Gender Differences From Kindergarten To Adulthood

Smiling In School Yearbook Photos: Gender Differences From Kindergarten To Adulthood

David K. Dodd

To explore the hypothesis that girls and women smile more frequently than boys and men, 16,514 photographs of students (kindergarten to college) from school yearbooks were studied, as were photos of faculty and staff members. The predicted gender difference in smiling was small and nonsignificant until Grade 4, when a statistically significant difference was first obtained. The gender difference reached its peak in grade 9 (effect size = .275) and remained relatively constant through adulthood. Systematic study of yearbook photos from one high school during the period 1968-1993 revealed no change in the gender difference over time. Discussion focused on the emergence of the smiling difference during preadolescence and the theoretical implications of such a finding.

Over the past 20 years, abundant empirical evidence has mounted showing that women smile more frequently than men across a variety of situations (Bugental, Love, & Gianetto, 1971; Chaiken, 1979; Frances, 1979; Halberstadt & Saitta, 1987; Henley, 1977; LaFrance & Carmen, 1980; Mackey, 1976; for reviews, see Hall, 1984, and Hall & Halberstadt, 1986). A number of theoretical explanations exist for this gender difference in smiling, including sex role conformity (LaFrance & Carmen, 1980; Mackey, 1976), status and power (Deutsch, 1990), submissiveness or subordination (Goffman, 1987; LaFrance, 1985), learned expressivity (see Hall, 1984), and generation of leniency (LaFrance & Hecht, 1995). Despite the abundance of research and theory linked to smiling, surprisingly little is known about the developmental age when this gender difference first occurs. A major goal of the present paper was to identify, through a largescale, systematic analysis of school yearbook photos, the age at which gender differences in smilin g emerge.

Based on a meta-analysis of 18 studies of infants, 20 of children, and 23 of adults, Hall (1984) concluded that there was no gender difference in social smiling among infants and children but a moderately strong difference among adults, with women smiling more than men. Clearly, the gender difference must develop sometime during adolescence or, perhaps, late childhood. Unfortunately, there is a dearth of research on adolescents, especially early adolescence, even though this may be a period of heightened awareness and exploration of gender roles (Hill & Lynch, 1983). Notably, two studies (Berman & Smith, 1984; Kolaric & Galambos, 1995) that used experimentally composed dyads of adolescents both reported significantly greater smiling among girls than boys. Still, additional research covering late childhood and early adolescence is clearly needed.

The study of gender differences in smiling can contribute to theory and research on the development of gender roles. According to both social learning theory (see Lott & Maluso, 1993) and gender schemata theory (Bem, 1985), the socialization of gender occurs during childhood, but gender schemas do change and evolve after childhood (Jacklin & Reynolds, 1993). Block (1976) reported that sex differences increase with age, appearing far more often after age 12 than prior to age 5. Learning the age at which gender differences in smiling emerge, relative to adolescence, can contribute both to a greater understanding of gender role development and, more specifically, to reasons for this gender difference. For example, Hall and Halberstadt (1986) found social tension to be the best situational predictor of smiling among adults. If a specific age at which girls begin smiling more than boys can be determined, then research into the causes and meanings of smiling can focus more narrowly on such a particular age group.

Because of the heightened level of self-consciousness among adolescents (Salkind, 1990), the study of smiling among adolescents, particularly in real-life social situations, may be especially difficult. One way in which gender differences in social smiling may be detected is by the examination of photographs. Systematic studies of advertisements in newspapers and magazines have shown that women, compared to men, tend to be portrayed as weak and passive (Goffman, 1987) and frivolous and lighthearted (Dodd, Harcar, Foerch, & Anderson, 1989). Despite the importance of such findings, media photographs may reflect the biases of editors and photographers and may also be influenced by social context.

