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Brain and Language 93 (2005) 267–276 www.elsevier.com/locate/b&l 0093-934X/$ - see front matter 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.bandl.2004.10.006 Spontaneous humor among right hemisphere stroke survivors Robin L. Heath a,¤ , Lee X. Blonder b a Faculty of Health Sciences, American University of Beirut, P.O. Box 11-0236, Riad El Solh Beirut 1107-2020, Lebanon b Department of Behavioral Science and the Stroke Program of the Sanders-Brown Center on Aging, University of Kentucky, USA Accepted 18 October 2002 Available online 7 December 2004 Abstract We analyzed spontaneous conversational humor production and response among 11 right hemisphere-damaged (RHD) patients, 10 left hemisphere-damaged (LHD) patients, 7 normal controls (NC), and their spouses. RHD patients and their spouses reported a statistically signiWcant decline in the patients’ orientation to humor post-stroke. Also, we found a signiWcant positive association between a RHD patient’s ability to decode prosody and their self-reported orientation to humor post-stroke. 2004 Elsevier Inc. All rights reserved. Keywords: Humor; Laterality; Right hemisphere 1. Introduction Humor is a vital source of social integration and vehi- cle for personal expression and has been under investiga- tion across multiple disciplines for centuries. Although few would disagree with the essential nature of humor in human society, as yet no mutual agreement has been established for a deWnition of the phenomenon. Much cognitive research on humor is predicated on the incon- gruity-resolution model of humor, which states that humor is a response to a perceived incongruity and entails two stages, the recognition of incongruity and then the resolution (Suls, 1972, but see Coulson & Kutas, 2001). “Getting” a joke is assumed to be a problem-solv- ing task in which an expectation of a scenario is devel- oped during the body of the joke. When the punch line arrives, the incoherence between the expectation and the punch line is detected. The individual resolves the inco- herence by revising the initial expectation. The assump- tion is that the right hemisphere is involved in establishing coherence between the body of the joke and the punch line. The incongruity-resolution model is usu- ally adopted by confrontation response research designs (Bihrle, Brownell, & Powelson, 1986; Brownell, Michel, Powelson, & Gardner, 1983; Dagge & Hartje, 1985; Goel & Dolan, 2001; Shammi & Stuss, 1999); but is occasion- ally applied to conversational humor (Dixon, 1980; Heath & Blonder, 2003). Heath and Blonder (2003) dem- onstrate the ecological relevance of incongruity and its resolution in a qualitative analysis of spontaneous con- versational humor among stroke patients. Since the mid 1970s, Gardner and his associates have documented the right cerebral hemisphere’s contribu- tion to complex linguistic processing (Bihrle et al., 1986; Brownell et al., 1983; Gardner, Ling, Flamm, & Silver- man, 1975; Wapner, Hamby, & Gardner, 1981). Their research designs rely on confrontational responses to cartoons or narratives selected to assess speciWc deWcits. In the Wapner et al. (1981) study, subjects are read sto- ries after which they recall as many of the details as they can and are then asked questions about the story. The research suggests that RHD patients have diYculty con- structing coherent narratives or understanding the over- all message of the narrative or joke. Also, RHD patients * Corresponding author. Fax: +961 1 744470. E-mail address: [email protected] (R.L. Heath).

Spontaneous humor among right hemisphere stroke survivors

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Page 1: Spontaneous humor among right hemisphere stroke survivors

Brain and Language 93 (2005) 267–276

www.elsevier.com/locate/b&l

Spontaneous humor among right hemisphere stroke survivors

Robin L. Heatha,¤, Lee X. Blonderb

a Faculty of Health Sciences, American University of Beirut, P.O. Box 11-0236, Riad El Solh Beirut 1107-2020, Lebanonb Department of Behavioral Science and the Stroke Program of the Sanders-Brown Center on Aging, University of Kentucky, USA

Accepted 18 October 2002Available online 7 December 2004

Abstract

We analyzed spontaneous conversational humor production and response among 11 right hemisphere-damaged (RHD) patients,10 left hemisphere-damaged (LHD) patients, 7 normal controls (NC), and their spouses. RHD patients and their spouses reported astatistically signiWcant decline in the patients’ orientation to humor post-stroke. Also, we found a signiWcant positive associationbetween a RHD patient’s ability to decode prosody and their self-reported orientation to humor post-stroke. 2004 Elsevier Inc. All rights reserved.

Keywords: Humor; Laterality; Right hemisphere

1. Introduction

Humor is a vital source of social integration and vehi-cle for personal expression and has been under investiga-tion across multiple disciplines for centuries. Althoughfew would disagree with the essential nature of humor inhuman society, as yet no mutual agreement has beenestablished for a deWnition of the phenomenon. Muchcognitive research on humor is predicated on the incon-gruity-resolution model of humor, which states thathumor is a response to a perceived incongruity andentails two stages, the recognition of incongruity andthen the resolution (Suls, 1972, but see Coulson & Kutas,2001). “Getting” a joke is assumed to be a problem-solv-ing task in which an expectation of a scenario is devel-oped during the body of the joke. When the punch linearrives, the incoherence between the expectation and thepunch line is detected. The individual resolves the inco-herence by revising the initial expectation. The assump-tion is that the right hemisphere is involved in

* Corresponding author. Fax: +961 1 744470.E-mail address: [email protected] (R.L. Heath).

