A study of the near-miss involving Weber’s law and pure-tone intensity discrimination

A study of pure-tone intensity discrimination is presented in which amplitude changes are detected in 1000 Hz tone bursts 15–20 msec in duration. The masking function (log detectable increment vs log background intensity) is found to have a slope of 9/10 when calculations are carried out via energy measurements. This near-miss to Weber’s law is in agreement with other data reported in the literature. The masking slope proves to be essentially independent of stimulus duration between 15 msec and 1.5 sec. Our stable slope parameter is interpreted as a detectability restriction generated by “mass-flow” phenomena in the auditory channel. These phenomena are thought to be similar to the fluctuations accompanying a noisy or turbulent stream of events. Pure-tone intensity discrimination is then analyzed as a special case of energy detection.     

Externalism and Authoritative Knowledge of Content: A New Incompatibilist Strategy

Philosophical Studies -     

Neural enhancement and pre-emptive perception: the genesis of attention and the attentional maintenance of the cortical salience map

One of the stable hypotheses in systems neuroscience is the relationship between attention and the enhancement of visual responses when an animal attends to the stimulus in its receptive field (Goldberg and Wurtz, 1972 Journal of Neurophysiology 35 560-574). This was first discovered in the superior colliculus of the monkey: neurons in the superficial layers of the superior colliculus responded more intensely to the onset of a stimulus during blocks of trials in which the monkey had to make a saccade to it than they did during blocks of trials in which the monkey had to continue fixating a central point and not respond to the stimulus. This enhancement has been found in many brain regions, including prefrontal cortex (Boch and Goldberg, 1987 Investigative Ophthalmology 28 Supplement, 124), V4 (Moran and Desimone, 1985 Science 229 782-784), and lateral intraparietal area (Colby et al, 1996 Journal of Neurophysiology 76 2841-2852; Colby and Goldberg, 1999 Annual Review of Neuroscience 22 319-349), and even V1 (Lamme et al, 2000 Vision Research 40 1507-1521). In these studies the assumption has been that the monkey attended to the stimulus because the stimulus evoked an enhanced response. In the experiments described here we show that for abruptly appearing stimuli, attention is not related to the initial response evoked by the stimulus, but by the activity present on the salience map in the parietal cortex when the stimulus appears. Attention to the stimulus may subsequently, by a top down signal, sustain the map, but stimuli can as easily be suppressed by top down features as they can be enhanced.     

INCOMMENSURABILITY,RELATIVISM, SCEPTICISM: REFLECTIONS ON ACQUIRING A CONCEPT

Some opponents of the incommensurability thesis, such as Davidson and Rorty, have argued that the very idea of incommensurability is incoherent and that the existence of alternative and incommensurable conceptual schemes is a conceptual impossibility. If true, this refutes Kuhnian relativism and Kantian scepticism in one fell swoop. For Kuhnian relativism depends on the possibility of alternative, humanly accessible conceptual schemes that are incommensurable with one another, and the Kantian notion of a realm of unknowable things‐in‐themselves gives rise to the possibility of humanly inaccessible schemes that are incommensurable with even our best current or future science. In what follows we argue that the possibility of incommensurability of either the Kuhnian or the Kantian variety is inescapable and that this conclusion is forced upon us by a simple consideration of what is involved in acquiring a concept. It turns out that the threats from relativism and scepticism are real, and that anyone, including Davidson himself, who has ever defended an account of concept acquisition is committed to one or the other of these two possibilities. 1     

Eye movements when looking at print advertisements: the goal of the viewer matters

Viewers looked at print advertisements as their eye movements were recorded. Half of them were asked to rate how much they liked each ad (for convenience, we will generally use the term ‘ad’ from this point on), while the other half were asked to rate the effectiveness of each ad. Previous research indicated that viewers who were asked to consider purchasing products in the ads looked at the text earlier and more often than the picture part of the ad. In contrast, viewers in the present experiment looked at the picture part of the ad earlier and longer than the text. The results indicate quite clearly that the goal of the viewer very much influences where (and for how long) viewers look at different parts of ads, but also indicate that the nature of the ad per se matters. Copyright © 2007 John Wiley & Sons, Ltd.     

Neuronal correlates of "free will" are associated with regional specialization in the human intrinsic/default network

Recently, we proposed a fundamental subdivision of the human cortex into two complementary networks-an "extrinsic" one which deals with the external environment, and an "intrinsic" one which largely overlaps with the "default mode" system, and deals with internally oriented and endogenous mental processes. Here we tested this hypothesis by contrasting decision making under external and internally-derived conditions. Subjects were presented with an external cue, and were required to either follow an external instruction ("determined" condition) or to ignore it and follow a voluntary decision process ("free-will" condition). Our results show that a well defined component of the intrinsic system-the right inferior parietal cortex-was preferentially activated during the "free-will" condition. Importantly, this activity was significantly higher than the base-line resting state. The results support a self-related role for the intrinsic system and provide clear evidence for both hemispheric and regional specialization in the human intrinsic system.     

Evaluating models of remember-know judgments: Complexity, mimicry, and discriminability

Remember-know judgments provide additional information in recognition memory tests, but the nature of this information and the attendant decision process are in dispute. Competing models have proposed that remember judgments reflect a sum of familiarity and recollective information (the one-dimensional model), are based on a difference between these strengths (STREAK), or are purely recollective (the dual-process model). A choice among these accounts is sometimes made by comparing the precision of their fits to data, but this strategy may be muddied by differences in model complexity: Some models that appear to provide good fits may simply be better able to mimic the data produced by other models. To evaluate this possibility, we simulated data with each of the models in each of three popular remember-know paradigms, then fit those data to each of the models. We found that the one-dimensional model is generally less complex than the others, but despite this handicap, it dominates the others as the best-fitting model. For both reasons, the one-dimensional model should be preferred. In addition, we found that some empirical paradigms are ill-suited for distinguishing among models. For example, data collected by soliciting remember/know/new judgments--that is, the trinary task--provide a particularly weak ground for distinguishing models. Additional tables and figures may be downloaded from the Psychonomic Society's Archive of Norms, Stimuli, and Data, at www.psychonomic.org/archive.     

Cognitive Coping Tool Kit for Psychosis: Development of a Group-Based Curriculum

This article outlines an 8-week curriculum that was created to help outpatients develop cognitive and behavioral skills for coping with delusions and hallucinations as well as to reduce patients’ comorbid subjective levels of distress (e.g., depression, anxiety). The manualized protocol consisted of psychoeducation and training in a variety of CBT skills that have shown promise in treating individuals with residual psychosis, using recovery-oriented “naturalistic” methods and culminating in the creation of an individualized “tool kit” of cognitive coping resources. A preliminary study of the effectiveness of this brief group-based CBT program for outpatients with chronic, residual symptoms of schizophrenia was conducted. Participants were 24 outpatients diagnosed with schizophrenia spectrum disorders who were stable on medications and connected to case management community follow-up. The Positive and Negative Syndrome Scale for Schizophrenia interview and the Symptom Checklist-90 self-report symptom scales were administered pre- and post-intervention. The results suggest that there were significant improvements in psychotic symptoms and self-reported distress from pre- to posttreatment.