Women's gender roles affect their visual interest in different infant facial expressions

Personality and Individual Differences 116 (2017) 109–114

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Women's gender roles affect their visual interest in different infant facial expressions Na Ta a,b, Gang Cheng c,1, Dajun Zhang a,b,⁎, Yuncheng Jia a,b, Fangyuan Ding a,b, Mu Xia d a

School of Psychology, Southwest University, 400715 Chongqing, China Center for Mental Health Education, Southwest University, 400715 Chongqing, China School of Educational Science, Guizhou Normal University, 550001 Guiyang, China d School of Educational Science, Guangxi University for Nationalities, 530006 Nanning, China b c

a r t i c l e

i n f o

Article history: Received 14 December 2016 Received in revised form 2 April 2017 Accepted 4 April 2017 Available online xxxx Keywords: Gender roles Infant facial expressions Visual interest Women's interest toward infants Eye-tracking

a b s t r a c t The present study tested whether women's gender roles were associated with interest in infants and examined the influence of infants' facial expressions on women's interest in them. Eye movements were measured in childless female undergraduates through presentations of adult and infant faces with three kinds of expressions. Nulliparous women had general visual preferences toward infant faces. Moreover, neutral infant facial expressions gained most attentional bias than smiling and crying infant faces compared to adult facial expressions. We assumed that gender roles might affect individual differences in women's interest in infants; results showed that masculinity affected women's visual attentional bias toward infants. Further, masculinity had a consistent negative effect on viewing preference toward infants regardless of their expressions. Atypical gender roles thus play an important role in women's differing interests in and caregiving behavior toward infants. We believe a better grasp of gender role effects and infant facial expression influences can improve our understanding of women's interests toward infants. © 2017 Published by Elsevier Ltd.

1. Introduction Harlow (1971, p. 6) once elucidated, “nature has not only constructed women to produce babies, but has also prepared them from the outset to be mothers.” Among humans, as primary caregivers, women are equipped, through natural selection, with psychological and behavioral tendencies that provide adequate investment in the offspring. Thus, researchers hold that females are commonly interested in infants and tend to be more involved in infant care (Berman, 1980; Blakemore, 1979; Fullard & Reiling, 1976; Maestripieri, 1999). Furthermore, social and cultural norms have also traditionally obliged women to occupy the role of primary caregivers. One important manifestation of women's numerous reactions to raising infants is that women have obvious preferential or attentional bias toward for infant faces. Cárdenas, Harris, and Becker (2013) reported that nulliparous women's interest in and attentional bias toward Abbreviations: DT, dwell time; FC, fixation counts; FF, first fixation location; SDT, special dwell time for infant faces; SFC, special fixation counts on infant faces; SFF, special first fixation location; MSDT, mixed special dwell time; MSFC, mixed special fixation counts. ⁎ Corresponding author at: School of Psychology, Southwest University, 400715 Chongqing, China. E-mail address: [email protected] (D. Zhang). 1 These authors contributed equally to this work.

http://dx.doi.org/10.1016/j.paid.2017.04.007 0191-8869/© 2017 Published by Elsevier Ltd.

infants are tougher and steadier. Irrespective of age, women are seen to be more interested in infants in all visual and verbal tests (Maestripieri & Pelka, 2002). In another study, women demonstrated their motivation to extend the viewing of infant faces (Charles, Alexander, & Saenz, 2013). For women in general, although a preference toward infant faces exist, there is likely to be considerable individual variability among them in their interest in infants and parenting motivation. Barber (2001) found that female roles of student and full-time worker are likely to delay the first birth to avoid childbearing and nurturing. Besides, many countries are becoming richer and better educated, thus leading to low fertility rate, and women in rich cities are opting for fewer children and remaining single (Karabchuk, 2016; Presser, 2017). Therefore, as for women, the primary caregivers, assessing individual differences and the influencing factors of interest in infants has more important research value. In the context of the existing research, social and cultural influences on infants' caregiving may be as important as evolutionary or biological influences. Moreover, numerous studies focus on men's parenting from social perspectives. Russell (1978) found that men with less rigid gender role identity were more involved than traditional “masculine” men in the day-to-day care of their infants. The egalitarian attitudes of males have a positive association with fathers' participation in childcare (Deutsch, Lussier, & Servis, 1993). Bonney, Kelley, and Levant (1999)

