La jerarquización de recursos constituye uno de los procedimientos más empleados para evaluar la subsistencia de los cazadores-recolectores en el pasado. Para el Centro Occidente Argentino (COA) esta jerarquización se fundaba en el tamaño corporal de las presas. Aquí incorporamos datos sobre los costos de manejo, generando el primer ordenamiento de recursos para la región que contempla los elementos requeridos por los modelos de optimización (Kcal/tiempo post-encuentro). Luego del guanaco (Lama guanicoe) —presa de mayor rendimiento— este ranking situó en segundo y tercer lugar a los huevos de Rheidae y los armadillos (Dasypodidae), respectivamente, resaltando la importancia de presas tradicionalmente consideradas de bajo rendimiento. Siguiendo la teoría de aprovisionamiento óptimo, elaboramos el modelo de amplitud de dieta (MAD) para los desiertos más representativos de Nordpatagonia: el de Monte y el patagónico. En este último, la mayor disponibilidad de guanacos tornó menos ventajosa la incorporación de nuevos ítems a la dieta. Para el Monte, la dieta óptima se amplió, incluyendo recursos menores como ciertos peces (i.e., Percichthys trucha). En definitiva, el MAD permitió reinterpretar tendencias temporales en la subsistencia humana, sosteniendo una ampliación en el espectro de recursos explotados hacia el Holoceno tardío en el COA. En general, las expectativas del MAD son confirmadas con el registro zooarqueológico regional.

Understanding how raptors select prey is important to determine taphonomic biases both in modern and paleo pellet assemblages. We tested whether pellets more closely represent raptor dietary specialization or local small mammal diversity by sampling pellets from seven raptor species across four study sites in Yellowstone National Park, Wyoming, USA. We identified small mammal craniodental elements from each pellet and tested for differences among small mammal assemblages for each raptor species and study site. We found that reconstructed avian predator diets clustered significantly by site but not by predator species. Bray-Curtis diet dissimilarities were also significantly lower when comparing different raptor species within a site than when comparing the same raptor species across different sites. Our results suggest that raptors choose to eat a diversity of small mammal species close to their roosts rather than fly long distances to specialize on a particular prey species. Neontologists and paleoecologists alike can therefore be confident that raptor pellets faithfully represent local small mammal diversity.

A series of farming experiments was conducted between 2013 and 2017 in Range Creek Canyon, Utah, to better understand the opportunities and constraints faced by prehistoric farmers in the Southwest. The experiments were designed to collect data on the optimal amount of supplemental water that should be applied to maize fields given the costs in labor and benefits in greater yield. We investigate expected variation in water management strategies using an optimal irrigation model (OIM). The model makes clear that the payoff for farming is best understood as a continuum of relative success and that irrigation is one activity (probably of many) that may improve farming efficiency as well as increase harvest yields. The optimal harvest will always be less than the maximum harvest when there are significant operating costs associated with irrigation. Estimating the costs and benefits of irrigation in a specific area allows for an assessment of whether irrigation is expected, and if so, how much effort should be devoted to water management. A local dendroclimatological study is used to provide the prehistoric context for the Fremont who occupied Range Creek Canyon, and irrigation is expected even in periods of greater precipitation.

Recently, researchers investigating the origins of domestication have debated the significance of resource intensification in the shift from foraging to food production. In eastern North America, one of several independent centers of domestication, this question remains open. To determine whether initial domestication may have been preceded by intensification in eastern North America at approximately 5000 cal BP, I evaluated the archaeofaunal assemblages from six sites in the middle Tennessee River valley. Analyses of these data suggest that overall foraging efficiency gradually declined prior to initial domestication, but patch-specific declines in foraging efficiency occurred in wetland habitats and not terrestrial ones. Climatic warming and drying during the Middle Holocene, growing human populations, and oak-hickory forest expansion were the likely drivers of these changes in foraging efficiency. These results support the hypothesis that initial domestication in eastern North America was an outcome of intensification driven by environmental change and human population increases. Finally, while the debate concerning the relationship of intensification to domestication has been framed in terms of a conflict between niche construction theory and optimal foraging theory, these perspectives are compatible and should be integrated to understand domestication more fully.

