In the absence of a legal regime enforcing promises, the classical prediction of contract theory is that promisees will unverinvest in reliance whenever the promisor has a self-interested reason to break her promise down the road. But if a promisor experiences guilt for breaking her promise, this guilt may be intensified by the promisee’s reliance on the promise. Anticipating this, the promisee...

Mutualisms are cooperative interactions between members of different species, often involving the trade of resources. Here, we suggest that otherwise-cooperative mutualists might be able to gain a benefit from actively restricting their partners' ability to obtain resources directly, hampering the ability of the restricted partner to survive and/or reproduce without the help of the restricting ...

H David Thoreau (1817–1862) is remembered and celebrated as an essayist, poet, philosopher, and naturalist; he was also a surveyor, historian, antislavery activist, tax resister, and teacher. Thoreau’s extensive writings are collected in more than 20 volumes, including books, articles, essays, journals, and poems. In his best known book, Walden; or, Life in the Woods, published in 1854, Thoreau...

Vertebrate photoreceptors are among the most metabolically active cells, exhibiting a high rate of ATP consumption. This is coupled with a high anabolic demand, necessitated by the diurnal turnover of a specialized membrane-rich organelle, the outer segment, which is the primary site of phototransduction. How photoreceptors balance their catabolic and anabolic demands is poorly understood. Here...