Emotions Are Expressed More Intensely on the Left Side of the Face Harold A. Sackeim; Ruben C. Gur; Marcel C. Saucy Science, New Series, Vol. 202, No. 4366. (Oct. 27, 1978), pp. 434-436. Stable URL: http://links.jstor.org/sici?sici=0036-8075%2819781027%293%3A202%3A4366%3C434%3AEAEMIO%3E2.0.CO%3B2-R Science is currently published by American Association for the Advancement of Science.
Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/about/terms.html. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/journals/aaas.html. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission.
The JSTOR Archive is a trusted digital repository providing for long-term preservation and access to leading academic journals and scholarly literature from around the world. The Archive is supported by libraries, scholarly societies, publishers, and foundations. It is an initiative of JSTOR, a not-for-profit organization with a mission to help the scholarly community take advantage of advances in technology. For more information regarding JSTOR, please contact
[email protected].
http://www.jstor.org Fri Feb 1 10:41:38 2008
stimuli. A and B. are presented at the same time, are compatible with the general idea. An acpreted as due to a "change for the the effect of A on the behavior controlled by B count invoking terminal-interim competition has worse" in the changed component, to a will depend on whether or not the behaviors ocrecently been offered for local contrast effects casioned by A and B are compatible. Hence by P. Killeen [in Advances in the Experimental change in relative value (15). Our results Analysis of Behavior. M. Zeiler and P. Harzem. stimuli cannot be categorized as absolutely exare not consistent with this hypothesis Eds.. vol. 1, in press]. The terminal-interim discitatory o r inhibitory in their effects. tinction was originated by Staddon and Sim- 15. T . M. Bloomfield, in Animal Discrimination since, if wheel-running has any value at Learning. R. M. Gilbert and N. S. Sutherland. melhag (II) and was reviewed, with emphasis on all for the animal, the change from VI to interim activities and interim versus terminal Eds. (Academic Press, London. 1%9), pp. 215competition. by Staddon (9). The utility to the 241: N. Mackintosh, The Psychology of Anrmal Ext in the changed component will entail animal of stimuli that allow it to allocate interim Learning (Academic Press, London, 1974). The and terminal activities efficiently has been suglack of contrast effects when reinforcement dua smaller reduction in the value of that ration (as opposed to frequency j is varied is also gested by L. Green and H. Rachlin [J. Exp. Ancomponent with the wheel available than inconsistent with a relative-value intemretat~on. al. Behav. 27, 255 (1977)l. J. F. Rand [ibid. 25. 103 (1977)) has shown that pigeons allocate inalthough congenial to our behavioral comwithout. terim activities preferentially to the unreinpetition account. since changes in re~nforcement The relation between the responseduration have l~ttleeffect on the amount of time forced stimulus in successive discrimination. devoted to reinforcement-related terminal reJ. E. R. Staddon and V. L. Simmelhag, Psychol. competition hypothesis and additivity 11. Rev. sponses [S. Shettleworth and J. A. Nevin. J. 78, 3 (1971). Exp. Anal. Behat,. 8, 199 (1%5); R. L. Shull and theory is not yet clear. Both involve 12. J. E. R. Staddon and S. L. Ayres. Behariour 54. M. Guilkey. ibid. 26, 415 (1976)l. 26 (1975); H. Davis and J. Hubbard, ibid. 43. 1 competition: between interim and termi16. We thank J. Vaughn for comments on the manu(1972). script. Supported by grants from the National nal responses in the first case, between 13. R. G. Weisman and M. Ramsden, J. Exp. Anal. Science Foundation to Duke University. Behav. 19, 55 (1973). incompatible instrumental and induced 14. In this theory. interactions between stimuli are mediated by the behaviors they control. If two 14 April 1978; revised 6 July 1978 terminal (Pavlovian) responses in the second. The induction of Pavlovian terminal responses by contrast manipulations, however, may itself be attributable (wholly or in part) to reallocation of terminal and interim behaviors between the Emotions Are Expressed More Intensely on the two schedule components according to Left Side of the Face the mechanisms here described. JOHNM. HINSON Abstract. Pictures of human faces posing six distinct emotions (plus a nerrtral J. E. R. STADDONexpression) and their mil-ror reversals were split down the midlines, and Ie'ft-side and Department of Psychology, right-side composites were constructed. Subjects judged left-side composites as exDuke University, pressing emotions more intensely than right-side composites. The finding indicates Durham, North Carolina 27706 hemispheric asymmetry in the control over emotional expression in the face. References and Notes 1. G. S. Reynolds. J. Exp. Anal. Behav. 4 , 57
,.,".,. 1101.1)
