A growing body of research is demonstrating that human intuitions often align with the various statutes, codes, and judicial decisions that constitute law (e.g., Cosmides & Tooby, Reference Cosmides, Tooby, Gigerenzer and Engel2006; Jones, Reference Jones2001; Patrick & Lieberman, Reference Patrick and Lieberman2017; Patrick & Lieberman, Reference Patrick, Lieberman, Strohminger and Kumar2018; Robinson, Kurzban, & Jones, Reference Robinson, Kurzban and Jones2007; Williams & Patrick, Reference Williams, Patrick, Al-Shawaf and Shackelfordin press). This effect has been demonstrated even where the person's intuitions and the laws in question originate from completely different cultures and time periods, suggesting that it is not the laws that are shaping the intuitions of the populace, but rather that evolved species-wide aspects of cognition are, and have been, shaping the law (Lieberman & Patrick, Reference Lieberman and Patrick2018; Sznycer & Patrick, Reference Sznycer and Patrick2020).

Though much of the research in this area has focused on the link between moral judgments and criminal law, many of the intuitions humans have regarding possession, ownership, and trade also have clear legal analogs in the law of property (Stake, Reference Stake2004). For example, the intuition that prior possession strengthens a claim of ownership is embodied in the long-standing legal doctrine of first possession, which grants ownership over a previously unowned resource – a hunted fox; a patent – to the first in time to possess it (e.g., Pierson v. Post, 1805). Likewise, the intuition that labor and investment in property can supersede first possession in claims for ownership is reflected in the legal concept of accession, which grants ownership to mistaken improvers of personal property (e.g., Wetherbee v. Green, 1871).

Boyer's minimalist model of ownership psychology – which purports to explain ownership intuitions in terms of an interaction between a resource-competition system and cooperation-maintenance system – goes further than existing cognitive models in its depth of computational description. As a result, it also offers more specific predictions regarding ownership intuitions: Namely, that they balance the perceived strength of someone's hold on a piece of property with indexes of any cooperative benefits that individuals might confer (via future sharing, trade, exchange, collective action, etc.).

In turn, these more specific predictions can be checked against what humans do in their actual rules governing property. If we assume that minds make societies, then we should expect, ceteris paribus, for these specific parameters of ownership psychology to be reflected in property law and other laws regulating ownership (Boyer, Reference Boyer2018). Although a systematic review is not feasible for a commentary of this length, early returns look promising. In certain instances, the rules not only match up in principle, but the elements of laws often align closely with the specific parameters of the proposed cognitive adaptation.

Consider the example of squatters. Under Boyer's model, our evaluations of squatters who occupy someone else's property trigger intuitions that balance the relationship between squatters and their property with any cooperative expectations we might register toward the landowner or squatter. The result is not a bright line intuition (landowner always wins) but rather a varying set of context-specific intuitions that balance, among other things, how long the squatters have squatted, whether the squatters improve the property, and whether the landowner has been tolerant of the squatter or attempted to protect the property from squatting.

The law carves along many of the same joints. The doctrine of adverse possession establishes that individuals can acquire ownership of another's real estate in cases where they can show that they have occupied the property (1) openly, (2) without the owner's permission, (3) exclusively, and (4) continuously for a statutorily determined number of years, all without the landowner taking measures to evict the squatter or assert their property rights (Powell, Reference Powell1949). For example, courts tend to look more favorably on the adverse possessor when they have constructed a building, erected a fence, or planted a crop on the property (e.g., Cousins v. McNeel, 2010). By the same token, courts tend to look less favorably on adverse possessors when they conceal their occupation, or where the landowner has given them express permission to use the land (e.g., Houghton v. Johnson, 2008). As one court phrased it, the adverse possessor “must unfurl his flag on the land, and keep it flying so that the owner may see, if he will, that an enemy has invaded his dominions and planted his standard of conquest” (Barrell v. Renehan, 1944, p. 333).

Notice two things. First, the possession cues that Boyer proposes as relevant for resource competition (contiguity, interaction, defense, and making modifications) map closely onto the elements required to establish adverse possession. Second, these elements are not considered in a vacuum, but instead are considered in light of the forthrightness (read: Cooperative expectations) of the landowner and adverse possessor.

These same elements appear in cases evaluating an owner's liability for damage done by the things they own (as in a falling tree, or a biting dog). Here the law tends to balance the dominion that the owner extends over something with judgments of the owner as a past and potential cooperator. For damage caused by fallen trees, the law considers possession cues such as who owns the property the tree is located on, as well as cooperation cues such as whether the property owner was aware of a tree's poor health and did nothing to prevent it (Klein v. Weaver, 2004). For damage caused by pets and other animals, legal rules balance the domesticity of the animal (read: Possession cues) with the owner's knowledge of any propensity for dangerousness and their diligence in keeping the animal in check (read: Cooperation cues) (e.g., State ex rel. Smith v. Donohue, 1887).

Given the distance between an intuition and the passing of a law, we wouldn't expect this framework to map cleanly onto every aspect of property law, and there are often sound reasons why we would not want it to (Patrick, Reference Patrick2023). Moreover, Boyer's model doesn't explicitly rule out other potential explanations that could also account for the intuitions of ownership or features of property law that we observe. As of now, however, it does represent the state of the art in both reconciling much of the psychological literature on ownership and explaining why certain recurrent elements span many disparate areas of the law of property.