How green defaults promote environmentally friendly decisions: Attitude‐conditional default acceptance but attitude‐unconditional effects on actual choices

Defaults (i.e., options that become effective without an active choice) have been found to be powerful tools to influence decision‐making in a range of behavioral domains. However, seemingly conflicting assumptions have been expressed regarding the interplay of defaults with individual attitudes. Whereas some expect attitude‐conditional effects (i.e., a statistical default‐by‐attitude interaction), others assume an attitude‐unconditional effectiveness of defaults (i.e., statistically additive effects). Integrating both assumptions, we argue that the interplay of defaults and attitudes depends on what is considered a default effect. Specifically, whereas default acceptance is likely to be attitude‐conditional, we predicted that defaults and attitudes would add up in explaining people's actual choices. We tested these hypotheses in an online shopping scenario presenting environmentally friendly or conventional default products to 231 participants. Participants’ environmental attitude was assessed with the General Ecological Behavior scale and actual product choices were identified if participants rejected a given default product. In line with our hypotheses, default acceptance was predicted by a default‐by‐attitude interaction. In contrast, actual environmentally friendly product choices were found to be an additive function of defaults and participants’ environmental attitude. From an applied perspective, our findings suggest that defaults can readily be applied even in attitude‐heterogeneous target populations. Concurrently, however, our findings also speak of the importance of people's attitudes for understanding individual decision‐making.     

System JLZ – rational default reasoning by minimal ranking constructions

We present a powerful quasi-probabilistic default formalism for graded defaults based on a well-motivated canonical ranking construction procedure, System JLZ. It implements the minimal construction paradigm and verifies the major inference principles and inheritance desiderata, including rational monotony for propositions and structured cumulativity for default conditionals. With help from a structured ranking semantics for defaults, it also avoids some drawbacks of semi-qualitative entropy maximization and other competing accounts.     

Constraints for Input/Output Logics

In a previous paper we developed a general theory of input/output logics. These are operations resembling inference, but where inputs need not be included among outputs, and outputs need not be reusable as inputs. In the present paper we study what happens when they are constrained to render output consistent with input. This is of interest for deontic logic, where it provides a manner of handling contrary-to-duty obligations. Our procedure is to constrain the set of generators of the input/output system, considering only the maximal subsets that do not yield output conflicting with a given input. When inputs are authorised to reappear as outputs, both maxichoice revision in the sense of Alchourrón/Makinson and the default logic of Poole emerge as special cases, and there is a close relation with Reiter default logic. However, our focus is on the general case where inputs need not be outputs. We show in what contexts the consistency of input with output may be reduced to its consistency with a truth-functional combination of components of generators, and under what conditions constrained output may be obtained by a derivation that is constrained at every step.     

默认选项设置的助推效果：来自元分析的证据

默认选项设置指通过设置默认选项以增加人们选择该选项可能性的助推方法, 近年来被越来越多地运用于促进公众积极行为上, 然而这种方法在有效性上却受到了来自公众和学者的质疑。据此, 本研究运用元分析法整合了近几年有关默认选项设置的已有实证研究, 分析该助推手段的有效性, 并进一步考察可能影响其有效性的相关变量。研究共纳入符合要求的原始文献56篇, 含92个研究, 结果发现：(1)默认选项设置的确能有效助推人们的行为; (2)默认选项设置的助推有效性在东、西方文化下存在显著差异, 其在西方文化背景下的助推效果要显著好于其在东方文化背景下的使用; (3)默认选项设置的助推有效性在不同情境应用领域中存在显著差异, 相较于健康和环保领域, 默认选项设置在金钱相关的情境领域下助推效果更好。     

Probabilistic Logic Under Coherence, Conditional Interpretations, and Default Reasoning

We study a probabilistic logic based on the coherence principle of de Finetti and a related notion of generalized coherence (g-coherence). We examine probabilistic conditional knowledge bases associated with imprecise probability assessments defined on arbitrary families of conditional events. We introduce a notion of conditional interpretation defined directly in terms of precise probability assessments. We also examine a property of strong satisfiability which is related to the notion of toleration well known in default reasoning. In our framework we give more general definitions of the notions of probabilistic consistency and probabilistic entailment of Adams. We also recall a notion of strict p-consistency and some related results. Moreover, we give new proofs of some results obtained in probabilistic default reasoning. Finally, we examine the relationships between conditional probability rankings and the notions of g-coherence and g-coherent entailment.     

