A text-stimuli presentation manager for the IBM PC with ipsatization correction for response sets and reaction times

IPSAPRO, an ipsative scoring program written for the IBM PC, aids in the detection and transformation of response sets that often contaminate rating scale and reaction time experiments. Response sets such as the tendency to use only extreme points of a rating scale or to work for speed over accuracy in reaction time experiments are removed in IPSAPRO by standardizing each subject’s ratings or times against their own means and standard deviations. Ipsatization can be applied to existing data sets or take place automatically at the data collection stage in a text-stimuli presentation manager that is provided with the program.     

Cerebral lateralization of visual stimulus recognition in stutterers and fluent speakers

Cerebral lateralization of stutterers and nonstutterers was assessed in terms of choice reaction times to stimuli presented to either the left or right visual hemifield on letter recognition and figure recognition tasks. Reaction times on both tasks were determined before and after a behavioral speech therapy program. Stutterers demonstrated a significant reduction in mean reaction times in the letter recognition task over the course of the therapy program. This change differed significantly from that obtained from stutterers in the figure recognition task. The stutterers' responses were in contrast to the responses of the nonstutterers, who showed no reduction in mean reaction times for the letter or figure recognition tasks. The results were discussed in terms of alterations in aspects of central nervous system processing as a result of participation in the behavioral speech therapy.     

Apple slide tachistoscope

We outline a BASIC program and subsidiary machine language timing routines that enable the Apple II series of computers to be employed as control devices for the tachistoscopic presentation of 35-mm slides and the collection of response latencies. The program is functional for experiments that require pictorial stimuli to be presented in up to three separate fields, with precise display times, precise interstimulus and intertriai intervals, and the collection of manual or vocal reaction times with millisecond accuracy. The major advantages of this system are that initial setup costs are substantially lower than those for other similar systems (e.g., Loftus, Gillispie. Tigre, & Nelson, 1984) and that user customization of the program may be accomplished by anyone possessing rudimentary knowledge of the BASIC programming language.     

The Radio Shack color computer in the experimental psychology laboratory: An evaluation

The Radio Shack color computer is examined from the viewpoint of capabilities needed to program, time, control, and acquire data from typical cognitive psychology experiments. Its capabilities are compared with those of the alternative inexpensive microcomputers discussed in an earlier article (Reed, 1980). The paper also includes a 6809 assembly language routine that permits the measurement of reaction times in video horizontal scan (HS = 4/63 msec) units without hardware modifications and an RSCC BASIC program for unbiased conversion of HS units to milliseconds.     

Effects of walking on reaction and movement times among elders

The purpose of this study was to examine the effects of a 6-wk. walking program on reaction times and movement times among 52 elders. Twenty-seven elderly, whose mean age was 71.8 yr. comprised the experimental group, and 25 elderly whose mean age was 71.8 yr. comprised the comparison group. The former subjects walked for 30 min. three times a week for 6 wk. while the latter maintained their normal activity. No significant differences in simple or choice reaction times and the associated movement times were found. To clarify the relationship of health and current and past physical activity, correlations of these with both simple and choice reaction times and movement times were examined. Except for the number of miles walked in a week, none of the correlations were significant. These results may not support previous findings that reaction and movement times were shorter with life-long participation in aerobic activity. However, the present study examined persons who were sedentary and were not involved in a life-long participation in aerobic exercise. Implications of these findings are discussed.     

Measurement of directional lever response reaction time with the Commodore 64

Routines are described for timing directional lever responses with the Commodore 64 micro-computer. Millisecond reaction timing is carried out with on-board hardware clocks, and lever responses are detected by monitoring the position of a joystick interfaced to a controller port. In a demonstration program, a machine code subroutine is used to measure the reaction times of lever responses in a spatial relations task. In addition, modifications to the demonstration program are suggested to adapt it for use with other tasks.     

Multidimensional scaling models for reaction times and same-different judgments

A method for joint analysis of reaction times and same-different judgments is discussed. A set of stimuli is assumed to have some parametric representation which uniquely defines dissimilarities between the stimuli. Those dissimilarities are then related to the observed reaction times and same-different judgments through a model of psychological processes. Three representation models of dissimilarities are considered, the Minkowski power distance model, the linear model, and Tversky's feature matching model. Maximum likelihood estimation procedures are developed and implemented in the form of a FORTRAN program. An example is given to illustrate the kind of analyses that can be performed by the proposed method.The work reported in this paper is supported by Grant A6394 to the first author from the Natural Sciences and Engineering Research Council of Canada. Portions of this study have been presented at the Psychometric Society meeting in Chapel Hill, N.C., in May, 1981. We thank Tony Marley, Jim Ramsay and anonymous reviewers for their helpful comments. MAXRT, a computer program which performs the computations described in this paper may be obtained by writing to the first author.     

