An individual’s decisions are often guided by those of his or her peers, i.e., neighbors in a social network. Presumably, being privy to the experiences of others aids in learning and decision making, but how much advantage does an individual gain by observing her neighbors? Such problems make appearances in sociology and economics and, in this paper, we present a novel model to capture such de...

We analyze the regret, measured in terms of log loss, of the maximum likelihood (ML) sequential prediction strategy. This “follow the leader” strategy also defines one of the main versions of Minimum Description Length model selection. We proved in prior work for single parameter exponential family models that (a) in the misspecified case, the redundancy of follow-the-leader is not 1 2 log n+O(...

There are many responses to Allais’s (1953) Paradox, some reconciling it with expected utility (EU) theory, others holding that the two cannot be reconciled (for better or worse for the theory). I here focus on a particular aspect of the debate—the extent to which EU axioms like Independence constrain the content of (not just the relationship between) our preferences. Many accept that an agent’...

We examine risk attitudes under regret theory and derive analytical expressions for two components—the resolution and regret premiums—of the risk premium under regret theory. We posit that regret-averse decision makers are risk seeking (resp., risk averse) for low (resp., high) probabilities of gains and that feedback concerning the forgone option reinforces risk attitudes. We test these hypoth...

Decision makers can become trapped by myopic regret avoidance in which rejecting feedback to avoid short-term outcome regret (regret associated with counterfactual outcome comparisons) leads to reduced learning and greater long-term regret over continuing poor decisions. In a series of laboratory experiments involving repeated choices among uncertain monetary prospects, participants primed with...

Previous studies showed that the understanding of others' basic emotional experiences is based on a "resonant" mechanism, i.e., on the reactivation, in the observer's brain, of the cerebral areas associated with those experiences. The present study aimed to investigate whether the same neural mechanism is activated both when experiencing and attending complex, cognitively-generated, emotions. A...

Online learning algorithms are designed to learn even when their input is generated by an adversary. The widely-accepted formal definition of an online algorithm’s ability to learn is the game-theoretic notion of regret. We argue that the standard definition of regret becomes inadequate if the adversary is allowed to adapt to the online algorithm’s actions. We define the alternative notion of p...

Reservoir control policies provide a flexible option to adapt the uncertain hydrologic impacts of climate change. This challenge requires robust capable navigating scenarios that are wetter, drier, or more variable than anticipated. While number prior studies have trained using large scenario ensembles, there remains need understand how properties training impact policy robustness. Specifically...

BACKGROUND The aim of this study was to examine impaired decision making in patients with schizophrenia and in patients with orbitofrontal cortex lesions. METHODS Schizophrenia patients (N=21), healthy controls (N=20) and an independent group of orbitofrontal patients (N=10) underwent a computerized version of the "Regret Gambling Task". Participants chose between two gambles, each having dif...