The psychological puzzle of Sudoku

Sudoku puzzles, which are popular worldwide, require individuals to infer the missing digits in a 9 × 9 array according to the general rule that every digit from 1 to 9 must occur once in each row, in each column, and in each of the 3-by-3 boxes in the array. We present a theory of how individuals solve these puzzles. It postulates that they rely solely on pure deductions, and that they spontaneously acquire various deductive tactics, which differ in their difficulty depending on their “relational complexity”, i.e., the number of constraints on which they depend. A major strategic shift is necessary to acquire tactics for more difficult puzzles: solvers have to keep track of possible digits in a cell. We report three experiments corroborating this theory. We also discuss their implications for theories of reasoning that downplay the role of deduction in everyday reasoning.     

Positive fantasies dampen charitable giving when many resources are demanded

Previous research found that positive fantasies about an idealized future yield low energy to pursue the fantasized future. We examined how positive fantasies about the resolution of a crisis (i.e., a lack of pain medication in Sierra Leone, the risk of flooding after Hurricane Irene) influence people's agreement to donate to charitable efforts directed at crisis resolution. In three studies, positive fantasies dampened the likelihood of agreeing to donate a relatively large amount of money, effort, or time, but did not affect the likelihood of agreeing to donate a relatively small amount of these resources. The effect of positive fantasies was mediated by perceiving the donation of larger (but not smaller) amounts of resources as overly demanding. These findings suggest that charitable solicitations requesting small donations might benefit from stimulating positive fantasies in potential donors, but those requesting large donations could be hurt.     

Young children’s analogical problem solving: Gaining insights from video displays

This study examined how toddlers gain insights from source video displays and use the insights to solve analogous problems. The sample of 2- and 2.5-year-olds viewed a source video illustrating a problem-solving strategy and then attempted to solve analogous problems. Older, but not younger, toddlers extracted the problem-solving strategy depicted in the video and spontaneously transferred the strategy to solve isomorphic problems. Transfer by analogy from the video was evident only when the video illustrated the complete problem goal structure, including the character’s intention and the action needed to achieve a goal. The same action isolated from the problem-solving context did not serve as an effective source analogue. These results illuminate the development of early representation and processes involved in analogical problem solving. Theoretical and educational implications are discussed.     

Variation in Coordination of a Discrete Multiarticular Action as a Function of Skill Level

The authors investigated coordination modes that emerged as a function of the interaction between skill level and task constraints in a multiarticular kicking action. Five skilled, 5 intermediate, and 5 novice participants attempted to satisfy specific height and accuracy constraints in kicking a ball over a barrier. Skilled and intermediate groups demonstrated a functional coordination mode involving less joint involvement at the proximal joints and greater joint involvement at distal joints, mimicking a chip-like action in soccer. Conversely, the novice group tended to produce larger ranges of motion throughout the kicking limb in a driving-like kicking action. Key differences were also found for task outcome scores, joint angle-angle relations, and ball-trajectory plots between the skilled and intermediate groups and the novice group. Findings from this study demonstrated that joint involvement during this discrete multiarticular action is a function of skill level and task constraints rather than a consequence of a global freezing-freeing strategy suggested in some previous research. The authors also highlight the merit of using a model of the acquisition of coordination in examining how coordination modes for multiarticular actions differ as a function of skill.     

An epistemic and dynamic approach to abductive reasoning: Abductive problem and abductive solution

We propose a study of abductive reasoning addressing it as an epistemic process that involves both an agent?s information and the actions that modify this information. More precisely, we present and discuss definitions of an abductive problem and an abductive solution in terms of an agent?s information, that is, in terms of knowledge and beliefs. The discussion is then formalised by ‘implementing’ our definitions in a dynamic epistemic logic framework, where the properties of these definitions are studied, an epistemic action that represents the application of an abductive step is introduced, and an illustrative example is provided. A number of the most interesting properties of abductive reasoning (those highlighted by Peirce) are shown to be better modelled within this approach.     

