ABSTRACT Humans routinely keep souvenirs objects retained for the memories they evoke, yet the evolutionary and cognitive consequences of mnemonic collecting remain unclear. Existing discussions of curated objects concentrate on later prehistory and modern humans and view such objects at the social level, as carriers of shared cultural meaning or as markers of status. Here, we address an earlier time period and locate the phenomenon at the personal rather than the social level. By integrating archaeology with theories of extended memory and niche construction, we synthesize evidence consistent with systematic curation of items beyond purely utilitarian needs from the terminal Lower Palaeolithic (~500 kya) onward, including transported distinctive stones, fossils, and the prolonged retention of patinated “old” stone tools whose earlier surfaces were deliberately preserved. We propose that curated keepsakes functioned as portable external memory devices. Beyond cueing recall, they may have helped authenticate self‐relevant past events by providing durable material traces that support source monitoring—distinguishing experienced from imagined events. As such practices became routine, they could have created a “souvenir niche” in which individuals who better integrated internal recollection with external tokens gained fitness benefits. The token's reference is personal, but its consequences can be social, supporting tasks like tracking alliances, reciprocity, and place‐based obligations. These benefits may have strengthened selection on neural systems facilitating the development of autobiographical memory and sense of self via gene–culture coevolution. We outline archaeological, developmental, and experimental predictions that distinguish this mnemonic‐authentication account from aesthetic or economic explanations and suggest approaches for testing them. Viewing curated objects as memory technology links early material culture to the evolutionary shaping of human autobiographical memory.
ABSTRACT While primates have traditionally been a focus of evolutionary anthropologists, the domestic dog represents a valuable complementary model due to its long shared evolutionary history with humans. The advantages of studying dogs are particularly evident in four key areas: (1) analyzing evolutionary adaptations, (2) understanding humanity's past, (3) examining humanity's cultural diversity, and (4) assessing factors that influence human health. Dogs have convergently evolved social cognition and local adaptations (including altitude adaptations and the ability to digest starches and lactose) that parallel those of humans, making them valuable models for testing evolutionary hypotheses. The global spread of dogs also illuminates human population histories, and isotopic analyses of dog remains can be proxies for human dietary data when sampling human remains is infeasible or inappropriate. Dogs' near‐universal presence across human societies and exposure to the same real‐world environments further make them uniquely powerful models for studying cultural variation and health.
Primate play is often interpreted as a developmental activity through which immature individuals acquire capacities used later in life. This essay uses play to examine a wider process in behavioral research: how classification helps produce behavioral data and shapes the explanations those data can support. It asks how juvenile actions are classified as play and become evidence for claims about development, evolution, and "human nature." I argue that the same analogies to adult behavior that help recognize and organize juvenile actions as play later reappear in explanations of the roles or capacities that play is proposed to develop. Examples show how such developmental hypotheses become entangled with culturally familiar narratives of gender and human evolution, particularly as scientific claims circulate publicly. A comparative anthropology of play should keep these evidentiary steps visible, distinguish adult analogies from demonstrated developmental outcomes, and situate play within immature primates' immediate social and material worlds.
We argue that current explanatory practice misses two situations that can arise in any lineage, not only ours. The first is dynamic: traits continue changing in one direction when a lineage's own niche construction keeps enlarging the problem it faces. The second is unifying: many traits change together and may require one explanation rather than several. Both cases bear on Tinbergen's four questions, the test of explanatory completeness, and both require extending his function question: what is a trait for? An answer that names a problem of fixed size cannot explain continued change. We call a problem of rising magnitude a gradient, and one that serves many traits a unifying gradient. We set out five questions that any complete gradient explanation must answer, map the major hypotheses of human evolution onto this scheme, and use our Prey-Size Decline hypothesis as a worked example. The proposed framework does not depend on that example.