A trio of investigations in the 1980s established the study of school yearbook photographs as a valuable technique for the study of gender differences in smiling. Examining photos from college and/or high school yearbooks, Morse (1982), Ragan (1982), and LaFrance (1985) all reported more frequent smiling by women than by men. Several other yearbook studies (e.g., Brennan-Parks, Goddard, Wilson, & Kinnear, 1991; Mills, 1984) have explored characteristics of the photographic setting that may influence smiling.

Although smiling in yearbook photos represents only one kind of smiling in a highly defined setting, there are probably at least three reasons for the popularity of this method for the study of smiling. First, the yearbook photo in the United States is a common experience for most high school students, many grade school students, and some college students. Second, the photographic situation is a relatively noncomplex social encounter between a photographer and a student, who is posing not only for the photographer but perhaps also for friends, family, and even future generations who will view the yearbook. Third, the structure of yearbooks seems to have remained remarkably fixed from generation to generation. A marker of tradition, yearbooks generally consist of individual photos of students and staff, group photos of clubs, and action photos of activities. They therefore provide an excellent framework for the study of possible temporal changes in the gender difference in smiling. Have historical changes in society, such as heightened feminism, produced changes in the gender difference in smiling? The present study addressed this question by analyzing data from 1968 to 1997.

In summary, the primary goal of the present research was to identify the age at which gender differences in smiling emerge, by studying yearbook photos across a broad span of grade levels (kindergarten through college) and into adulthood (faculty and staff). A second goal was to explore possible historical trends in the gender difference in smiling by studying photos over a 25-year period in one high school. A third goal of our study was to demonstrate population generalization by replicating and extending previous findings based on high school and college students. Most researchers have studied only one age group from only a few schools and years. We studied yearbooks spanning a very broad range of grade levels, schools, and years, providing an excellent test of the external validity of the gender difference in smiling in yearbook photographs.

Method

Units of Analysis

The total student sample consisted of 16,514 yearbook photos of students ranging in grade level from primary school (kindergarten [K] through 8th grade), to high school (9th and 12th grade), and college (1st and 4th years). As shown in Table 1, no fewer than 328 students were rated at each grade level, and more than 1,000 were rated for all grades above Grade 5. In order to reduce sampling bias, samples were selected from a number of schools (described below) and years. In order to examine the most extreme age groups (and because resources did not allow the study of all grades), only 9th and 12th graders in high school and 1st- and 4th-year students in college were selected. In addition, photos of 946 members of the faculty and staff of one high school, from six selected years, were also analyzed.

Procedure

Yearbooks were obtained from friends and family of the authors and from local school systems, and hence might be considered a nonsystematically selected sample, both in terms of schools and years. Twenty different years were represented by these yearbooks, ranging from 1968 to 1997. A more systematic sampling was conducted for one large, suburban high school (School L) that retained yearbooks in its library for many years. In order to pursue possible temporal trends in the gender-smiling findings, six years were systematically selected from School L: 1968, 1973, 1978, 1983, 1988, and 1993. (In 1968, the school was a 3-year high school, so 10th rather than 9th graders were studied.)

Yearbooks came from nine different primary schools, three high schools, and two colleges, all in the United States. Among the primary and high schools, 10 were public and 2 were private; 5 were located in major cities, 5 in suburban areas, and 2 in small towns. Among the two colleges, one was a small, private college, and the other was a moderately sized state university. All schools were Midwestern except one located in the East. All could be considered to enroll students predominantly from middle class families. The racial composition of the schools generally reflected the geographical area served by the schools. Racial minorities comprised about 2% to 40% of the various subsamples, with African Americans representing the largest minority group. (Unfortunately, because of the relative small numbers of racial minorities in most of the samples, it was not possible to analyze the gender difference in smiling separately for racial groups.)

The photos were pictures of individual students who posed before a professional photographer taken during typical, “assembly line” photo sessions at the individual schools. Photos for the high school seniors and college students appeared typically to have been taken more formally in professional studios. About one half of the pictures of faculty and administration were photos of individuals, with about half of these posed and half impromptu. The remainder of pictures tended to be small group photos of four to six persons, usually grouped by unit such as “social studies department” or “main office staff?”

