Knowledge as a thick concept: explaining why the Gettier problem arises

The Gettier problem has stymied epistemologists. But, whether or not this problem is resolvable, we still must face an important question: Why does the Gettier problem arise in the first place? So far, philosophers have seen it as either a problem peculiar to the concept of knowledge, or else an instance of a general problem about conceptual analysis. But I would like to steer a middle course. I argue that the Gettier problem arises because knowledge is a thick concept, and a Gettier-like problem is just what we should expect from attempts at analyzing a thick concept. Section 2 is devoted to establishing the controversial claim that knowledge is thick, and, in Sect. 3, I show that there is a general problem for analyzing thick concepts of which the Gettier problem is a special instance. I do not take a stand on whether the Gettier problem, or its general counterpart, is resolvable. My primary aim is to bring these problems into better focus.     

Attention and executive function in children with and without single-suture craniosynostosis

Children with single-suture craniosynostosis (SSC) have higher rates of learning disabilities and related neurocognitive problems than unaffected peers. Executive function (EF) and attention are thought to be areas of particular vulnerability, though studies to date have been limited by small sample sizes and a lack of control groups. We evaluated 179 school-aged children with SSC (cases) and 183 unaffected controls at an average age of 7 years using clinician-administered and parent and teacher report measures of EF and attention. Among children with SSC, we examined differences as a function of suture location (sagittal, metopic, unicoronal, or lambdoid) and age of corrective surgery. We used linear regression analyses, adjusted for potential confounders, to compare the two groups on all outcome measures. Cases scored lower than controls on most measures, though the magnitude of these differences was small and most were statistically insignificant. The largest relative deficit was on a measure of inhibitory control. Results changed little in sensitivity analyses adjusting for potential attrition bias and for the effects of developmental and academic interventions. Among cases, there were few differences in relation to the location of suture fusion or timing of surgery. Overall, we found limited evidence of broad deficits in EF or attention in children with SSC relative to unaffected controls. Neurocognitive development for children with SSC appears to be variable, across affected children and outcomes assessed. Further research is needed to understand the potential sources of this variability.     

Evidence for the Modulation of Sub-Lexical Processing in Go No-Go Naming: The Elimination of the Frequency �� Regularity Interaction

The Frequency (high vs. low) × Regularity (regular vs. exception) interaction found on naming response times is often taken as evidence for parallel processing of sub-lexical and lexical systems. Using a Go/No-go naming task, we investigated the effect of nonword versus pseudohomophone foils on sub-lexical processing and the subsequent Frequency × Regularity interaction. We ran two experiments: (1) a Go/No-go naming task with nonword foils (e.g., bint) and (2) a Go/No-go naming task with pseudohomophone foils (e.g., pynt). Experiment 1 replicated the Frequency × Regularity interaction on naming response times supporting the notion of parallel sub-lexical and lexical processing. Experiment 2 eliminated the Frequency × Regularity interaction providing evidence for the modulation of sub-lexical information. These results indicate that using pseudohomophones in the Go/No-go naming task minimized information provided from sub-lexical processing and maximized information provided from the lexical system.     

Parental involvement, child temperament, and parents' work hours: Differential relations for mothers and fathers

This study examined how child temperament was related to parents' time spent accessible to and interacting with their 2-year-olds. Bivariate analyses indicated that both fathers and mothers spent more time with temperamentally challenging children than easier children on workdays, but fathers spent less time with challenging children than easier children on non-workdays. After accounting for work hours, some associations between temperament and fathers' workday involvement dropped to non-significance. For fathers, work hours also moderated the relation between irregular temperament and workday play. For mothers, work hours moderated the relation between both difficult and irregular temperament and workday interaction. Mothers also spent more time with girls (but not boys) who were temperamentally irregular. Results speak to the influence of child temperament on parenting behavior, and the differential construction of parenting roles as a function of child characteristics and patterns of work.     

