Cultivating the Arts of Inquiry, Interpretation, and Criticism: A Peircean Approach to our Educational Practices

Peirce was a thinker who claimed that his mind had been thoroughly formed by his rigorous training in the natural sciences. But he was also the author who proclaimed that nothing is truer than true poetry. In making the case for Peirce’s relevance to issues of education, then, it is necessary to do justice to the multifaceted character of his philosophical genius, in particular, to the experimentalist cast of his mind and his profound appreciation for the aesthetic, the imaginative, and (more narrowly) the metaphorical in their myriad guises. My aim in this paper is to go some distance, however small, toward doing such justice to Peirce.     

The effects of simulated stuttering and prolonged speech on the neural activation patterns of stuttering and nonstuttering adults

Functional magnetic resonance imaging was used to investigate the neural correlates of passive listening, habitual speech and two modified speech patterns (simulated stuttering and prolonged speech) in stuttering and nonstuttering adults. Within-group comparisons revealed increased right hemisphere biased activation of speech-related regions during the simulated stuttered and prolonged speech tasks, relative to the habitual speech task, in the stuttering group. No significant activation differences were observed within the nonstuttering participants during these speech conditions. Between-group comparisons revealed less left superior temporal gyrus activation in stutterers during habitual speech and increased right inferior frontal gyrus activation during simulated stuttering relative to nonstutterers. Stutterers were also found to have increased activation in the left middle and superior temporal gyri and right insula, primary motor cortex and supplementary motor cortex during the passive listening condition relative to nonstutterers. The results provide further evidence for the presence of functional deficiencies underlying auditory processing, motor planning and execution in people who stutter, with these differences being affected by speech manner.     

Must Differences in Cognitive Value be Transparent?

Frege’s ‘differential dubitability’ test is a test for differences in cognitive value: if one can rationally believe that p while simultaneously doubting that q, then the contents p and q amount to different ‘cognitive values’. If subject S is rational, does her simultaneous adoption of different attitudes towards p and q require that the difference between p and q (as cognitive values) be transparent to her? It is natural to think so. But I argue that, if attitude anti-individualism is true, then rational differential dubitability does not presuppose that differences in cognitive value are transparent. The significance of this argument lies in what it tells us, both about the notion of cognitive value and its relation to the differential dubitability test, but also about the prospects for a Burge-type position which aims to combine attitude anti-individualism with a (qualified) reliance on the differential dubitability test.

Whistle rates of wild bottlenose dolphins (Tursiops truncatus): influences of group size and behavior

In large social groups acoustic communication signals are prone to signal masking by conspecific sounds. Bottlenose dolphins (Tursiops truncatus) use highly distinctive signature whistles that counter masking effects. However, they can be found in very large groups where masking by conspecific sounds may become unavoidable. In this study we used passive acoustic localization to investigate how whistle rates of wild bottlenose dolphins change in relation to group size and behavioral context. We found that individual whistle rates decreased when group sizes got larger. Dolphins displayed higher whistle rates in contexts when group members were more dispersed as in socializing and in nonpolarized movement than during coordinated surface travel. Using acoustic localization showed that many whistles were produced by groups nearby and not by our focal group. Thus, previous studies based on single hydrophone recordings may have been overestimating whistle rates. Our results show that although bottlenose dolphins whistle more in social situations they also decrease vocal output in large groups where the potential for signal masking by other dolphin whistles increases.     

Left-right differences on timed motor examination in children.

Age-related change in the difference between left- and right-side speed on motor examination may be an important indicator of maturation. Cortical maturation and myelination of the corpus callosum are considered to be related to increased bilateral skill and speed on timed motor tasks. We compared left minus right foot, hand, and finger speed differences using the Revised Physical and Neurological Assessment for Subtle Signs (PANESS; Denckla, 1985); examining 130 typically developing right-handed children (65 boys, 65 girls) ages 7-14. Timed tasks included right and left sets of 20 toe taps, 10 toe-heel alternation sequences, 20 hand pats, 10 hand pronate-supinate sets, 20 finger taps, and 5 sequences of each finger-to-thumb apposition. For each individual, six difference scores between left- and right-sided speeded performances of timed motor tasks were analyzed. Left-right differences decreased significantly with age on toe tapping, heel-toe alternations, hand pronation-supination, finger repetition, and finger sequencing. There were significant gender effects for heel-toe sequences (boys showing a greater left-right difference than girls), and a significant interaction between age and gender for hand pronation-supination, such that the magnitude of the left-right difference was similar for younger, compared with older girls, while the difference was significantly larger for younger, compared to older boys. Speed of performing right and left timed motor tasks equalizes with development; for some tasks, the equalization occurs earlier in girls than in boys.     

Distinct contributions of the basolateral amygdala and the medial prefrontal cortex to learning and relearning extinction of context conditioned fear

We studied the roles of the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC) in learning and relearning to inhibit context conditioned fear (freezing) in extinction. In Experiment 1, pre-extinction BLA infusion of the NMDA receptor (NMDAr) antagonist, ifenprodil, impaired the development and retention of inhibition but post-extinction infusion spared retention. Pre-extinction infusion of the GABA(A) agonist, muscimol, depressed freezing and impaired retention as did post-extinction infusion. In Experiment 2, pre-extinction mPFC infusion of ifenprodil spared the development of inhibition whereas muscimol depressed freezing. Both impaired retention when infused pre- or post-extinction. Thus, the development of inhibition involves NMDAr activation in the BLA, whereas its consolidation involves both NMDAr activation in the mPFC and NMDAr-independent mechanisms in the BLA. In Experiment 3, BLA infusion of ifenprodil impaired relearning and retention of inhibition when infused before but did not impair retention when infused after re-extinction. BLA infusion of muscimol depressed freezing but did not impair retention when infused before or after re-extinction. In Experiment 4, mPFC infusion of ifenprodil impaired relearning when infused before re-extinction, whereas muscimol depressed responses. Both drugs impaired retention when infused into the mPFC before or after re-extinction. Thus, relearning to inhibit fear responses involves NMDAr activation in both the BLA and mPFC and consolidation of the inhibitory memory involves NMDAr activation in the mPFC. However, relearning and consolidation occur in the absence of neuronal activity within the BLA. We propose that NMDAr in the mPFC supports relearning inhibition when the BLA is inactivated.     

Experts,Semantic and Epistemic

In this paper I argue that the tendency to defer in matters semantic is rationalized by our reliance on the say‐so of others for much of what we know about the world. The result, I contend, is a new and distinctly epistemic source of support for the doctrine of attitude anti‐individualism.     

Reliabilism in philosophy

The following three propositions appear to be individually defensible but jointly inconsistent: (1) reliability is a necessary condition on epistemic justification; (2) on contested matters in philosophy, my beliefs are not reliably formed; (3) some of these beliefs are epistemically justified. I explore the nature and scope of the problem, examine and reject some candidate solutions, compare the issue with ones arising in discussions about disagreement, and offer a brief assessment of our predicament.