Exploiting asymmetric signals from choices through default selection

Setting defaults is an effective nudge, but few studies have examined situations where individuals can select their own default settings. Past research suggests that even when the final outcome is identical, observers perceive stronger signals from choices that switch from, rather than stay with, the default. In five experiments using hypothetical scenarios and an incentivized economic game, we test whether decision-makers driven by image concerns could strategically exploit that asymmetric signal. We found that in the presence of observers, participants were more likely to self-select into defaults that require them to switch to enhance a positive signal and into defaults that require them to stay to attenuate a negative signal. Our results support the framework of choice architecture as an implicit social interaction, and have potential implications for behavioral interventions in real-world settings.

     

Minimally inconsistent LP

The paper explains how a paraconsistent logician can appropriate all classical reasoning. This is to take consistency as a default assumption, and hence to work within those models of the theory at hand which are minimally inconsistent. The paper spells out the formal application of this strategy to one paraconsistent logic, first-order LP. (See, Ch. 5 of: G. Priest, In Contradiction, Nijhoff, 1987.) The result is a strong non-monotonic paraconsistent logic agreeing with classical logic in consistent situations. It is shown that the logical closure of a theory under this logic is trivial only if its closure under LP is trivial.     

Partitioning default effects: why people choose not to choose

Default options exert an influence in areas as varied as retirement program design, organ donation policy, and consumer choice. Past research has offered potential reasons why no-action defaults matter: (a) effort, (b) implied endorsement, and (c) reference dependence. The first two of these explanations have been experimentally demonstrated, but the latter has received far less attention. In three experiments we produce default effects and demonstrate that reference dependence can play a major role in their effectiveness. We find that the queries formulated by defaults can produce differences in constructed preferences and further that manipulating queries can also mitigate default effects. The experimental context involves two environmentally consequential alternatives: cheap, inefficient incandescent light bulbs, and expensive, efficient compact fluorescent bulbs. Within this context we also measure the impact of each potential rationale for a default effect.     

Explaining default intuitions using maximum entropy

While research into default reasoning is extensive and many default intuitions are commonly held, no one system has yet captured all these intuitions nor given a formal account to motivate them. This paper argues that the extended maximum entropy approach which incorporates variable strength defaults provides a benchmark for default reasoning that is not only objectively motivated but also satisfies all the accepted default intuitions. It is shown that the behaviour of the approach coincides with a wide range of default intuitions taken from examples in the literature, and can be used to explain why some examples have led to confusion. Moreover, analysing the solutions produced by the maximum entropy approach enables clearer differentiation between the default knowledge they contain and the default inferences required of the reasoning system. This suggests that the maximum entropy approach can be used as a benchmark both for eliciting default knowledge when building a knowledge base and, by comparison, for clarifying the underlying biases of other default reasoning systems.     

Non-monotonicity and Informal Reasoning: Comment on Ferguson (2003)

In this paper, it is argued that Ferguson’s (2003, Argumentation 17, 335–346) recent proposal to reconcile monotonic logic with defeasibility has three counterintuitive consequences. First, the conclusions that can be derived from his new rule of inference are vacuous, a point that as already made against default logics when there are conflicting defaults. Second, his proposal requires a procedural “hack” to the break the symmetry between the disjuncts of the tautological conclusions to which his proposal leads. Third, Ferguson’s proposal amounts to arguing that all everyday inferences are sound by definition. It is concluded that the informal logic response to defeasibility, that an account of the context in which inferences are sound or unsound is required, still stands. It is also observed that another possible response is given by Bayesian probability theory (Oaksford and Chater, in press, Bayesian Rationality: The Probabilistic Approach to Human Reasoning, Oxford University Press, Oxford, UK; Hahn and Oaksford, in press, Synthese).     