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reported that men who have liberal gender role ideology held more progressive feelings toward father roles. Moreover, primary caregiving homosexual fathers, who nurtured infants within a partnered relationship, without maternal involvement, had high amygdala activation similar to primary caregiving mothers (Eyal et al., 2014). Thus, socialization, especially gender roles, may have an important effect on an individual's parenting roles (Aradhye, Vonk, & Arida, 2015; Charles et al., 2013). The shift from traditional to more egalitarian gender roles has influenced men's interest in infants and caregiving roles. However, only a few direct studies have examined the effect of gender roles on women's interest in infants. With traditional gendered divisions of labor, women do more childcare activities in most societies and cultures. However, in today's rapid economic development, women are required to participate in the labor force. Bianchi, Robinson, and Milkie (2006) have asserted that gendered beliefs continue to forcefully influence family life today. Specifically, the shift from traditional to more egalitarian gender roles will influence women's work and nurturing roles. More masculine features are accepted by women, more positive attitudes toward female work roles but not toward caregiver roles. High masculinity alone is disadvantageous in coping with the stresses of motherhood in the first few months, but is advantageous for women in adjusting to the army (Dimitrovsky, Singer, & Yinon, 1989). Women who are more committed to work also tend to report less commitment to family (Friedman & Weissbrod, 2005). Dimitrovsky, Levy-Shiff, and Perl (2000) found that women high on femininity had a more positive experience through the early months of motherhood than women high on masculinity. Therefore, although traditional gendered beliefs maintain women's innate tendency toward infants, along with the transformation from traditional to more egalitarian gender roles, the different effects of gender roles on women's interest and behaviors toward infants have significant research value. Previous studies have used multiple techniques to detect adults' attentional bias and viewing interest toward infants. However, only neutral infant faces were used as stimuli without investigating the influence of infants' expressions. In fact, facial expressions are a primary mode of infant communication that can release innate caretaking behavior and affective identity from adults (Lorenz, 1943). Furthermore, our previous studies that used three kind of expressions (smiling, neutral, and crying) showed that neutral infant faces stimulate the strongest parental motivation, got the most attentional bias, and activated larger brain responses compared to neutral adult faces (Ding, Zhang, & Gang, 2016; Jia et al., 2017; Li et al., 2016). Accordingly, we used eye-tracking technology to investigate the effects of nulliparous women's gender roles on interest in and visual interest toward infants' different facial expressions. To date, no studies have investigated this aspect using eye-tracking technology. We believe that the eye-tracking method provides a more objective and accurate measure of visual interest toward infants than self-report, observational methods or physiological tests, such as dot probe paradigm or key press. Thus, this study aimed to 1. verify that women have a general visual preference for infant faces; 2. verify that neutral facial expression may bring about strongest attentional bias toward infants; 3. understand whether more femininity predicts more visual interest, and more masculinity indicates less visual interest toward infant faces; and 4. explore whether there are interactions between gender roles (femininity and masculinity) and expressions among childless women. 2. Methods 2.1. Participants Voluntary female participants (N = 149) were recruited via our university's campus network. Participants were aged 18–29 years