2. See B. Schwartz and E. Gamzu [in Handbook of Operant Behavior. W. K. Honig and J. E. R. Staddon, Eds. (Prentice-Hall. Englewood Cliffs, N.J.. 1977). pp. 53-97] for a review. 3. J. E. R. Staddon, in Reinforcement: Behavioral Analyses, R. M . Gilbert and J. R. Millenson, Eds. (Academic, New York, 1972), pp. 209-262. 4. H. Rachlin, Psychol. Rev. 80. 217 (1973); E. Hearst and H. M. Jenkins, Psychon. Soc. Monoar. (1974): R. A. B0akes.J. . E m. . Anal. Behav. f9, 293 (1973). 5. E. Gamzu and D. R. Williams, Science 171,923 (1971); E. Schwam and E. Gamzu, BUN. Psychon. Soc. 5, 369 (1975); K. Keller, J. Exp. Anal. Behav. 21, 249 (1974); R. G. Westbrook, ibid. 20, 499 (1973); N. Hemmes, J. Comp. Physiol. Psychol. 85, 171 (1973). 6. A. Gutman, J. Exp. Anal. Behav. 27,219(1977). 7. F . K. McSweeney, ibid. ?.3, 193 (1975). 8. The term "interim activit~es"is used here in the broader sense discussed by Staddon (9) to refer to all those activities that compete with the terminal response. It is not necessary for the present theory that these competing activities be specifically facilitated or "induced" by the schedule, although they may be. See also P. J. Dunham [J. Exp. Anal. Behav. 17, 443 (1972)l for experimental evidence on competltlon. 9. J. E. R. Staddon, in Handbook of Operant Behavior, W. K. Honig and J. E. R. Staddon, Eds. (Prentice-Hall. Englewood Cliffs. N.J., 1977). pp. 125-152. 10. The minimal condition for the contrast prediction is that an increase in the time available for the competing activity (that is, the time in the changed component made available by the abolition of food-related activities in that component) reduces its competitive effect on the temiinal resmnse in the unchanged comwnent. This is iust the well-accepted be-haviord equivalent of-the economic law of diminishing marginal utility [H. Rachlin and B. Burkhard, Psychol. Rev. 55, 22 (1978); J. Allison, M. Miller, M. W0zny.J. Exp. Psychol. General, In press]. A formal account of the competition hypothesis, applied to the generalization-gradient peak shift and inhibitory gradients, as well as to contrast, is given in J. E. R. Staddon [in Operant-Pavlovian Interactions, H. Davis and H. M. B. Hurwitz, Eds. (Lawrence Erlbaum, Hiusdale, N.J., 1977), pp. 1 0 s 1311. This account assumes for simplicity that competition can be represented by a system of linear equations, but many quantitative models
Anecdotal and experimental evidence left side and one made up of the right has suggested that the left and right sides (Fig. 1). of the face are physiognomically asymGenerally, the right-side composite metrical (I). On the basis of case studies, face is judged more similar to the original Wolff (1, 2) proposed that the right side face than the left-side composite (4). of the face is consciously expressive and However, these studies failed to obtain "public," while the left side of the face is judgments of the similarity of the commore inhibited and "private." Further- posites to a mirror reversal of the origimore, Wolffclaimed that the right side of nal face. Gilbert and Bakan (3) demonthe face is perceived as more similar to strated that when this condition is inthe whole face than the left side is. Al- cluded, subjects judge whichever side of though the first proposition has never the face appearing more to their left to be been examined experimentally, the sec- more similar to the whole face than ond has (3,4). In such studies the proce- whichever side appears more to their dure has been to split photographs of a right. They concluded that judgments of full face and its mirror reversal down the facial asymmetry in expression are demidline to construct composite photo- termined by biases of the perceiver graphs of the face, one made up of the rather than by asymmetry in actual ex-
Fig. I. (A) Left-side composite, (B)original (19). and (C) right-side composite of the same face. The face is expressing disgust. 434$00.5010 Copyright O 1978 AAAS
SCIENCE, VOL. 202, 27 OCTOBER 1978
pression. These findings notwithstanding, W o l f s first proposition that the sides of the face differ in expressiveness may nevertheless be valid. Indeed, the fact that subjects can discriminate between left-side and right-side composites of the same face underscores the existence of perceptible physiognomic differences. The question we posed for investigation is whether these difference~ are consistent and, in particular, whether the left and right sides of the face are asymmetrical in emotional expressiveness. Cross-cultural data (5) indicate that at least six distinct emotions can be reliably recognized in the human face: happiness, surprise, fear, sadness, anger, and disgust. A set of photographs of posed facial expressions of these emotions as well as photographs of faces expressing emotional neutrality collected by Ekman and Friesen (6) produce reliable and accurate judgments of emotional expression in large samples of subjects. Seventy photographs of 14 posers were chosen for our study so that the seven emotions and photographs of males and females were equal in representation and that the quality of the photographs was uniform (7). Slides were