earlier; 95% confidence interval: 6 to 32%; t 5 2.850, p 5 .008). Figure 2 also shows that the Affect and Control groups established that a liver disease was the cause of the patient’s problem at similar points in the protocol (p 5 .89). The Affect group showed significantly less anchoring as a reasoning style than did

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FIG. 2. Means and 1 SEM (standard error of the mean) of scores of main dependent measures among conditions: Liver domain hypothesis generation, Hypothesis confirmation, and anchoring. Significance level p 5 .05, t test.

controls, a difference of 2.4 in a scale of 1 to 10 (95% confidence interval ; 0.3 to 4.5) (mean values 6 SD of 1.5 6 1.5, and 3.9 6 3.7, respectively; t 5 2.271, p 5 .031), as shown in Fig. 2. No physician decided without sufficient evidence (premature closure) that liver disease was the cause of the patient’s problem. No differences were found between the affect and control groups in the number of diagnoses, number of pieces of information relevant to liver disease considered, or in deterministic reasoning, regardless of the portion of the protocol examined. The Statements group did not differ from the Control group on any dependent measures; see Fig. 2 and Table 1. DISCUSSION

Our findings suggest that physicians in the affect group organized and integrated information more efficiently than did those in the control group, and did not engage in more superficial or hasty processing as they did so. Practicing physicians in whom positive affect had been induced integrated information to achieve correct hypothesis generation (considered liver), earlier. The reasoning style characterizing their decision process demonstrated less anchoring (distortion or discounting of disconfirming evidence) compared with controls, and showed no evidence of premature closure or other superficial processing. Just to highlight the relevant findings, consider that physicians who received a small gift generated the liver disease hypothesis significantly earlier in the

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TABLE 1 Means, Standard Deviations, and Percentages of Exploratory Dependent Measures on Decision Making among Conditions (Significance Level p 5 .003) p

Number of diagnoses considered Any diagnosis, before liver considered New diagnoses onlya Any diagnosis, non-liver relateda Number of pieces of information relevant to liver disease Before liver considered Between liver considered and established Total Number of deterministic examples (see text) Before liver considered Between liver considered and established Tests Number Cost ($) Liver established during physical examb Premature closureb Consult obtainedb Reminded of a similar patientb Diagnosis of chronic active hepatitis madeb

Affect Statement Statements vs vs (n 5 13) Control Control

Affect (n 5 14)

Control (n 5 15)

3.6 6 2.2 1.7 6 1.1

4.7 6 1.9 0.7 6 1.0

4.3 6 2.8 0.9 6 0.9

.15 .02

.66 .69

2.8 6 2.1

1.4 6 0.6

2.3 6 2.5

.10

.33

1.9 6 0.8

3.1 6 2.0

3.1 6 1.4

.04

.93

4.5 6 2.4 6.4 6 2.3

2.9 6 1.6 6.1 6 1.9

2.1 6 1.5 5.2 6 0.9

.05 .72

.16 .14

1.1 6 0.9

1.5 6 1.1

1.7 6 1.5

.38

.65

0.9 6 0.9

1.5 6 1.1

1.2 6 0.8

.16

.36

6.4 6 6.1 180 6 244

5.5 6 5.4 136 6 175

3.7 6 2.4 55 6 57

.70 .58

.26 .12

21% 0% 14% 43%

27% 0% 60% 47%

23% 0% 38% 31%

1 — .02 1

1 — .44 .46

79%

80%

69%

1

.67

a

Between a liver disease was considered and a liver disease was established as the cause of the patient’s problem (hypothesis confirmation). b Percentage equals yes.

protocol than did controls (20% vs 39% of the protocol; or 19% earlier; 95% confidence interval 6 to 32%; t 5 2.850, p 5 .008). This confidence interval means that the true value lies between 6 and 32%. Compared to physicians in the control condition, those in the affect group were more open to new information as a reasoning style, as they went about the diagnostic process and considered possibilities. The groups did not differ significantly in the point in the protocol at which they reached certainty regarding the hypothesis of liver disease (hypothesis confirmation). In the exploratory analyses, no differences were found between physicians who received a small gift and the controls on any of the dependent measures: number of pieces of information requested in order to consider or establish liver disease, cost and number of tests, number