0093-934X/$ - see front matter 2004 Elsevier Inc. All rights reserved.doi:10.1016/j.bandl.2004.10.006

establishing coherence between the body of the joke andthe punch line. The incongruity-resolution model is usu-ally adopted by confrontation response research designs(Bihrle, Brownell, & Powelson, 1986; Brownell, Michel,Powelson, & Gardner, 1983; Dagge & Hartje, 1985; Goel& Dolan, 2001; Shammi & Stuss, 1999); but is occasion-ally applied to conversational humor (Dixon, 1980;Heath & Blonder, 2003). Heath and Blonder (2003) dem-onstrate the ecological relevance of incongruity and itsresolution in a qualitative analysis of spontaneous con-versational humor among stroke patients.

Since the mid 1970s, Gardner and his associates havedocumented the right cerebral hemisphere’s contribu-tion to complex linguistic processing (Bihrle et al., 1986;Brownell et al., 1983; Gardner, Ling, Flamm, & Silver-man, 1975; Wapner, Hamby, & Gardner, 1981). Theirresearch designs rely on confrontational responses tocartoons or narratives selected to assess speciWc deWcits.In the Wapner et al. (1981) study, subjects are read sto-ries after which they recall as many of the details as theycan and are then asked questions about the story. Theresearch suggests that RHD patients have diYculty con-structing coherent narratives or understanding the over-all message of the narrative or joke. Also, RHD patients

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268 R.L. Heath, L.X. Blonder / Brain and Language 93 (2005) 267–276

may not respect the boundaries of the story and mayconfabulate narrative items. Gardner (1981) character-izes the deWcits overall as lacking a “plausibility metric.”

The Brownell et al. (1983) study requires subjects tocomplete a story or a nonverbal cartoon by selecting oneof four endings that would make the story or cartoonfunny. The selections are straightforward endings (neu-tral and sad) or surprising endings (funny and nonsequi-turs). The results demonstrate that RHD patientsrecognize the two-part prepared joke format, that is thebody of the story and the surprise ending, but they haveproblems choosing between a nonsequitur and an endingthat makes the joke funny. That is, they could detect thesurprise ending but they have diYculty establishingcoherence between the body of the joke and the punchline. In order to distinguish between the roles of the fron-tal lobe and the right hemisphere in narrative humor,Bihrle et al. (1986) use a pictorial version of the Brownellet al. (1983) stimuli and compare subjects with largelyanterior or posterior lesions. The LHD anterior groupdoes not show the characteristic proWle of errorsobtained for RHD patients in the Brownell et al. (1983)study, whereas the RHD posterior group does; thereforefrontal lobe pathology is unlikely to account for the pat-tern of deWcits.

Shammi and Stuss (1999) argue that the right frontallobe plays the primary role in mediating humor appreci-ation. In their study, the authors administer a joke andstory completion task, which is the same set of stimuliused by Brownell et al. (1983), a verbal humor apprecia-tion test, a nonverbal cartoon appreciation, a battery oftests to assess cognitive functions related to humorappreciation such as working memory, verbal abstrac-tion and mental shifting, and as well, observe partici-pants’ spontaneous responses to the stimuli. They Wndthat individuals with right frontal lobe damage have lessappreciation of humor and a diminished spontaneousaVective response to humor.

Prior studies indicate that the right hemisphere maybe involved in the mediation of emotion (Borod, Andel-man, Obler, Tweedy, & Welkowitz, 1992; Buck, 1984;Heilman & Bowers, 1990; Ross, 1985). In a studydesigned to determine if deWcits of aVect underlie impair-ments in humor, Dagge and Hartje (1985) distinguishbetween aVective and cognitive deWcits by varying thecognitive complexity of cartoon stimuli. They Wnd thatthe errors made by RHD patients are caused by visuo-perceptive and cognitive deWcits over and above anyaVective deWcits that result from damage to the righthemisphere. The correct interpretation of an aspect ofspontaneous conversation as a “play setting” andsocially appropriate for humor production or response,requires the ability to decode facial emotion and pros-ody of the interlocutors. Previous studies indicate thatRHD patients have deWcits in their ability to perceiveemotion in faces and voices (Blonder, Bowers, &

Heilman, 1991; Heilman, Blonder, Bowers, & Valenstein,2003, for a review).

Spontaneous humor production is often overlookedin laterality studies of humor as it is problematic to carryout in a laboratory, mainly because humor production isunder the control of the subject rather than the examinerand therefore it is more diYcult to develop measurementinstruments speciWc to the elements under investigation.The present study was a component of a larger 5-yearproject conducted by the second author. Selected testsand scales and interviews were taken from the 5-yearstudy. Two raters analyzed quantitative and qualitativeaspects of humor production and response identiWed inthe videotaped semi-structured interviews with strokepatients, normal controls and their spouses. These datawere also correlated with: (1) patient and spouse self-reported ratings of the patient’s orientation to humorboth before and after the stroke, and (2) patient perfor-mance on a mental status exam, aphasia battery andemotional perception tasks.

Our goal was to assess the extent to which laboratory-generated Wndings implicating the right hemisphere inhumor were observable in a naturalistic setting. Weanticipated that RHD patients would produce less con-versational humor than left hemisphere-damagedpatients (LHD) and normal control patients (NC). Oursecond prediction was that RHD patients wouldrespond less frequently than the other patients. Third,spouses of RHD patients would observe a diminishingof the patients’ involvement in day-to-day humorouscommunication, whereas the spouses of LHD and NCpatients would not.

