BRIEF ARTICLES 181

HARVEY, 0. J. Reactions to unfavorable evaluationsof self by others. Technical Report No. 8, 1958,Vanderbilt University, Contract NONR 2149(02),Office of Naval Research.

HARVEY, 0. J. Personality correlates of concept func-tioning and change across situations. TechnicalReport No. 3, 1959, University of Colorado,Contract NONR 1147(07), Office of Naval Re-search.

HARVEY, 0. J., & BEVERLY, G. D. Some personalitycorrelates of concept change through role playing.Journal of Abnormal and Social Psychology, 1961,63, 125-130.

HARVEY, 0. J., & CALDWELL, D. F. Assimilation andcontrast in response to environmental variation.Journal of Personality, 1959, 27, 125-135.

HARVEY, 0. J., KEIXEY, H. H., & SHAPIRO, M. M.Reactions to unfavorable evaluations of the selfmade by other persons. Journal of Personality,1957, 25, 393-411.

HOVLAND, C., HARVEY, 0. J., & SHERIT, M. Assimila-tion and contrast effects in relation to communica-tion and attitude change. Journal of Abnormaland Social Psychology, 1957, 55, 244-252.

OSGOOD, C. E., & TANNENBAUM, P. H. The principleof congruity in the prediction of attitude change.Psychological Review, 1955, 62, 42-55.

ROBERTS, A. H., & JESSOR, R. Authoritariansm, puni-tiveness, and perceived social status. Journal ofAbnormal and Social Psychology, 1958, 56, 311-314.

THIBAUT, J. W., & RIECKEN, H. W. Some determi-nants and consequences of the perception of socialcausality. Journal of Personality, 1955, 24, 113-133.

WAGMAN, M. Attitude change and authoritarian per-sonality. Journal of Psychology, 1955, 40, 3-24.

(Received June 10, 1963)

Journal of Personality and Social Psychology1965, Vol. 1, No. 2, 181-186

FACILITATING EFFECTS OF "EATING-WHILE-READING" ONRESPONSIVENESS TO PERSUASIVE COMMUNICATIONS1

IRVING L. JANIS, DONALD KAYE, AND PAUL KIRSCHNERYale University

This experiment was designed to test the hypothesis that food, as an extraneousgratification accompanying exposure to a persuasive communication, will in-crease acceptance, even though the donor of the food is not the source of thecommunication and does not endorse it. 2 replicating experiments were carriedout with 216 male college students. In both experiments there were 3 groupsof Ss, assigned on a random basis to the following conditions, which involvedexposure to: (a) 4 persuasive communications while eating desirable food;(b) the same 4 communications with no food present; (c) no relevant com-munications (control condition). Both experiments provide confirmatory evi-dence, indicating that more opinion change tends to be elicited under conditionswhere the Ss are eating while reading the communications. The theoreticalimplications are discussed with respect to psychological processes involved inchanging attitudes.

It is commonly assumed that people are morelikely to yield to persuasion at a time when theyare eating or drinking than at a time when theyare not engaged in any such gratifying activity.Salesmen, business promoters, and lobbyists oftentry to "soften up" their clients by inviting themto talk things over at a restaurant or cafe. Repre-sentatives of opposing economic or politicalgroups, when unable to settle their disputeswhile seated formally around a conference table,

1 This experimental investigation was conductedunder the auspices of the Yale Studies in Attitudeand Communication, which is supported by a grantfrom the Rockefeller Foundation.

may find themselves much more amenable tomutual influence, and hence more conciliatory,while seated comfortably around a dinner table.

Little systematic research has been done, asyet, to determine the conditions under whichpleasant stimulation will augment the acceptanceof persuasive communications. One might expectthat when the communicator is the perceivedsource of the gratifying stimulation, a morefavorable attitude toward him will ensue, whichwould tend to lower the recipient's resistanceto his persuasive efforts (see Hovland, Janis, &Kelley, 1953, pp. 19-55). But a more complicatedsituation often arises at educational symposia,