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of diagnoses, and degree of premature closure. This indicates that the affect subjects did not jump to a conclusion regarding the diagnosis, but rather that they were earlier to realize how the symptoms and signs best fit together, but kept an open mind and considered evidence judiciously. Our findings are compatible with prior work in which positive affect induced in any of several ways (e.g., report of success on a task, receipt of a small gift, exposure to a few minutes of humorous material, reading positive words, and others), was found to improve cognitive organization, flexibility, and decision making (Isen et al., 1985, 1987; Isen & Daubman, 1984; Isen & Means, 1983; Carnevale & Isen, 1986). For example, in a study reported by Isen et al. (1991), 32 medical students were asked to decide which one of 6 hypothetical patients with a solitary pulmonary nodule was most likely to have lung cancer. Students in the affect group began to focus on the correct patient at an earlier point in the protocol than did those in the control group (17% earlier, p , .05, t test). This compares to our present study where the correct diagnosis, a liver disorder, was considered at an earlier point in the protocol by the affect group (19% earlier; t 5 2.850, p 5 .008). Medical students who received the affect induction were also more likely to go beyond the assigned task, showed more configural or integrative consideration of the material, and showed less evidence of confusion (Isen et al., 1991). However, the present study extends and advances that prior work, in several ways. First, the method we used better approximates the reasoning process that practicing physicians actually use when making a diagnosis. Our design allowed them to explore as much or as little information as they wanted, and to move back and forth in their search for information, rather than being constrained by limited and uniform categories, as the design used with the medical students had done. Moreover, the format and content of the materials were realistic; further, although there were no actual patients seen, the task was of a type that physicians often encounter when asked to provide a consultation on a patient. Finally, the setting was the real one of a busy hospital, and the decision makers were genuine experts, practicing physicians in the midst of a busy day. Finding these effects of positive affect in such settings and among practicing physicians, rather than medical students or college students, adds to the strength of the earlier findings and provides support for the interpretation offered in this program of research. It may also have significant practical implications. In addition, these findings help answer some theoretical questions recently at issue in the affect literature, having to do with whether positive affect facilitates only heuristic, superficial thinking and impairs systematic processing (e.g., Mackie & Worth, 1991; Schwarz & Bless, 1991). The results of the present study indicate that, quite to the contrary, positive affect fosters openness to ideas and flexibility, not heuristic, simplified, superficial, closedminded processing. Although people in the positive affect condition were more efficient, the anchoring data and other analyses indicate that this was not accomplished through simplistic or hurried thinking. Positive affect, induced in diverse ways, has been shown to improve creative

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problem solving among undergraduate students, young adolescents, and physicians. Creativity is defined as the ability to associate, usefully, elements that are not usually seen as related (Koestler, 1964; Mednick, 1962). Briefly, in a series of studies, undergraduate psychology students who received a small gift, or who watched five minutes of a comedy film, performed better on a creative problem solving task than did those in control groups (Isen et al., 1987). In a concurrent study, the same physicians who received a small gift also scored better on a creative problem solving test (Estrada et al., 1994). In fostering creative problem solving, positive affect may promote the physicians’ ability to see relatedness among concepts, ideas, and symptoms, possibly facilitating the generation of hypotheses (or, more particularly, of the correct hypothesis). At the same time, our evidence suggests that positive affect increases openness to ideas, so that this increased ability to see relevant connections and generate the correct hypothesis does not result in a closed-minded approach, a factor as important for good doctor-patient interaction as for accurate diagnoses. There is no way to determine with certainty whether positive affect was induced in our study. However, previous research provides us with a large body of convergent validation of the candy condition used in this study, suggesting that positive affect can be assumed to have been induced by the gift of candy and can be believed to have been the cause of the difference between the Affect and the Control conditions. Previous studies have used similar, as well as other (converging), means of affect induction, and other (both converging and discriminant) dependent measures to show that positive affect promotes flexibility in thinking, cognitive organization, and problem solving, specifically. All of this work supports the link between the small gift and positive affect, and our conclusion that it is this affect that best accounts for our findings in the present study. This is because in the supporting body of research, which found results compatible with those reported here, positive affect was induced in diverse ways and yet produced similar results. This indicates that any other potential, inadvertent, influence of our method of affect induction (the gift) cannot explain the findings across all of the studies, since other studies used different methods of inducing affect which would not share any such inadvertent influence. For example, although one might wonder if people who received a gift might be trying harder because of having gotten “something for nothing,” this cannot be said of those who performed the way affect subjects in this study did, but after having gotten a report of success on a task (Isen et al., 1991; Isen & Means, 1983). Similarly, improved performance on difficult tasks of creative problem solving has been found after affect inductions of a small gift and brief exposure to humor (Greene & Noice, 1988; Isen et al., 1987). We did not use self-report scales to measure the affective state induced in any of our conditions, for two reasons: Such measures are themselves of unknown validity; and that method of assessment is too reactive and may cause the subjects to focus their attention on their feelings and preclude natural responses to the task of interest. Consequently, even without a self-report measure of induced affect, for the reasons described here, we believe it is appropriate to

