“Parental” responses to human infants (and puppy dogs): Evidence that the perception of eyes is especially influential, but eye contact is not. Brandon M. Woo, Mark Schaller. PLoS, May 6, 2020. https://doi.org/10.1371/journal.pone.0232059
Abstract: The present investigation tests: (i) whether the perception of an human infant’s eyes, relative to other facial features, especially strongly elicits “parental” responses (e.g., appraisals of cuteness and vulnerability); (ii) if, so, whether effects of the visual perception of eyes may be partially attributable to eye contact; (iii) whether the perception of non-human animals’ (puppy dogs’) eyes also especially strongly influence appraisals of their cuteness and vulnerability; and (iv) whether individual differences in caregiving motives moderate effects. Results from 5 experiments (total N = 1458 parents and non-parents) provided empirical evidence to evaluate these hypotheses: Appraisals of human infants were influenced especially strongly by the visual perception of human infants’ eyes (compared to other facial features); these effects do not appear to be attributable to eye contact; the visual perception of eyes influenced appraisals of puppy dogs, but not exactly in the same way that it influenced appraisals of human infants; and there was no consistent evidence of moderation by individual differences in caregiving motives. These results make novel contributions to several psychological literatures, including literatures on the motivational psychology of parental care and on person perception.
General discussion
At the outset of this article we identified four main research questions, and the results obtained from five experiments provide answers to these questions. The following paragraphs provide a summary of the empirical answers to those questions, and their implications.
Are “parental” appraisals of young children influenced especially strongly by the visual perception of their eyes? The answer—obtained across 3 experiments—appears to be yes. Compared to control conditions (that provided perceptual access to other babyish features instead), when perceivers had perceptual access to human infants’ eyes, they perceived those infants to be cuter. There was also some evidence—which was less consistent across studies—that they also perceived those infants to be more vulnerable and in need of protection. Of course, it will be useful for future work to further replicate this result, ideally with different stimuli, to assure that these effects are not idiosyncratic to the specific stimuli employed in Experiments 1–3. It would also be useful to conduct replications that include additional control conditions too. Although previous research has linked appraisals of cuteness to the physical dimensions of eyes and other babyish features [
11,
13], the present findings reveal that, even compared to other facial babyish features, eyes play an outsized role in influencing the kinds of appraisals that promote caregiving responses to young children.
Is this effect attributable to eye contact? Results from 2 additional experiments indicate that the answer is no—or, at least, these results provided no evidence to compel a more affirmative answer. These null results cannot easily be attributed to floor or ceiling effects (results summarized in Tables
4 and
5 reveal ample variability on the variables of interest), nor to a failure of the eye gaze manipulation (as indicated by results on a manipulation check). These null results are interesting, given that eye contact does amplify appraisals and judgments in other domains of person perception [
23–
24,
32,
34]. It remains unclear why no analogous effect emerged in this particular domain. Regardless, if indeed human infants’ eyes are an especially influential feature within the broader set of babyish features (as indicated by the results of Experiments 1–3), we suspect that is not because of what those eyes look at, but is instead because of what those eyes look like. The particular appearance of a person’s eyes is instrumental in conveying specific kinds of information that are relevant to parental caregiving, such as fatigue and sickness [
35,
36]. Adults might be especially vigilant for these kinds of clues in the faces of preverbal children, who lack the linguistic capability to communicate their needs.