182 BRIEF ARTICLES

political conventions, cocktail parties, and in-formal dinners where: (a) the donor (that is, theperson who is perceived as being responsible forthe gratification) is not the communicator and(b) the donor does not endorse the persuasivecommunications that happen to be presented atthe particular time when the recipients are beingindulged. If a positive gain in effectiveness isfound to occur under these conditions, where thegratifying activity is entirely extraneous to thecontent, source, or endorsement of the communi-cations, a number of important theoretical ques-tions will arise—questions concerning some ofthe basic processes of attitude change which willrequire systematic experimental analysis. Forexample, when eating has a facilitating effect onacceptance of persuasive messages, does it alwaysdepend entirely upon the heightened motivationof the recipients to conform with the donor'swishes? If so, a positive outcome under non-endorsement conditions will be paradoxical unlessit turns out that there is a general tendency forpeople to assume, consciously or unconsciously,that the donor would like them to be influencedby whatever communications are presented (eventhough he explicitly says that he does not endorsethe point of view being expressed). Or does theextraneous gratification operate as a source ofreinforcement independently of the recipient'sattitude toward the donor? If this is the case,we might be led to assume that the food cor-responds to an "unconditioned stimulus," and itsfacilitating effects might be accounted for interms of the laws of conditioning.

The latter theoretical possibility is suggestedby Razran's (1940) brief research note, published25 years ago, in which he gave a summarystatement of the following two experimental ob-servations : (a) an increase in ratings of "personalapproval" occurred when a series of sociopoliticalslogans were presented to experimental subjectswhile they were enjoying a free lunch and (b) adecrease in such ratings occurred when theslogans were presented while the subjects werebeing required to inhale a number of unpleasant,putrid odors. In his report, however, Razrandoes not mention certain important details, suchas whether the experimenter was the donor ofthe free lunch and whether he said anything tothe subjects about his personal attitude towardthe slogans.

So far as the authors have been able toascertain, no subsequent experiments have beenpublished pertinent to checking Razran's ob-servations. Nor has any published research beenfound bearing on the related questions of whether

or not (and under what limiting conditions)extraneous pleasant or unpleasant stimulation canaffect the degree to which a recipient will accepta series of persuasive arguments that attemptto induce him to change a personal belief orpreference.

As a preliminary step toward reopening experi-mental research on the above-mentioned set oftheoretical problems, the present study wasdesigned to investigate the alleged phenomenonof enhanced communication effectiveness arisingfrom "eating-while-reading," The research wasdesigned primarily to answer the followingquestion: If an experimenter gives the subjectsdesirable food and drink but states explicitlythat the persuasive messages to be presented areones with which he does not necessarily agree,will there be a significant increase in acceptancefrom the gratifying activity of eating thataccompanies exposure to the communications?

METHOD AND PROCEDUREExperimental Design

The basic design involved randomly assigning thesubjects to two different experimental conditions. Onewas a condition in which a substantial quantity offood was offered to the subjects during the timethey were engaged in reading a series of four per-suasive communications. Upon entering the experi-mental room, the subjects found the experimenterimbibing some refreshments (peanuts and Pepsi-Cola) and they were offered the same refreshmentswith the simple explanation that there was plentyon hand because "I brought some along for you too."The contrasting "no-food" condition was identicalin every respect except that no refreshments werein the room at any time during the session.

The same measures of opinion change were usedin the two experimental groups and also in a thirdgroup of unexposed controls, who were included inthe study in order to obtain a base line for ascer-taining the effectiveness of each communication perse. The subjects randomly assigned to the controlcondition were given the same pre- and postcom-munication questionnaires, separated by the sametime interval as in the other two experimental con-ditions, but without being exposed to any relevantcommunications.

The Communications and the Opinion MeasuresOn the basis of extensive pretesting, we prepared

four communications, each of which advocated anunpopular point of view and had been found tobe capable of inducing a significant degree ofopinion change. These communications were at-tributed to fictitious authors who were described asjournalists or news commentators. The main con-clusions, all of which involved quantitative predic-tions or preferences about future events, were asfollows:

BRIEF ARTICLES 183

1. It will be more than 25 years before satis-factory progress can be expected in the searchfor a cure for cancer.

2. The United States Armed Forces do not needadditional men and can be reduced to less than85% of their present strength.

3. A round-trip expedition to the moon will beachieved within the next decade.2

4. Within the next 3 years, three-dimensionalfilms will replace two-dimensional films in prac-tically all movie theaters.

In order to assess opinion changes, four keyquestions were included in both the pre- and thepostcommunication questionnaires, each of whichasked the subject to express his opinion in theform of a quantitative estimate (for example, "Howmany years do you think it will be before anextremely effective cure is found for cancer so thatcancer will no longer be a major cause of death?About years.")

Experiments I and II: Similarities and Differ-ences

The same experimental design, described above,was used in two separate experiments, during suc-cessive semesters at the same college. In all essentialfeatures the first (Experiment I) was identical withthe second (Experiment II) in that exactly the sameexperimental variations were used along with thesame instructions, the same communications, andthe same pre- and postcommunication questionnaires.But the two experiments differed in several minorways. The main difference was that in Experiment Ithe time interval between the precommunicationquestionnaire and exposure to the communicationswas about 2 months; whereas in Experiment IIthe precommunication questionnaire was given at thebeginning of the experimental session, immediatelypreceding the communications.