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conclude that it was positive affect that was responsible for the differences between conditions in our study. We raised the issue earlier of whether positive affect might lead to hasty, incomplete, superficial processing of information, as has been suggested by some authors in the literature; and we pointed out that our data argue against such an interpretation. Now, we would like to address that issue in greater detail. For example, let us consider whether such an alternative hypothesis could explain our findings. Is there reason to believe that the positive affect physicians considered a liver disorder earlier in their protocols because they concluded too soon (premature closure) that liver disease was the problem, for example? Or, is it possible that they considered only liver disease, ignoring other reasonable hypotheses, for another example?. We think these possibilities are unlikely, for several reasons. First, premature closure did not explain our findings. The protocol analyses revealed that none of the subjects (in any condition) concluded prematurely (without sufficient evidence) that a liver disease was the cause of the patient’s problem. Moreover, people in the affect condition were not more likely than controls to go about the decision process in a closed-minded way. In fact, as shown in Table 1, protocol analyses revealed that after the subjects considered a liver disease as a likely explanation, they continued considering and exploring additional new diagnoses (mean of 1.7 and 0.7 new diagnoses, in the affect and control groups, respectively), and they also considered other non-liver diagnoses (mean of 2.8 and 1.4 different non-liver diagnoses, in the affect and control groups, respectively). Thus, the positive affect group was more open (and generated more different diagnoses), not less, than the control group. Although they saw the connection earlier than controls (between the patient’s signs and indication of liver disease), this did not stop them from considering other possible diagnoses. In addition, a liver disorder was not the only problem initially entertained in either condition (mean of 3.6 and 4.7 diagnoses, in the affect and control groups, respectively), as also shown in Table 1. The fact that the number of diagnoses did not differ between groups, and that this number is not zero supports the hypothesis that subjects in the affect group did not “jump” to a conclusion and were not limited in their thinking only to liver disease. Second, as indicated by our data on “anchoring” as a global reasoning style, the affect group was notably less likely to demonstrate that kind of inflexible way of thinking, which involves distortion of material. Therefore, a process such as “anchoring” on a particular diagnosis (liver disease) does not explain why liver disease was considered earlier in the affect condition. Exploratory analyses were done to shed light on the questions just considered—in particular to see whether there was any merit to the suggestion that the affect group had jumped to conclusions, prematurely closed, not considered relevant information, or in any other way, not considered information systematically. These analyses, however, did not support any such conclusion. Rather, it appears that the affect group’s earlier realization and consideration of the correct hypothesis (domain) represents efficiency, improved integration of material and improved correct hypothesis generation.

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Turning now to our examination of the influence of reading humanistic statements, on none of our measures did we find an effect of reading and concentrating on those statements. Initially, it was thought that reading such statements itself might induce positive affect, but there was no evidence that this was the case: In a prior study on creative problem solving, using the same subjects, physicians in the Statements group obtained scores no different from Controls on the creativity test (Estrada et al., 1994), whereas those in the affect condition showed significantly improved scores. Indeed, in this study, the Statements condition did not differ in any way at all from the Control. The strengths of our study include the following: a randomized controlled trial, assessment of dependent measures in a blinded (unbiased) fashion, and having practicing physicians as decision-making subjects solving the case. In addition, obtaining verbal protocols enabled us to discover more about the process engaged in, and more about the impact of affect, than looking only at selected outcome measures, such as correct problem solution. The observed interrater initial agreement may seem low. Upon discussion we found that the raters’ preliminary interpretations of the definitions were slightly different, and after further discussion agreement was achieved with no difficulty. The quantitative measurement of transcript analysis is not an easy task. We feel that the observed agreements are good for this type of study, especially since all cases of initial disagreement were easily resolved. The introduction of measurement error (in this case possible “noise” originated by the disagreement) only strengthens our findings because we obtained a positive result for two of the primary hypothesis. The limitations of the study are that we used a “paper and pencil” format with a single case (Elstein et al., 1990; Jones, Gerrity, & Earp, 1990; Elstein, Kleinmuntz, Rabinowitz, McAuley, Murakami, Heckerling, & Dod, 1993), and that the applicability of these findings for daily clinical work is uncertain. However, it should be noted that, although there may be limitations to the validity of “paper-and-pencil” patients in some circumstances, there are others, such as requested consults, in which physicians do not actually see the patient either. Thus, presenting the patient’s information as we did is not an invalid method for assessing physicians’ diagnostic reasoning processes. Further, several important implications, both practical and theoretical, follow from the work. One is the realization that positive affect (sufficient to influence thought processes, creative problem solving ability and orientation to patients and medical practice) can be induced so readily in physicians, just as had been found previously for people in other walks of life (undergraduates, medical students, shoppers in a suburban mall, etc.). The second, is the realization of how impactful in a facilitating way these seemingly mild or small affect interventions can be in both diagnostic reasoning and interpersonal processes. Together with a large body of other work, the present results suggest, for example, that teaching environments that are pleasant and supportive might lead to more understanding, as well as more insightful, physicians. Third, our results shed light on theoretical questions related to the nature of affect and its fundamental influence on cognitive processing. They show that