2. Methods

2.1. Subjects

The participants included 11 RHD patients (7 menand 4 women), 10 LHD patients (4 men, 6 women), 7 NCpatients (5 men, 2 women), and their spouses (Table 1).Orthopedic patients were selected as a control group asthey faced similar physical challenges of rehabilitationprograms. The subjects were recruited from the Univer-sity of Kentucky Medical Center, the Veterans’ Admin-istration Medical Center and Cardinal HillRehabilitative Hospital, all located in Lexington, Ken-tucky.

The subjects were married and/or cohabiting exceptfor hospitalization during the acute or rehabilitativestage of their illness, spoke American English as a Wrstlanguage, and were right-handed as determined by a 6-item handedness inventory. The stroke patients had asingle unilateral infarct as indicated by computerizedtomography (CT) and/or magnetic resonance (MR)scan. None of the stroke patients had global or mixed

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R.L. Heath, L.X. Blonder / Brain and Language 93 (2005) 267–276 269

nonXuent aphasia as determined by an interview withthe patient and medical chart review, or if the report wasnot on Wle, then consultation with a speech pathologist.No subjects had histories of substance abuse, neurologi-cal disease other than stroke, or psychiatric diseaseincluding developmental disorders and learning disabili-ties. Further exclusionary criteria included a loss of con-sciousness for more than 30 minutes due to head trauma,a hearing loss requiring a hearing aid, and blindness inone or both eyes not associated with stroke. No patientshad metastatic cancer, renal failure involving dialysis,systemic lupus erythematosus, or pernicious anemia.Both the patient and the spouse had to agree to partici-pate and be able to give informed consent. An attemptwas made to match the three groups for age and sex.None of the participants were aware that the interviewswould be analyzed for humor content, nor were any ofthem aware of the study hypotheses.

The Kruskal–Wallis ANOVA (analysis of variance)determined that there were no between-group diVerencesby neurological status (RHD, LHD, and NC) in ages,years of formal education, number of days elapsing fromonset of stroke or day of surgery, or degree of facialparesis as determined by the National Institutes ofHealth Stroke Scale, if a stroke patient (Brott et al.,1989). There were no diVerences in gender distributionby neurological status (Pearson Chi Square p D .37). Allpatients scored in the normal range on the Geriatric

Depression Scale (Yesavage et al., 1983) and CornellScale for Depression in Dementia (Alexopoulos,Abrams, Young, & Shamoian, 1988).

Additional subjects who were participants in anotherproject and who were subject to the same inclusionaryand exclusionary criteria but did not undergo the inter-view were included in the analyses of the Humor Orien-tation Scale (Booth-ButterWeld & Booth-ButterWeld,1991). The additional subjects were one man RHDpatient, two men and one woman NC patients, and theirspouses, one woman LHD patient and three women NCpatients, whose spouses did not complete the HumorOrientation Scale. With these individuals added, theKruskal–Wallis ANOVA indicated that there were nobetween-group diVerences by neurological status or gen-der in any of the means of the patients’ ages, education,or days post-stroke or surgery.

2.2. Raters

The two raters were men, 20 and 22 years of age andenrolled as senior year psychology undergraduates at theUniversity of Kentucky. Both raters were blind to thehypotheses of the study. To lessen the inXuence of diVer-ing humor styles, as part of the rater selection processthe raters completed three diVerent humor scales, Situa-tion Humor Response Questionnaire (Martin & Lef-court, 1984), Sense of Humor Questionnaire (Svebak,

Table 1Demographic and clinical information

ID Sex Age Years of education Days post event Site of lesion

1 M 48 8 25 Right frontal, medial, temporal, parietal2 F 53 12 43 Right posterior parietal3 M 42 8 16 Right frontal4 M 50 10 62 Right temporal5 M 77 18 38 Right frontal6 M 67 8 39 Right parietal7 M 56 13 19 Right posterior frontal, temporal-parietal, anterior occipital8 F 40 16 46 Right parietal9 F 59 18 21 Right frontal, temporal, basal ganglia

10 F 37 12 38 Right basal ganglia, external capsule11 M 67 18 26 Right frontal, parietal, temporal12 F 56 12 21 Left frontal13 M 75 8 46 Left frontal, parietal14 M 34 12 14 Left posteriomedial occipital15 M 52 12 46 Left anterior parietal16 F 61 12 30 Left temporal, parietal17 F 61 8 39 Left frontal, parietal, subcortical extension18 M 67 15 155 Left posterior frontal, anterior parietal19 F 47 16 49 Left basal ganglia20 F 67 8 62 Left frontal, basal ganglia21 F 43 16 49 Left posterior temporal, occipital22 M 59 12 168 Normal control23 F 71 14 112 Normal control24 M 35 18 30 Normal control25 M 70 11 130 Normal control26 M 69 10 30 Normal control27 F 73 12 148 Normal control28 M 66 12 18 Normal control

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270 R.L. Heath, L.X. Blonder / Brain and Language 93 (2005) 267–276

1974), and the Humor Orientation Scale (Booth-Butter-Weld & Booth-ButterWeld, 1991). Both raters were withinone standard deviation of the norm mean for all thetests. The raters underwent three two-hour training ses-sions on the identiWcation of the humor events and thecategorization of the events according to a humor code-book. Practice sessions were conducted using a set ofvideotaped interviews with a similar subject population.

