In this target article, Tomasello tackles the internalized motivations that he believes drive the morality of a collective “we” that is foundational to our distinctly cooperative and moral species. He argues for a human-specialized feeling and cognitive understanding of obligation that is “coercive.” It drives us like a “stick” rather than a “carrot.” The emotions that surround it, such as guilt and shame, are reflective ones.
We agree that obligations and the emotions surrounding them are (1) understudied yet importantly linked to the prosocial, group-serving proclivities of our species, (2) early developing in children, and (3) from current evidence seemingly absent in our closest primate relatives. We also agree that child developmental and primate-comparative findings can be used to support evolutionary hypotheses. But we think Tomasello has overlooked a crucial place to examine evidence for the evolution and development of obligation. Specifically, he writes that obligative forces arise only between individuals who can hold one another mutually accountable: thus, human infants are excluded from obligatory “contracts.” No doubt mutual accountability is foundational to obligatory understandings. But, one-sided caregiver relationships may be precisely where the emotional and cognitive precursors to obligation have their evolutionary and ontogenetic starts.
In species that care for their young, there are few forces more emotionally “coercive” than an infant in danger. Even non-parents may see to their needs. For example, female ring-tailed lemurs permit infants who are not theirs to leap onto their backs when a raptor flies overhead (Gould Reference Gould1992), colobus monkey males clutch infants to their chests for safety when chimpanzees hunt them (Reddy, personal observations, 2019), and teenaged chimpanzees may whimper and search for their orphaned younger siblings if they fall behind the group, risking becoming lost themselves (Reddy & Mitani Reference Reddy and Mitani2019).
The preceding behaviors do not necessarily reveal the sort of action and feelings that Tomasello emphasizes as “mature” signs of obligation. No current evidence exists, for example, that nonhuman primates of any age ruminate upon their guilt if their vulnerable charges (or their “mutually accountable” friends) are killed when they could have acted (despite exhibiting grief-like symptoms upon the deaths of close companions, e.g., Engh et al. Reference Engh, Beehner, Bergman, Whitten, Hoffman, Seyfarth and Cheney2006). Yet, the swiftness with which they act protectively, and the visible distress they show when others are in danger indicate the probability of coercive emotions that prompt these actions – emotions that could provide evolutionary and developmental foundations to a more reflective emotion like guilt and the actions it prompts (e.g., apology).
Moreover, although young human infants (and nonhuman primates) may not understand “terms” of obligation in full force, they do appear to have expectations about their social relationships and show distinct responses in situations when those expectations are violated. For example, when adults do not smile at them in the classic “still face” paradigm, human infants cry. From 8–10 months of age they also show distress and act proactively if they witness moral violations or unfairness or experience it themselves (Hamlin Reference Hamlin2013).
When their mothers attempt to wean them, young chimpanzees throw “tantrums,” screaming, wailing, and occasionally hitting and biting their mothers. When young humans don't get their way, they throw tantrums too, as characteristic of the “terrible twos.” The distress shown by infants of both species toward their caregivers may reflect their displeasure at the experience alone (e.g., hunger) and their knowledge that their caregiver will tolerate such an outburst. However, tantrums may also reflect a proto-form of emotional “outrage” that infants have when their caregivers behave differently from “usual” within their relationship. How caregivers respond in these situations is further interesting. Chimpanzee mothers attempt to ignore their infants’ tantrums, but occasionally appear to become distressed and frustrated themselves: when their infants hit them repeatedly on the back, for example, mothers may turn around, grab infants by the arms and shake them. Critically, however, mothers often then swiftly pull infants into tight embraces (Van Lawick-Goodall Reference Van Lawick-Goodall1968; Reddy, unpublished data, 2019). The human parallels are obvious: parents often report guilt about how angry they become in the face of child tantrums. We do not suggest that anything like “guilt” and “apology” motivate these “reconciliatory” actions in chimpanzees (cf. de Waal & van Roosmalen Reference de Waal and van Roosmalen1979), but chimpanzee mothers do follow their aggressive actions with a comforting one that ameliorates their infants’ distress.
Furthermore, the emotions and expectations human infants and non-human primates have about their own caregiving relationships suggest that it is some quality of social bonds themselves, not collaborative capability or willingness of the individuals alone, that provide the basis for proto-obligatory “terms.” Consider one of Tomasello's own examples: Chimpanzees do not share meat with all others who attempted to hunt, but they do share with and beg from friends who are their allies over others (Mitani et al. Reference Mitani, Merriwether and Zhang2000). They continue to share meat when one of the friends has grown old and weak and is no longer a competent collaborative partner. Furthermore, at older ages (at least) both nonhuman primates and human children show emotion and form social expectations not only about their own relationships, but also about the relationships of third parties (e.g., Cheney & Seyfarth Reference Cheney and Seyfarth1980; Rhodes & Wellman Reference Rhodes and Wellman2017).
Essentially, we propose that proto-obligatory motivations and expectations may begin with, “X helps me because X is my mother/I must help X because X is my offspring.” As individuals in group-living species grow up, this understanding may develop into “because X is my friend” and “because X is Y's daughter.” In our species, children (from at least age 3 onward) may develop obligatory feelings and understanding as Tomasello describes of a more self-reflective nature: “I must help X.” It is nearly impossible to disentangle the preceding motivations in natural contexts, suggesting the need for work that will integrate “natural” observations of relationships with experimental studies. For children, how and when do actions and feelings of obligation arise when the other person is a caregiver (e.g., mother)? For chimpanzees and children, students of Tomasello have already begun related work, finding that friendships influence helping propensities in both chimpanzees and human children (Engelmann et al. Reference Engelmann, Haux and Herrmann2019).
