Learning of rules that have high-frequency exceptions: New empirical data and a hybrid connectionist model

Theorists of human learning, in domains as various as category learning and language acquisition, have grappled with the issue of whether learners induce rules or remember exemplars, or both. In this article we present new dau that reflect both rule induction and exemplar encoding, and we present a new connectionist model that specifies one way in which rule-based and exemplar-based mechanisms might interact Our empirical study was motivated by analogy to past tense acquisition, and specifically by the previous work of Palermo and Howe (1970). Human subjects learned to categorize items, most of which could be classified by a simple rule, except for a few frequently recurring exceptions. The modeling was motivated by the idea of combining an exemplar-based module (ALCOVE, Kruschke, 1992) and a rule-based module in a connectionist architecture, and allowing the system to learn which module should be responsible for which instances, using the competitive gating mechanism introduced by Jacobs, Jordan, Nowlan, and Hinton (1991). We report quantitative fits of the model to the learning data

Ostracism and fines in a public goods game with accidental contributions: The importance of punishment type

Punishment is an important method for discouraging uncooperative behavior. We use a novel design for a public goods game in which players have explicit intended contributions with accidentally changed actual contributions, and in which players can apply costly fines or ostracism. Moreover, all players except the subject are automated, whereby we control the intended contributions, actual contributions, costly fines, and ostracisms experienced by the subject. We assess subject’s utilization of other players’ intended and actual contributions when making decisions to fine or ostracize. Hierarchical Bayesian logistic regression provides robust estimates. We find that subjects emphasize actual contribution more than intended contribution when deciding to fine, but emphasize intended contribution more than actual contribution when deciding to ostracize. We also find that the efficacy of past punishment, in terms of changing the contributions of the punished player, influences the type of punishment selected. Finally, we find that the punishment norms of the automated players affect the punishments performed by the subject. These novel paradigms and analyses indicate that punishment is flexible and adaptive, contrary to some evolutionary theories that predict inflexible punishments that emphasize outcomes

The Disappearance of Moral Choice in Serially Reproduced Narratives

How do narratives influence moral decision-making? Our ongoing studies use serial reproduction of narratives, that is multiple retellings as in the telephone game, of morally ambiguous situations. In particular, we tested stories that include a minor misdemeanor, but leave open whether the wrongdoer will be punished by a bystander. It turns out that serial reproduction (retelling) of stories tends to eliminate the possibility of intervention by the bystander under certain conditions. We reason that this effect can be explained either by preferences of the readers or by the reader\u27s discomfort to get involved. A second finding is that retellings of third-person narratives of moral situations lead to a higher degree of change and invention of the outcome than first-person narratives

Dissociating Stimulus-Set and Response-Set in the Context of Task-Set Switching

The primary aim of the present research was to determine how stimulus-set and response-set components of task-set contribute to switch costs and conflict processing. Three experiments are described wherein participants completed an explicitly cued task-switching procedure. Experiment 1 established that task switches requiring a reconfiguration of both stimulus- and response-set incurred larger residual switch costs than task switches requiring the reconfiguration of stimulus-set alone. Between-task interference was also drastically reduced for response-set conflict compared with stimulus-set conflict. A second experiment replicated these findings and demonstrated that stimulus- and response-conflict have dissociable effects on the decision time and motor time components of total response time. Finally, a third experiment replicated Experiment 2 and demonstrated that the stimulus- and response- components of task switching and conflict processing elicit dissociable neural activity as evidence by event-related brain potentials