In Experiment I, the initial questionnaire wasadministered in regular undergraduate class sessions.It was introduced as a "survey of student opinions"and the key questions were embedded among nu-merous filler questions on a variety of other con-troversial issues. After a period of 2 months, thesubjects were contacted by telephone and asked tobe unpaid volunteers for a study on reading prefer-ences. The vast majority volunteered and each sub-ject was seen in a private interview session, at thebeginning of which he was randomly assigned tothe "food with communication" condition or the"no food with communication" condition or theunexposed control condition. After answering the

2 This study was carried out before the majordevelopments in space flights had occurred, at atime when few people were optimistic about therate of technical progress in this field. In responseto the moon-flight question on the initial question-naire, almost all the students gave estimates of 10years or more before a successful round-trip flightcould be expected.

final set of postcommunication questions, each sub-ject was briefly interviewed concerning his reactionsto the experimental situation.

In Experiment II, the same essential procedureswere used except for the fact that the precom-munication questionnaire was given at the beginningof the experimental session. Another minor differ-ence was that the unexposed controls were givensome extracts from a popular magazine on irrelevanttopics, which took approximately the same readingtime as the four persuasive communications. More-over, unlike the unexposed controls in Experiment I,those in Experiment II were given the same food inthe same way as in the main experimental condition,so that they too were eating while reading the(irrelevant) articles.

In addition to the three conditions that were setup to replicate the essential features of Experiment I,a fourth experimental condition was introduced inExperiment II in order to investigate a subsidiaryproblem, namely, the effects of extraneous unpleasantstimuli. The fourth experimental group, while readingthe four persuasive communications, was exposed toan unpleasant odor (produced by a hidden bottleof butyric acid), for which the experimenter dis-claimed any responsibility.

In both experiments, the experimenter explainedthat the purpose was to assess the students' readingpreferences. He asserted that he did not endorse thecommunications and casually mentioned that he hap-pened to agree with certain of the ideas expressedand not with others (without specifying which).He asked the subjects to read the articles as thoughthey were at home reading a popular magazine. Inline with the alleged purpose, the postcommunicationquestionnaire in both Experiments I and II included20 filler questions asking for interest ratings of thearticles (for example, ratings of how much interestthey would expect the average college student tohave in each topic).

SubjectsA total of 216 Yale undergraduate students were

used in the two experiments. In Experiment I, 35men were in the unexposed control group, 32 in the"no food with communication" condition, and 33 inthe "food with communication" condition. In Experi-ment II, the corresponding numbers were 23, 31,and 31, respectively. There were also 31 subjects inthe fourth experimental group exposed to the"unpleasant" condition.

RESULTSIn both experiments, observations of the sub-

jects' eating behavior in the "food" conditionshowed that every one of them ate at least onehandful of peanuts and drank at least one-halfglass of the soft drink. The main findings con-cerning the effects of eating desirable food onthe acceptance of the four persuasive communi-cations are shown in Table 1. In general, the

184 BRIEF ARTICLES

TABLE 1OPINION CHANGES INDUCED BY EXPOSURE TO FOUR PERSUASIVE COMMUNICATIONS

UNDER Two DIFFERENT CONDITIONS: "FOOD" VERSUS "No FOOD"GIVEN BY THE EXPERIMENTERS

Communicationtopic

1. Cure for cancerPositive changeNegative changeNo change

TotalNet changeP

2. Preferred size ofUnited StatesArmed Forces

Positive changeNegative changeNo change

TotalNet changeP

3. Round trip tomoon

Positive changeNegative changeNo change

TotalNet changeP

4. Three dimen-sional movies

Positive changeNegative changeNo change

TotalNet change

P

% opinion change

Experiment I

No food(N = 32)

68.721.89.5

100.046.9

65.69.4

25.0100.056.2

<

53.221.924.9

100.031.3

68.721.89.5

100.046.9

Food(2V = 33)

81.812.16.1

100.069.7

'll

81.80.0

18.2100.081.8

05

75.912.112.0

100.063.8

05

75.912.112.0

100.063.8

= .20

Experiment II

No food(AT =31)

80.73.2

16.1100.077.5

*<

29.00.0

71.0100.029.0

<

48.419.432.2

100.029.0

74.20.0

25.8100.074.2

Food(N =31)