(M = 21.68, SD = 1.72); they were unmarried and nulliparous; 85% were ethnically Han. The entire sample reported having normal or corrected-to-normal vision. Each participant received 15 yuan as payment. Written consent was obtained when all the participants came to the study. Participants were told that they could withdraw from the study at any time without giving any reasons. The Ethics Committee of our university (No. 2014179) approved the study and consent procedure. 2.2. Gender role The Bem Sex Role Inventory (BSRI) (Bem, 1974) categorizes individuals into four gender role identities: masculine, feminine, androgynous, and undifferentiated. It can also be scored as a continuous variable appropriate for both sexes. In this study, we tended to use the latter method. The BSRI contains 60 items: masculinity scale, femininity scale, and neutral personality characteristics, each containing 20 characteristics. Responses are given on a seven-point Likert scale, ranging from 1 “not at all characteristic of me” to 7 “very characteristic of me.” A higher score indicates greater identification with the scale. The present study used the Chinese version of the BSRI translated by Yang et al. (Robinson, Shaver, & Wrightsman, 1997). In this study, internal consistencies were 0.873 for masculinity and 0.784 for femininity. 2.3. Stimuli The eye-tracking procedure included adult and infant facial stimuli (144 pictures), with one of three expressions: smiling, neutral, and crying. The infant faces (3–6 months of age, gender neutral; 24 for each expression, 72 total) and the adult photos (half men and half women; 24 for each expression, 72 total) were selected from the Chinese Infant Affective Face Picture System (Cheng, Zhang, Guan, & Chen, 2015b) and the Chinese Affective Face Picture System (Gong, Huang, Wang, & Luo, 2011), respectively. All faces were standardized with identical orientation and similar inter-pupil distance. Only the facial outline was visible. The hair, ears, and background were removed. All images were presented in grayscale, and the size and luminosity were matched. Any non-face area of the image region (260 × 300 pixels) was filled with a black background (RGB: 0, 0, 0). Infant stimuli did not differ from adult stimuli in intensity (t (71) = 0.59, p = 0.56). Face pairs were similar in facial expression intensity. 2.4. Procedure E-prime was used to program the task. The faces were presented on a 19.7-in. CRT monitor placed 70 cm from the participant. The display resolution was set to 1024 × 768 pixels with a refresh rate of 85 Hz. Monocular eye movements were recorded (right eye, Pupil-CR tracking mode) at a sampling rate of 250 Hz using EyeLink II (SR Research Ltd., Mississauga, Ontario, Canada). Participants were asked to hold their heads with a chinrest. Upon arrival, we stated the following to the participants, “we are interested in learning about the characteristics of interpersonal communication and how people look at faces. Questionnaires are used to test distinction of communication, and eye movements reflect how you look at faces. You don't need to do anything; just look at the faces freely.” Their participation was confirmed by written consent. Participants were asked to complete a demographic questionnaire and the BSRI. Thereafter, participants completed an eye-tracking free-viewing task (see Fig. 1). Each participant needed to calibrate the eye tracker and validate the eye positions before the experimental trials. For calibration, participants fixated on a sequence of nine points on the display until the average visual angle tracking error was b 0.4 degrees. Validation assessed the accuracy of the system in predicting gaze position from pupil position by using an identical random sequence of nine

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Fig. 1. Study procedure. A fixation-cross appeared in the center of the screen for 1000 ms and then disappeared; a pair of faces presented vertically for 6000 ms followed. The interval for each trial was 1000 ms. Participants were guided to fixate on the cross and then freely view the face pairs.

display points. After the eye positions had been validated, the experimental trials began. Two identical blocks were included in experimental trials with a one-minute rest between them. In each block, 72 pairs of faces were presented. Each pair consisted of one infant face (260 × 300 pixels) and one adult face (260 × 300 pixels, man or woman). Two faces were shown above (x: 512, y: 576) and below (x: 512, y: 192) the fixation point randomly. One study showed that emotional stimuli in the left visual field tended to be more salient (Borod, Zgaljardic, Tabert, & Koff, 2001); thus, vertical placement was chosen to avoid cerebral lateralization. Each pair was presented for 6 s. All trials were counterbalanced by age (infant or adult), sex (man or woman), and display location (above or below fixation). All participants received a unique set of paired infant and adult faces randomly. The entire procedure took approximately 40 min to finish.

3. Results 3.1. Data pre-analysis The whole face images were created as interest areas to analyze eye movements. Three measures of attentional bias data were analyzed in this study: each face's dwell time (DT), fixation counts on each face (FC), and first fixation location (FF). To investigate whether there was a general visual preference for infant faces and whether expressions had an effect on such an attentional bias, 2 × 3 repeated-measures ANOVA were conducted on eye-tracking data by face and expression as within-participants factors. Table 1 2 × 3 repeated-measures ANOVA of eye-tracking data (n = 149). Face (1, 148)

DT FC FF

Expression (2, 296)

Table 2 Descriptive statistics of eye-tracking data (n = 149).