2.3. The interview

Spontaneous humor was examined by coding andanalyzing conversational humor demonstrated by studyparticipants during a videotaped, semi-structured inter-view. A woman interviewer, who underwent several tech-nical training sessions regarding camera setup andlighting, conducted the interviews. The interviewer wasaware that, among other analyses, the interviews wouldlater be examined for patient humor content but was notaware of the speciWc hypotheses.

The semi-structured interview took place on average4 months post-stroke or surgery and at the completionof the test battery and included the patient, the spouse,and the interviewer. All interviews took place in a famil-iar environment and were video- and audiocassetterecorded. The interview was composed of the followingopen-ended questions that were asked in this order: his-tory of the illness, how the patient felt since hospital dis-charge, changes in the patient’s appearance, mobility,memory, communication patterns or mood, how thepatient felt about themselves post-stroke, how they weretreated by others, what problems the stroke caused forthe spouse, what adjustments the couple had to make,how the stroke aVected their marital relationship, did thecouple feel they understood each other, what they dis-agreed about, occasions when they found each other’sbehavior diYcult to tolerate, description of their person-alities, activities they enjoyed doing together, how theyspent their last vacation, description of a situation inwhich they felt happy and a situation in which they feltsad, and where did they hope to be in a year.

The test battery preceded the interview and tookplace over an average of 20 h. An extended time periodwas needed for the tests to accommodate post-strokefatigue and cognitive slowing. Also, ongoing programsof the rehabilitation hospital interrupted the testing. Thelimited number of participants in the interview helped tominimize the inXuence of cognitive slowing and lan-guage deWcits consequent to some forms of brain dam-age. The duration of the interviews depended on thelength of the participant’s answers and ranged from41 min to 2 h.

Twenty-six of the 28 interviews were conducted in thehomes of the participants. On one occasion the interviewtook place in a hotel room and on another occasion, ittook place in a quiet room in Cardinal Hill Rehabilita-

tion Hospital. The familiar environment fostered a natu-ralistic setting. Further, the interviewer and the patientand spouse had previously established a relationship inthe process of completing the extended test battery.

The Wrst six interviews were recorded with a singlePanasonic S-VHS AG-450 tripod-supported camcorder.The Wrst two of the six interviews visually encompassedonly the patients’ faces and the other four interviewsincluded both the patient and the spouse. The remaining22 interviews were recorded with two tripod-supportedcamcorders, a Panasonic S-VHS AG-455 trained onlyon the face of the patient, and a Panasonic S-VHS AG-450 set at a wider angle and encompassing the inter-viewer, the patient and the spouse. Whenever available,the wide-angled videocassette was used for the humorstudy. All videos were recorded on a 120-min MaxwellProfessional ST126 BQ/SE-180 SVHS BQ videocassette.

All participants were seated comfortably in front ofthe cameras. When two camcorders were used, the seat-ing was arranged in a curve so that all three individualsreceived the maximum visual coverage possible on thewide setting. The frame included the top of the head ofthe tallest individual and included at minimum the kneesof the participants.

2.4. Scales and tests

The study utilized the following tests from the largerstudy conducted by the second author: Florida AVectBattery-Revised (Bowers, Blonder, & Heilman, 1991),Mini Mental Status Examination (Folstein, Folstein, &McHugh, 1975), Western Aphasia Battery (Kertesz,1982), Geriatric Depression Scale (Yesavage et al., 1983)and Cornell Scale for Depression in Dementia, (Alexo-poulos et al., 1988). These tests were selected from thelarger battery because the factors they assess have apotential inXuence on humor production and response.The Florida AVect Battery—Revised (FAB-R) wasincluded to determine a subject’s ability to decode emo-tions in facial expression and in prosody. The FAB-R isan examiner-administered battery consisting of threesubtests: the FAB-Face IdentiWcation (FAB-FA)assesses the ability to discriminate faces, the FAB-Pros-ody (FAB-PR) tests the comprehension of neutral andemotional prosody and the FAB-Cross Modal (FAB-CM) examines the subject’s ability to match a facialexpression with an appropriate prosodic contour.

For the purposes of the present study, the HumorOrientation Scale (Booth-ButterWeld & Booth-Butter-Weld, 1991) was added to the test battery. The HumorOrientation Scale (HOS) is a 17-item self-report Likert-type scale that measures individual diVerences in the pre-disposition to produce humor in terms of frequency,eYcacy or funniness, and variety of behaviors andrehearsal strategies. The scale focuses on humor produc-tion rather than response. Scores range from a low of 17

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to a high of 85. The HOS has demonstrated unidimen-sionality, good reliability, and test–retest stability. Wan-zer, Booth-ButterWeld, and Booth-ButterWeld (1995)reported a mean of 59.4, Cronbach’s � of. 92, for internalconsistency, and a Spearman–Brown (corrected) esti-mate of. 93 for reliability. The fact that the HOS wasnormed on student populations should not aVect theresults of the HOS with an older population as variousage ranges diVer in the salience of humorous materialrather than in eYcacy, frequency or vehicle. Mostaspects of humor have a high degree of stability over alife span (McGhee, 1986).

