IBM PC Tachistoscope: Text stimuli

Due to cost, speed, and flexibility, the IBM PC and compatibles are good computers for laboratory use. Outlined here is a program that allows a computer from this class of machines to be used as a tachistoscope. The example given is for visual half-field presentation and can be easily modified for other presentation paradigms.     

Michel de Certeau's keys of political discernment in May 1968: The theological-spiritual assumptions that informed his tools of analysis

This article seeks to identify the theoretical tools that supported Michel de Certeau's political discernment during the crisis of May 1968 in France. De Certeau's ability to elucidate the novelty and complexity of this event is linked to the intertwining of his experiences as a historian, traveller (voyageur), and Christian (specifically a Jesuit). De Certeau's articulation of a 'theology of difference' allowed him to construct the intellectual and spiritual tools that enabled a lucid discernment of May 1968. Through this theology, derived from negative theology, de Certeau made the experience of faith operative at a moment of cultural crisis. The article also analyses possibilities involved in the ‘rupture’, that is, the fracture that is implied in modernity; in the notion of an event that highlights the deficiency of language, its incapacity to establish ‘a truthful communication’ in society; and the recognition of the poetic dimension of speech, which is capable of interweaving speech and action. The May 1968 event invites these elements mutually to redefine themselves.     

The perception of semantic relations in pictures

Three picture processing experiments are reported that present evidence of an “agent advantage effect,” that is, faster processing of the performer of the action depicted the agent of the action than of the element acted upon (the patient). Experiment 1 demonstrated the effect in a paradigm in which reaction time to manually indicate the location of a target (agent or patient) was faster for agent targets. Experiment 2 demonstrated that the critical time required for subjects to encode the agent was shorter than the time required for encoding patients. Experiment 3 again demonstrated the agent advantage effect in a directed attention paradigm. Together, the results of the experiments indicated that subjects were able to encode agent information faster than patient information. The results also indicated that subjects did not adopt a strategy whereby encoding of patient information was necessarily dependent upon encoding agent information.     

Lateralization for reading musical chords: Disentangling symbolic, analytic, and phonological aspects of reading

It has been repeatedly shown that the left hemisphere (right visual field) is superior to the right hemisphere (LVF) in reading English, a bias possibly due to any or all of three confounded factors: (1) the symbolic nature of the coding system; (2) the analytic requirements of the decoding process; and (3) the phonological associations of the elements. Recent work on reading Japanese ideograms (Kanji) disentangles (1) from (2) and (3), but leaves the latter two confounded. We further disentangle (2) and (3) by examining visual field preference for reading musical chords, representatives of an analytic, nonphonological symbol system. The strong RVF advantage is interpreted as indicating that the left hemisphere is dominant for reading an analytic symbol system that is not phonologically based. We conclude that the left-hemisphere advantage traditionally found for reading phonological symbols is due to their analytic nature in addition to any effect due to their linguistic association.     

Predicting child language impairment from too many variables: overinterpreting stepwise discriminant function analysis

Tallal (1999) defends an earlier presentation of 160 variables predicting classification of 59 children for specific language impairment (SLI) from the statistical criticisms of Zhang and Tomblin (1998). I present here 3 additional reasons why it is wrong to conclude from Tallal's original 1985 analysis and presentation that it is specifically temporal processing variables that underlie SLI. On the contrary, these data lend no support to this position.     

Signal-to-noise ratio sensitivity in ERPs to stimulus and task complexity: different effects for early and late components

Traditionally, early and late ERP components are evaluated by the latency and amplitude of their components. We investigated their signal-to-noise (S/N) ratio: how well individual ERP trials correlate with their overall averaged ERP. High correlations indicate minimal noise or individual trial variability while low correlations reflect greater trial variability. Continuous EEG activity was recorded from 57 university students during single- and dual-task conditions in a within-subjects paradigm (easy and difficult tone discrimination; with and without verbal working memory task). For early components, the addition of the second task increased the correlations between the individual trials and the averaged ERPs. For the late components, both the addition of the second task and an increase in stimulus difficulty decreased individual trial correlations. Results suggest that the S/N ratio analysis is a useful method for highlighting differences between early and late components associated with stimulus processing manipulations.     

Neurocognitive mechanisms of cognitive control: the role of prefrontal cortex in action selection, response inhibition, performance monitoring, and reward-based learning

Convergent evidence highlights the differential contributions of various regions of the prefrontal cortex in the service of cognitive control, but little is understood about how the brain determines and communicates the need to recruit cognitive control, and how such signals instigate the implementation of appropriate performance adjustments. Here we review recent progress from cognitive neuroscience in examining some of the main constituent processes of cognitive control as involved in dynamic decision making: goal-directed action selection, response activation and inhibition, performance monitoring, and reward-based learning. Medial frontal cortex is found to be involved in performance monitoring: evaluating outcome vis-a-vis expectancy, and detecting performance errors or conflicting response tendencies. Lateral and orbitofrontal divisions of prefrontal cortex are involved in subsequently implementing appropriate adjustments.     

ERNAN MCMULLIN ON CONTINGENCY,COSMIC PURPOSE,AND THE ATEMPORALITY OF THE CREATOR

This article reviews, and offers supportive reflections on, the main points of Ernan McMullin's provocative 1998 article, “Cosmic Purpose and the Contingency of Human Evolution,’’ reprinted in this issue of Zygon. In it he addresses the important science‐theology issue of how the Creator's purpose and intention to assure the emergence of human beings is consonant with the radical contingency of the evolutionary process. After discussing cosmic and biological evolution and critically summarizing recent solutions to this question by Keith Ward, John Polkinghorne, Arthur Peacocke, Alvin Plantinga, and others, who presuppose in different ways that God is subject to time, McMullin compellingly argues for the traditional position, that God is unconditioned by time, and this enables God to work purposefully through contingency, randomness, and chance just as easily as through law‐like regularity.