then made of the original and the left-side and right-side composite photographs (8). Four groups of subjects were each presented 54 slides, with six of the slides presented to all groups to examine possible group biases (9). The other 48 slides diiTered for each group. In all, 210 different slides were presented. The size of the groups varied from 20 to 26 subjects with a total of 86 subjects (57 males, 29 females). In order to examine differences between the composites in intensity of expression, subjects were asked to rate on a 1 to 7 scale the intensity of expression for the emotion portrayed in each slide. Each slide was projected for 10 seconds and subjects were given 35 seconds in which to record their responses. The left-side composites were judged to express emotions more intensely than the right-side composites. An analysis of covariance on mean ratings of intensity on the left-side and right-side composites, with ratings for the original face as a covariate, yielded a significant main effect for the type of composite [F(1,56) = 9.39, P = .004], with left-side composites being judged more intense. The main effect for the type of emotion portrayed was also significant [F(6,55) = 4.05, P = .002], indicating that subjects judged the emotions to differ overall in intensity. Sex of the face expressing the emotions did not have a 27 OCTOBER 1978
main effect, nor were there any significant interactions in this analysis. Mean ratings of intensity were higher for leftside than right-side composites for all emotions except happiness (10). Of the 70 different faces presented, 45 were judged as expressing emotion more intensely on the left side ( P < .005). Leftside composites were judged as more intense than right-side composites for 11 of 14 posers (P < .01) (11). Substantial evidence supports righthemispheric superiority for facial recognition (12) and some evidence indicates right-hemispheric specialization for the processing of emotional information (13). Neuroanatomically, both hemispheres have ipsilateral and contralateral projections innervating facial muscles, with a greater preponderance of contralateral projections, particularly in the lower part of the face (14, 15). In addition, evidence from studies of braindamaged patients suggests greater righthemispheric cortical control over the left side of the face (16, 17). In light of these findings, our results point to greater right-hemispheric involvement in the production of emotional expression. A puzzling implication of these findings emerges when one considers the role of emotional expression as a communication system. In a face-to-face situation, the right side of the face of a person expressing an emotion will most likely fall in the perceiver's left visual field, which projects to the perceiver's right hemisphere. Furthermore, the perceiver has a bias to judge the half of a face appearing more to the left as more similar to the whole face than the half which appears more to the right (3). This creates a situation in which the side of the face which is more intense in emotional expression is more likely to be projected to the hemisphere which is relatively inferior in facial recognition and in the processing of emotional information. This situation may be viewed either as advantageous or as disadvantageous depending upon the desirability of effective communication of emotional intensity. It is also possible that the greater emotional expressiveness of the left side of the face evolved in order to compensate for the relative inferiority of the left hemisphere in facial recognition and the processing of emotional information. The issue of hemispheric control of emotional expression may be related to the degree to which emotions are posed or voluntarily expressed as compared to involuntary or reflexive expression. Brain lesion studies point to the possibility of a dissociation in the control of voluntary and the involuntary emotional
expressions (18). The slides used in this study were taken of subjects deliberately attempting to convey particular emotions. Whether or not the same asymmetry in intensity of expression would be obtained with more spontaneously occurring emotional expressions is a matter for future investigation. Findings of differences in hemispheric control over these two types of emotional expression may help further elucidate the nature of functional brain asymmetry. On the other hand, given our knowledge about the functional differences between the two hemispheres, the asymmetry between the two hemispheres in the production of emotional expression may shed some light on the organization of emotions and emotional communication. HAROLD A. SACKEIM* RUBENC. GUR MARCEL C . SAUCY Department of Psychology, Urziversity ofPennsylt.~a~ziu, Philadelphiu 19104 References and Notes 1. W. Wolff, The Expression of Personality (Harper, New York, 1943). Charact. Pers. 2 , 168 (1933); see also ( I ) . 2. ---, 3. C. Gilbert and P. Bakan, Neuropsycholoyia 11, 355 09731. 4. G.i;dzky, B. Prince, H. K. Wright, J . Pers.