93.50.06.5

100.093.5

loT"

51.60.0

48.4100.051.6

OS

58.012.929.1

100.045.1

20

77.46.5

16.1100.070.9

=140i

Combined data fromExperiments I and II

No food(N = 63)

74.612.712.7

100.061.9

<

47.64.8

47.6100.042.8

<

50.820.628.6

100.030.2

<

71.511.117.4

100.060.4

Food(N = 64)

87.46.36.3

100.081.1

"05

67.20.0

32.8100.067.2

01

67.212.520.3

100.054.7

05

76.69.4

14.0100.067.2

<.20

results indicate that "eating-while-reading" hasa facilitating effect on the amount of opinionchange. In Experiment I, the differences betweenthe food and no-food conditions are consistentlyin the predicted direction for all four communi-cations, two of which are significant at the .05level. (All p values are one-tailed and wereobtained on the basis of the formula for assess-ing the difference between two net percentagechanges, given by Hovland, Lumsdaine, & Shef-field, 1949.) The results for Experiment II showdifferences in the same direction for three of thefour communications, two of which are significantat the .10 level. There is a very small, non-significant difference in the reverse direction onthe fourth communication.

The p values based on the combined data fromboth experiments, shown in the last column ofTable 1, can be regarded as a satisfactory sum-mary of the overall outcome inasmuch as: (a)the numbers of cases in each experiment arealmost equal; and (6) the two experiments dif-fered only in minor features that are irrelevantto the main comparison under investigation. Thecombined data show that all four communicationsproduced differences in the predicted directionand for three of them the differences are largeenough to be statistically significant. Thus, theresults support the conclusion that, in general,the extraneous gratification of eating while read-ing a series of persuasive communications tendsto increase their effectiveness.

BRIEF ARTICLES 185

That each communication was effective ininducing a significant degree of opinion change,whether presented under food or no-food condi-tions, is indicated by the comparative data fromthe unexposed controls. In both experiments, thecontrol group showed very slight positivechanges, if any, on each of the four key questionsand the amount of change was always signifi-cantly less than the corresponding net changeshown by the food and no-food experimentalgroups.3 There were no consistent differencesbetween the control group in Experiment I andthe one in Experiment II, which indicates thatthe different time intervals between the beforeand after measures and the other minor pro-cedural differences between the two experimentshad no direct effect on the opinion measures.

The condition of unpleasant stimulation intro-duced into Experiment II had no observable ef-fect on the amount of opinion change. The netchanges obtained from the group exposed to thefoul odor (N = 31) were as follows: cancer cure,67.7%; size of armed forces, 25.8%; round tripto moon, 38.7%; three-dimensional movies,64.5%. These values differ only very slightlyfrom those obtained from the group exposed tothe no-food condition in Experiment II (seeTable 1); none of the differences are largeenough to approach statistical significance. Asexpected, however, all the net changes for theunpleasant odor condition are smaller than thosefor the food condition and in two of thefour instances the differences are statisticallysignificant at beyond the .05 level.

3 In all but one instance, the net change shownby the unexposed controls was not significantly dif-ferent from zero. The one exception occurred in thecontrol group in Experiment I with respect to thefirst issue (cancer cure), on which a significant netchange of —34% was found. This change, however,was in the reverse direction from that advocated bythe communication (probably as a consequence ofoptimistic publicity concerning new advances incancer research that appeared in the newspapersduring the months between the before and afterquestionnaires). Thus, on this item, as well as onthe other three, the control group showed signifi-cantly less change in the expected direction thanthe two experimental groups.

An analysis of responses to the precommunicationquestionnaire from both experiments showed thatinitially, on each of the four key opinion questions,there were only very slight, nonsignificant differencesamong the experimental and control groups. None ofthe results in Table 1 and none of the other observeddifferences in amount of opinion change are at-tributable to initial differences.

DISCUSSION

Our finding that the extraneous gratifyingactivity of eating tended to increase the degreeto which the accompanying persuasive messageswere accepted may prove to have importantimplications for the psychology of attitudechange, especially if subsequent research showsthat the gains tend to be persistent, giving riseto sustained modifications of personal beliefs orpreferences. Since the control group in Experi-ment II (which received food along with ir-relevant communications) showed net opinionchanges that were practically zero and weresignificantly less than those shown by the mainexperimental group, the food alone appears tohave had no direct effect on any of the opinionmeasures. Hence the observed outcome seems toimplicate psychological processes involved in theacceptance of persuasive influences.