The HOS was modiWed by using the original itemsbut adding a short phrase to the beginning of each testitem that tailored each item as to whether the respondentwas a stroke patient, a stroke patient’s spouse, an ortho-pedic patient or an orthopedic patient’s spouse andwhether the item pertained to their sense of humor priorto the stroke or surgery or after the stroke or surgery. Allthe HOS questionnaires dealt only with the patient’sbehavior.

2.5. Humor codebook likert scales

The humor codebook classiWed humor events intoproduction, response, and the nature of the humor. Thecodebook included 7-point Likert-type unipolar scales,which were developed for the humor study to determinelevels of aggressiveness, appropriateness, and predict-ability in humor production, and response intensity inhumor response. To enhance the reliability of the scalesand at the same time retain the integrity of the concept, abalance had to be struck between concretely deWning allpoints of each scale and supplying comparable examples.As much detail as was feasible was included in the train-ing manual.

Aggression was judged as the degree to which vio-lence or threat against another was encoded in thehumor. Although the Wndings are mixed and perhapsgender related, previous research indicates that aggres-sive humor is rated as funnier than other topics (Love &Deckers, 1989; McCauley, Wood, Coolidge, & Kulick,1983; but see Deckers & Carr, 1986). RHD patientssometimes joke inappropriately, speciWcally, in a “fatu-ous, euphoric or ironical” manner (Gainotti, 1972, p. 44).The appropriateness scale was included to determine ifthis tendency was manifested in their humor production.This scale was couched in terms of how well the humorWtted into the social context at the point it was produced.The factors considered in the scoring of this scale werethe extent to which the humor matched the emotionaltone and content of the preceding conversation, and wasit socially appropriate for the situation. The predictabil-ity scale required the raters to determine the degree towhich the humor presented a novel situation or imageand was included to assess the level of incongruity

present in the humor. Finally, the response intensityscale was designed to record the degree to which thepatient responded and it ranged from no reaction to anexplosive laugh with profound body movements. Thescale is an ampliWcation of a 4-step model of humorresponse employed by Pollio, Mers, and Lucchesi (1972)to describe a graduated series of bodily responses tohumor.

2.6. Coding the humor event

To code samples equally across the interview, theinterview was divided into three sections. Thirteen min-utes were taken from the beginning, 14 min from themiddle and 14 min from the ending, for a total of 41 minper interview. The number of minutes to be sampled wascalculated by dividing the shortest interview, which was41 min in length, into three sections. The raters indepen-dently reviewed each of the three sections to familiarizethemselves with the conversation and to make mentalnotes of the occurrences of humor. They then returnedto the beginning of each section and coded the eventsaccording to the guidelines set out in the trainingmanual.

Conversational humor was operationalized as twodistinct phenomena in tandem: the production of ahumorous event and the response to the event. Weloosely deWned the humor event as a verbal or nonverbalattempt to amuse oneself and/or a recipient, as people(i.e., our raters) intuitively know when humor hasoccurred (Berlyne, 1972; Ziv, 1984). Beyond that, thehumor event had to be a single utterance or nonverbalcommunicative gesture bounded by conversational turntaking. We anticipated that there would be occasions inwhich laughter occurred in the absence of humor andconversely, a humor event would not evoke a response.There is no isomorphic relationship between the degreeof experienced humor and degree of visible response(LaFrance, 1983) and smiles and laughter occur in awide range of social behaviors. The humor may havebeen a hurtful remark directed towards a member of theconversational group or generally inappropriate, thehumor may have failed, or the others may not haveunderstood the intent. In the conversational phenomenaknown as “troubles talk,” the speaker will laugh aftertalking about his or her own misfortune, but it is notexpected that anyone else should laugh in response(JeVerson, 1979, 1984). These situations were consideredas an attempt at humor even though there was noresponse.

The interviews were standardized to the extent thatthey were all conducted in a quiet room and were semi-structured by the same questions; however, we had nocontrol over events prior to the interview, nor could weanticipate how either the patient or spouse would reactat a given time to a given question. The above factors

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potentially inXuence the willingness of an individualmember of the group to joke, which in turn aVects thecollective emotional tone of the group. Therefore, inorder to reduce measurement errors across conversa-tional groups, the quantity of the patients’ humor eventswere calculated as a percentage of the total humorevents in the conversation as well as an absolute number.The total number of humor events per interview repre-sented the sum of the humor production of the patient,spouse, and interviewer.

For every humor event, the raters marked as manydiVerent types of responses as the patient made to theparticular humor event, and the categories were noresponse, smile/laugh, cry, gesture, verbal, and nonverbalvocalization. The number of times that a patientresponded to conversational humor was calculated as apercentage of the total number of responses of thepatient, spouse, and interviewer and as an absolute num-ber. Smiles, laughter, and crying and their onset andoVset were deWned in the training manual and timed bystopwatch.

3. Results

The quantitative and qualitative aspects of humorproduction and response captured in the interview bythe two raters, plus the psychological and neuropsy-chological tests and scales, were entered and analyzedin SPSS for Windows—Release 5.0.2 (SPSS, 1992)software system. As the sample size was small, non-parametric tests (Kruskal–Wallis ANOVA) were usedfor between-group analyses. If the Kruskal–Wallisproved to be signiWcant at the .05 level, Mann–WhitneyU tests were performed to determine which groupsdiVered. Within-group correlations were performedwith Spearman Correlation CoeYcients.