Nationwide survey of contraceptive and sexually transmitted infection knowledge,attitudes and skills of university students in Portugal

Sexually transmitted infections and (STIs) unintended pregnancies are contemporary public health concerns. Understanding factors (e.g. knowledge, attitudes and skills) influencing sexual behaviours of university students are critical to develop targeted and tailored risk-reduction interventions for this vulnerable population. Thus, the goals of this study were to describe sexual behaviours and analyze differences between genders for sexual behaviours; to identify whether differences exist between genders and age groups regarding knowledge, attitudes and skills concerning contraceptive methods and STIs, and to evaluate the association of knowledge with attitudes and skills with sexual behaviour among university students in Portugal. The sample included 3278 students. Results show that the majority were sexually active and use condoms and oral contraceptives. In general, university students have high knowledge, positive attitudes and skills about contraception and STIs. Gender analyses indicated that women had greater knowledge, and more favourable attitudes, and higher skills toward contraceptive and STI preventive behaviour College students, in particular, face new challenges in sexual health and would benefit from more comprehensive education aimed at promoting healthy decision-making about family planning and STI prevention.     

Power of the desired self: Influence of induced perceptions of the self on reasoning

This research shows that the motivation to posses a desired characteristic (or to avoid an undesired one) results in self-perceptions that guide people’s use of base rate in the Lawyer–Engineer problem (Kahneman & Tversky, 1973). In four studies, participants induced to believe (or recall, Exp. 2) that a rational cognitive style is success-conducive (or an intuitive cognitive style failure-conducive) subsequently viewed themselves as more rational and relied more on base rate in their probability estimates than those induced to believe that a rational cognitive style is failure-conducive (or an intuitive cognitive style success-conducive). These findings show that the desired self had an influence on reasoning in the self-unrelated lawyer–engineer task, since the use of base rates was mediated by changes in participants’ perceptions of their own rationality. These findings therefore show that the desired self, through the working self-concept that it entails, constitutes another factor influencing people’s use of distinct modes of reasoning.     

Intuition, reason, and metacognition

Dual Process Theories (DPT) of reasoning posit that judgments are mediated by both fast, automatic processes and more deliberate, analytic ones. A critical, but unanswered question concerns the issue of monitoring and control: When do reasoners rely on the first, intuitive output and when do they engage more effortful thinking? We hypothesised that initial, intuitive answers are accompanied by a metacognitive experience, called the Feeling of Rightness (FOR), which can signal when additional analysis is needed. In separate experiments, reasoners completed one of four tasks: conditional reasoning (N = 60), a three-term variant of conditional reasoning (N = 48), problems used to measure base rate neglect (N = 128), or a syllogistic reasoning task (N = 64). For each task, participants were instructed to provide an initial, intuitive response to the problem along with an assessment of the rightness of that answer (FOR). They were then allowed as much time as needed to reconsider their initial answer and provide a final answer. In each experiment, we observed a robust relationship between the FOR and two measures of analytic thinking: low FOR was associated with longer rethinking times and an increased probability of answer change. In turn, FOR judgments were consistently predicted by the fluency with which the initial answer was produced, providing a link to the wider literature on metamemory. These data support a model in which a metacognitive judgment about a first, initial model determines the extent of analytic engagement.     

Mental abilities and school achievement: A test of a mediation hypothesis

This study analyzes the interplay of four cognitive abilities - reasoning, divergent thinking, mental speed, and short-term memory - and their impact on academic achievement in school in a sample of adolescents in grades seven to 10 (N = 1135). Based on information processing approaches to intelligence, we tested a mediation hypothesis, which states that the complex cognitive abilities of reasoning and divergent thinking mediate the influence of the basic cognitive abilities of mental speed and short-term memory on achievement. We administered a comprehensive test battery and analyzed the data through structural equation modeling while controlling for the cluster structure of the data. Our findings support the notion that mental speed and short-term memory, as ability factors reflecting basic cognitive processes, exert an indirect influence on academic achievement by affecting reasoning and divergent thinking (total indirect effects: β = .22 and .24, respectively). Short-term memory also directly affects achievement (β = .22).