21, 68 (1952); H. G. McCurdy, J. Abnorm. Soc.
Psychol. 44, 553 (1949).
5. C. Darwin, The Expression of the Emotions in Man and Animals (Murray, London, 1872); P. Ekman, W. Friesen, P. Ellsworth, Emotion in the Human Face (Pergamon, New York, 1972): C. E. Izard, The Face of Emotion (AppletonCentury-Crofts, New York, 1971); Patterns of Emotions (Academic Press, New York, 1972). 6. P. Ekman and W. Friesen, Unmasking the Face
(Prentice-Hall, Englewood Cliffs, N.J., 1975).
7. Ten photographs (four male and six female),
were taken of neutral faces: for each of the six
emotions, five male and five female faces were
photographed. Handedness was determined for
12 of the 14 posers, all of whom were right-hand-
ed. No information could be obtained with re-
gard to the handedness of the other two posers.
The results for the latter two posers did not dif-
fer in trend from those of the identified posers.
For an extended report of the procedure and
results, see H. A. Sackeim and R . C. Gur, Neu-
ropsychologiu, in press.
8. Two black and white photographs, 11'12 by 17
cm, were made of each face, one in the original
orientation and one in the reversed orientation.
The original and reversed prints were cut verti-
cally through the midline of the face and two left
sides and the two right sides were joined to
make left-side and right-side composites. Each
composite was therefore exactly symmetrical.
Slides (35 mm) were then made of the original
photograph and the two composites.
9. No effects of group were found. With the ex-
ception of the six slides presented to all four
groups, the assignment of slides, as well as the
order of slides within groups, was random.
10. Strictly speaking, the absence of a significant interaction between type of emotions and composites precludes post hoc comparisons among the means to test the effect separately for each emotion. However, such comparisons may be useful for exploratory purposes. Mean ratings of intensity were significantly higher for left-side than for right-side composites for the emotions of disgust and anger ( P < .01). 11. Subjects were also instructed to rank order the four out of seven emotions most likely expressed in each slide in order to examine differences among the composite and original face in accuracy of recognition of the emotions. The original and the two com osites did not differ with regard to accuracy ofrecognition. 12. A. L. Benton, M. W. Van Allen, K. DeS. Hamsher, H. S. Levine, Test of Facial Recognition
(University of Iowa Hospitals. Iowa City, 1975); 17. T . L. Peele, The -Verrroonnlomic Birsisfor CliniE. DeRenzi and H. Spinnler, -Verrrologv 16, 145 cal !Veirrulogy (McGraw-Hill, New York, 1961). (1966): H. Hecaen and R. Angelergues, Arch. 18. As is seen in cases of the Nothnagel syndrome Veurul. 7.92 (1962): J . Levy, C. Trevarthen, R. [ A . J . Gatz in (14): T. L. Peele 117): G. H. MonW, Sperry, Bruin 95, 61 (1972): B. Milner. Xeurad-Krohn. Brain 47, 22 (1924). r'up.\yc/rolu#iri 6 , 191 (1968): M. Moscovitch, D. 19. The photograph of the original face was obScullion, D. Christie, J. Ea). Psvchol. I f ~ m . tained from P. Eckman [Pictures qf Fuciiil AfPerrept. Pervfioi.tii.2, 4 (1976). fect (Consulting Psychologists Press, Palo Alto, 13. K. J . Ilavidson and G. E. Schwartr. PsxchoCalif., 1976)l. Printed with permission of the popliyaio/u#v 13. 62 (1976): G. E. Schwartz, R. J . ser. Davidson. F. Maer. Sriencr 190. 286 (1975). H. 20. Supported by national research service award Gardner, P. K . King, I > . Flamm, J . Silverman, IF31 MH05779-01 from the National Institute of Bririn 98, 399 (1975): K. M. Heilman. R. SchoMental Health to N . A . S . and by grant BNS75ler. R. T. Watson, J. 1I~rtrul.R.'curu.