The tendency to choose a larger, more delayed reinforcer over a smaller, less delayed one has frequently been termed “selfcontrol.” Three very different research traditions – two models emphasizing the control of local contingencies of reinforcement (Mischel's social learning theory and Herrnstein's matching law) and molar maximization models (specifically optimal foraging theory) – have all investigated behavior within the self-control paradigm. A framework is proposed to integrate research from all three research areas. This framework consists of three parts: a procedural analysis, a causal analysis, and a theoretical analysis. The procedural analysis provides a common procedural terminology for all three areas. The causal analysis establishes that, in all three research traditions, self-control varies directly with the current physical values of the reinforcers; that is, choices increase with reinforcer amount and decrease with reinforcer delay. But self-control also varies according to past events to which a subject has been exposed, and according to current factors other than the reinforcers. Each of the three models has therefore incorporated these indirect effects on self-control by postulating unobservable mechanisms. In all three cases, these mechanisms represent a subject's behavior as a function of a perceived environment. The theoretical analysis demonstrates that evolutionary theory can encompass the research from all three areas by considering differences in the adaptiveness of self-control in different situations. This integration provides a better and more predictive description of self-control.

Behaving organisms are continually choosing. Recently the theoretical and empirical study of decision making by behavioral ecologists and experimental psychologists have converged in the area of foraging, particularly food acquisition. This convergence has raised the interdisciplinary question of whether principles that have emerged from the study of decision making in the operant conditioning laboratory are consistent with decision making in naturally occurring foraging. One such principle, the “parameter-free delay-reduction hypothesis, ” developed in studies of choice in the operant conditioning laboratory, states that the effectiveness of a stimulus as a reinforcer may be predicted most accurately by calculating the decrease in time to food presentation correlated with the onset of the stimulus, relative to the length of time to food presentation measured from the onset of the preceding stimulus. Since foraging involves choice, the delay-reduction hypothesis may be extended to predict aspects of foraging. We discuss the strategy of assessing parameters of foraging with operant laboratory analogues to foraging. We then compare the predictions of the delay-reduction hypothesis with those of optimal foraging theory, developed by behavioral ecologists, showing that, with two exceptions, the two positions make comparable predictions. The delay-reduction hypothesis is also compared to several contemporary pscyhological accounts of choice. Results from several of our experiments with pigeons, designed as operant conditioning simulations of foraging, have shown the following: The more time subjects spend searching for or traveling between potential food sources, the less selective they become, that is, the more likely they are to accept the less preferred outcome; increasing time spent procuring (“handling”) food increases selectivity; how often the preferred outcome is available has a greater effect on choice then how often the less preferred outcome is available; subjects maximize reinforcement whether it is the rate, amount, or probability of reinforcement that is varied; there are no significant differences between subjects performing under different types of deprivation (open vs. closed economies). These results are all consistent with the delay-reduction hypothesis. Moreover, they suggest that the technology of the operant conditioning laboratory may have fruitful application in the study of foraging, and, in doing so, they underscore the importance of an interdisciplinary approach to behavior.

Recent decades have seen a number of influential attacks on the comparative psychology of learning and intelligence. Two specific charges have been that the use of distantly related species has prevented us from making valid evolutionary inferences and that learning mechanisms are species-specific adaptations to ecological niches and hence not properly comparable between species. It is argued here that work using distantly related species may yield valuable insights into the structure of intelligence and that the question of whether or not learning mechanisms are niche-specific is one which can only be answered by comparative work in “nonnatural” situations. The problems involved in defining and assessing intelligence are discussed. Experimental work has not succeeded in demonstrating differences in intellect among nonhuman vertebrates. Hence the null hypothesis – that there are no differences in intellect among nonhuman vertebrates – should be adopted; the superiority of human intelligence stems from our possessing a species-specific language-acquisition device. One implication of the null hypothesis is that general problem-solving capacity is independent of niche-specific adaptations. A second implication is that problem-solving may involve relatively simple mechanisms; association formation in particular may play a central role in nonhuman intelligence, allowing the successful detection of causal links between events. Causality is a constraint common to all ecological niches.