Reward context determines risky choice in pigeons and humans

Whereas humans are risk averse for monetary gains, other animals can be risk seeking for food rewards, especially when faced with variable delays or under significant deprivation. A key difference between these findings is that humans are often explicitly told about the risky options, whereas non-human animals must learn about them from their own experience. We tested pigeons (Columba livia) and humans in formally identical choice tasks where all outcomes were learned from experience. Both species were more risk seeking for larger rewards than for smaller ones. The data suggest that the largest and smallest rewards experienced are overweighted in risky choice. This observed bias towards extreme outcomes represents a key step towards a consilience of these two disparate literatures, identifying common features that drive risky choice across phyla

The power of nothing : risk preference in pigeons, but not people, is driven primarily by avoidance of zero outcomes

When making risky decisions, people and pigeons often show similar choice patterns. When people learn the reward probabilities through repeated exposure to the outcomes, their preference is disproportionately influenced by the extreme (highest and lowest) outcomes occurring in the decision context. Overweighting of these extremes increases preference for risky alternatives that lead to the highest outcome and decreases preference for risky alternatives that lead to the lowest outcome, termed the extreme-outcome rule. This rule predicts greater risk seeking for choices between safe and risky high-value outcomes than for choices between safe and risky low-value outcomes, when both choices occur in the same context. In a series of studies, we examine how this extreme-outcome rule generalizes within and across two evolutionary distant species: pigeons (Columba livia) and humans (Homo sapiens). Both species showed risky choices consistent with the extreme-outcome rule when a low-value risky option could yield an outcome of zero. When all outcome values were increased such that none of the options could lead to zero, people but not pigeons were still consistent with the extreme-outcome rule. Unlike people, pigeons no longer avoided a low-value risky option when it yielded a non-zero food outcome. These results suggest that, despite some similarities, different mechanisms underlie risky choice in pigeons and people

Methane Emission in a Specific Riparian-Zone Sediment Decreased with Bioelectrochemical Manipulation and Corresponded to the Microbial Community Dynamics

Dissimilatory metal-reducing bacteria are widespread in terrestrial ecosystems, especially in anaerobic soils and sediments. Thermodynamically, dissimilatory metal reduction is more favorable than sulfate reduction and methanogenesis but less favorable than denitrification and aerobic respiration. It is critical to understand the complex relationships, including the absence or presence of terminal electron acceptors, that govern microbial competition and coexistence in anaerobic soils and sediments, because subsurface microbial processes can effect greenhouse gas emissions from soils, possibly resulting in impacts at the global scale. Here, we elucidated the effect of an inexhaustible, ferrous-iron and humic-substance mimicking terminal electron acceptor by deploying potentiostatically poised electrodes in the sediment of a very specific stream riparian zone in Upstate New York state. At two sites within the same stream riparian zone during the course of six weeks in the spring of 2013, we measured CH4 and N2/N2O emissions from soil chambers containing either poised or unpoised electrodes, and we harvested biofilms from the electrodes to quantify microbial community dynamics. At the upstream site, which had a lower vegetation cover and highest soil temperatures, the poised electrodes inhibited CH4 emissions by ~45% (when normalized to remove temporal effects). CH4 emissions were not significantly impacted at the downstream site. N2/N2O emissions were generally low at both sites and were not impacted by poised electrodes. We did not find a direct link between bioelectrochemical treatment and microbial community membership; however, we did find a correspondence between environment/function and microbial community dynamics

Increased and Accessible Illinois Judicial Rulemaking

This Article discusses the problems which result from vesting the authority for making procedural rules governing the Illinois courts in both the General Assembly and the Illinois Supreme Court. After examining the constitutional history and applying policy rationales, the Article suggests that the constitution should give various types of primary authority for judicial rulemaking to the judiciary, with only secondary authority afforded to the legislature

Men's Health : the healing of Prometheus

This thesis investigates the state of men's health, which is in silent crisis. The male mortality rate is 60% higher then the female mortality rate in Canada. Furthermore it is higher for all 10 leading causes of death. The difference in life expectancy is over 5 years between men and women. Contributing to their early demise are so-called preventable deaths, homicide, suicide, vehicle accidents and work accidents which are much more prevalent among males than females. In the U.S. from infancy, males die and suffer serious illnesses at greater rates than females. In fact between the age of 15 and 24, male die at a rate more than three times that of females. This constitutes a silent health crisis---silent because it is not acknowledged, it is in fact, ignored. In Canada there are five Centres of Excellence devoted to women's health---yet there are none for men's health, which is far worse. In the U.S., the morbidity and mortality rates are proportionally similar. There are eleven Specialized Centers of Research for Women's Health, and none for men. We will explore in this thesis both the reasons for men's ill health relative to women's, and the paradox of the silence. Three major theoretical perspectives: the bio-medical, the environmental, and lifestyle, are examined extensively, as are gender specific theories concerning the role that masculinity plays in contributing to male health. Lastly, I present recommendations for improving men's health. Not only is there an appalling loss of men's lives and to a lesser extent women's for many reasons, but also it is extremely expensive. The economic costs of male potential years of life lost in 2001 (U.S. data), amounted to $329,836, million dollars per annum. This money would be better invested in preventive care and Centers of Excellence devoted to men's health

Lexicographic Bit Allocation for MPEG Video

We consider the problem of allocating bits among pictures in an MPEG video coder to equalize the visual quality of the coded pictures, while meeting bu er and channel constraints imposed by the MPEG Video Bu ering Veri er. We address this problem within a framework that consists of three components: 1) a bit production model for the input pictures, 2) a set of bit-rate constraints imposed by the Video Bu ering Veri er, and 3) a novel lexicographic criterion for optimality. Under this framework, we derive simple necessary and su cient conditions for optimality that lead to e cient algorithms

Exhumation of the Inyo Mountains, California: Implications for the Timing of Extension along the Western Boundary of the Basin and Range Province and Distribution of Dextral Fault Slip Rates across the Eastern California Shear Zone

New geologic mapping, tectonic geomorphologic, 10Be terrestrial cosmogenic nuclide, and (U-Th)/He zircon and apatite thermochronometric data provide the first numerical constraints on late Cretaceous to late Quaternary exhumation of the Inyo Mountains and vertical slip and horizontal extension rates across the eastern Inyo fault zone, California. The east-dipping eastern Inyo fault zone bounds the eastern flank of the Inyo Mountains, a prominent geomorphic feature within the western Basin and Range Province and eastern California shear zone. (U-Th)/He zircon and apatite thermochronometry yield age patterns across the range that are interpreted as indicating: (1) two episodes of moderate to rapid exhumation associated with Laramide deformation during the late Cretaceous/early Tertiary; (2) development of a slowly eroding surface during a prolonged period from early Eocene to middle Miocene; (3) rapid cooling, exhumation, and initiation of normal slip along the eastern Inyo fault zone, accommodated by westward tilting of the Inyo Mountains block, at 15.6 Ma; and (4) rapid cooling, exhumation, and renewed normal slip along the eastern Inyo fault zone at 2.8 Ma. Fault slip continues today as indicated by fault scarps that cut late Pleistocene alluvial fan surfaces. The second episode of normal slip at 2.8 Ma also signals onset of dextral slip along the Hunter Mountain fault, yielding a Pliocene dextral slip rate of 3.3 ± 1.0 mm/a, where a is years. Summing this dextral slip rate with estimated dextral slip rates along the Owens Valley, Death Valley, and Stateline faults yields a net geologic dextral slip rate across the eastern California shear zone of 9.3 + 2.2/–1.4 to 9.8 + 1.4/–1.0 mm/a