\i~rg.P.\y23061 to J. Levy, R.C.G., and R. E. Gurfrom the c h i n i q 38, 69 (1975). National Science Foundation. We thank C. R. 14. A. J . Gatz. .Munier'.\ Essentiiils of Cliniciil -VeuGallistel, R. E. Ciur, J. Levy, Vlf. J . H. Nauta. P. rounnto,ily and .VeuropIiy.\ioluyv (Davis, PhilaRozin, and M. E. P. Seligman for their comdelphia, 1970). ments. 15. l-. G. J . M. Kuypers, Brniu 81, 3Q1 (1958). * Present address: Department of Psychology. 16. FI. G. Crocketl and N. M. Estridge, Bull. Los Columbia University, New York 10027. An#eler .'eirrol. S o c . 18, 71 (1951): R. Zollinger, Arch. Neirrol. Psychiatry 34, 1055 (1935). 28 December 1977
effects. Such efEects as resorption. stillbirth, reduced weight and length, cleft palate, and decreased thymus weight have been observed in chick embryos and mouse, rat. and rabbit fetuses exposed to corticoids (2, 7, 8 ) . However, the dosages administered in most of these investigations were proportionally higher than those used for therapeutic treatment in humans. T o our knowledge, no studies have been conducted with animals subjected to long-term treatment with low doses of corticosteroids analogous to the treatment used frequently for human infertility. Since no study of human offspring exposed to low dosages of corticosteroids throughout gestation could be found, we Prernatal Exposure $0Prednisapne in Humans and Animals studied a large sample of offspring of who were treated with c o ~ t i c o steroids for infertility and for mainteAbstract. P,-ctftli.vone tr.patrnetlt jhr. inf;.r.tility u r ~ dsub.seyrrerrr pregrlurlcy 17lnintr- nance of pregnancy. In any study of the r1once ir~h ~ l t i r.csiilted ~ ~ t ~ ~ir~11 signifific.ant decrcasr in tile hirtl? \t,rigllt i?f'jirll-term ofspring of women treated with drugs ir!far~tsclt~tla rriurketl ivicr-c,asc~in the percetltu~cqf'11(~1oho1.17 it!fur~tsit.eighin,o 2500 during pregnancy, the most serious congrclr?i,\ or Ir.$s, rllur is, "ligl7t.for. dutes" it1 conipcrr.i,sunto cot~trvloffsprir~g. A purullel founding variable is the maternal disease e.upcritnc,i~t \tit// ;?lice irzdicatrtf that thr r.ediictior~ of' birth weight lvac c~uci.vedhy o r malfunction which necessitated the t o ( ~ ~ r f i c ~ o \ ~ e rrutl~er o i ~ i . st/lnrl to /nuternul d i ~ p u s por 17zu~iirlfic,tio11. (~,u/7o.\~rrc~ initiation of therapeutic intervention. This makes it difficult. if not impossible, Since their synthesis nearly three dec- types of experiments, little risk of ex- to extricate the effects of the treatment ades ago, corticosteroids have been the posure was [noted for either mother o r from those of the maternal complaint. treiitmerit of choice for such life-threat- offspring, although somewhat higher fre- Therefore, we undertook a simultaneous eninp disorders as lupus erythmatosus, quencies of stillbirth and spontaneous study of laboratory animals treated with Addison's disease, and asthma to less se- abortion as well as isolated instances of corticosteroids in dosages proportional rious complaints such as dermatitis and cleft palate occasionally were reported to those given humans. Thus, if similar effects were obtained from the human tcrlnis elbow ( I ) . Serious threats to ma- (4, 6). These reports of negligible effects on and animal subjects, any observed conternal well being, ;it times, necessitate corticosteroid therapy during pregnancy the human fetus are in marked contrast sequences could be more confidently as(2-4). M oreover. adrenocortical hor- to data derived from animals in whish cribed to the treatment. Furthermore. by mones have been used expressly to in- exposure lo corticosteroids during ges- terminating pregnancy in mice at various