In this target article, Tomasello tackles the internalized motivations that he believes drive the morality of a collective “we” that is foundational to our distinctly cooperative and moral species. He argues for a human-specialized feeling and cognitive understanding of obligation that is “coercive.” It drives us like a “stick” rather than a “carrot.” The emotions that surround it, such as guilt and shame, are reflective ones.
We agree that obligations and the emotions surrounding them are (1) understudied yet importantly linked to the prosocial, group-serving proclivities of our species, (2) early developing in children, and (3) from current evidence seemingly absent in our closest primate relatives. We also agree that child developmental and primate-comparative findings can be used to support evolutionary hypotheses. But we think Tomasello has overlooked a crucial place to examine evidence for the evolution and development of obligation. Specifically, he writes that obligative forces arise only between individuals who can hold one another mutually accountable: thus, human infants are excluded from obligatory “contracts.” No doubt mutual accountability is foundational to obligatory understandings. But, one-sided caregiver relationships may be precisely where the emotional and cognitive precursors to obligation have their evolutionary and ontogenetic starts.
In species that care for their young, there are few forces more emotionally “coercive” than an infant in danger. Even non-parents may see to their needs. For example, female ring-tailed lemurs permit infants who are not theirs to leap onto their backs when a raptor flies overhead (Gould Reference Gould1992), colobus monkey males clutch infants to their chests for safety when chimpanzees hunt them (Reddy, personal observations, 2019), and teenaged chimpanzees may whimper and search for their orphaned younger siblings if they fall behind the group, risking becoming lost themselves (Reddy & Mitani Reference Reddy and Mitani2019).
The preceding behaviors do not necessarily reveal the sort of action and feelings that Tomasello emphasizes as “mature” signs of obligation. No current evidence exists, for example, that nonhuman primates of any age ruminate upon their guilt if their vulnerable charges (or their “mutually accountable” friends) are killed when they could have acted (despite exhibiting grief-like symptoms upon the deaths of close companions, e.g., Engh et al. Reference Engh, Beehner, Bergman, Whitten, Hoffman, Seyfarth and Cheney2006). Yet, the swiftness with which they act protectively, and the visible distress they show when others are in danger indicate the probability of coercive emotions that prompt these actions – emotions that could provide evolutionary and developmental foundations to a more reflective emotion like guilt and the actions it prompts (e.g., apology).
Moreover, although young human infants (and nonhuman primates) may not understand “terms” of obligation in full force, they do appear to have expectations about their social relationships and show distinct responses in situations when those expectations are violated. For example, when adults do not smile at them in the classic “still face” paradigm, human infants cry. From 8–10 months of age they also show distress and act proactively if they witness moral violations or unfairness or experience it themselves (Hamlin Reference Hamlin2013).
When their mothers attempt to wean them, young chimpanzees throw “tantrums,” screaming, wailing, and occasionally hitting and biting their mothers. When young humans don't get their way, they throw tantrums too, as characteristic of the “terrible twos.” The distress shown by infants of both species toward their caregivers may reflect their displeasure at the experience alone (e.g., hunger) and their knowledge that their caregiver will tolerate such an outburst. However, tantrums may also reflect a proto-form of emotional “outrage” that infants have when their caregivers behave differently from “usual” within their relationship. How caregivers respond in these situations is further interesting. Chimpanzee mothers attempt to ignore their infants’ tantrums, but occasionally appear to become distressed and frustrated themselves: when their infants hit them repeatedly on the back, for example, mothers may turn around, grab infants by the arms and shake them. Critically, however, mothers often then swiftly pull infants into tight embraces (Van Lawick-Goodall Reference Van Lawick-Goodall1968; Reddy, unpublished data, 2019). The human parallels are obvious: parents often report guilt about how angry they become in the face of child tantrums. We do not suggest that anything like “guilt” and “apology” motivate these “reconciliatory” actions in chimpanzees (cf. de Waal & van Roosmalen Reference de Waal and van Roosmalen1979), but chimpanzee mothers do follow their aggressive actions with a comforting one that ameliorates their infants’ distress.
Furthermore, the emotions and expectations human infants and non-human primates have about their own caregiving relationships suggest that it is some quality of social bonds themselves, not collaborative capability or willingness of the individuals alone, that provide the basis for proto-obligatory “terms.” Consider one of Tomasello's own examples: Chimpanzees do not share meat with all others who attempted to hunt, but they do share with and beg from friends who are their allies over others (Mitani et al. Reference Mitani, Merriwether and Zhang2000). They continue to share meat when one of the friends has grown old and weak and is no longer a competent collaborative partner. Furthermore, at older ages (at least) both nonhuman primates and human children show emotion and form social expectations not only about their own relationships, but also about the relationships of third parties (e.g., Cheney & Seyfarth Reference Cheney and Seyfarth1980; Rhodes & Wellman Reference Rhodes and Wellman2017).
Essentially, we propose that proto-obligatory motivations and expectations may begin with, “X helps me because X is my mother/I must help X because X is my offspring.” As individuals in group-living species grow up, this understanding may develop into “because X is my friend” and “because X is Y's daughter.” In our species, children (from at least age 3 onward) may develop obligatory feelings and understanding as Tomasello describes of a more self-reflective nature: “I must help X.” It is nearly impossible to disentangle the preceding motivations in natural contexts, suggesting the need for work that will integrate “natural” observations of relationships with experimental studies. For children, how and when do actions and feelings of obligation arise when the other person is a caregiver (e.g., mother)? For chimpanzees and children, students of Tomasello have already begun related work, finding that friendships influence helping propensities in both chimpanzees and human children (Engelmann et al. Reference Engelmann, Haux and Herrmann2019).