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1. Indecision Modeling

   McElfresh, Duncan C; Chan, Lok; Doyle, Kenzie; Sinnott-Armstrong, Walter; Conitzer, Vincent; Schaich Borg, Jana; Dickerson, John P (April 2021, Proceedings of the AAAI Conference on Artificial Intelligence)

   AI systems are often used to make or contribute to important decisions in a growing range of applications, including criminal justice, hiring, and medicine. Since these decisions impact human lives, it is important that the AI systems act in ways which align with human values. Techniques for preference modeling and social choice help researchers learn and aggregate peoples' preferences, which are used to guide AI behavior; thus, it is imperative that these learned preferences are accurate. These techniques often assume that people are willing to express strict preferences over alternatives; which is not true in practice. People are often indecisive, and especially so when their decision has moral implications. The philosophy and psychology literature shows that indecision is a measurable and nuanced behavior---and that there are several different reasons people are indecisive. This complicates the task of both learning and aggregating preferences, since most of the relevant literature makes restrictive assumptions on the meaning of indecision. We begin to close this gap by formalizing several mathematical indecision models based on theories from philosophy, psychology, and economics; these models can be used to describe (indecisive) agent decisions, both when they are allowed to express indecision and when they are not. We test these models using data collected from an online survey where participants choose how to (hypothetically) allocate organs to patients waiting for a transplant. 

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2. Complex sensory environments alter mate choice outcomes

   https://doi.org/10.1242/jeb.233288  

   Taylor, Ryan C.; Wilhite, Kyle O.; Ludovici, Rosalind J.; Mitchell, Kelsey M.; Halfwerk, Wouter; Page, Rachel A.; Ryan, Michael J.; Hunter, Kimberly L. (December 2021, Journal of Experimental Biology)

   Noise is a common problem in animal communication. We know little, however, about how animals communicate in noise using multimodal signals. Multimodal signals are hypothesized to be favoured by evolution because they increase the efficacy of detection/discrimination in noisy environments. We tested the hypothesis that female túngara frogs’ responses to attractive male advertisement calls are improved in noise when a visual signal component is added to the available choices. We tested this at two levels of decision complexity (two and three choices). In a two-choice test, the presence of noise did not reduce female preferences for attractive calls. The visual component of a calling male, associated with an unattractive call, also did not reduce preference for attractive calls in the absence of noise. In the presence of noise, however, females were more likely to choose an unattractive call coupled with the visual component. In three-choice tests, the presence of noise alone reduced female responses to attractive calls and this was not strongly affected by the presence or absence of visual components. The responses in these experiments fail to support the multimodal signal efficacy hypothesis. Instead, the data suggest that audio-visual perception and cognitive processing, related to mate choice decisions, are dependent on the complexity of the sensory scene. 

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3. Beyond killing one to save five: Sensitivity to ratio and probability in moral judgment

   https://doi.org/10.1016/j.jesp.2023.104499  

   Ryazanov, Arseny A.; Wang, Shawn Tinghao; Nelkin, Dana Kay; McKenzie, Craig R.M.; Rickless, Samuel C. (September 2023, Journal of Experimental Social Psychology)

   A great deal of current research on moral judgments centers on moral dilemmas concerning tradeoffs between one and five lives. Whether one considers killing one innocent person to save five others to be morally required or impermissible has been taken to determine whether one is appealing to consequentialist or non-consequentialist reasoning. But this focus on tradeoffs between one and five may obscure more nuanced commitments involved in moral decision-making that are revealed when the numbers and ratio of lives to be traded off are varied, and when the probabilities of each outcome occurring are less than certain. Four studies examine participants’ reactions to scenarios that diverge in these ways from the standard ones. Study 1 examines the extent to which people are sensitive to the ratio of lives saved to lives ended by a particular action. Study 2 verifies that the ratio rather than the difference between the two values is operative. Study 3 examines whether participants treat probabilistic harm to some as equivalent to certainly harming fewer, holding expected ratio constant. Study 4 explores an analogous issue regarding the sensitivity of probabilistic saving. Participants are remarkably sensitive to expected ratio for probabilistic harms while deviating from expected value for probabilistic saving. Collectively, the studies provide evidence that people’s moral judgments are consistent with the principle of threshold deontology. 