Face × expression (2, 296)

F

p

η2

F

p

η2

F

p

η2

38.746 3.530 35.711

0.000 0.062 0.000

0.207 0.023 0.194

6.485 53.562 1.000

0.002 0.000 0.369

0.042 0.266 0.007

17.378 29.831 5.778

0.000 0.000 0.003

0.105 0.168 0.038

DT, dwell time; FC, fixation counts; FF, first fixation location.

For DT and FC (Table 1), face had significant or marginal significant main effects, with infant faces (DT, M = 2821.492, SD = 46.133; FC, M = 7.005, SD = 0.124) having visual preference significantly higher than adult faces (DT, M = 2297.920, SD = 44.917; FC, M = 6.683, SD = 0.148). Both significant main effects of expression existed. For DT, smiling (M = 2561.065, SD = 17.480) and neutral expressions (M = 2568.029, SD = 17.532) were not significantly different, whereas a crying expression (M = 2550.023, SD = 18.024) was. For FC, all three expressions had significant differences (smiling M = 6.812, SD = 0.109; neutral M = 7.012, SD = 0.106; crying M = 6.708, SD = 0.107). Significant interactions between face and expression were also found. As for FF (Table 1), face had a significant main effect; FF on adult faces (M = 24.756, SD =0.137) was significantly higher than on infant faces (M = 23.141, SD = 0.136). Expression had no significant main effect, while a significant interaction between face and expression was found. Results indicated that women looked longer and fixated more significantly on infant faces than adult faces, while the first fixation was located on the adult's face more than the infant's face. These results are consistent with a previous research (Cárdenas et al., 2013). Thus, a special score was used to highlight infant face preference by subtracting adult face from infant face dwell time (here we refer to it as “special dwell time for infant faces,” SDT). Thus, positive scores mean longer viewing duration for infant faces and negative scores indicate longer viewing duration for adult faces. The same subtraction equation was used for fixation count (“special fixation counts on infant faces,” SFC) and first fixation location (“special first fixation location,” SFF). The descriptive statistics regarding eye-tracking data in different facial expressions are presented in Table 2.

Smiling

SDT SFC SFF

Neutral

Crying

M

SD

M

SD

M

SD

510.032 0.320 -2.410

1097.596 2.259 5.094

641.342 0.689 −0.790

1076.583 2.310 4.353

419.342 −0.044 −1.640

1006.205 1.994 4.640

SDT, special dwell time for infant faces; SFC, special fixation counts on infant faces; SFF, special first fixation location.

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no significant effect on SFF (Table 3); thus, no further analysis of the first fixation was conducted.

3.2. Random intercept multilevel regression Next, eye-tracking data were analyzed with random intercepts multilevel regression, with expressions (level 1) nested within gender roles (level 2). Multilevel models were estimated with Hierarchical Linear and Nonlinear Modeling software (using maximum likelihood estimation).

3.3. Linear regression analysis Linear regression analysis using SPSS 20 examined the unique contributions of gender roles in predicting the infant viewing bias. Because there was no significant interaction between gender roles and expressions, we combined three expressions into one index (i.e., MSDT, mixed special dwell time; MSFC, mixed special fixation counts) to highlight the effects of gender roles on viewing bias of infant faces. Linear regressions were performed between gender roles and the observed attentional bias. The results showed that masculine characteristics negatively predicted MSDT and MSFC significantly, whereas feminine characteristics didn't predict either MSDT or MSFC (Table 4).

3.2.1. Special dwell time for infant faces A baseline model without explanatory variables showed that 89.54% of the variance in SDT was explained by participants' gender roles. In the expression-level analysis, smiling and crying faces had a significant effect on dwell time compared to neutral faces. However, when compared with neutral expressions, participants showed less viewing duration for smiling and crying expressions (Table 3). A significant variation in the variance of the intercept (χ2 (148) = 4381.762, p b 0.001) indicates that individuals' gender roles may explain SDT. As expected, there was a significant negative effect for masculinity on viewing duration in the second step of the analysis, with no significant interaction between masculinity and expressions (Table 3). Participants with more masculine features tended to look more briefly at infant faces regardless of expressions. However, femininity did not have a significant effect on viewing duration toward infants.