Inter-rater reliability was calculated by Pearson’sCorrelation CoeYcient for those measures using the Lik-ert-type scales and for the duration of the patients’responses. The scores of the two raters were then aver-aged. Rosenthal’s formula (Rosenthal, 1982) was thenapplied to the correlations to obtain reliability scores,which were as follows: aggression .77, appropriateness.67, predictability .45, duration of response .88, andintensity of response .93. The reliability scores for pre-dictability were too low to support further analysis.Kruskal–Wallis tests indicated no signiWcant between-group diVerences by neurological status or gender formean aggression, appropriateness, duration of responseor intensity of response scores.

If there was a discrepancy between the two raters withregard to the designation of a passage as a humorousevent, the rater who did not identify the behavior as ahumor attempt was asked to re-evaluate that particularsegment in case it had been inadvertently overlooked. If

the rater still did not agree that the event was intended tobe humorous, the event was not included in the analysis.The rate of discarded events was 13.4% for RHD, 12.7%for LHD, and 7.4% for NC patients and there were nosigniWcant between-group diVerences concerning dis-cards.

Results of the neurobehavioral scales and tests areshown on Table 2. The Kruskal–Wallis test showed thatLHD patients’ Mini Mental Status Exam (MMSE) andthe Western Aphasia Battery (WAB) mean scores werestatistically lower than those of RHD and NC patients.The Mann–Whitney test did not indicate a diVerencebetween RHD and NC patients for these test scores. Thelower mean scores of LHD patients were expected as the

Table 2Test and scale results

a RHD, NC mean scores > LHD scores, p < .05.

Test n Mean SD Range

Min Max

MMSEa

RHD 11 27.6 2.7 23.0 30.0LHD 9 22.2 4.9 15.0 30.0NC 7 29.0 0.8 28.0 30.0

WABa

RHD 11 98.9 1.1 96.8 100.0LHD 10 74.7 21.5 33.9 99.0NC 7 98.6 0.8 97.8 100.0

FAB-FARHD 11 77.4 15.3 50.0 96.0LHD 10 73.4 15.1 56.0 98.0NC 7 86.4 9.5 72.0 98.0

FAB-PRRHD 11 81.4 14.5 44.6 98.3LHD 10 72.8 19.4 41.3 100.0NC 7 89.0 8.0 73.8 98.3

FAB-CMRHD 11 72.0 21.5 40.0 100.0LHD 10 67.5 25.7 25.0 100.0NC 7 96.8 11.5 70.0 100.0

HOSPatient before

RHD 10 62.2 15.6 36.0 85.0LHD 9 56.3 10.3 40.0 68.0NC 9 46.8 18.2 17.0 73.0

Spouse beforeRHD 9 63.3 8.4 47.0 74.0LHD 7 55.3 17.8 30.0 85.0NC 6 61.3 13.7 42.0 75.0

Patient afterRHD 10 52.9 13.5 38.0 73.0LHD 9 47.7 13.2 33.0 65.0NC 9 47.8 12.9 30.0 73.0

Spouse afterRHD 8 57.5 5.7 51.0 65.0LHD 8 42.5 14.8 17.0 61.0NC 6 57.5 17.0 40.0 83.0

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WAB assesses language functions and the MMSE isbiased towards a greater language competence (Nelson,Fogel, & Faust, 1986).

The Wrst hypothesis, which stated that RHD patientswould produce less conversational humor, did not proveto be the case with our patients. There were no statisti-cally signiWcant diVerences, by neurological status orgender, in the percentage of patient-produced humorevents either when all three sections were groupedtogether or analyzed singly (Table 3). Interviews withRHD patients and their spouses produced a greatermean number of total events, and a greater range com-pared to groups with LHD patients or NC patients andtheir spouses, but the diVerences were not signiWcant. Ifthis group of RHD patients had impairments that mighthave been apparent in a confrontation design, such asinsensitivity to antonymic contrasts (Gardner, Silver-man, Wapner, & Zurif, 1978), incongruous relationshipsand deWcits in their ability to organize a narrative into acoherent whole (Wapner et al., 1981), these factors didnot translate into a reduced humor production in theirspontaneous conversation.

To examine the Shammi and Stuss (1999) hypothesisthat RHD patients with frontal lesions respond less tohumor, we conducted Mann–Whitney tests with thegrouping factor of patients with infarcts extending intothe frontal lobe and those with no frontal lobe involve-ment. We did not Wnd within-group diVerences for RHDpatients. However, LHD patients with frontal lobeextensions produced signiWcantly smaller mean percent-ages of conversational humor than did LHD patientswithout frontal lobe involvement (Mann–WhitneyU D 2.0, p D .03). Language or mental status was notlikely to play a part in these particular results, as theMann–Whitney test did not demonstrate a diVerence inthe mean LHD or RHD patients’ WAB or MMSEscores when frontal and nonfrontal lesions were used asthe grouping factor.