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positive affect does not, by its nature, lead to interference with systematic cognitive processing, but rather tends to promote thoroughness and the ability to incorporate new data. Physicians often need to integrate the symptoms, signs, and laboratory findings into a clinical pattern to identify the connection to a syndrome or disease. In addition to knowledge and experience, these processes require the ability to see potentially useful relationships among the elements and to associate them. They also require flexibility to adapt to and integrate newly presented information. This is a necessary step in revising probabilities or priorities in diagnostic reasoning. Thus, we have shown in the present study that the induction of positive affect influences clinical reasoning in a positive way. Finally, we would like to suggest that this same kind of flexibility and willingness to see things in different ways, keeping an open mind to alternative possibilities and views, may facilitate doctor–patient interaction, as well. The relevance of our current findings for doctor–patient interaction should be explored. APPENDIX Summary of Clinical Case

Information Provided to All Subjects History: A 45-year-old female presents with a 6 month history of arthralgias, fatigue, dark urine and “red spots” in both legs. She was seen at another hospital and was told she could have lupus. Information Available to Subjects (Covered by Stickers) Additional information: arthralgias: symmetric, small joints, does not limit activity; fatigue: tired all day; dark urine: urine is “tea-colored”, stains underwear; “red spots”: asymptomatic, small, few, both legs, new 3 weeks; drug allergies: none; medications: none; past medical history: broken femur 25 years ago, surgery required; Social: family: married with 3 kids; travel: Toronto 2 years ago; occupation: housewife; drug use and alcohol: never; caffeine: no; smoking: no; race: white; family history: father had stroke at age 80. Review of systems: breasts: none; cardiopulmonary: none; ear, nose, throat: none; endocrine: none; eye: yellow for 3 weeks; gastrointestinal: some nausea; general: no weight loss, poor appetite; genito-reproductive: last period 3 months ago; hematologic: at age 20, blood transfusion; musculoskeletal: feeling weak; neurological: none; oral: none; peripheral vascular: none; psychiatric: none; renal/ urinary: none; skin: “red spots.” Physical exam: vital signs: 388C, HR 80/min, BP 100/70, RR 16/min; general description: chronically ill; skin: jaundice, petechia (non-palpable, ,20, both shins), spider angiomas upper chest, scar right thigh; head and neck: jaundice, one oral ulcer (5mm); lymph nodes: none; breasts: normal; chest: normal; heart: I/VI SEM, LSBorder; peripheral vascular: normal; abdomen: some right upper

