In their target article, Anselme & Güntürkün posit that “incentive hope” serves as an evolutionarily shaped motivational mechanism that increases animals’ foraging effort and food hoarding as insurance against starvation, especially in environments where food is scarce. The authors further suggest that the incentive hope hypothesis may be useful in explaining such human-related phenomena as addiction, gambling, and obesity. However, is incentive hope hypothesis alone able to explain human food-wasting behaviors? We posit that although it seems to be doing so effectively in industrialized societies, the incentive hope hypothesis should be complemented by ecological and cultural characteristics, such as mobility, animal domestication, and behavior visibility, to effectively explain food wasting in traditional societies.

Food wasting is a global problem that contributes to food crises (World Economic Forum 2016) and influences climate change (Vermeulen et al. Reference Vermeulen, Campbell and Ingram2012), deforestation (Houghton Reference Houghton2012), and water shortages (Chapagain & James Reference Chapagain and James2011). Although in many countries, food wasting is conditioned by specific factors, no overarching theory is available that allows prediction of future patterns of food wasting among human populations. The incentive hope hypothesis may serve as a promising starting point for such theorizing.

According to the incentive hope hypothesis, human populations living in environments where food availability is predictable exhibit fewer behaviors associated with food hoarding. That should lead to a larger amount of food being wasted. Yet, although the incentive hope hypothesis might fit the patterns observed in industrialized societies (Secondi et al. Reference Secondi, Principato and Laureti2015), it is not certain in the case of traditional societies. In industrialized societies, food wasting is associated primarily with the lack of peoples’ behaviors aimed at utilizing the surplus of food (Quested et al. Reference Quested, Marsh, Stunell and Parry2013). On the contrary, food wasting hardly ever takes place in traditional societies. Let's consider two examples.

The population of the Hadza hunter-gatherers from Tanzania is exposed to unpredictable access to food. Hadza foraging methods are quite representative of human evolutionary past: Women spend each day collecting wild plants, and men, hunting. In doing so, both men and women cover very long distances (Blurton-Jones Reference Blurton-Jones2016). After they make use of the surrounding natural resources, they move their camps to locations where food is more abundant. The incentive hope hypothesis predicts that the Hadza hoard food, yet it is not the case (Marlowe Reference Marlowe2010). The Hadza do not store their food and do not have any hoarding methods because of their mobility. But they also do not waste the surplus of their food – they share it with the camp members. When a Hadza man hunts down a large animal, instead of leaving the surplus of meat for wild animals, he shares the food with other Hadza. This cultural norm works reciprocally, and the same hunter can expect other hunters to share their surplus with him (Marlowe Reference Marlowe and Alvard2004). Prevalent food-sharing behaviors among the Hadza minimize the effects of food unpredictability. Thus, Hadza mobility prevented the development of food-hoarding methods and resulted in a cultural norm of food sharing.

Not only did hunter-gatherers develop cultural adaptations that minimize food wasting, but recent study (Misiak et al. Reference Misiak, Butovskaya and Sorokowski2018) reported that two traditional populations – the Maasai from Tanzania (Endulen) and the Yali from West Papua – developed strong moral disapproval for food wasting. It serves as a cultural adaptation that motivates individuals to not waste the surplus of food. Both populations do not use any hoarding methods and do not deposit high levels of fat reserve. The Maasai of Endulen are seminomadic pastoralists, and the lack of hoarding behavior among this population stems from their mobility, similarly to the Hadza. The Yali, however, are horticulturalists, yet they do not use any methods of food hoarding either. The Yali do not waste the surplus of food: Instead, they feed the pigs and dogs – the only domesticated species in this population. Although feeding the stock and dogs is not a method of hoarding literally, it minimizes food unpredictability through raising of pigs for pork. Furthermore, the Yali use dogs for hunting, thus increasing their hunting outcome.

Except for mobility and animal domestication, another factor increases the prevalence of behaviors that minimize food wasting: visibility. In industrialized societies, food-wasting behaviors are far less visible than in traditional societies (Quested et al. Reference Quested, Marsh, Stunell and Parry2013). Therefore, social norms aimed at influencing the management of food surpluses are not likely to prevent people from wasting food. High visibility of food-wasting behavior among traditional populations could reinforce the development of cultural norms.

The incentive hope hypothesis offers an attractive framework for understanding animal foraging behavior, and in doing so, it provides an interesting explanation for human-related phenomena. It also has the potential to explain and predict food wasting in human populations. That being said, we believe that the incentive hope hypothesis would benefit from accounting for such ecological characteristics as mobility, animal domestication, and behavior visibility, which informed cultural adaptations like food sharing and harsh moral judgments of food wasting. Enriched by moderating ecological factors, the incentive hope hypothesis could and should be examined in such traditional populations as Hadza; they form real-life cases that allow for testing the mathematical models presented in the target article.