4. Discussion In this study, we explored the influence of nulliparous women's gender roles on visual interest in different infants' facial expressions. Eye movements were measured in women through presentations of adult and infant faces. We verified that women had a general visual preference toward infant faces, indicating that Kindchenschema (Lorenz, 1943) has an obvious effect on women, even women without children. Furthermore, based on the hierarchical linear model, significant individual differences between women's visual attentional bias toward infants can be found, indicating that it is necessary to study the factors influencing these individual differences. Additionally, compared to adult facial expressions, women looked the longest and fixated the most on neutral infant facial expressions, followed by infant smiling and crying expressions. This result is consistent with our previous studies (Charles et al., 2013; Cheng, Zhang, Sun, Jia, & Na, 2015a; Ding et al., 2016; Jia et al., 2017; Li et al., 2016) that infant neutral facial expressions elicit powerful caregiving behavior. Why do neutral infant facial expressions receive more attentional bias? The possible reason may be that infant expressions change frequently; this seems to provide considerable information to the caregivers about infants' continuously changing conditions. The variations in infant facial expression can be regarded as an indicator of infants' current affective states and the possibility of having energetic interactions with them (Karraker & Stern, 1990; Wiesenfeld & Klorman, 1978). In this view, infant faces with expressions of smiling and crying are clear indicators of infants' current affective states, whereas neutral infant expression is more indefinite or vague; it cannot be explicitly interpreted as an infant's emotion presentation. Thus, it may require greater

3.2.2. Special fixation counts on infant faces Similarly, a baseline model demonstrated that 83.62% of the total variance in SFC was by participants' gender roles. Smiling and crying faces had significant effects on fixation counts in comparison with neutral faces in emotion-level analysis; however, participants had fewer fixation counts on smiling and crying expressions compared with neutral expressions (Table 3). The variation in the intercept variance was significant (χ2 (148) = 2881.464, p b 0.001). In gender role-level analysis, there was a significant effect for masculinity on fixation counts and no significant interaction between masculinity and expressions (Table 3). Masculinity negatively predicted fixation counts on any expressions on infant faces. At the same time, femininity did not significantly predict SFC. 3.2.3. Special first fixation location Only 22.56% of variance in SFF was by participants' gender roles. The emotion-level analysis indicated that the effects of smiling and crying faces versus neutral faces were significant or almost significant. Nevertheless, participants tended to look at adult faces rather than infant faces first, especially in smiling expressions (Table 3). There was still a significant variation in the intercept variance (χ2 (217) = 286.315, p b 0.001). However, the gender role-level analysis revealed that gender roles had

Table 3 Summary of a two-level random intercept multilevel model of special attentional bias for infant faces. Fixed effects

SDT

SFC

SFF

Estimate

SE

t

Estimate

SE

t

Estimate

SE

t

Level 1 Condition 1 (neutral) Condition 2 (smiling) Condition 3 (crying)

641.342 −131.310 −222.001

87.901 32.966 37.554

7.296⁎⁎⁎ −3.983⁎⁎⁎ −5.912⁎⁎⁎

0.690 −0.370 −0.733

0.189 0.082 0.100

3.653⁎⁎⁎ −4.508⁎⁎⁎ −7.305⁎⁎⁎

−0.792 −1.617 −0.852

0.355 0.488 0.460

−2.228⁎ −3.314⁎⁎⁎ −1.851+

Level 2 Masc Condition 2 × masculinity Condition 3 × masculinity Fem Condition 2 × femininity Condition 3 × femininity

−11.722 −0.647 1.230 8.513 0.297 0.987

4.903 2.326 2.389 6.616 3.114 3.635

−2.391⁎ −0.278 0.515 1.287 0.095 0.272

−0.030 −0.003 0.006 0.015 0.002 0.001

0.011 0.006 0.006 0.016 0.007 0.010

−2.794⁎ −0.542 0.963 0.963 0.213 0.095

0.006 −0.078 −0.016 −0.017 0.017 0.001

0.023 0.029 0.027 0.038 0.034 0.034

0.279 −2.714 −0.589 −0.458 0.505 0.028

SDT, special dwell time for infant faces; SFC, special fixation counts on infant faces; SFF, special first fixation location. ⁎ p b 0.05. ⁎⁎⁎ p b 0.001. + p = 0.06.