Nudges and signposts: The effect of smart defaults and pictographic risk information on retirement saving investment choices

The authors tested two interventions to improve retirement savings investment decisions. In an incentive‐compatible experiment, 459 participants engaged in a task simulating their working life. Periodically during the simulation, participants chose between different investment options. The authors examined the effectiveness of a “nudge” by manipulating the default option and the effectiveness of a “signpost” by manipulating the display of a pictograph summarizing the expected return of each option. Participants often followed the default option, particularly when it was “smart” (i.e., became more conservative as retirement approached) and when presented together with dynamic pictographs (i.e., updated each year assuming the investment was held until retirement). Those most likely to make optimal choices (i.e., consistent with the life cycle model) were presented with a smart default or dynamic pictographs. These findings reveal how different choice architecture interventions can be used to positively influence behavior. Retirement funds and regulators can support retirement savings decisions by the provision of smart defaults and better risk information in the form of pictographs.     

Is Default Logic a Reinvention of Inductive-Statistical Reasoning?

Currently there is hardly any connection between philosophy of science and Artificial Intelligence research. We argue that both fields can benefit from each other. As an example of this mutual benefit we discuss the relation between Inductive-Statistical Reasoning and Default Logic. One of the main topics in AI research is the study of common-sense reasoning with incomplete information. Default logic is especially developed to formalise this type of reasoning. We show that there is a striking resemblance between inductive-statistical reasoning and default logic. A central theme in the logical positivist study of inductive-statistical reasoning such as Hempels Criterion of Maximal Specificity turns out to be equally important in default logic. We also discuss to what extent the relevance of the results of Logical Positivism to AI research could contribute to a reevaluation of Logical Positivism in general.     

Mass Nouns in a Logic of Classes as Many

A semantic analysis of mass nouns is given in terms of a logic of classes as many. In previous work it was shown that plural reference and predication for count nouns can be interpreted within this logic of classes as many in terms of the subclasses of the classes that are the extensions of those count nouns. A brief review of that account of plurals is given here and it is then shown how the same kind of interpretation can also be given for mass nouns.     

助推爱心：利用默认选项促进捐赠行为

本研究采用实验室和现场实验的方法检验了默认选项的助推策略是否能够促进慈善捐赠行为。结果发现：（1）相较于把被试费的“保留选项”设置为默认,把“捐献选项”设置为默认时,被试捐献的概率和金额更高;（2）在多个捐款选项情景中,默认选项的设置总体上提高了默认选项被选择的概率;将最大金额选项设置为默认选项有助于提高被试平均捐赠额。这些发现表明,应用默认选项的助推策略能够有效促进人们的捐赠行为。本研究结果对减少募捐成本、提高募捐效率有所启示。     

Frege on the generality of logical laws

Frege claims that the laws of logic are characterized by their “generality,” but it is hard to see how this could identify a special feature of those laws. I argue that we must understand this talk of generality in normative terms, but that what Frege says provides a normative demarcation of the logical laws only once we connect it with his thinking about truth and science. He means to be identifying the laws of logic as those that appear in every one of the scientific systems whose construction is the ultimate aim of science, and in which all truths have a place. Though an account of logic in terms of scientific systems might seem hopelessly antiquated, I argue that it is not: A basically Fregean account of the nature of logic still looks quite promising.     

Consistency,Truth and Ontology

After a brief survey of the different meanings of consistency, the study is restricted to consistency understood as non-contradiction of sets of sentences. The philosophical reasons for this requirement are discussed, both in relation to the problem of sense and the problem of truth (also with historical references). The issue of mathematical truth is then addressed, and the different conceptions of it are put in relation with consistency. The formal treatment of consistency and truth in mathematical logic is then considered, with particular attention paid to the relation between syntactic and semantic properties of sets and calculi. After the crisis of mathematical intuition and the dominance of the formalistic view, it seemed that consistency could totally replace the requirement of truth in mathematics, also in the sense that the existence of “objects” of axiomatic systems could be granted by their consistency. A rejection of this claim is presented, whose central point is a detailed analysis of the theorem that any consistent set S of sentences of first order logic has a model. A critical scrutiny shows that this model is very peculiar, being offered by the elements of the same language that is being interpreted, and the satisfiability conditions for any sentence being constituted by the mere fact of belonging to S. Though not being insignificant from a metatheoretical point of view, this theorem fails to endow consistency (even in this privileged case) with an “ontological creativity”, that is, with the capability of providing a model ontologically distinct from the language itself (which is the precondition for the classical notion of truth that is also preserved in the Tarskian semantics and model theory). A final discussion regarding the different “ontological regions” and the referential nature of truth clarifies the different aspects of the whole issue discussed.     