Our results on the positive effects of food aresimilar to Razran's (1940) findings on the in-crease in favorable ratings of sociopoliticalslogans induced by a free lunch. Razran hasindicated that he regards his observations asevidence of Pavlovian conditioning, resultingfrom the contiguity of the conditioned stimuli(the slogans) and the unconditioned pleasantstimuli (food). Before accepting any such inter-pretation, however, further investigations areneeded to check systematically on the possibilitythat the change in acceptability is brought aboutby creating a more favorable attitude towardthe donor. We attempted to minimize this pos-sibility in both Experiments I and II by havingthe experimenter give the subjects an intro-ductory explanation in which he clearly statedthat he was not sponsoring the persuasive com-munications. Despite this attempt, however, thesubjects may have ignored or forgotten his re-marks and assumed that he was sponsoring them.We have no evidence bearing directly on thismatter, but we did note that in the informalinterviews conducted at the end of each experi-mental session, many more favorable commentsabout the experimenter were made by the sub-jects who had been in the food condition thanby those who had been in the no-food condition.

Our failure to confirm Razran's findings onthe negative effects of unpleasant stimulationmight be accounted for in terms of attitudetoward the experimenter. In Razran's experiment,the experimenter "required" the subjects tosniff the putrid odors, and hence he might havebeen directly blamed for the unpleasant stimula-tion; whereas in our Experiment II, the un-pleasant odor was presented as an accidental

186 BRIEF ARTICLES

occurrence for which the experimenter was notresponsible. Further experimental analysis isobviously needed to determine if the effects ofpleasant and unpleasant stimulation observed inour experiment are dependent upon whether ornot the experimenter is perceived as the causalagent.

The fact that the experimenter himself par-ticipated in eating the food might have influ-enced the subjects' perceptions of the generalatmosphere of the reading session and henceneeds to be investigated as a possible variable,independently of the subjects' food consumption.The limiting conditions for positive effects from"eating-while-reading" also require systematic in-vestigation, particularly in relation to unpleasantinterpersonal stimuli, such as those provokingembarrassment, outbreaks of hostility, or otherforms of emotional tension that could counter-act the positive atmosphere created by theavailability of desirable food.

It is also important to find out whether varia-tions in the experimenter's endorsement of thecommunications play a crucial role in determiningthe facilitating effects of the preferred food. Forexample, if subsequent research shows that theexperimenter's positive versus negative endorse-ments make a difference, then an explanationin terms of increased motivation to please thedonor will be favored, rather than a simpleconditioning mechanism, and a more complicatedexplanation will be required to account for thepositive effects obtained under conditions where

the experimenter explicitly detaches himself fromsponsorship of the communications.* These impli-cations are mentioned to illustrate the new linesof research suggested by comparing the resultsfrom the present experiment with those fromRazran's earlier study.

4 The potential importance of positive versus nega-tive endorsement by the experimenter as an inter-acting variable was suggested by some unexpectedresults obtained in a pilot study by Dabbs andJanis, which was carried out as a preliminary steptoward replicating the present experiment underconditions where the experimenter indicates that hepersonally disagrees with the persuasive communica-tions. The pilot study results led us to carry out anew experiment in which we compared the effectsof eating-while-reading under two different endorse-ment conditions (the experimenter agreeing or dis-agreeing with the communications). A report onthe effects of the interacting variables, as revealedby the data from the Dabbs and Janis experiment,is currently being prepared for publication.

REFERENCES

HOVLAND, C. I., JANIS, I. L., & KELLEY, H. H. Com-munication and persuasion. New Haven: YaleUniver. Press, 1953.

HOVLAND, C. I., LUMSDAINE, A. A., & SHEFFIELD,F. D. Experiments on mass communication. Prince-ton: Princeton Univer. Press, 1949.

RAZRAN, G. H. S. Conditioned response changesin rating and appraising sociopolitical slogans.Psychological Bulletin, 1940, 37, 481.

(Early publication received July 21, 1964)

ERRATUM

In Table 2 (page 311) of the article "Cooperation and Competitionin Means-Interdependent Triads," by Bertram H. Raven and H.Todd Eachus (Journal of Abnormal and Social Psychology, 1963,67, 307-316), the interaction effect was actually not significant. TheA X B row of the table should indicate that the mean sum of squaresis 14.40 and the F value is .40, with no indication of significance. Thischange is in no way relevant to the substantive findings of the article,since there had been no expectation of an interaction effect. However,in the interests of accuracy, the last two sentences on page 310, whichrefer to the significance of the interaction, should be omitted.