Software synchronizing of video displays and Z-80 processing in the Model III TRS-80

A machine language technique is described whereby the Z-80 microprocessor of the Model III TRS-80 can be programmed to monitor position of the electron beam during CRT scanning. This technique provides the opportunity to synchronize the appearance of video displays with Z-80 processing. The programmer can therefore be assured of crisp stimulus displays and precisely recorded reaction times. The computer’s real-time clock operates on video circuitry as part of a routine that is initiated by a maskable interrupt. The real-time clock interrupt can be vectored from its normal use to a routine that signals the Z-80 when the electron beam is at a known screen location. A machine language program and a TRSDOS BASIC program that demonstrate the technique are described.     

The illusion of clarity: Image segmentation and edge attribution without filling-in

It comes as no surprise that viewing a high-resolution photograph through a screen reduces its clarity. Yet when a coarsely quantized (i.e., pixelated) version of the same photo is seen through a screen its clarity is increased. Six experiments investigated this illusion of clarity. First, the illusion was quantified by having participants rate the clarity of quantized images with and without a screen (Experiment 1). Interestingly, the illusion occurs both when the wires of the screen are aligned with the blocks of the quantized image and when they are shifted horizontally and vertically (Experiments 2 and 3), casting doubt on the hypothesis that a local filling-in process is involved. The finding that no illusion occurs when the photo is blurred rather than quantized (Experiment 4) and that the illusion is sharply reduced when visual attention is divided (Experiment 5) argue for an image segmentation process that falsely attributes the edges of the quantized blocks to the screen. Finally, the illusion is larger when participants adopt an active rather than a passive cognitive strategy (Experiment 6), pointing to the importance of cognitive control in the illusion.     

Visual and auditory choice reaction times

Choice reaction times are measured for three values of a priori signal probability with three well-practiced observers. Two sets of data are taken with the only difference being the modality of the reaction signal. In one set of conditions it is auditory, in the other, visual. The auditory reaction times are faster than the visual and in addition several other differences are noted. The latency of the errors and correct responses are nearly equal for the auditory data. Error latencies are nearly 30% faster for the visual data. Non-stationary effects, autocorrelation between successive latencies and non-homogeneous distribution of errors, are clearly evident in the visual data, but are small or non-existent in the auditory data. The data are compared with several models of the choice reaction time process but none of the models is completely adequate.     

A Case for an Empirically Demonstrable Notion of the Vacuum in Quantum Electrodynamics Independent of Dynamical Fluctuations

A re-evaluation of the notion of vacuum in quantum electrodynamics is presented, focusing on the vacuum of the quantized electromagnetic field. In contrast to the ‘nothingness’ associated to the idea of classical vacuum, subtle aspects are found in relation to the vacuum of the quantized electromagnetic field both at theoretical and experimental levels. These are not the usually called vacuum effects. The view defended here is that the so-called vacuum effects are not due to the ground state of the quantized electromagnetic field. Nevertheless it is possible to maintain an empirically demonstrable notion of vacuum state that is consistent with the interpretation of the formalism of the theory.     

Accurate display timing using an enhanced BASIC for the Tandy Color Computer

The general suitability of the Tandy Color Computer as an inexpensive laboratory microcomputer is discussed. A program is described that adds several useful timing-related functions to the native BASIC in the Tandy Color Computer, thus allowing BASIC to be used for programming experiments involving tachistoscopic displays and reaction times.     

Recognition of all basic emotions varies in accuracy and reaction time: A new verbal method of measurement

To study different aspects of facial emotion recognition, valid methods are needed. The more widespread methods have some limitations. We propose a more ecological method that consists of presenting dynamic faces and measuring verbal reaction times. We presented 120 video clips depicting a gradual change from a neutral expression to a basic emotion (anger, disgust, fear, happiness, sadness and surprise), and recorded hit rates and reaction times of verbal labelling of emotions. Our results showed that verbal responses to six basic emotions differed in hit rates and reaction times: happiness > surprise > disgust > anger > sadness > fear (this means these emotional responses were more accurate and faster). Generally, our data are in accordance with previous findings, but our differentiation of responses is better than the data from previous experiments on six basic emotions.     

