Avoidance of plant foods in infancy.

Expectations about plant edibility in 6-month-old infants (Rioux & Wertz)

“…The different pattern of findings across the Fruit and Leaf Conditions is in line with the literature showing that humans specialize in foraging and consuming the fruits, roots, and nuts of plants rather than the leaves (Cordain et al, 2000;Hardy & Kubiak-Martens, 2016;Henry et al, 2014;Ungar & Sponheimer, 2011). This is also convergent with recent findings showing that older infants engage in more social looking to adults when confronted with leaves compared to fruits (Rioux & Wertz, 2021), suggesting that infants view fruits and leaves differently in other contexts. Importantly, this finding suggests that it is not the green color of the whole plants alone that triggers differential edibility expectations, similar to other results showing that avoidance and social looking behaviors directed towards plants are not only due to their green color (e.g., Elsner & Wertz, 2019;Wertz & Wynn, 2014b;Włodarczyk et al, 2018).…”

“…Taking together, the findings from Experiments 1 and 2 demonstrate that preverbal infants without extensive experience with solid foods differentially expect whole plants to be food sources and suggest that these edibility inferences are more likely tied to fruits than leaves. These results demonstrate the robustness of the original findings with 6-month-olds from Wertz and Wynn (2014a), add to the growing literature highlighting the role of social learning in the development of food behaviors (for a recent review see DeJesus et al, 2018), and converge with research showing an interaction between the content of social information and how that content is learned (e.g., Barrett et al, 2012; extend to fruits and leaves presented on their own, albeit to a lesser degree (Rioux & Wertz, 2021), mirroring the present findings. Interestingly, this work has also shown that infants' avoidance of whole plants is attenuated for whole plants with fruits, compared to whole plants without fruits (Rioux & Wertz, 2021), while other visible plant parts (e.g., thorns) do not substantially affect infants' avoidance behaviors (Włodarczyk et al, 2018), suggesting that whole plants with fruits may have a special status for infants.…”

“…The stimuli in Experiment 2 were presented without any context and infants may simply not have always recognized that these were plant parts. Recent work suggests that infants can recognize fruits and leaves presented on their own (Rioux & Wertz, 2021), but in that study actual fruits and leaf bouquets were placed directly in front of infants, whereas in the current study they were shown only as part of a larger video display. Future studies can examine whether the results we observed in Experiment 2 originate from our stimuli being difficult to distinguish.…”

“…Twenty-nine individual trials (out of 240) were excluded from the analysis, either due to the live coder ending the trial too early (14 trials), infants not looking at the action during the trial (11), parental interference (1), and procedure error (3; see SI sections 1.3-1.5 for a detailed description of the coding procedure and exclusion criteria). At the end of the session, parents filled in two questionnaires related to their infant's (i) prior experience with plants (the Plant Experience questionnaire, Rioux & Wertz, 2021;Wertz & Wynn, 2014a;2014b), notably their experience of watching their parent eat fruit off a plant and (ii) familiarity with both dried apricots and plums (see SI section 1.7 for details of these questionnaires).…”

“…Therefore, we do not yet know whether it is necessary for infants to be confronted with a whole plant to make these kinds of inference, or if infants would make similar selective edibility inferences about subcomponents of plants (e.g., fruits and leaves) when they are presented separately. Recent work has shown that for other types of behaviors toward plants (i.e., an initial reluctance to touch; Wertz & Wynn, 2014b;Włodarczyk et al, 2018), infants show a similar, albeit attenuated, response to plant parts relative to whole leafy plants (Rioux & Wertz, 2021).…”