Definition of Smiling

Using criteria similar to those of Ragan (1982), raters individually evaluated each target person according to the following criteria: full smile (teeth visible), simple smile (corners of mouth upturned but mouth closed or teeth not visible), and no smile. As shown by the interrater reliability (below), it was very easy to determine the “full smile” and “no smile” facial positions. It was far more difficult, however, to identify the “simple smile,” because the photos were sometimes small, slightly unclear, and lacking in sufficient detail to observe the corners of the mouth. For these reasons and because we sought a focused statistical test (Rosenthal & Rosnow, 1991) of our hypotheses, the “simple” and “no” smile categories were combined. Although these definitions yielded highly reliable data, a slight difficulty was the relatively few individuals (fewer than 2%) whose teeth were clearly visible but whose expression lacked the upward turning of the mouth corners that is characteristic of smiling. Because th is expression was so infrequent and appeared to be unrelated to gender, these individuals were classified as smiling. [1]

Reliability

Each photo was rated by one of three primary raters (two women, one man), who were not blind to the research hypothesis. Unfortunately, because of financial restraints, it was not possible to hire raters who were hypothesis-blind. To partially protect against possible experimenter bias, [2] however, three secondary raters (all women) who were hypothesis-blind independently rated a random sample of approximately 10% of the photos, and data from these raters provided the basis for interrater reliability of the smiling data. The ratings of each primary rater were paired with one secondary rater. For the dichotomous categories of smiling and no smiling, the percentages of agreement between rater pairs ranged from 95% to 98%, with an overall reliability index of 97%. Gender was readily determined by appearance or gender-specific first names. The infrequent photos for which gender could not be clearly determined were excluded from analyses.

Results

For each grade level, a chi-square analysis was conducted to compare the percentage of girls (women) versus boys (men) who smiled in their school photos. To determine the effect size, phi was calculated for each analysis. At every grade level, a higher proportion of girls (women) smiled than did boys (men). Table 1 shows that for Grades K through 3 the size of the effect was small (ranging from .045 to .092) and significant only for Grade 2. For Grades 4 through college, however, the effect sizes were much larger (ranging from .129 to .275), and all chi-square values were significant. Effect sizes reached at least .210 in Grades 6 and 8, and were even greater for Grades 9 and 12 and for college. The highest effect size was for Grade 9 (.275), with 70% of the girls smiling compared to only 43% of the boys. The effect sizes for college students (.262) and faculty and staff (.260) were nearly as strong as for Grade 9.

Figure 1 reveals an increasing tendency for both girls and boys to smile from Grade K to 4, followed by a decline, especially steep for boys, from Grades 5 to 9. Thereafter, smiling was more frequent for both genders. Figure 1 also shows that the gender gap in smiling widened at Grade 4, peaked at Grade 9, and remained essentially the same width thereafter.

By studying six years spread evenly from 1968-1993 in School L, we were able to explore temporal trends in the gender difference in smiling. An examination of the effect sizes shown in Table 2 clearly reveals no reliable changes across the years. Girls (women) consistently “outsmiled” boys (men) throughout the 25-year period studied. This was true for Grade 9 (overall effect size = .300), Grade 12 (.241), and faculty and staff (.260).

Discussion

Our findings are highly consistent with other studies of yearbook photos (LaFrance, 1985; Mills, 1984; Morse, 1982; Ragan, 1982) but extend previous research by successfully identifying the age at which the gender difference in smiling, at least in school yearbooks, emerges. Prior to fourth grade, the difference in smiling was small and almost negligible. From Grades 4 to 6, corresponding to the ages of 9 to 12 years, the gender difference first reached statistical significance, with gender accounting for about 3% of the variation in smiling. By Grade 9 (approximately age 14) and into adulthood, however, the tendency for girls (and women) to smile more frequently than boys (and men) in yearbook photos was much stronger, with gender accounting for approximately 6% of the variance in smiling.