Type and token bigram frequencies for two-through nine-letter words and the prediction of anagram difficulty

Recent research on anagram solution has produced two original findings. First, it has shown that a new bigram frequency measure called top rank, which is based on a comparison of summed bigram frequencies, is an important predictor of anagram difficulty. Second, it has suggested that the measures from a type count are better than token measures at predicting anagram difficulty.Testing these hypotheses has been difficult because the computation of the bigram statistics is difficult. We present a program that calculates bigram measures for two-to nine-letter words. We then show how the program can be used to compare the contribution of top rank and other bigram frequency measures derived from both a token and a type count. Contrary to previous research, we report that type measures are not better at predicting anagram solution times and that top rank is not the best predictor of anagram difficulty. Lastly we use this program to show that type bigram frequencies are not as good as token bigram frequencies at predicting word identification reaction time.     

Effects of directional uncertainty on visually-guided joystick pointing

Reaction times generally follow the predictions of Hick's law as stimulus-response uncertainty increases, although notable exceptions include the oculomotor system. Saccadic and smooth pursuit eye movement reaction times are independent of stimulus-response uncertainty. Previous research showed that joystick pointing to targets, a motor analog of saccadic eye movements, is only modestly affected by increased stimulus-response uncertainty; however, a no-uncertainty condition (simple reaction time to 1 possible target) was not included. Here, we re-evaluate manual joystick pointing including a no-uncertainty condition. Analysis indicated simple joystick pointing reaction times were significantly faster than choice reaction times. Choice reaction times (2, 4, or 8 possible target locations) only slightly increased as the number of possible targets increased. These data suggest that, as with joystick tracking (a motor analog of smooth pursuit eye movements), joystick pointing is more closely approximated by a simple/choice step function than the log function predicted by Hick's law.     

An external millisecond timer for the Apple Macintosh with applications to cross-modal lexical priming

The circuit and program described in this report allow researchers to use Macintosh personal computers to conduct research that requires timing with millisecond accuracy. This is accomplished with external response keys and an external clock that sends characters through the Macintosh’s serial port. For researchers interested in cross-modal lexical priming tasks, a tachistoscopic slide shutter is incorporated to allow for accurately timed presentation of visual stimuli. Because the visual display and response keys are external to the computer, display and reaction times are not subject to the timing constraints inherent to the keyboard or the Macintosh Event Manager. All circuit diagrams and code are in the public domain.     

We Interrupt This Program. Attention for Television Sequences

This experiment assesses the variable amounts of attention that are required for a viewer to process two kinds of interruptions common to television: the shift from one message to a different, unexpected message and the reference to previously presented material that follows an interruption. Respondents viewed 24 television sequences composed of three segments: an initial segment drawn from one program, an interrupt segment drawn from a second program, and a reorient segment that continued the presentation from the first program. Initial and interrupt segment lengths were either 10 seconds or 30 seconds in length to produce a factorial combination of four message sequences. Attention to these interruptions was measured using reaction times to audio tones located 1 and 6 seconds after a shift. More attention was required to view the interrupt segments following 30-second initial sequences, especially at the 6-second tone location. For the reorient segments, sequences containing 30-second initial segments required more attention, as did 30-second interrupt segments. These results are interpreted in terms of limited capacity and attentional inertia models of attention.     

Tachistoscopic software for the Macintosh

The emulation of a tachistoscope with a Macintosh microcomputer and Pascal language is presented here. The software described is a complete program for the presentation of textual stimuli on the Macintosh screen and includes the recording of reaction times. The stimulus coordinates on the screen are user defined and variable from trial to trial for specific visual angles. The position of a fixation point on the screen and the distance between the subject and the plane of the screen, as well as the particular screen resolution, are taken into account in computing the visual angle.     

The KIM-1 microcomputer as an eight-channel data logger

A machine language program and interface hardware to operate the KIM-1 microcomputer as an eight-channel data logger are described. All channels can operate simultaneously, and the data are stored in a specified area of memory. Double precision is used, enabling numbers greater than 255 to be recorded. Data can be collected over sampling intervals of 1 to 255 times 5 sec or 1 to 255 times 10 min. The time base is derived from 50- or 60-Hz mains ac. A method of transferring the data to a PET microcomputer and storing it on eight separate tape or disk files is also given.