Do the visual perception of eyes and eye contact influence appraisals of non-human animals? Our experiments focused on puppy dogs and—consistent with other research documenting both similarities and differences in adults’ responses to children and to dogs [
37]—produced an answer that is not easily boiled down to a simple yes or no. Two experiments produced evidence that “parental” appraisals of puppy dogs are influenced especially strongly by the perception of puppy dogs’ eyes. But this effect was limited to appraisals of puppy dogs’ vulnerability and need for protection; in contrast to the positive effect of eye-visibility on appraisals of human infants’ cuteness, there was no analogous effect on appraisals of puppy dogs’ cuteness. The similar effects (on appraisals of vulnerability and need for protection) may reflect an overgeneralization effect of the same sort that leads people to judge baby-faced adults to be less capable than mature-faced adults [
27]. The different effects (on appraisals of cuteness) might simply reflect idiosyncratic differences in the small samples of stimuli that were used in these studies; therefore, before drawing any confident conclusions based on these differences, it will be important for future studies to determine whether these differences also emerge when using additional sets of stimuli that, ideally, might be more representative of the entire populations of human infants and puppy dogs. If indeed these differences do replicate in future studies, they might plausibly reflect the functional different relationships that adults have with house pets [
38–
39] and with children. The former is primarily associated with caregiving behaviors that help pets to survive; whereas the latter is associated with many additional forms of caregiving behavior that help children not merely to survive but also to thrive (e.g., to succeed in academic pursuits and social relationships). Subjective appraisals of cuteness may tacitly connote potential to thrive and may elicit behavioral inclinations accordingly [
20], and so may be more functionally relevant to adults’ relationships with children than to their relationships with dogs.
Are these effects moderated by individual differences in the protective and nurturant responses that characterize the parental care motivational system? Again, the results cannot compel a simple yes or no answer. Four of the 5 experiments yielded some evidence that these individual differences (assessed by the PCAT questionnaire) may moderate effects of eye visibility and/or eye contact; but the specific effects differed, and none of these specific moderating effects replicated across multiple studies.
Further analyses of PCAT scores revealed additional findings that—although ancillary to the four main research questions identified above—did replicate across studies and may have implications for understanding differences in adults’ responses to human infants and puppy dogs. These findings pertained to the unique predictive utility of the “protection” and “nurturance” subscales of the PCAT questionnaire. In experiments that employed photographs as stimuli (but not in experiments that employed cartoons as stimuli), individual differences in parental protectiveness more strongly predicted appraisals of puppy dogs than appraisals of human infants, whereas individual differences in parental nurturance more strongly predicted appraisals of human infants than appraisals of puppy dogs. These different patterns of association—like some of the other effects summarized above—likely reflect differences in the functional relationships that people typically have with pets and children. These novel findings extend previous results documenting different implications associated with motivational inclinations toward parental protectiveness and nurturance [
30], and highlight the utility of conceptually distinguishing between—and measuring—these two underlying facets of the parental care motivational system.
Collectively, these findings contribute to the psychological literature attesting to the importance of eyes in the domain of person perception and social inference [
14]. In particular, these results provide evidence that the perception of eyes is especially influential—even more influential than other facial features—in eliciting prototypically “parental” appraisals of young children. The dependent measures in these studies were limited to appraisals (e.g., subjective rating of cuteness and vulnerability) and, in future research, it would be informative to assess whether similar effects might be obtained on additional responses that may be associated with these appraisals (e.g., visual attention) and on actual caregiving behaviors (including both protective and nurturant behaviors). Additional applications to care-giving behavior might be worth exploring too—such as the implied possibility that people who are generally more attentive to other’s eyes might generally perceive children to be cuter and, consequently, to respond to children in a more caring way.
Additional results indicated that the perception of eyes may also be especially influential in eliciting specific kinds of appraisals of puppy dogs too, and these findings too might be fruitfully followed up in studies that focus on other kinds of outcomes. For instance, people find baby animals—compared to adult animals—to be less appetizing as sources of meat [
40]. Might the size of this effect depend on the extent to which those animal’s eyes are perceptible? A different line of research reveals that the presence of dogs and other house pets can reduce humans’ experience of stress [
41]. Might this stress-buffering effect also be moderated by visual access to those animals’ eyes? More generally, if indeed eyes have an outsized effect on “parental” responses to human infants and puppy dogs, there are a wide range of potential implications that may merit closer attention.
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