How our brains reason logically

The aim of this article is to strengthen links between cognitive brain research and formal logic. The work covers three fundamental sorts of logical inferences: reasoning in the propositional calculus, i.e. inferences with the conditional “if...then”, reasoning in the predicate calculus, i.e. inferences based on quantifiers such as “all”, “some”, “none”, and reasoning with n-place relations. Studies with brain-damaged patients and neuroimaging experiments indicate that such logical inferences are implemented in overlapping but different bilateral cortical networks, including parts of the fronto-temporal cortex, the posterior parietal cortex, and the visual cortices. I argue that these findings show that we do not use a single deterministic strategy for solving logical reasoning problems. This account resolves many disputes about how humans reason logically and why we sometimes deviate from the norms of formal logic.

Good News for the Logical Autonomy of Ethics

Toomas Karmo claims that his taxonomy of ethical sentences has the result that there does not exist a sound argument with all non-ethical premises and an ethical conclusion. In a recent paper, Mark T. Nelson argues against this claim. Nelson presents a sound argument that he takes to be such that (i) Karmo’s taxonomy classifies that argument’s single premise as non-ethical and (ii) Karmo’s taxonomy classifies that argument’s conclusion as ethical. I attempt to show that Nelson is mistaken about (ii). For any possible world at which the premise of Nelson’s argument is true, Karmo’s taxonomy classifies the conclusion of Nelson’s argument as non-ethical.

Logical information and epistemic space

Gaining information can be modelled as a narrowing of epistemic space. Intuitively, becoming informed that such-and-such is the case rules out certain scenarios or would-be possibilities. Chalmers’s account of epistemic space treats it as a space of a priori possibility and so has trouble in dealing with the information which we intuitively feel can be gained from logical inference. I propose a more inclusive notion of epistemic space, based on Priest’s notion of open worlds yet which contains only those epistemic scenarios which are not obviously impossible. Whether something is obvious is not always a determinate matter and so the resulting picture is of an epistemic space with fuzzy boundaries.     

Tractarian objects and logical categories

It has been much debated whether Tractarian objects are what Russell would have called particulars or whether they include also properties and relations. This paper claims that the debate is misguided: there is no logical category such that Wittgenstein intended the reader of the Tractatus to understand his objects either as providing examples of or as not providing examples of that category. This is not to say that Wittgenstein set himself against the very idea of a logical category: quite the contrary. However, where Russell presents his logical variety of particulars and the various types of universal, and Frege presents his of objects and the various types of function, Wittgenstein denies the propriety of such a priori expositions. Wittgenstein envisages a variety of logical types of entity but insists that the nature of these types is something to be discovered only through analysis. This research was conducted whilst holding a Jacobsen Research Fellowship at the University of London.     

From Glossy to Greasy: The Impact of Learned Associations on Perceptions of Food Healthfulness

We demonstrate that consumers have learned that unhealthy snacks such as potato chips tend to be sold in glossy packages, whereas healthier snacks such as crackers tend to be sold in matte packages (in studies 1–3). As a result, consumers who see a snack food package with a glossy [matte] surface will infer lesser [greater] healthfulness of its contents (study 4), consume less [more] of it (study 5), and be more likely to choose a glossy [matte] package from an assortment of snack packages if motivated to engage in tasty [healthful] eating (study 6). Theoretical and managerial implications as well as future research opportunities are discussed.     

知觉者与行为者贫富对自发特质推理的影响

本研究采用探测词再认范式,分3个研究考察了知觉者和行为者的贫富对个体自发特质推理的影响。研究1考察了知觉者贫富对自发特质推理的影响,结果表明富裕启动条件下的被试更可能进行自发特质推理。研究2考察了行为者贫富对自发特质推理的影响,结果表明被试更有可能对富人刻板一致的行为句子进行自发特质推理。研究3考察了知觉者和行为者贫富对自发特质推理的交互影响,结果发现仅富裕启动条件下的被试更可能对富人刻板一致句子进行自发特质推理。本研究为自发特质推理发生的灵活性提供了新证据。     

Priming divergent thinking promotes logical reasoning in 6- to 8-year olds: But more for high than low SES students

Divergent thinking is a component of creativity. In the following study, we argue that this form of thinking also underlies logical reasoning. A total of 205 early elementary school children in Grades 1 and 2, from high and moderately low SES environments, were given a short-term prime for divergent thinking and simple reasoning problems. Overall, receiving this prime significantly improved logical reasoning at both grade levels. High and low SES students had similar levels of working memory, inhibitory control, performance on the divergent thinking task, and levels of logical reasoning without the prime. However, also consistent with our predictions, only high SES students showed overall improved logical reasoning following the divergent thinking prime, with the SES difference concentrated in the younger students. These results suggest that environmental differences in openness to alternatives and divergent thinking might underlie developing SES differences in levels of logical thinking.     

Facial first impressions and partner preference models: Comparable or distinct underlying structures?

Given the frequency of relationships nowadays initiated online, where impressions from face photographs may influence relationship initiation, it is important to understand how facial first impressions might be used in such contexts. We therefore examined the applicability of a leading model of verbally expressed partner preferences to impressions derived from real face images and investigated how the factor structure of first impressions based on potential partner preference-related traits might relate to a more general model of facial first impressions. Participants rated 1,000 everyday face photographs on 12 traits selected to represent (Fletcher, et al. 1999, Journal of Personality and Social Psychology, 76, 72) verbal model of partner preferences. Facial trait judgements showed an underlying structure that largely paralleled the tripartite structure of Fletcher et al.'s verbal preference model, regardless of either face gender or participant gender. Furthermore, there was close correspondence between the verbal partner preference model and a more general tripartite model of facial first impressions derived from a different literature (Sutherland et al., 2013, Cognition, 127, 105), suggesting an underlying correspondence between verbal conceptual models of romantic preferences and more general models of facial first impressions.