Smiling is one of the easiest nonverbal ways we communicate positive feelings toward one another. In general, prior studies have shown that girls and women tend to smile more than boys and men during their social interactions. In a new study from the Center for Autism Research (CAR) at Children’s Hospital of Philadelphia (CHOP), researchers found that this also extends to autistic youth.
The findings, recently published in the journal Autism, further emphasize the sex-based differences in social-emotional behavior that exist in autism. Understanding these differences will help minimize the risk of females being misdiagnosed and misunderstood.
Generally speaking, societal expectations for social-emotional behavior differ across sexes. However, the diagnostic definitions of autism do not account for these differences. Traditional models for diagnosing autism were based mainly on boys, given that autism has long been considered to have a male-skewed prevalence rate. CAR has been looking for novel ways to account for differences in behavior among autistic males and females, as many girls and women who are undiagnosed or misdiagnosed do not receive supports and interventions that may be appropriate for meeting their unique needs.
“Smiling is one social cue that is associated with particularly strong gender biases. Women tend to be socialized to be more emotionally expressive, especially with respect to warm behavior that facilitates positive interaction. Thus, as children age, girls tend to smile more than boys,” said study first author Casey Zampella, PhD, a psychologist and scientist with the Department of Child and Adolescent Psychiatry and Behavioral Sciences and a core investigator at CAR at CHOP. “We have historically lacked methods for characterizing facial expressions that are both easily integrated into natural social contexts and sufficiently precise to capture variation across sexes and genders within the autism spectrum, leaving it unclear whether this population trend is also true for autistic females.”
In this study, Zampella and colleagues used computer vision, an automated video analysis approach, to examine whether autistic males and females exhibit different smiling profiles during a conversation with an unfamiliar person. To help overcome long-standing vague clinical descriptions of “atypicality” or “lower quality” in autistic people’s facial expressions, the use of computer vision allows for quantification of specific components of expressions and how they unfold over time, providing researchers with more objective measures of smiling.
In total, videos of 60 autistic (20 female) and 67 neurotypical (25 female) youth were analyzed with computer vision to examine smiling during a brief, unstructured interaction with an unfamiliar social partner. Effects of sex and autism diagnosis were examined on factors such as degree of smiling, smile quality, changes in smiling and the impact of smiling on broader interaction quality.
The study showed that sex differences in smiling persisted across autistic and neurotypical groups, in that females smiled more than males, and their smiles were more prototypical, or more likely to use the regions of the face that move during a standard smile. Autistic youth smiled less as well as less prototypically than neurotypical youth. In autistic youth, the association between smile activity and interaction quality was more pronounced in males than females, though not statistically significant in either group.
“This study has important implications for how we think about autistic traits in the context of gendered societal norms,” Zampella said. “Being autistic does not eliminate girls’ and women’s unique social propensities, and to best support autistic females, we need to be able to account for these different patterns of social-emotional behaviors. An important first step is a concerted effort to increase female representation in autism research and to use study designs that compare autistic females’ behavior to the most relevant comparison group – neurotypical females, rather than autistic or neurotypical males.”
“The Center for Autism Research continues to be committed to increasing understanding of how to best support all autistic people, by improving understanding of how sex, gender, race, ethnicity, age, and other demographic and sociocultural factors may contribute to key differences in how autism presents itself,” said senior study author John Herrington, PhD, a Psychologist in the Department of Child and Adolescent Psychiatry and Behavioral Sciences and Co-Director of the Developmental Neuroimaging Program at CAR at CHOP.
This work was supported by the National Institute of Mental Health grants R01MH125958 and R01MH118327 and the Eagles Autism Foundation.
Zampella et al, “‘You should smile more’: Population-level sex differences in smiling also exist in autistic people.” Autism. Online November 19, 2024. DOI: 10.1177/13623613241301113.
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Smiling is one of the easiest nonverbal ways we communicate positive feelings toward one another. In general, prior studies have shown that girls and women tend to smile more than boys and men during their social interactions. In a new study from the Center for Autism Research (CAR) at Children’s Hospital of Philadelphia (CHOP), researchers found that this also extends to autistic youth.
The findings, recently published in the journal Autism, further emphasize the sex-based differences in social-emotional behavior that exist in autism. Understanding these differences will help minimize the risk of females being misdiagnosed and misunderstood.
Generally speaking, societal expectations for social-emotional behavior differ across sexes. However, the diagnostic definitions of autism do not account for these differences. Traditional models for diagnosing autism were based mainly on boys, given that autism has long been considered to have a male-skewed prevalence rate. CAR has been looking for novel ways to account for differences in behavior among autistic males and females, as many girls and women who are undiagnosed or misdiagnosed do not receive supports and interventions that may be appropriate for meeting their unique needs.
“Smiling is one social cue that is associated with particularly strong gender biases. Women tend to be socialized to be more emotionally expressive, especially with respect to warm behavior that facilitates positive interaction. Thus, as children age, girls tend to smile more than boys,” said study first author Casey Zampella, PhD, a psychologist and scientist with the Department of Child and Adolescent Psychiatry and Behavioral Sciences and a core investigator at CAR at CHOP. “We have historically lacked methods for characterizing facial expressions that are both easily integrated into natural social contexts and sufficiently precise to capture variation across sexes and genders within the autism spectrum, leaving it unclear whether this population trend is also true for autistic females.”
In this study, Zampella and colleagues used computer vision, an automated video analysis approach, to examine whether autistic males and females exhibit different smiling profiles during a conversation with an unfamiliar person. To help overcome long-standing vague clinical descriptions of “atypicality” or “lower quality” in autistic people’s facial expressions, the use of computer vision allows for quantification of specific components of expressions and how they unfold over time, providing researchers with more objective measures of smiling.
In total, videos of 60 autistic (20 female) and 67 neurotypical (25 female) youth were analyzed with computer vision to examine smiling during a brief, unstructured interaction with an unfamiliar social partner. Effects of sex and autism diagnosis were examined on factors such as degree of smiling, smile quality, changes in smiling and the impact of smiling on broader interaction quality.
The study showed that sex differences in smiling persisted across autistic and neurotypical groups, in that females smiled more than males, and their smiles were more prototypical, or more likely to use the regions of the face that move during a standard smile. Autistic youth smiled less as well as less prototypically than neurotypical youth. In autistic youth, the association between smile activity and interaction quality was more pronounced in males than females, though not statistically significant in either group.
“This study has important implications for how we think about autistic traits in the context of gendered societal norms,” Zampella said. “Being autistic does not eliminate girls’ and women’s unique social propensities, and to best support autistic females, we need to be able to account for these different patterns of social-emotional behaviors. An important first step is a concerted effort to increase female representation in autism research and to use study designs that compare autistic females’ behavior to the most relevant comparison group – neurotypical females, rather than autistic or neurotypical males.”
“The Center for Autism Research continues to be committed to increasing understanding of how to best support all autistic people, by improving understanding of how sex, gender, race, ethnicity, age, and other demographic and sociocultural factors may contribute to key differences in how autism presents itself,” said senior study author John Herrington, PhD, a Psychologist in the Department of Child and Adolescent Psychiatry and Behavioral Sciences and Co-Director of the Developmental Neuroimaging Program at CAR at CHOP.
This work was supported by the National Institute of Mental Health grants R01MH125958 and R01MH118327 and the Eagles Autism Foundation.
Zampella et al, “‘You should smile more’: Population-level sex differences in smiling also exist in autistic people.” Autism. Online November 19, 2024. DOI: 10.1177/13623613241301113.
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