Relative Necessity Reformulated

This paper discusses some serious difficulties for what we shall call the standard account of various kinds of relative necessity, according to which any given kind of relative necessity may be defined by a strict conditional - necessarily, if C then p - where C is a suitable constant proposition, such as a conjunction of physical laws. We argue, with the help of Humberstone (Reports on Mathematical Logic, 31, 33–421, 1981), that the standard account has several unpalatable consequences. We argue that Humberstone’s alternative account has certain disadvantages, and offer another - considerably simpler - solution.     

Up-regulation of exploratory tendencies does not enhance general learning abilities in juvenile or young-adult outbred mice

"General cognitive ability" describes a trait that transcends specific learning domains and impacts a wide range of cognitive skills. Individual animals (including humans) exhibit wide variations in their expression of this trait. We have previously determined that the propensity for exploration is highly correlated with the general cognitive abilities of individual outbred mice. Here, we asked if inducing an increase in exploratory behaviors would causally promote an increase in animals' general learning abilities. In three experiments, juvenile and young-adult male CD-1 outbred mice were exposed to 12 novel environments starting at post-natal days 39 (juvenile) and 61 (young adult), after which they underwent a series of cognitive and exploratory tests as adults (beginning at post-natal day 79). Exposure to novel environments promoted increases in exploration (across multiple measures) on two different tasks, including an elevated plus maze. However, a subsequent test of general learning abilities (aggregate performance across five distinct learning tasks) determined that exposure to novel environments as juveniles or young-adults had no effect on general learning abilities in adulthood. Therefore, while exposure to novel environments promotes long-lasting increases in mice's exploratory tendencies, these increases in exploration do not appear to causally impact general learning abilities.     

Competitive state anxiety and self-confidence: intensity and direction as relative predictors of performance on a golf putting task

This study considered relationships between the intensity and directional aspects of competitive state anxiety as measured by the modified Competitive Sport Anxiety Inventory-2(D) (Jones & Swain, 1992) in a sample of 12 experienced male golfers. Anxiety and performance scores from identical putting tasks performed under three different anxiety-manipulated competitive conditions were used to assess both the predictions of Multidimensional Anxiety Theory (MAT; Martens et al., 1990) and the relative value of intensity and direction in explaining performance variance. A within-subjects regression analysis of the intra-individual data showed partial support for the three MAT hypotheses. Cognitive anxiety intensity demonstrated a negative linear relationship with performance, somatic anxiety intensity showed a curvilinear relationship with performance, and self-confidence intensity revealed a positive linear relation. Cognitive directional anxiety illustrated a positive linear relationship with putting performance. Multiple regression analyses indicated that direction (42% of variance) was a better predictor of performance than intensity (22%).     

Essence and definition by abstraction

We may define words or concepts, and we may also, as Aristotle and others have thought, define the things for which words stand and of which concepts are concepts. Definitions of words or concepts may be explicit or implicit, and may seek to report preexisting synonymies, as Quine put it, but they may instead be wholly or partly stipulative. Definition by abstraction, of which Hume’s principle is a much discussed example, seek to define a term-forming operator, such as the number operator, by fixing the truth-conditions of identity-statements featuring terms formed by means of that operator. Such definitions are a species of implicit definition. They are typically at least partly stipulative. Definitions of things, or real definitions, are, by contrast, typically conceived as true or false statements about the nature or essence of their definienda, and so not stipulative. There thus appears to be an obvious and head-on clash between taking Hume’s principle as an implicit and at least partly stipultative definition of the number operator and taking it as a real definition, stating the nature or essence of cardinal numbers. This paper argues that this apparent tension can be resolved, and that resolving it sheds light on part of the epistemology or essence and necessity, showing how some of our knowledge of essence and necessity can be a priori.

     

Tridimensional personality traits of college student marijuana users

The present study examined the possibility that marijuana use among college students might be associated with particular personality traits. College student volunteers (N = 176) were administered the Tridimensional Personality Questionnaire and a drug-use questionnaire. Analysis of variance showed that the mean score on Novelty Seeking was significantly higher and on Persistence significantly lower among lifetime marijuana users than among nonmarijuana using peers. Programs for prevention among college students may be enhanced by approaches tailored to individuals scoring high on Novelty Seeking and low on Persistence.     

Analysis of group differences in processing speed: Brinley plots,Q-Q plots,and other conspiracies

Researchers in a growing number of areas (including cognitive development, aging, and neuropsychology) use Brinley plots to compare the processing speed of different groups. Ratcliff, Spieler, and McKoon (2000) argued that a Brinley plot is a quantile-quantile (Q-Q) plot and that therefore Brinley plot regression slopes measure standard deviation ratios rather than relative speed of processing. We show that this argument is incorrect. Brinley plots, by definition, are not Q-Q plots; the former are based on unranked data and the latter are based on ranked data. Furthermore, the relationship between standard deviation ratios and slopes is a general property of regression lines and has no implications for the use of Brinley plot regression slopes as processing speed measures. We also show that the relative speed interpretation of Brinley plot slopes is strongly supported by converging evidence from a metaanalysis of visual search, mental rotation, and memory scanning in young and older adults. As to Ratcliff et al.'s hypothesis that age differences in response time are attributable to greater cautiousness on the part of the elderly, rather than true processing speed differences, this hypothesis has been extensively tested in previous studies and found wanting.