A base logic for default reasoning

Based on a close study of benchmark examples in default reasoning, such as Nixon Diamond, Penguin Principle, etc., this paper provides an in depth analysis of the basic features of default reasoning. We formalize default inferences based on Modus Ponens for Default Implication, and mark the distinction between “local inferences” (to infer a conclusion from a subset of given premises) and “global inferences” (to infer a conclusion from the entire set of given premises). These conceptual analyses are captured by a formal semantics that is built upon the set-selection function technique. A minimal logic system M of default reasoning that accommodates Modus Ponens for Default Implication and suitable for local inferences is proposed, and its soundness is proved. __________ Translated from Zhexue Yanjiu 哲学研究 (Philosophical Studies), 2003 (special issue) by Ye Feng     

Three paradoxes of medical diagnosis

Sadegh-zadeh [23] has proposed a theory of the relativity of medical diagnosis in terms of the time at which a diagnosis is accepted, the patient to whom the diagnosis applies, the physician who renders the diagnosis, the medical knowledge used, the diagnostic method applied, and the set of patient observations. Use of classical formal logic as the ‘diagnostic method’ may result in three paradoxes: the paradoxes of consistency, completeness, and justifiable ignorance. These paradoxes may be resolved by the addition of two non-classical operators, the ‘certainty’ and ‘effort’ operators, akin to the non-classical operators of modal logic.     

Logic with numbers

Many people regard utility theory as the only rigorous foundation for subjective probability, and even de Finetti thought the betting approach supplemented by Dutch Book arguments only good as an approximation to a utility-theoretic account. I think that there are good reasons to doubt this judgment, and I propose an alternative, in which the probability axioms are consistency constraints on distributions of fair betting quotients. The idea itself is hardly new: it is in de Finetti and also Ramsey. What is new is that it is shown that probabilistic consistency and consequence can be defined in a way formally analogous to the way these notions are defined in deductive (propositional) logic. The result is a free-standing logic which does not pretend to be a theory of rationality and is therefore immune to, among other charges, that of “logical omniscience”.     

An encompassing framework for Paraconsistent Logic Programs

We propose a framework which extends Antitonic Logic Programs [Damásio and Pereira, in: Proc. 6th Int. Conf. on Logic Programming and Nonmonotonic Reasoning, Springer, 2001, p. 748] to an arbitrary complete bilattice of truth-values, where belief and doubt are explicitly represented. Inspired by Ginsberg and Fitting's bilattice approaches, this framework allows a precise definition of important operators found in logic programming, such as explicit and default negation. In particular, it leads to a natural semantical integration of explicit and default negation through the Coherence Principle [Pereira and Alferes, in: European Conference on Artificial Intelligence, 1992, p. 102], according to which explicit negation entails default negation. We then define Coherent Answer Sets, and the Paraconsistent Well-founded Model semantics, generalizing many paraconsistent semantics for logic programs. In particular, Paraconsistent Well-Founded Semantics with eXplicit negation (WFSX_p) [Alferes et al., J. Automated Reas. 14 (1) (1995) 93–147; Damásio, PhD thesis, 1996]. The framework is an extension of Antitonic Logic Programs for most cases, and is general enough to capture Probabilistic Deductive Databases, Possibilistic Logic Programming, Hybrid Probabilistic Logic Programs, and Fuzzy Logic Programming. Thus, we have a powerful mathematical formalism for dealing simultaneously with default, paraconsistency, and uncertainty reasoning. Results are provided about how our semantical framework deals with inconsistent information and with its propagation by the rules of the program.