The epistemology of absence-based inference

Our main aim in this paper is to contribute towards a better understanding of the epistemology of absence-based inferences. Many absence-based inferences are classified as fallacies. There are exceptions, however. We investigate what features make absence-based inferences epistemically good or reliable. In Section 2 we present Sanford Goldberg’s account of the reliability of absence-based inference, introducing the central notion of epistemic coverage. In Section 3 we approach the idea of epistemic coverage through a comparison of alethic and evidential principles. The Equivalence Schema–a well-known alethic principle–says that it is true that $p$ if and only if $p$ . We take epistemic coverage to underwrite a suitably qualified evidential analogue of the Equivalence Schema: for a high proportion of values of $p$ , subject $S$ has evidence that $p$ due to her reliance on source $S^{*}$ if and only if $p$ . We show how this evidential version of the Equivalence Schema suffices for the reliability of certain absence-based inferences. Section 4 is dedicated to exploring consequences of the Evidential Equivalence Schema. The slogan ‘absence of evidence is evidence of absence’ has received a lot of bad press. More elaborately, what has received a lot of bad press is something like the following idea: absence of evidence sufficiently good to justify belief in $p$ is evidence sufficiently good to justify belief in $\sim p$ . A striking consequence of the Evidential Equivalence Schema is that absence of evidence sufficiently good to justify belief in p is evidence sufficiently good to justify belief in $\sim p$ . We establish this claim in Section 4 and show how this supports the reliability of an additional type of absence-based inference. Section 4 immediately raises the following question: how can we make philosophically good sense of the idea that absence of evidence is evidence of absence? We address this question in Section 5. Section 6 contains some summary remarks.     

The staccato roller coaster: a simple physical model of the staccato run

I present a simple model of Grünbaum’s staccato run in classical mechanics, the staccato roller coaster. It consists of a bead sliding on a frictionless wire shaped like a roller coaster track with infinitely many hills of diminishing size, each of which is a one-dimensional variant of the so-called Norton dome. The staccato roller coaster proves beyond doubt the dynamical (and hence logical) possibility of supertasks in classical mechanics if the Norton dome is a proper system of classical mechanics with metaphysical import. If not, challenges raised against the metaphysical significance of the Norton dome are shown to be challenges against various arguments for the dynamical possibility of supertasks, and the staccato roller coaster clearly shows the importance of meeting these challenges. And the staccato roller coaster can provide, as well as interesting lessons, illuminating analyses of Burke’s (Mod Schoolman 78:1–8, 2000) attempt to refute the dynamical possibility of the staccato run and Pérez Laraudogoitia’s (Synthese 148:433–441, 2006) rebuttal of it.     

Major memory for microblogs

Online social networking is vastly popular and permits its members to post their thoughts as microblogs, an opportunity that people exploit, on Facebook alone, over 30 million times an hour. Such trivial ephemera, one might think, should vanish quickly from memory; conversely, they may comprise the sort of information that our memories are tuned to recognize, if that which we readily generate, we also readily store. In the first two experiments, participants’ memory for Facebook posts was found to be strikingly stronger than their memory for human faces or sentences from books—a magnitude comparable to the difference in memory strength between amnesics and healthy controls. The second experiment suggested that this difference is not due to Facebook posts spontaneously generating social elaboration, because memory for posts is enhanced as much by adding social elaboration as is memory for book sentences. Our final experiment, using headlines, sentences, and reader comments from articles, suggested that the remarkable memory for microblogs is also not due to their completeness or simply their topic, but may be a more general phenomenon of their being the largely spontaneous and natural emanations of the human mind.     

The Relationship Between Trajectories of Family/Cultural Stressors and Depression and Suicidal Ideation Among Substance Using Mexican-American Adults

We used an intersectional minority stress perspective to examine the association between family/cultural stress and mental health among substance-using Mexican-Americans. Employing a unique longitudinal sample of 239 socioeconomically disadvantaged, non-injecting heroin-using Mexican-Americans from San Antonio, Texas, we examined how culturally relevant stressors are related to depression and suicidal ideation. First, we identified depression and suicidal ideation prevalence rates for this disadvantaged sample. Second, we determined how cultural stress is experienced over time using stress trajectories. Third, we evaluated how family/cultural stressors and stress trajectories are related to depression and suicidal ideation outcomes. Results showed high rates of baseline depression (24 %) and suicidal ideation (30 %). We used latent class growth analysis to identify three primary stress trajectories (stable, high but decreasing, and increasing) over three time points during 1 year. We found that the increasing stressors trajectory was associated with higher rates of depression and suicidal ideation, and that stress trajectories had unique relationships with mental illness. We also showed that baseline stressors, sum stressors, and high but decreasing stressors maintained positive associations with mental illness after controlling for baseline depression. Our results highlight the importance of focusing on within-group, culturally specific stressors and addressing both operant and cumulative stressors in the study of mental health for marginalized populations and suggest the importance of early intervention in minimizing stressors.     

Learning time-varying categories

Many kinds of objects and events in our world have a strongly time-dependent quality. However, most theories about concepts and categories either are insensitive to variation over time or treat it as a nuisance factor that produces irrational order effects during learning. In this article, we present two category learning experiments in which we explored peoples’ ability to learn categories whose structure is strongly time-dependent. We suggest that order effects in categorization may in part reflect a sensitivity to changing environments, and that understanding dynamically changing concepts is an important part of developing a full account of human categorization.     

Maternal Psychopathology and Early Child Temperament Predict Young Children’s Salivary Cortisol 3 Years Later

Neuroendocrine dysfunction is hypothesized to be an early emerging vulnerability marker for depression. We tested whether the main and interactive effects of maternal psychopathology and early child temperamental vulnerability for depression assessed at age three predicted offspring’s basal cortisol function at age 6 years. 228 (122 males) children participated in the baseline and follow-up assessments. At age three, maternal lifetime psychopathology was assessed with a diagnostic clinical interview, and child temperamental positive affectivity (PA) and negative affectivity (NA) were assessed using laboratory observations. At age six, children’s waking and evening cortisol were assessed on 2 days. Maternal lifetime anxiety predicted offspring’s higher morning cortisol at age six. Child temperamental NA at age three predicted higher evening cortisol at age six. There was a significant interaction between maternal lifetime depression and child temperamental PA at age three in predicting offspring’s morning cortisol at age six. For the offspring of mothers with lifetime depression, higher PA at age 3 predicted lower morning cortisol at age 6. These findings highlight the importance of examining the main and interactive effects of maternal psychopathology and early child temperamental vulnerability in predicting the development of offspring’s stress physiology. Findings hold significance in identifying etiological mechanisms of risk and delineating the complex developmental pathways to psychopathology.