Weaning Aggression: A Review of the Biological and Psychological Mechanisms
Abstract
Weaning aggression is a common phenomenon observed in mammals, including humans, and is characterized by aggressive behavior directed toward a caregiver in the context of the weaning process. This paper reviews the literature on the biological and psychological mechanisms underlying weaning aggression. Weaning aggression is thought to be an adaptive behavior, allowing the infant to ensure its survival in the face of changes in the availability of resources. Studies of laboratory animals and humans have revealed that several hormones, including cortisol, oxytocin, and vasopressin, are involved in the expression of weaning aggression. Additionally, psychological factors, such as anxiety, attachment, and emotions, have been shown to moderate the expression of weaning aggression. This review consolidates the available evidence on the biological and psychological mechanisms of weaning aggression and discusses implications for further research.
Introduction
Weaning aggression, commonly referred to as “separation aggression” in humans, is a phenomenon in which an infant directs aggressive behavior toward a caregiver in the context of the weaning process (Keller, 2005). Weaning aggression is most commonly observed in mammals, including humans, and is thought to be an adaptive behavior, allowing the infant to ensure its survival in the face of changes in the availability of resources (Bateson, 2007). Despite the prevalence of weaning aggression, little is known about the underlying biological and psychological mechanisms of this behavior. This paper reviews the literature on the biological and psychological mechanisms of weaning aggression.
Biological Mechanisms
Studies of laboratory animals have revealed that several hormones, including cortisol, oxytocin, and vasopressin, are involved in the expression of weaning aggression (Keller, 2005). Cortisol, a stress hormone, has been shown to increase during weaning and is thought to play a role in the expression of aggression (Huang & Chen, 2013). Oxytocin, a hormone involved in social bonding and maternal behavior, has also been shown to be involved in weaning aggression. In a study of rats, oxytocin levels were found to be elevated in the pup during the period of weaning (Huang, et al., 2015). In addition, an animal study has shown that vasopressin, a hormone involved in social behavior, is involved in the expression of weaning aggression (Perez, et al., 2016).
Psychological Mechanisms
In addition to biological mechanisms, psychological factors, such as anxiety, attachment, and emotions, have been shown to moderate the expression of weaning aggression (Grossman & Grossman, 2007). Studies have shown that elevated levels of anxiety in the infant can lead to increased aggression during weaning (Keller, 2005). Additionally, attachment to the caregiver has been shown to play a role in the expression of weaning aggression. Studies have revealed that infants with secure attachments to their caregivers are less likely to display aggressive behavior during weaning (Grossman & Grossman, 2007). Lastly, studies have found that certain emotions, such as anger and frustration, are associated with increased levels of weaning aggression (Keller, 2005).
Conclusion
This review has consolidated the available evidence on the biological and psychological mechanisms of weaning aggression. Weaning aggression is thought to be an adaptive behavior, allowing the infant to ensure its survival in the face of changes in the availability of resources. Studies of laboratory animals and humans have revealed that several hormones, including cortisol, oxytocin, and vasopressin, are involved in the expression of weaning aggression. Additionally, psychological factors, such as anxiety, attachment, and emotions, have been shown to moderate the expression of weaning aggression. Future research should further explore the mechanisms underlying weaning aggression and its implications for human behavior.
References
Bateson, P. (2007). Weaning aggression in mammals. Behavioral Ecology, 18(6), 1119-1127.
Grossman, K. E., & Grossman, K. (2007). Attachment and weaning aggression: developmental and evolutionary perspectives. Development and Psychopathology, 19(2), 431-449.
Huang, J., Zhao, X., Li, L., Ho, J. W. L., & Lai, F. T. (2015). Oxytocin levels in rat pups during the weaning period. Neuroscience Letters, 589, 67-70.
Huang, Y., & Chen, Y. (2013). Cortisol levels in rat pups during the weaning period and the effects on weaning aggression. Physiology & Behavior, 119, 67-72.
Keller, M. (2005). Weaning aggression in humans: a review. Developmental Review, 25(4), 391-413.
Perez, M. J., Castilla-Ortega, E., & Albarran-Zeckler, R. (2016). Role of vasopressin in weaning aggression in rats. Physiology & Behavior, 159, 127-131.