The Selective Laziness of Reasoning

Reasoning research suggests that people use more stringent criteria when they evaluate others' arguments than when they produce arguments themselves. To demonstrate this “selective laziness,” we used a choice blindness manipulation. In two experiments, participants had to produce a series of arguments in response to reasoning problems, and they were then asked to evaluate other people's arguments about the same problems. Unknown to the participants, in one of the trials, they were presented with their own argument as if it was someone else's. Among those participants who accepted the manipulation and thus thought they were evaluating someone else's argument, more than half (56% and 58%) rejected the arguments that were in fact their own. Moreover, participants were more likely to reject their own arguments for invalid than for valid answers. This demonstrates that people are more critical of other people's arguments than of their own, without being overly critical: They are better able to tell valid from invalid arguments when the arguments are someone else's rather than their own.     

Evidentialism and skeptical arguments

Cartesian skepticism about epistemic justification (??skepticism??) is the view that many of our beliefs about the external world??e.g., my current belief that I have hands??aren??t justified. I examine the two most influential arguments for skepticism??the Closure Argument and the Underdetermination Argument??from an evidentialist perspective. For both arguments it??s clear which premise the anti-skeptic must deny. The Closure Argument, I argue, is the better argument in that its key premise is weaker than the Underdetermination Argument??s key premise. Next I examine ways of motivating each argument??s key premise. I argue that attempts to motivate them which appeal to one??s having the same evidence in skeptical scenarios, to skeptical hypotheses?? alleged ability to explain our evidence just as well as real world hypotheses, or to the fact that if skeptical scenarios were true everything would appear just as it does all fail to provide any motivation for the premises or for skepticism. But I close by considering a different argument for the key premises and skepticism that lacks the central defect of these other arguments. Future work on skepticism should focus on this final argument at the expense of the others.     

The diversity principle in the testing of arguments

According to the diversity principle of scientific reasoning, hypotheses receive greater confirmation when they are supported by diverse rather than similar sets of data. This article examines whether people reason like intuitive scientists by conforming to the diversity principle in the testing of arguments. The results of two experiments demonstrate that people do indeed conform to the diversity principle by choosing a set of diverse rather than similar premises to test the conclusion of an argument. These findings are discussed in terms of the different reasoning processes involved in argument evaluation, argument testing, and rule discovery.     

When controversial leaders with charisma are effective: the influence of terror on the need for vision and impact of mixed attitudinal messages

We investigated the idea that a charismatic leader with a controversial message is most likely to persuade people in times of terror, because in those times people have a high need for vision, and vision is what a charismatic leader provides. In addition, we argued that the leader's message should contain a pro‐attitudinal position as well, as this makes the counter‐attitudinal message more palatable. In line with our hypotheses, we found in Experiment 1 that thinking about terrorism increases people's need for vision. Experiment 2 revealed that only when people have a high need for vision they will be influenced by a controversial charismatic leader. Experiment 3 showed that existential threats also directly increase the influence of a controversial charismatic leader. Further, this was especially so when the charismatic leader was both attractive and communicated his message in a charismatic way. Finally, Experiment 4 revealed that after thinking about their own death or about terrorist attacks, people were most likely to be persuaded by a controversial charismatic leader whose counter‐attitudinal message also contained pro‐attitudinal statements. Together, this research suggests that in times of terror people's need for vision increases, which opens them up to a counter‐attitudinal message of a charismatic leader as long as this message also includes some pro‐attitudinal statements. Copyright © 2006 John Wiley & Sons, Ltd.     

Leaping to Conclusions: Why Premise Relevance Affects Argument Strength

Everyday reasoning requires more evidence than raw data alone can provide. We explore the idea that people can go beyond this data by reasoning about how the data was sampled. This idea is investigated through an examination of premise non‐monotonicity, in which adding premises to a category‐based argument weakens rather than strengthens it. Relevance theories explain this phenomenon in terms of people's sensitivity to the relationships among premise items. We show that a Bayesian model of category‐based induction taking premise sampling assumptions and category similarity into account complements such theories and yields two important predictions: First, that sensitivity to premise relationships can be violated by inducing a weak sampling assumption; and second, that premise monotonicity should be restored as a result. We test these predictions with an experiment that manipulates people's assumptions in this regard, showing that people draw qualitatively different conclusions in each case.     