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4. Inferred Attractiveness: A generalized mechanism for sexual selection that can maintain variation in traits and preferences over time

   https://doi.org/10.1371/journal.pbio.3002269  

   DuVal, Emily H.; Fitzpatrick, Courtney L.; Hobson, Elizabeth A.; Servedio, Maria R. (October 2023, PLOS Biology)

   Patricelli, Gail L. (Ed.)

   Sexual selection by mate choice is a powerful force that can lead to evolutionary change, and models of why females choose particular mates are central to understanding its effects. Predominant mate choice theories assume preferences are determined solely by genetic inheritance, an assumption still lacking widespread support. Moreover, preferences often vary among individuals or populations, fail to correspond with conspicuous male traits, or change with context, patterns not predicted by dominant models. Here, we propose a new model that explains this mate choice complexity with one general hypothesized mechanism, “Inferred Attractiveness.” In this model, females acquire mating preferences by observing others’ choices and use context-dependent information to infer which traits are attractive. They learn to prefer the feature of a chosen male that most distinguishes him from other available males. Over generations, this process produces repeated population-level switches in preference and maintains male trait variation. When viability selection is strong, Inferred Attractiveness produces population-wide adaptive preferences superficially resembling “good genes.” However, it results in widespread preference variation or nonadaptive preferences under other predictable circumstances. By casting the female brain as the central selective agent, Inferred Attractiveness captures novel and dynamic aspects of sexual selection and reconciles inconsistencies between mate choice theory and observed behavior. 

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5. Little evidence for color- or size-based mating preferences by male strawberry poison frogs (Oophaga pumilio)

   https://doi.org/10.1007/s00265-024-03436-9  

   Lehman, Mik R; González-Santoro, Marco; Richards-Zawacki, Corinne L (February 2024, Behavioral Ecology and Sociobiology)

   AbstractWhile there are many studies documenting female mating preferences across taxa, male mate choice remains relatively understudied. Male mate choice often develops when there is variation in female quality and thus the fitness benefits of mating with particular females. Specifically, males tend to prefer females with traits that confer direct fitness benefits such as large body size, which may be linked with high fecundity. Prior work has shown that females of the strawberry poison frog,Oophaga pumilio, prefer males bearing certain coloration (most often the female’s own color), and that this preference can be learned through maternal imprinting. Females have been shown to prefer larger males as well. Here we test whether similar mate preferences for color and size exist in males of this species using two-way choice tests on captive bred maleO. pumilio. In each test focal males were placed in an arena with two stimulus females: either both of the same size but differing in color, or both of the same color but differing in size. We found only weak evidence for behavioral biases toward particular colors and no evidence for biases toward larger females, suggesting that males ofO. pumiliodo not predictably choose mates based on these female traits. Despite several aspects of their natural history that suggest males have reasons to be choosy, our findings suggest that the cost of mate rejection may outweigh any fitness benefits derived from being selective of mates. Studies of additional populations, ideally conducted on wild individuals, are needed to better understand the range of conditions under which males may exhibit mate choice and the types of traits on which they base these choices. Significance statementTo fully understand the fitness landscapes and evolutionary trajectories that result from sexual selection, we need to understand when and how the mate preferences of the two sexes act and interact. While female mate choice has been widely studied, male mate choice remains poorly understood. To help bridge this gap, we studied male mate preferences in the strawberry poison frogOophaga pumilio, a small brightly colored frog for which female preferences for male color and size have been well-documented. We found no evidence that maleO. pumilioexhibit mate preferences based on female size and little evidence for male mate preferences based on female color. This is surprising given that larger females are often more fecund, maleO. pumilioare known to exhibit color-based behavioral biases in the context of male-male competition, and both sexes provide parental care. 

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