Affection exchange theory (AET) was introduced in 2001 by Kory Floyd, who is currently a professor of communication at the University of Arizona.
The paper was titled "Elements of an affection exchange theory: Socioevolutionary paradigm for understanding affectionate communication".
Many studies had been done up to this point (including some of Floyd’s own research pieces) regarding affection and its involvement in interpersonal relationships, particularly between romantic partners and between parents and their children.
According to Floyd (2005), “given the breadth of relational experience in which affectionate communication is common, it is little wonder that it plays such an important role in individual well-being (p. 286).
Another facet of AET was that the exchange of affection served as an indicator to another individual that he or she was a good prospect for parenthood (Floyd, 2001).
Affection exchange is a basic human need and ability, as an innate and stable experience across different historical and social conditions(Floyd, 2006, p.161).
People have different preferences about the behaviors of affection exchange, such as the skin contacts, so there is not a general standard of affectionate expressions.
For example, Schwartz and Russek (1998) found that college students would experience less physical and psychological distress with the love and caring showed by their parents, while Shuntich, Loh, and Katz (1998) found “received affection to be negatively related to alcohol abuse and physical aggression toward family members”.
Canary et al. (2008) also note, “In AET, affection is thought of as an adaptive behavior that is helpful to long-term human survival by promoting bonding and increased access to resources.
A great deal of this theory’s premise can be linked back to Darwin’s principles that state that reproductivity and survival are what serve as humans’ most fundamental motivations.
With these ideas in mind, it follows that humans would do everything they could to make sure that their genes carry on, even if that means (intentionally or unintentionally) showing more affection to a child that the parent knew was more likely to reproduce.
In general, AET presents the idea that parents are more likely to show affection to their children who are most likely to pass on the family genes.
In fact, McEwan (1999) estimated that “stress and stress-related disorders take an annual economic toll of nearly $200 billion in the United States alone”.
This research supports the idea that "communicating affection following exposure to an acute stressor accelerates adrenocortical recovery" (Floyd et al., 2007, p130).
“Alexithymia is a personality trait characterized by a relative inability to understand, process, and describe emotions” (Hesse & Floyd, 2008, p.796).
From related studies based on Affection exchange theory, grandchildren received more love and esteem from grandmothers and more humor and memories from grandfathers(Mansson, 2013).