The second hypothesis, which stated that RHDpatients would respond less frequently and with ashorter duration than LHD or NC patients, was par-tially demonstrated by our subjects. Orthopedic controlsshowed a tendency to respond more frequently thanRHD or LHD patients (Kruskal–Wallis p D .08). BothRHD and LHD frontal patients demonstrated lowerpercentages of responses than did nonfrontal RHD or

LHD patients (RHD Mann–Whitney U D 5.5, p D .08;LHD Mann–Whitney U D 3.0, p D .05). Our within-group results supported the Wnding of Shammi and Stuss(1999) to the extent that RHD patients with frontal lobeinvolvement had a reduced response to humor comparedto RHD patients without frontal lobe involvement.However, right and left hemisphere comparisons wereproblematic given the fact that LHD patients who hadlesions extending into the frontal lobe both producedand responded less to conversational humor.

There were no incidences of pathological laughterand the only responses detected by the raters were smil-ing and laughing and no response at all. We found nosigniWcant between-group diVerences by neurologicalstatus or gender in duration of response, percentage oftimes patients responded, or percentage of responses inwhich the raters disagreed if the patient responded ornot.

The third hypothesis, which stated that the spouses ofRHD patients would report a diminishing of thepatient’s engagement in humor post-stroke, was demon-strated by the results of the Humor Orientation Scales(HOS). To determine if patients and spouses perceived adiVerence in the patients’ orientation to humor post-stroke, HOS Before and After scores were comparedusing the Paired Samples T Test. A higher score on theHOS indicates a greater orientation to humor produc-tion in daily communication, which includes both funni-ness and volume. Mean HOS-Before scores weresigniWcantly higher for both RHD patients (p D .01) andLHD patients (p D .006), but not for NC patients (p D .8)or for any spouses. Analyses were then conducted on amodiWed version of the HOS scale in which all items thataddressed language use were removed, such as referencesto telling jokes or stories. When Paired Samples T Testswere conducted on the modiWed HOS-Before and Afterscores, RHD patients’ scores decreased signiWcantly(p D .02) post-stroke as did their spouses’ scores (p D .01),but not for LHD and NC patients or their spouses.Thus, when the HOS was controlled for language, onlyRHD patients and their spouses reported a signiWcantchange in the patients’ orientation to humor post-stroke.

Although not speciWcally hypothesized, we were inter-ested in identifying the variables that contributed to adiminished humor production post-stroke. We createdthe HOS-Change variable to describe the degree of

Table 3Mean percentages and numbers of humor events and responses to humor events

RHD (n D 11) Mean (SD) LHD (n D 10) Mean (SD) NC (n D 7) Mean (SD)

Humor eventsPercent of events 42.3 (16.6) 33.1 (18.7) 44.5 (9.1)Number of events 26.1 (17.7) 17.7 (12.5) 18.4 (5.5)

Humor responsesPercent of responses 56.5 (25.7) 63.0 (16.9) 73.4 (19.4)Number of responses 35.1 (14.3) 30.7 (14.9) 29.7 (8.3)

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274 R.L. Heath, L.X. Blonder / Brain and Language 93 (2005) 267–276

change in humor production post-stroke. The HOS-Change variable was calculated by subtracting HOS-Before scores from HOS-After scores. No statisticallysigniWcant correlations were found between the patientand spouse HOS-Change scores and the MMSE or theWAB. Unfortunately, we were unable to include NCpatients and spouses as too few NC couples completedboth the HOS and the interview (n D 3), the primary rea-son being that the HOS was added to the test batteryafter the 5-year project was underway.

We found a trend for an association between RHDpatient HOS-Change scores and their mean aggressionscores (r D .64, p D .09). To further explore the relation-ship between aggression and RHD patient humor, wecorrelated their percentages of humor production andaggression ratings, and the results were moderately posi-tive (r D .58, p D .05). Therefore, the more an RHDpatient encoded aggression into their conversationalhumor, the more humor they produced and the funnierthey considered themselves post-stroke. As well, wefound a signiWcant correlation between RHD spouseHOS-Change scores and the prosody subtest on theFAB-R (r D ¡.75, p D .003). Thus, according to theirspouses, RHD patients who were better able to correctlyidentify emotion in voices also considered themselvesmore inclined, or more conWdent, to communicate withhumor post-stroke.

For LHD patients, we found an association betweentheir HOS-Change scores and duration of theirresponses such that the more preserved their sense ofhumor, the longer they smiled and laughed in responseto conversation humor (r D .80, p D .02). We also founda relationship between the FAB-R subtests and HOS-Change scores for both LHD patients and theirspouses. For LHD patients, the FAB-CM scores wereassociated with their HOS-Change scores (r D .72,p D .03) and for their spouses, all subtests were associ-ated (FAB-FA r D .83, p D .01; FAB-PR r D .73, p D .06;FAB-CM r D .86, p D .01). The correlations betweenHOS-Change scores and the FAB-R were likely theresult of language diYculties. The FAB-R requires thatthe informant follow multi-step instructions. The expla-nation of a language confound for LHD patients wassupported by a positive correlation between patientscores on the FAB-R with their WAB score (FAB-FAr D .74, p D .009; FAB-PR r D .81, p D .004; FAB-CMr D .74, p D .02).

4. Discussion and conclusions

Our study contributed to the literature on lateralityand humor by selecting a diVerent kind of research para-digm, namely spontaneous conversational humor pro-duction and response rather than cartoon, joke or storycompletion tasks. Although they intuitively seem to

form an inextricable pair, humor production and humorresponse are rarely assessed in conjunction. In lateralitystudies, humor production is for the most part indirectlyinferred by joke and story completion tasks. Our studysystematically examined both the encoding and decod-ing of spontaneous humorous communication by strokepatients.

