Inverse Foraging

Users' engagement with pervasive displays has been extensively studied, however, determining how their content is interesting remains an open problem. Tracking of body postures and gaze has been explored as an indication of attention; still, existing works have not been able to estimate the interest of passers-by from readily available data, such as the display viewing time. This article presents a simple yet accurate method of estimating users' interest in multiple content items shown at the same time on displays. The proposed approach builds on the information foraging theory, which assumes that users optimally decide on the content they consume. Through inverse foraging, the parameters of a foraging model are fitted to the values of viewing times observed in practice, to yield estimates of user interest. Different foraging models are evaluated by using synthetic data and with a controlled user study. The results demonstrate that inverse foraging accurately estimates interest, achieving an R2 above 70% in comparison to self-reported interest. As a consequence, the proposed solution allows to dynamically adapt the content shown on pervasive displays, based on viewing data that can be easily obtained in field deployments.

A Test of Foraging Models Using Dietary Diversity Indices for the Lomako Forest Bonobos

Optimal diet and functional response models are used to understand the evolution of primate foraging strategies. The predictions of these models can be tested by examining the geographic and seasonal variation in dietary diversity. Dietary diversity is a useful tool that allows dietary comparisons across differing sampling locations and time periods. Bonobos (<i>Pan paniscus</i>) are considered primarily frugivorous and consume fruits, leaves, insects, vertebrates, terrestrial herbaceous vegetation, and flowers. Frugivores, like bonobos, are valuable for examining dietary diversity and testing foraging models because they eat a variety of species and are subject to seasonal shifts in fruit availability. Frugivorous primate species thus allow for tests of how variation in dietary diversity is correlated with variation in ecological factors. We investigated measures of dietary diversity in bonobos at two research camps across field seasons within the same protected area (N’dele and Iyema) in Lomako Forest, Democratic Republic of the Congo. We compared the results of behavioral observation (1984/1985, 1991, 1995, 2014, and 2017) and fecal washing analysis (2007 and 2009) between seasons and study period using three diversity indices (Shannon’s, Simpson’s, and SW evenness). The average yearly dietary diversity indices at N’dele were Shannon’s <i>Hʹ</i> = 2.04, Simpson’s D = 0.82, and SW evenness = 0.88 while at Iyema, the indices were Shannon’s <i>Hʹ</i> = 2.02, Simpson’s D = 0.82, and SW evenness = 0.88. Behavioral observation data sets yielded significantly higher dietary diversity indices than fecal washing data sets. We found that food item (fruit, leaf, and flower) consumption was not associated with seasonal food availability for the 2017 behavioral observation data set. Shannon’s index was lower during periods when fewer bonobo dietary items were available to consume and higher when fruit was abundant. Finally, we found that optimal diet models best-explained patterns of seasonal food availability and dietary diversity. Dietary diversity is an essential factor to consider when understanding primate diets and can be a tool in understanding variation in primate diets, particularly among frugivores. Dietary diversity varies across populations of the same species and across time, and it is critical in establishing a complete understanding of how primate diets change over time.

Prehistoric Dogs as Hunting Tools

This chapter explores the role of hunting dogs in forager groups and as the advent of animal biotechnology. It outlines the ways in which dogs can be used as hunting biotechnology, how dogs can be incorporated into existing subsistence models, and how we can identify hunting dogs in the archaeological record. The analysis of cross-cultural utilization of dogs as a hunting tool in the ethnographic and ethnohistoric record is used to suggest insights into the ways dogs may have been utilized as a hunting adaptation by people in the past. Similarly, cost-benefit analyses employed for non-living tools, such as lithics, are employed to contextualize dogs as a quantifiable technology within optimal foraging models.

Biased belief updating and suboptimal choice in foraging decisions

In many choice scenarios, including prey, employment, and mate search, options are not encountered simultaneously and so cannot be directly compared. Deciding which ones optimally to engage, and which to forego, requires developing accurate beliefs about the overall distribution of prospects. However, the role of learning in this process – and how biases due to learning may affect choice – are poorly understood. In three experiments, we adapted a classic prey selection task from foraging theory to examine how individuals kept track of an environment’s reward rate and adjusted their choices in response to its fluctuations. In accord with qualitative predictions from optimal foraging models, participants adjusted their selectivity to the richness of the environment: becoming less selective in poorer environments and increasing acceptance of less profitable options. These preference shifts were observed not just in response to global (between block) manipulations of the offer distributions, but also to local, trial-by-trial offer variation within a block, suggesting an incremental learning rule. Further offering evidence into the learning process, these preference changes were more pronounced when the environment improved compared to when it deteriorated. All these observations were best explained by a trial-by-trial learning model in which participants estimate the overall reward rate, but with upward vs. downward changes controlled by separate learning rates. A failure to adjust expectations sufficiently when an environment becomes worse leads to suboptimal choices: options that are valuable given the environmental conditions are rejected in the false expectation that better options will materialize. These findings offer a previously unappreciated parallel in the serial choice setting of observations of asymmetric updating and resulting biased (often overoptimistic) estimates in other domains.