Category-based induction: An effect of conclusion typicality

Category-based induction involves the willingness of a thinker to project some newly learned property of one or more classes of objects to another class on the basis of their shared membership in a common superordinate category. Previous research has established that the perceived strength of arguments of the form "Class A has Property P; therefore, Class B has Property P" is influenced by the similarity of A to B and by the typicality or representativeness of A in a shared category, superordinate to both A and B. (The nature of P is also crucial, but we do not examine it in this study.) There is, however, no prior evidence that the relation between B and the category is influential. Three experiments were designed to test whether the typicality of B in the superordinate category also has an effect on inductive argument strength. By using multiple regression (Experiment 1) and an experimental design (Experiment 3), an effect of conclusion typicality was found, so that people are more willing to project properties to more typical conclusions. Experiment 2 ruled out conclusion familiarity as a potential confounding variable. The results are interpreted in the light of current models of category-based induction.     

Food rejection and the development of food category-based induction in 2–6 years old children

We studied children’s inductive inferences within the domain of food categories. There has so far been little research on inductive reasoning about food among children, despite the theoretical and practical importance of knowing what knowledge children bring to the table and how they use it. We tested the hypotheses that children’s food category-based induction performances and their food rejection are negatively correlated, and that these performances are influenced by the colour typicality of the food items. We recruited 126 children aged 2–6 years, and administered a category-based induction task. Participants were successively shown 8 sets of three pictures containing one target picture (a vegetable) and two test pictures (a vegetable dissimilar in colour to the target picture and a fruit similar in colour to the target picture). For each set, participants were told a novel property about the target picture and asked to generalise this property to one of the two test pictures. Additionally, the parents of each child filled out a questionnaire about his or her food rejection tendencies. Results on accuracy (i.e. if participants generalised the properties according to category membership, not perceptual similarity) provided the first empirical evidence in favour of a negative relationship between children’s food rejection and food category-based induction.     

Differences in the Evaluation of Generic Statements About Human and Non‐Human Categories

Generic statements (e.g., “Birds lay eggs”) express generalizations about categories. Current theories suggest that people should be especially inclined to accept generics that involve threatening information. However, previous tests of this claim have focused on generics about non‐human categories, which raises the question of whether this effect applies as readily to human categories. In Experiment 1, adults were more likely to accept generics involving a threatening (vs. a non‐threatening) property for artifacts, but this negativity bias did not also apply to human categories. Experiment 2 examined an alternative hypothesis for this result, and Experiments 3 and 4 served as conceptual replications of the first experiment. Experiment 5 found that even preschoolers apply generics differently for humans and artifacts. Finally, Experiment 6 showed that these effects reflect differences between human and non‐human categories more generally, as adults showed a negativity bias for categories of non‐human animals, but not for categories of humans. These findings suggest the presence of important, early‐emerging domain differences in people's judgments about generics.     

Induction as conditional probability judgment

Existing research on category-based induction has primarily focused on reasoning about blank properties, or predicates that are designed to elicit little prior knowledge. Here, we address reasoning about nonblank properties. We introduce a model of conditional probability that assumes that the conclusion prior probability is revised to the extent warranted by the evidence in the premise. The degree of revision is a function of the relevance of the premise category to the conclusion and the informativeness of the premise statement. An algebraic formulation with no free parameters accurately predicted conditional probabilities for single- and two-premise conditionals (Experiments 1 and 3), as well as problems involving negative evidence (Experiment 2).     

How many processes underlie category-based induction? Effects of conclusion specificity and cognitive ability

Two studies investigated participants' sensitivity to the amount and diversity of the evidence when reasoning inductively about categories. Both showed that participants are more sensitive to characteristics of the evidence for arguments with general rather than specific conclusions. Both showed an association between cognitive ability and sensitivity to these evidence characteristics, particularly when the conclusion category was general. These results suggest that a simple associative process may not be sufficient to capture somekey phenomena of category-based induction. They also support the claim that the need to generate a superordinate category is a complicating factor in category-based reasoning and that adults' tendency to generate such categories while reasoning has been overestimated.     

Modulation of the leniency bias in the discursive dilemma

We experimentally approach the discursive dilemma to gain insight into people's procedural appropriateness judgments. We relied on a vignette in which three people had formed opinions about two skills (premises) of a candidate to decide whether to hire her/him (conclusion). The dilemma arises when different outcomes (hire vs. not hire) are achieved depending on whether the majority opinion is independently considered for each premise or for the global conclusion of each judge. Participants were asked to choose the procedure they thought to be more appropriate to reach a decision. In Experiment 1, we found a leniency effect (a bias to prefer the aggregation procedure that led to hiring the candidate), which was reduced by introducing the participant as a juror with an exogenously provided negative opinion about the candidate's skills. In Experiment 2, we replicated the opinion effect, even when subjects did not participate as jury members. In Experiment 3, we found that the leniency bias was only reduced when participants' negative opinion was aligned with a majority of negative premises, but not with a majority of negative conclusions. We discuss present findings in terms of the identification of empirical regularities that may affect people's procedural legitimacy judgments.     