N. Ta et al. / Personality and Individual Differences 116 (2017) 109–114 Table 4 Regressions between gender roles and eye-tracking data (n = 149). MSDT (ΔR2 = 0.034)

Masculinity Femininity

MSFC (ΔR2 = 0.047)

β

t

p

β

t

p

−0.172 0.100

−2.083 1.217

0.039 0.225

−0.213 0.087

−2.607 1.064

0.010 0.289

MSDT, mixed special dwell time; MSFC, mixed special fixation counts.

cognitive processing and prolong focus time on neutral infant's faces. Karraker and Stern (1990) have concluded that independent of cuteness, infants' positive facial expressions elicited social approach by adults, while infants' negative facial expressions elicited avoidance. In our study, women had visual interest in smiling but not crying infants. Future studies should use various infant facial expressions to determine the reasons for different effects elicited by varying infant facial expressions. We believe that there are individual differences between women regarding their preferences toward infants, and gender roles play a stronger role in it. In this study, we got a result that partly validated our third hypothesis, that only masculinity had an effect on women's visual interest toward infants. However, femininity did not predict women's viewing bias toward infants. The possible reason for this conclusion is that previous studies have mainly used self-report or observational methods, which are vulnerable to social desirability and common method bias. Researchers found that because of societal expectations or social desirability, women were inclined to report enjoying childcare more than they actually do (Haas, 1992; Wilson, 2002). Therefore, the correlation between femininity and interest in infants or parenting motivation could be overestimated. Eye-tracking method, however, provides a more objective and accurate measure of visual interest toward infants, and may avoid common method biases that may occur with self-report or observational methods. Besides, as a fundamental cognitive ability, preference for infants is an inherent capacity for women. Even though women's femininity maintains this inherent bias, it may not lead to significant changes since this infant bias has already reached a high level. Atypical gender roles, however, followed by the opposite direction of evolutionary preference and social expectations, may have stronger negative-direction influence on women's individual differences in interest in infants. Thus, masculinity may produce more evident impacts on individuals' (even nulliparous women's) preference toward infants. In this study, we also explored whether there are interactions between gender roles and expressions. The result showed that masculinity did not interact with different expressions of infant faces; in other words, masculinity had a consistent negative effect on viewing preference toward infants regardless of expression. Similar results were shown by the two types of eye movements (SDT and SFC). In modern society, men and women play both paid labor and nurturing labor roles, and gender roles became increasingly interchangeable. Given this social context, the concept of gender roles is a fruitful topic to study considering the potential impact on future parenting behaviors. Modern women face more requirements and challenges in today's society, and this trend pushes them to equip themselves with more masculine features (Dimitrovsky et al., 1989). Atypical gender roles help women become more competent when dealing with social requirements and concurrently influences females' family and nurturing roles. Women with high masculinity alone are likely to pursue social and professional achievements but not want children and neglect family and nurturing responsibilities (Friedman & Weissbrod, 2005). From this viewpoint, the individual differences in and the effects of gender roles on parent-child relationships should be examined. Our study provides a novel finding that masculinity affects women's visual interest in infants and different infant facial expressions influence women's viewing bias, and this may illuminate individual differences in women's interest

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and nurturing motivations toward infants. Thus, future studies should further clarify these relationships by using participants at different points across the life span and by using multiple measures and diverse, advanced technology to get the complete picture of the dynamic relationship. Finally, limitations remain in this study. First, although we acquired a general internal difference of women's interest in infants, the data would have been more accurate and comprehensive if married women had been included as participants. Second, single frontal-view faces as stimuli differ from real life experiences, which may affect the reliability of the study. Third, facial expressions' influences were found, whereas the reasons for this influence require further study. Acknowledgments We want to express our gratitude toward all participants who agreed to sign up for the study. We would like to thank Editage [http://online.editage.cn/] for English language editing. 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