BEHAVIORAL RESPONSE OF THE MARA(Dolichotis patagonum) TO FOOD DENSITY IN ARGENTINA

Optimal foraging models predict animals will consume more food from patches of higher initial densities. They also predict that when food is scarce in the environment, animals will have greater foraging efforts in the patch and hence shorter vigilance times. As an anti-predator behavior an increase in group size is correlated with a reduction of individual vigilance time. We evaluated Dolichotis patagonum´s (mara) behaviors: feeding, vigilance, walking, and others (sniffing, grooming, resting) in relation to different food densities (100 g, 70 g and 40 g of alfalfa pellet, mixed with 5kg of sifted soil, offered in wooden box) in a field experiment by using camera traps. As a novelty, maras showed nocturnal activity. They also showed an increase in vigilance time when they were in pairs compared to when they were alone, by alternating feeding and vigilance behaviors. When food density changed, no variation in vigilance was observed and food intake only changed between 100 g and the other two food densities offered. We propose that: first, maras are cathemeral animals. Second, mara´s knowledge about patches is critical to assess patch quality. Finally, alternating feeding and vigilance when in pairs, could be and efficient anti-predator strategy in environments with high predator pressure.Key words: activity pattern, camera traps, Dolichotis patagonum, food consumption, San Luis, vigilance. ResumenLos modelos de forrajeo óptimo predicen que los animales van a consumir más alimento en aquellos parches con mayores densidades iniciales. Además, predicen que cuando el alimento sea escaso, los animales tendrán mayores esfuerzos de forrajeo en cada parche y por tanto menores tiempos de vigilancia. La vigilancia individual también disminuirá al aumentar el tamaño de grupo. En este experimento de campo evaluamos, a través de cámaras trampa, el comportamiento de: alimentación, vigilancia, desplazamiento y otros (ej.: olfatear, acicalarse, descansar) de Dolichotis patagonum (mara) en relación a diferentes densidades de alimento (100 g, 70 g y 40 g de pelets de alfalfa mezclado con arena cernida dentro de cajones de madera). Como dato novedoso se observó actividad nocturna. También se observó un aumento en la vigilancia cuando estaban en pareja que al estar solas, dado que alternaban la vigilancia y la alimentación. Entre las densidades de alimento no se observó variación en la vigilancia y la ingesta de alimento cambió solo entre 100 g y las otras dos densidades ofrecidas. Por lo cual proponemos que, primero, la mara es un animal catemeral. Segundo, el conocimiento que las maras tienen de los parches es crítico para evaluar su calidad. Finalmente, la alternancia de comportamientos en la pareja podría ser una estrategia anti-predatoria en ambientes con altas presión de depredación.Palabras clave: patrón de actividad, cámaras trampas, consumo de alimento, Dolichotis patagonum, vigilancia, San Luis.

The Evolutionary Explanation of What?

The paper examines evolutionary explanations of risk preferences. First, the paper argues that evolutionary psychology is ill-suited for explaining prospect theory risk preferences since the empirical evidence does not support the universality of the fourfold pattern of risk preferences postulated by prospect theory. Second, the paper argues that explaining prospect theory risk preferences by means of risk-sensitive foraging models is incomplete since this approach does not offer a rationale for the observed diversity in human decision making involving monetary gambles. Finally, the paper suggests adopting a wider perspective on evolutionary approaches to human behaviour that also takes into account the role of cultural processes in shaping risk preferences.

Overlapping neural processes for stopping and economic choice in orbitofrontal cortex

ABSTRACTEconomic choice and stopping are not traditionally treated as related phenomena. However, we were motivated by foraging models of economic choice to hypothesize that they may reflect similar neural processes occurring in overlapping brain circuits. We recorded neuronal activity in orbitofrontal cortex (OFC), while macaques performed a stop signal task interleaved with a structurally matched economic choice task. Decoding analyses show that OFC ensembles predict successful versus failed stopping both before the trial and immediately after the stop signal, even after controlling for value predictions. These responses indicate that OFC contributes both proactively and reactively to stopping. Moreover, OFC neurons’ engagement in one task positively predicted their engagement in the other. Finally, firing patterns that distinguished low from high value offers in the economic task distinguished failed and successful trials in the stopping task. These results endorse the idea that economic choice and inhibition may be subject to theoretical unification.