The aim of our research was to see if laboratory-based Wndings regarding RHD patients’ diminishedsense of humor post-stroke were observable in a naturalsetting. The Wrst and second hypotheses regardinghumor production and response and based on the raters’analyses of the interviews, did not support laboratoryWnding that individuals with right hemisphere damagehave a compromised orientation to humor; whereas thethird hypothesis, which was based on the patients’ andspouses’ assessments of the diVerence in the patients’humor orientation pre- and post-stroke, did. The appar-ent insensitivity of the raters’ data collection proceduresto the patient and spouse reports may be explained bythe fact that the raters were trained to identify humorattempts regardless of the success; while the HOS isdesigned to assess successful and stereotypical humorproduction, such as the telling of funny stories. ThediVerent results led us to believe that a portion of RHDpatients’ humor identiWed in the interview missed itsmark or fell Xat. As the raters were neither aware of thestudy hypotheses, the neurobehavioral characteristics ofstroke patients, nor looking for speciWc deWcits, the gen-eral lack of clarity in RHD patients’ humorous behavior,including nonsequiturs, may be reXected in the percent-age of humor event discards. When we conducted PairedT Tests and applied Rosenthal’s formula (Rosenthal,1982) to arrive at reliability scores for patients groupedby neurological status, we found that reliability forappropriateness was higher for NC patients (0.75) thanRHD (0.57) or LHD (0.67), as was predictability(NC D 0.57; RHD D 0.33, LHD 0.26). We conclude thatthe qualitative aspects of conversational humor of nor-mal controls had a greater clarity of intent and thereforewas easier for the raters to assess than was the humor ofstroke patients. Finally, the interview might have evokeda pattern of humorous communication developed overyears of living together; therefore dyadic humor may bepartially determined by a level of subjectivity that makesit diYcult for the nonparticipant observer to access.

The Wnding of a reduced percentage of humorresponses but not a reduced percentage of humor pro-duction for RHD patients is most parsimoniously inter-preted in the light of Gainotti’s (1972) Wnding of anincreased inappropriate joking among RHD patients.Individuals with right hemisphere lesions often display adisinhibition syndrome, which includes an increase intalkativeness and aggression, among other manifesta-tions of mania (see Starkstein & Robinson, 1997, for areview). Shammi and Stuss (1999) report a dissociation

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R.L. Heath, L.X. Blonder / Brain and Language 93 (2005) 267–276 275

between RHD patients’ cognitive and aVective responsesto the humorous stimuli whereby the patients appear tounderstand the joke, and they rate the joke as funny, butthey do not respond with smiles or laughter, unlike theirnormal controls and patients with lesions in other loca-tions. The disinhibition syndrome also provide insightinto the association between increased joking andincreased aggression. We speculate that the ratersdetected aggression rather than lack of appropriatenessbecause, as previously mentioned, aggression was a moreconcrete scale with direct reference to humor content,and therefore more easily judged by the raters. The datacollection procedures were not designed to distinguishbetween subtle deWcits in humor; hence, although itappears likely, we are unable to conclusively state thatthe reduced humor production and response of LHDpatients with lesions in or extending into the frontal lobewas due to frontal lobe pathology.

Much of the conversational humor appeared to be ameans of facilitating the Xow of conversation rather thandesigned solely to amuse. While degree of incongruityand narrative complexity in a laboratory are examiner-selected, in a spontaneous conversation they are speaker-selected. The level of challenge presented by the conversa-tion may be adjusted to accommodate the patients and issubject to ceiling eVects; therefore, detecting speciWcimpairments identiWable in a laboratory is problematic asthe deWcits are diVused by social and environmental cuesprovided by the spouse, interviewer, and familiar setting.

Our results demonstrated the importance of prosodyin humor post-stroke. In a natural setting, humorousexchanges depend on timing in conjunction with an accu-rate understanding of social nuance. Those who are moreconWdent in decoding emotions in voices may be betterable to situate their humor in a social context. RHDpatients who performed better at perceiving aVect invoices also considered themselves more inclined to com-municate with humor post-stroke. With regard to post-stroke communication and social re-integration, furtherinformation on the association between humor produc-tion and humor response and on the extent to whichRHD patients access their social environment to guidetheir conversation would be valuable to caregivers andthose in the rehabilitation Weld. To determine the relativeinXuences of speciWc RHD patient deWcits and cues pro-vided by the social environment on conversationalhumor, we recommend that conversational humor be fur-ther investigated by a research design that evaluates, withthe same subjects, confrontation tasks, and spontaneousconversational humor and compares the performances.

Acknowledgments

We thank Amy Kirkpatrick, who conducted the inter-views, Robert King and Justin Yandell who analyzed the

interviews, Cardinal Hill Rehabilitation Hospital andUniversity of Kentucky Hospital for permitting us torecruit informants from their facilities, Dr. L. Creed Pet-tigrew, Dr. Fred Schmitt and the staV of the Stroke Pro-gram at the University of Kentucky, and the people ofKentucky who participated in the study. We also thankanonymous reviewers for their comments on our manu-script. The research was supported in part by a grantfrom University Funds, University of Kentucky, to Dr.Robin Heath and a FIRST Award from the NationalInstitute of Neurological Disorders to Dr. Lee Blonder(R29NS29082).

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