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quadrant tenderness, no visceromegaly, no ascites, bowel sounds normal; musculoskeletal: mild generalized weakness, no arthritis or synovitis; neurologic: mild generalized weakness; genitalia: normal; rectal: guaiac (2), no masses. Information Available from Researcher Tests, imaging studies, procedures: Anti-smooth muscle ab: (1) at 1: 80 (nl , 1:20); Bilirrubin: total 4.6, direct 3.9; biopsy liver: piecemeal necrosis, bridging fibrosis consistent with chronic active hepatitis; biopsy skin: extravasation of RBC, no vasculitis; C3: 40 (nl 80–180), C4: 10 (nl 15–45), CH50: 50 (nl 80–170), ICS 60 (nl , 46); CBC: WBC 8, 500 Hg 10 (nl indices); ESR: 60; ANA (1) 1: 640 homogeneous; Iron studies: Fe 50 (60–140), TIBC 200 (250–400), Ferritin 200 (9–125); LFT’s: GOT 940, GPT 600, GGT 50 (nl , 30), Alk Phos 100 (nl , 140), Bili Total 4.6, Bili Dir 3.9, LDH: 300 (nl 100–200); antimitochondrial ab: (1) at 1: 40 (nl , 1: 20); platelets: 120, 000; PT 18, PTT 50; RF: 1: 320; SPEP: hypoalbuminemia; SSa 1: 320, SSb 1: 320 (nl is negative); urinalysis: bilirrubin 31, no casts; CT abdomen or MRI: liver mildly enlarged, no obstruction, trace ascites, normal pancreas; US abdomen: liver mildly enlarged, no obstruction, trace ascites, pancreas not well visualized. All other tests, diagnostic procedures were normal, they were presented as the actual value with reference values, or as normal, or as negative. REFERENCES Carnevale, P. J., & Isen, A. M. (1986). The influence of positive affect and visual access on the discovery of integrative solutions in bilateral negotiations. Organizational Behavior and Human Decision Processes, 37, 1–13. Deldin, P. J., & Levin, I. P. (1986). The effect of mood induction in a risky decision-making task. Bulletin of the Psychonomic Society, 24, 4–6. Elstein, A. S., Kleinmuntz, B., Rabinowitz, M., McAuley, R., Murakami, J., Heckerling, P. S., & Dod, J. M. (1993). Diagnostic reasoning of high- and low-domain-knowledge clinicians: A reanalysis. Medical Decision Making, 13, 21–29. Elstein, A. S., Shulman, L. S., & Sprafka, S. A. (1990). Medical problem solving: A ten-year retrospective. Evaluation of the Health Professions, 13, 5–36. Estrada, C. A., Isen, A. M., & Young, M. J. (1994). Positive affect improves creative problem solving and influences reported source of practice satisfaction in physicians. Motivation and Emotion, 18, 285–299. Greene, T. R. & Noice, H. (1988). Influence of positive affect upon creative problem solving in children. Psychological Reports, 63, 895–898. Isen, A. M. (1987). Positive affect, cognitive processes, and social behavior. Advances in Experimental and Social Psychology, 20, 203–253. Isen, A. M. (1990). The influence of positive and negative affect on cognitive organization: Some implications for development. In N. L. Stein & T. Trabasso (Eds.), Psychological and biological approaches to emotion (pp. 75–94). Hillsdale, NJ: Erlbaum. Isen, A. M. (1993). Positive affect and decision making. In M. Lewis & J. M. Haviland (Eds.), Handbook of emotions (pp. 261–277). New York, NY: Guilford Press. Isen, A. M., & Baron, R. A. (1991). Positive affect as a factor in organizational behavior. In L. L. Cummings & B. M. Starr (Eds.), Research in organizational behavior (Vol. 13, pp. 1–53). Greenwich, CT: JAI Press.

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Isen, A. M., & Daubman, K. A. (1984). The influence of affect on categorization. Journal of Personality and Social Psychology, 47, 1206–1217. Isen, A. M., & Means, B. (1983). The influence of positive affect on decision-making strategy. Social Cognition, 2, 18–31. Isen, A. M., Daubman, K. A., & Nowicki, G. P. (1987). Positive affect facilitates creative problem solving. Journal of Personality and Social Psychology, 52, 1122–1131. Isen, A. M., Johnson, M. S., Mertz, E., & Robinson, G. F. (1985). The influence of positive affect on the unusualness of word associations. Journal of Personality and Social Psychology, 48, 1413– 1426. Isen, A. M., Rosenzweig, A. S., & Young, M. J. (1991). The influence of positive affect on clinical problem solving. Medical Decision Making, 11, 221–227. Jones, T. V., Gerrity, M. S., & Earp, J. (1990). Written case simulations: Do they predict physicians’ behavior?. Journal of Clinical Epidemiology, 43, 805–815. Kassirer, J. P. (1989). Diagnostic reasoning. Annals of Internal Medicine, 110, 893–900. Koestler, A. (1964). The act of creation. New York: Macmillan. Mackie, D. M. & Worth, L. T. (1991). Feeling good, but not thinking straight: The impact of positive mood on persuasion. In J. P. Forgas (Ed.), Emotion and social judgments. International series in experimental social psychology (pp. 201–219). Oxford, England: Pergamon Press, Inc. Mednick, S. A. (1962). The associative basis of the creative process. Psychological Review, 69, 220– 232. Schwarz, N. & Bless, H. (1991). Happy and mindless, but sad and smart? The impact of affective states on analytic reasoning. In J. P. Forgas (Ed.), Emotion and social judgments. International series in experimental social psychology (pp. 55–71). Oxford, England: Pergamon Press, Inc. Sox, H. C., Blatt, M. A., Higgins, M. C., & Marton, K. I. (1988). Medical decision making. Boston, MA: Butterworths. Received: March 12, 1997