Choosing among multiple alternatives: Relative and overall reinforcer rates

Choice behavior among two alternatives has been widely researched, but fewer studies have examined the effect of multiple (more than two) alternatives on choice. Two experiments investigated whether changing the overall reinforcer rate affected preference among three and four concurrently scheduled alternatives. Experiment 1 trained six pigeons on concurrent schedules with three alternatives available simultaneously. These alternatives arranged reinforcers in a ratio of 9:3:1 with the configuration counterbalanced across pigeons. The overall rate of reinforcement was varied across conditions. Preference between the pair of keys arranging the 9:3 reinforcer ratio was less extreme than the pair arranging the 3:1 reinforcer ratio regardless of overall reinforcer rate. This difference was attributable to the richer alternative receiving fewer responses per reinforcer than the other alternatives. Experiment 2 trained pigeons on concurrent schedules with four alternatives available simultaneously. These alternatives arranged reinforcers in a ratio of 8:4:2:1, and the overall reinforcer rate was varied. Next, two of the alternatives were put into extinction and the random interval duration was changed from 60 s to 5 s. The ratio of absolute response rates was independent of interval length across all conditions. In both experiments, an analysis of sequences of visits following each reinforcer showed that the pigeons typically made their first response to the richer alternative irrespective of which alternative was just reinforced. Performance on these three‐ and four‐alternative concurrent schedules is not easily extrapolated from corresponding research using two‐alternative concurrent schedules.     

Choice among two and three alternatives

Although choice between two alternatives has been widely researched, fewer studies have examined choice across multiple (more than two) alternatives. Past models of choice behavior predict that the number of alternatives should not affect relative response allocation, but more recent research has found violations of this principle. Five pigeons were presented with three concurrently scheduled alternatives. Relative reinforcement rates across these alternatives were assigned 9:3:1. In some conditions three keys were available; in others, only two keys were available. The number of available alternatives did not affect relative response rates for pairs of alternatives; there were no significant differences in behavior between the two and three key conditions. For two birds in the three‐alternative conditions and three birds in the two‐alternative conditions, preference was more extreme for the pair of alternatives with the lower overall pairwise reinforcer rate (3:1) than the pair with higher overall reinforcer rate (9:3). However, when responding during the changeover was removed three birds showed the opposite pattern in the three‐alternative conditions; preference was more extreme for the pair of alternatives with the higher overall reinforcer rate. These findings differ from past research and do not support established theories of choice behavior.     

Sleep quality in healthy and mood-disordered persons predicts daily life emotional reactivity

Disordered sleep has been linked to impaired emotional functioning in healthy and depressed individuals. Little is known, however, about how chronic sleep problems influence emotional reactivity in everyday life. Participants with major or minor unipolar depressive disorder (n?=?60) and healthy controls (n?=?35) reported on sleep and emotional responses to daily life events using a computerised Experience Sampling Method. We examined whether impaired sleep quality influenced emotional reactivity to daily events, and if this relationship was altered by unipolar mood disorders. Among healthy individuals, sleep difficulties were associated with enhanced negative affect (NA) to unpleasant events and a dulled response to neutral events. However, among mood-disordered persons, sleep difficulties were associated with higher NA across all types of everyday life events. Impaired sleep quality differentially affects daily life emotional reactions as a function of depression.     

Getting to Know Me: Social Role Experiences and Age Differences in Self‐Concept Clarity During Adulthood

ABSTRACT The current research had 2 aims: (1) to determine the cross‐sectional age differences in self‐concept clarity during adulthood and (2) to examine the importance of social role experiences for age differences in self‐concept clarity. These aims were addressed in 2 large samples of adults ranging in age from 18 to 94 years. In both studies, self‐concept clarity had a curvilinear relation to age such that self‐concept clarity was positively related to age from young adulthood through middle age and negatively related to age in older adulthood. This relationship was moderated by annual income and community investment. In addition, annual income and health‐related social role limitations mediated age differences in self‐concept clarity. Findings are discussed in terms of modern theories of identity development.