Category-based and attribute-based reactions to others: Some informational conditions of stereotyping and individuating processes

This paper suggests that people can form impressions in a variety of ways that range from primarily category-based processes to primarily attribute-based processes, and that the process partially depends on the configuration of available information. Easily categorized configurations are hypothesized to elicit relatively category-based processes, while not easily categorized configurations are hypothesized to elicit relatively attribute-based processes. In Experiment 1, subjects first rated the likability of job-category labels and relevant trait attributes, in isolation from each other. At a later session, stimulus people were depicted by category labels (occupations) and relevant attributes (traits) in varying combinations. Typicality ratings confirmed the manipulated ease of categorizing the various information combinations. Correlations between subjects' evaluations of each stimulus person and their independent prior ratings of the components supported the idea of a continuum anchored respectively by relatively category-based and by relatively attribute-based impression formation processes. In the second study, think-aloud data further supported the current hypotheses: subjects spontaneously examined the fit between category and attributes, and they used the attributes more in the attribute-based conditions than in the category-based conditions. The protocol data also reveal some processes intermediate on the continuum between primarily category-based and primarily attribute-based processes; these include subcategorizing, generating new categories, and self-reference. Social perceivers apparently use flexible impression formation processes, depending on the configuration of available information.     

When others cross psychological distance to help: Highlighting prosocial actions toward outgroups encourages philanthropy

Prior research has found several factors that affect people's willingness to participate in philanthropy. In the present article, we explore whether people feel more inspired to engage in philanthropy after learning about individuals who help targets who are socially close or distant from those individuals. Specifically, we propose that when people learn about others who help socially distant (vs. close) targets, such prosocial actions will be more salient because it violates people's lay belief about distance and helping; therefore, people will be more attracted to the idea of engaging in prosocial actions after learning that prosocial actions have been directed toward socially distant (vs. close) targets. We present four experiments in support of our hypotheses.     

How do people learn from negative evidence? Non-monotonic generalizations and sampling assumptions in inductive reasoning

A robust finding in category-based induction tasks is for positive observations to raise the willingness to generalize to other categories while negative observations lower the willingness to generalize. This pattern is referred to as monotonic generalization. Across three experiments we find systematic non-monotonicity effects, in which negative observations raise the willingness to generalize. Experiments 1 and 2 show that this effect emerges in hierarchically structured domains when a negative observation from a different category is added to a positive observation. They also demonstrate that this is related to a specific kind of shift in the reasoner’s hypothesis space. Experiment 3 shows that the effect depends on the assumptions that the reasoner makes about how inductive arguments are constructed. Non-monotonic reasoning occurs when people believe the facts were put together by a helpful communicator, but monotonicity is restored when they believe the observations were sampled randomly from the environment.     

Perceptions of entitativity and attitude change

The current work explored the properties of groups that lead them to be persuasive and the processes through which such persuasion occurs. Because more entitative groups induce greater levels of information processing, their arguments should receive greater elaboration, leading to persuasion when members of groups present strong (vs. weak) counter attitudinal arguments. Experiment 1 explored these hypotheses by examining if idiosyncratic perceptions of group entitativity and manipulations of argument strength affect attitude change and argument elaboration. Experiment 2 experimentally manipulated group entitativity and argument strength independently to examine the causal relationship between entitativity, attitude change, and argument elaboration. In both experiments, it was found that groups greater in entitativity were more persuasive when presenting strong (vs. weak) arguments and induced greater argument elaboration. Implications for our understanding of entitativity, persuasion, and information processing about social groups are discussed.     

Feature-based versus category-based induction with uncertain categories

Previous research has suggested that when feature inferences have to be made about an instance whose category membership is uncertain, feature-based inductive reasoning is used to the exclusion of category-based induction. These results contrast with the observation that people can and do use category-based induction when category membership is known. The present experiments examined the conditions that drive feature-based and category-based strategies in induction under category uncertainty. Specifically, 2 experiments investigated whether reliance on feature-based inductive strategies is a product of the lack of coherence in the categories used in previous research or is due to the use of a decision-only induction procedure. Experiment 1 found that feature-based reasoning remained the preferred strategy even when categories with relatively high internal coherence were used. Experiment 2 found a shift toward category-based reasoning when participants were trained to classify category members prior to feature induction. Together, these results suggest that an appropriate conceptual representation must be formed through experience with a category before it is likely to be used as a basis for feature induction.     