duce ovulation and support pregnancy in tation apparently produces deleterious intervals during adrenocortical hormone administration, we could make a time-rewomen suffering from infertility. Specifilatect assessment of drug exposure. cally, steroid therapy is administered The full-term off'spl-ing of all women when the sufpected etiology of the diswho received prednisone ('I)during pregorder is a mild abnormal elevation of adnansy (,V = 119) at a private southern renal androgen levels (5). Thus, both the California infertility clinic between 1955 incidental and deliberate treatment of and 1975, served as the experimental pregnancy with corticosteroids have resubjects. The women in this group resulted in the exposure of large numbers ceived 10 mg of prednisone per day for of fetuses to augmented adrenal horinfertility and treatment was continued mone levcls. throughout pregnancy. No other steroid The paucity of reports on the possible hormone therapy was administered to cfyects on the human fetus of these powwomen in this group during these preger.tul substances is surprising. Those renancies. The comparison group was ports which d o exist are based on small composed of the offspring of 67 women numbcrs of individuals and fall into one from the same clinic population who did of two categories. In one type of study, prednlsonea Untreated prednisoneb not require prednisone o r any other horsubjects received relatively large Group monal therapy during pregnancy. Thus, amounts of co~-ticosteroidsfor the alleFig. 1. Mean bir-th weight of male and fernale viation of severe syrnptomatology unre- human infants exposed or not exposed pre- mothers of offspring from both the exlated to pregnancy (2-4). In the second natally to prednisone. (Prednisc,17e'~)based on perimental and comparison groups were type, the offspring were evaluated during data from all prednisone-exposed offspring. ccjmparable in that they were subject to e ~ on data from only those problems of infertility sometime during clinical trials in which low doses of corti- ( P r u d t ~ i s n t ~based subjects that did not qualify as "light for costeroids were administered over long dates" (weighing 2500 g or less at birtli): only their reproductive lives. Length of gestation in most cases was pcriods for infertility and subsequent one subject in the untreated group was "light calculated from temperature charts and lnainienance of pregnancy (5, 6 ) . In both for dates." 436
0036-8075~70~1027-0~136$000050~0 Copyright C 1998 A h h S
SCIENCE, VOL. 202. 27 OCTOBER 1978
http://www.jstor.org
LINKED CITATIONS - Page 1 of 1 -
You have printed the following article: Emotions Are Expressed More Intensely on the Left Side of the Face Harold A. Sackeim; Ruben C. Gur; Marcel C. Saucy Science, New Series, Vol. 202, No. 4366. (Oct. 27, 1978), pp. 434-436. Stable URL: http://links.jstor.org/sici?sici=0036-8075%2819781027%293%3A202%3A4366%3C434%3AEAEMIO%3E2.0.CO%3B2-R
This article references the following linked citations. If you are trying to access articles from an off-campus location, you may be required to first logon via your library web site to access JSTOR. Please visit your library's website or contact a librarian to learn about options for remote access to JSTOR.
References and Notes 13
Right Hemisphere Lateralization for Emotion in the Human Brain: Interactions with Cognition Gary E. Schwartz; Richard J. Davidson; Foster Maer Science, New Series, Vol. 190, No. 4211. (Oct. 17, 1975), pp. 286-288. Stable URL: http://links.jstor.org/sici?sici=0036-8075%2819751017%293%3A190%3A4211%3C286%3ARHLFEI%3E2.0.CO%3B2-8
NOTE: The reference numbering from the original has been maintained in this citation list.
