Vocal and manual response latencies to bilateral and unilateral tachistoscopic letter displays

Bilateral rows of eight letters and unilateral rows of four letters were presented in randomized sequences for 100 ms. Subjects were required to recall all letters in a trial (Experiment I); recall letters from one hemifield cued at exposure (Experiment II); recognize a single letter, making a vocal response (Experiment III); recognize a single letter, making a manual response (Experiment IV). In Experiments I, II and III, identification errors were fewer and vocal response latencies were faster for RVF stimuli, except in the bilateral condition on Experiment I; in Experiment IV manual response latencies were the same, for left and right, bilateral and unilateral conditions. Collectively, the results could not be satisfactorily accounted for by any one hypothesis: report-order, trace-scanning, or cerebral dominance. The relative contribution of each process to the laterality effect was discussed.     

Using hardware interrupts for timing visual displays and reaction-time key interfacing on the Commodore 64

The use of hardware interrupts for presenting and timing visual displays and for controlling reaction timing on the Commodore 64 is described. The three sources of interrupts discussed are reaction-time keys interfaced through the user port to on-board hardware timers, the alarm of the 60-Hz real-time clocks, and the video raster. In a demonstration program, these interrupts are used to measure display durations, to change screen displays, and to coordinate the onset of reaction timing with the onset of screen changes. In addition, an externally generated interrupt caused by a keypress is used to control reaction timing independently of CPU operations.     

Development of differences in response latencies to right and left visual fields

Robust lateralization developed in right-handed adults who were asked to judge letter pairs as "same" or "different" during 4608 trials. By the end of the first two blocks (768 trials) "same" responses were favored when presented in the RVF (transmitted directly to the left hemisphere) and "different" responses were favored when presented in the LVF (transmitted direction to the right hemisphere). This gradually reversed over sessions with "same" responses becoming faster for letters presented in the LVF, and "different" responses becoming faster for stimuli presented in the RVF. The laterality acquired under these conditions was cumulative and reproducible, appeared in all 16 subjects, and was preserved between sessions a week apart. The data suggest that laterality is a flexible and reversible characteristic of the human brain even when stimulus and task remain constant.     

A rudimentary touch input device for visual displays

An inexpensive and simple device that can be fitted to existing computer visual display units and that gives a limited touch input capability is described. Small transparent acrylic pieces are held in front of the CRT by stiff wires attached to microswitches. The device has proved useful in the provision of computer-assisted instruction for young children.     

A multiprocessor system for generating visual displays and controlling experiments

A laboratory is described that is based on an IMSAI 8080 microcomputer and an IMLAC graphics display system. Procedures for using the system are described and illustrated.     

SCORIT: A computer subroutine for scoring electrodermal responses

Given digitized electrodermal response records sampled at a rate of 20/sec and at a sensitivity level between 140 and 170 ohms, a computer subroutine for scoring skin resistance responses is described. It is designed to score multiple responses on a trial, which makes it particularly suitable for classical conditioning experiments involving long interstimulus intervals. The subroutine returns to the main program response latency, base resistance, peak resistance, and time from base to peak. Since SCORIT is written in FORTRAN IV, it can be employed in virtually any modern central computing facility at costs substantially below those involved in hand scoring.     

A low-cost computer-controlled function generator suitable for generating visual grating displays

This paper reports a simple low-cost computer peripheral for generation of gratings. Its advantages are minimal CPU operations, reliability, and variety of programmable output functions.     

A study of timing in a manual and a spoken language: American sign language and English

A comparative analysis of the time variables in the production of speech and sign reveals that signers modify their global physical rate primarily by altering the time they spend articulating, whereas speakers do so by changing the time they spend pausing. When signers increase or decrease their pause time, however little they do so, they alter the number and the length of the pauses equally, whereas speakers primarily alter the number of pauses and leave their pause durations relatively constant. An analysis of the durations of signs reveals that signs are longer at the end of sentences than within sentences and that the first occurrence of a sign is longer than the second when syntactic location is controlled (both these findings have already been reported for spoken language). The inherent duration of a sign can be accounted for almost totally by the movement characteristic; handshape, location, and number of hands in a sign are of little importance. Finally, signers retain their regular quiet-breathing respiratory pattern across signing rates and inhale at locations independent of syntactic importance. In this they are quite unlike speakers, who breathe at syntactic breaks.This research was supported in part by Grant R03 MH 28133, Department of Health, Education, and Welfare.     

A comparison of BASIC language timing loops for the TRS-80 microcomputer

For users who wish to program the TRS-80 microcomputer exclusively in BASIC, the FOR-NEXT timing loop provides almost twice as fine temporal resolution as the incrementing loop. A temporal resolution of 6.62 msec is possible with the FOR-NEXT loop.     

躯体表情与面部表情加工进程比较

躯体和面孔是个体情绪识别的敏感线索。与面部表情的早期视觉加工相似, P1成分对恐惧、愤怒等负性躯体表情更加敏感, 反映了对躯体威胁信息快速且无意识的加工。情绪躯体和面孔还有着类似的构型加工, 表现为二者都能诱发颞枕区视觉皮层相似的N170成分, 但涉及的神经基础并不完全相同。在构型编码加工中, 面部表情的N170与顶中正成分(Vertex Positive Potential, VPP)较躯体表情的N170、VPP更加明显。在面部表情和躯体表情的后期加工阶段, 早期后部负波(Early Posterior Negativity, EPN)反映了面孔和躯体视觉编码的注意指向加工, 随后出现的P3与晚期正成分(Late Positive Component, LPC)代表了顶额皮层对复杂情绪信息的高级认知加工。躯体表情还存在与外纹状皮层躯体区相关的N190成分, 其对躯体的情绪和动作信息敏感。今后的研究应进一步探讨动作对情绪知觉的影响、动态面孔−躯体情绪的加工机制等。     

Matfit: A fortran subroutine for comparing two matrices in a subspace

This research was supported by grant APA 3020 from the Natural Sciences and Engineering Research Council of Canada. The author would like to thank Dr. David O'Hare for providing the data used to illustrate the use of the program MATFIT.