Our findings also fit neatly into the broader picture of gender differences in two ways. First, Lott & Maluso (1993) noted that gender generally explains no more than 5% of the variance, and usually much less, in a variety of social behaviors, including aggression, which is commonly considered to be one of the most consistent gender differences. Our finding of 6% of variance explained suggests that the gender difference in smiling among adolescents and adults is at least as strong as other gender differences. Second, Petersen (1980), in reviewing the work of others, concluded that gender differences are far more likely to be discovered in persons older than 12 years, as opposed to children younger than 5. It has been hypothesized that gender-related role expectations intensify during early adolescence (Hill & Lynch, 1983), but our data suggest that some important gender differences may emerge even earlier, during preadolescence.

Why would the gender difference in smiling, at least in school photographs, emerge during the ages of 9 to 12 years? In a general sense, it seems likely that younger children are not fully attuned to social expectations related to gender roles (Salkind, 1990) and have thus not yet incorporated smiling as part of their gender identities. According to gender schema theory (Bem, 1985), ideas about gender develop throughout childhood, but these schemas change and evolve to organize new information and influences (Jacklin & Reynolds, 1993). Preadolescence (roughly from ages 9 to 12) is characterized by an increased interest in opposite-sex friendships and increased interest in sexual information (Westney, Jenkins, & Benjamin, 1983), along with prepubertal physical changes (Hyde, 1979; McCandless & Coop, 1979). With a developing interest in sex and sexuality, preadolescents may turn to the media for definitions of the “ideal” man and woman, and the analysis of Dodd et al. (1989) suggests that they are likely to fi nd stereotypical portrayals of serious, unsmiling men and lighthearted, smiling women.

The research of Stiles, Gibbons, and Schnellmann (1987) is particularly relevant. These researchers asked ninth grade students to rank the qualities of the “ideal man” and the “ideal woman.” Boys depicted the ideal man as a “frowning football player” and both girls and boys described the ideal woman as smiling. It seems plausible that these “ideals” or similar ones play a role when preadolescents or young adolescents pose for a yearbook photo.

Was there evidence that the gender difference in smiling has declined over the years studied? Our data showed no consistent trend over the 25-year period studied for women to smile less frequently and men to smile more frequently, as might be predicted if there has been a loosening of gender-role expectations. Furthermore, the effect sizes, representing the gender difference in smiling, remained relatively constant. Perhaps expectations regarding smiling have changed little over the period studied. Alternatively, it is possible that there have been broad changes in social smiling, but just not in yearbook photographs, which might be particularly resistant to cultural change. Further research is needed to generalize our findings to more spontaneous settings, different age groups, and different social situations. (A study by Halberstadt and Saitta, 1987, provides an excellent model for the study of nonverbal gender differences in natural settings.)

An alternative explanation for our findings focuses on the social nature of the event of being photographed for a school yearbook. Girls and young women may view “picture day” as a unique social event, in which there is social pressure to dress up and present their best “face” for the camera. They are socialized to go to great lengths to improve their physical appearance, and they may view picture day as an important opportunity to “look good” not only for their school mates and families but even for future generations who will view the yearbook. A smile may be perceived as essential to puffing one’s “best face” forward. For boys, in contrast, the physical attractiveness of their photos may not carry such importance; instead the goal may be to project an image of seriousness, an important characteristic of “masculinity.” Again, observational studies of smiling in natural settings are needed to corroborate our findings.

Facial expression is clearly a form of self-presentation, and the degree to which it is consciously chosen may vary dramatically according to individual differences, age, situation, and “audience.” Our analysis, based heavily upon the assumption that the situation and audience in yearbook photos are relatively stable, has demonstrated the strength of gender in determining smiling in such photos. Our findings replicate those of many other researchers but also provide an interesting and valuable extension: The greater tendency for girls and women to smile more than boys and men, at least in school yearbooks, begins between the ages of 9 to 12, is firmly rooted by age 14, and persists into adulthood. Future research needs to explore the generality of this finding in social situations other than yearbook photos and with different audiences, such as friends, family, acquaintances, and strangers.