On the Interaction of Theory and Data in Concept Learning

Standard models of concept learning generally focus on deriving statistical properties of a category based on data (i.e., category members and the features that describe them) but fail to give appropriate weight to the contact between people's intuitive theories and these data. Two experiments explored the role of people's prior knowledge or intuitive theories on category learning by manipulating the labels associated with the category. Learning differed dramatically when categories of children's drawings were meaningfully labeled (e.g., “done by creative children”) compared to when they were labeled in a neutral manner. When categories are meaningfully labeled, people bring intuitive theories to the learning context. Learning then involves a process in which people search for evidence in the data that supports abstract features or hypotheses that have been activated by the intuitive theories. In contrast, when categories are labeled in a neutral manner, people search for simple features that distinguish one category from another. Importantly, the final study suggests that learning involves an interaction of people's intuitive theories with data, in which theories and data mutually influence each other. The results strongly suggest that straight-forward, relatively modular ways of incorporating prior knowledge into models of category learning are inadequate. More telling, the results suggest that standard models may have fundamental limitations. We outline a speculative model of learning in which the interaction of theory and data is tightly coupled. The article concludes by comparing the results to recent artificial intelligence systems that use prior knowledge during learning.     

Effects of conflicting scientific arguments on belief change: Argument evaluation and expert consensus perception as mediators

In our society, people are often exposed to conflicting information about a scientific issue. However, our knowledge about the effects of exposure to conflicting scientific information is still highly limited. By combining paradigms of research on belief polarization and science communication, two experiments examined whether and how exposure to conflicting scientific arguments influences scientific belief change and behavioral intentions. Participants (Experiment 1, N = 102; Experiment 2, N = 115) received two conflicting arguments (favorable and unfavorable to the effects of vitamin C supplementation on the prevention and treatment of the common cold) or two nonconflicting arguments (unfavorable to and neutral on the vitamin C supplementation effects). Exposure to conflicting arguments changed participants' beliefs about the preventing and treating effects of vitamin C supplementation less than exposure to nonconflicting arguments but did not cause actual belief polarization. Compared with participants who received nonconflicting arguments, those who received conflicting arguments perceived the quality of unfavorable argument to be low and experts' opinions about the issues to be divided, resulting in modest belief change. Exposure to conflicting arguments also promoted the formation of moderate behavioral intentions to take a regular high dose of vitamin C as a result of the belief change.     

类别不确定下的特征推理是基于类别还是基于特征联结

共有3个实验探讨归类不确定情况下的特征推理是基于类别进行还是基于特征联结进行。实验1在中文条件下重复了Verde等人2005的实验,得出了与之相符的结果,这个结果用基于类别的理性模型的设想或者是用基于特征联结的设想都可以解释。实验2考察被试在靶类别的类别特征频次并且特征结合出现频次高低不同的条件下特征推理的情况,实验2的结果表明,高集中与低集中两种条件下特征推理没有显著差异,不符合特征推理是基于类别进行的设想,而与特征推理是基于特征联结进行的设想吻合。实验3进一步考察被试在特征结合出现的总频次并且靶类别中特征结合出现的总频次高低不同的条件下特征推理的情况,结果表明,在高结合条件下进行特征推理要优于在低结合条件,支持了在归类不确定情况下的特征推理是基于特征联结进行的设想。据此可以认为,人们的特征推理是基于特征之间联结的频次进行,而不是基于类别进行     

Stable Causal Relationships Are Better Causal Relationships

We report three experiments investigating whether people's judgments about causal relationships are sensitive to the robustness or stability of such relationships across a range of background circumstances. In Experiment 1, we demonstrate that people are more willing to endorse causal and explanatory claims based on stable (as opposed to unstable) relationships, even when the overall causal strength of the relationship is held constant. In Experiment 2, we show that this effect is not driven by a causal generalization's actual scope of application. In Experiment 3, we offer evidence that stable causal relationships may be seen as better guides to action. Collectively, these experiments document a previously underappreciated factor that shapes people's causal reasoning: the stability of the causal relationship.