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(1.) One of our reviewers expressed that it would have been preferable to have eliminated photos in which teeth were visible but a smile was not clearly evident. In retrospect, we agree with this point and encourage future researchers to follow this more conservative strategy.

(2.) Experimenter bias in ratings is a possible concern, because the three primary raters were not blind to the hypothesis that women would smile more than men. This concern is largely eliminated, however, for three reasons. First, a random sample of approximately 10% of the photos was selected to be rated by secondary raters, who were hypothesis blind, and at the time of their ratings the primary raters were unaware of which photos were selected for secondary ratings. Second, the extremely high agreement (97%) between primary and secondary raters suggests that little if any bias occurred. Finally, the primary raters had no clear hypothesis about the age at which the gender difference would emerge or whether the difference would exist in the adult (faculty and staff) sample.

Gender Differences in Smiling By Grade Level

Boys/Men Girls/Women Effect

Grade Level N % Smiling N % Smiling [[chi].sup.2] Size

K 265 54% 301 59% 1.74 .055

1 244 59% 243 68% 4.16 [*] .092

2 205 66% 187 72% 1.57 .063

3 174 75% 154 79% 0.68 .045

4 144 77% 189 89% 8.38 [***] .159

5 184 72% 200 83% 6.39 [**] .129

6 521 63% 538 82% 46.92 [****] .210

7 629 55% 635 71% 36.12 [****] .169

8 534 53% 542 74% 49.37 [****] .214

9 2299 43% 2386 70% 353.82 [****] .275

12 2122 65% 2380 84% 218.70 [****] .220

College 637 64% 801 87% 98.88 [****] .262

Staff 544 56% 402 80% 64.12 [****] .260

Note. All chi-square analyses have df = 1.”Effect size” is phi.”K”

indicates kindergarten, and “staff” refers to faculty and staff.

(*.)p [less than] .05. (**.)p [less than] .02. (***.)p [less than] .01.

(****.)p [less than] .001.

Gender Differences in Smiling By High School L

Boys/Men Girls/Women

Year N % Smiling N % Smiling

9th Grade Students

1968 403 28% 440 58%

1973 503 30% 566 66%

1978 407 53% 379 81%

1983 228 56% 216 86%

1988 232 41% 212 77%

1993 146 61% 191 76%

Total 1919 41% 2004 71%

12th Grade Students

1968 260 72% 304 84%

1973 351 72% 396 89%

1978 443 69% 447 94%

1983 320 70% 315 90%

1988 174 75% 235 93%

1993 136 58% 163 80%

Total 1684 70% 1860 89%

Faculty/Staff/Administrat ion

1968 68 46% 44 73%

1973 130 52% 91 71%

1978 116 47% 82 83%

1983 98 69% 74 85%

1988 78 64% 51 84%

1993 54 59% 60 88%

Total 544 56% 402 80%

Effect

Year [X.sup.2] p Size

9th Grade Students

1968 74.11 [less than].001 .055

1973 131.52 [less than].001 .351

1978 69.50 [less than].001 .297

1983 48.64 [less than].001 .331

1988 58.78 [less than].001 .364

1993 9.40 [less than].01 .167

Total 355.18 [less than].001 .300

12th Grade Students

1968 12.59 [less than].001 .149

1973 35.13 [less than].001 .217

1978 89.60 [less than].001 .317

1983 40.82 [less than].001 .254

1988 25.68 [less than].001 .250

1993 16.54 [less than].001 .235

Total 205.53 [less than].001 .241

Faculty/Staff/Administrat

1968 8.00 [less than].01 .267

1973 8.80 [less than].01 .200

1978 25.75 [less than].001 .361

1983 5.76 [less than].02 .183

1988 6.26 [less than].02 .220

1993 12.67 [less than].001 .333

Total 64.12 [less than].001 .260

Note. All chi-square analyses have df = 1. All effect sizes are in terms of

phi. For 1968, School L was a three-year high school, so 10th graders were

analyzed instead of 9th graders.

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