Psychophysics of lateral tachistoscopic presentation

Human visual performance depends upon the retinal position to which a target is delivered. A general finding is that performance measured in a variety of psychophysical tasks deteriorates as a target is presented to more eccentric retinal regions. One purpose of this paper is to describe differences between foveal and peripheral vision in a number of psychophysical tasks. A second purpose is to review studies which have attempted to account for the fall off in visual performance between central and peripheral target presentations. A third purpose is to consider the contribution of the periphery to perception since targets which are sufficiently large project not only on receptors in the fovea but also on those in the periphery. In addition, stimuli presented to the peripheral retina can influence the processing of a target presented to the central retinal region. A fourth purpose is to review studies which have attempted to compensate for foveal and peripheral differences by scaling the target in size or some other attribute in proportion to the cortical magnification factor. A final purpose of this paper is to consider whether the fovea and the periphery are specialized for different functions.     

eXpTools: A C++ class library for animation, tachistoscopic presentation, and response timing

The eXpTools Library is a general-purpose tool for developing psychological experiments that combine animation with tachistoscopic presentation. The library’s C++ classes and assembly language functions are specialized for the creation of visual response time experiments. Its use is limited to variants of standard, 16-color, VGA high-graphics modes. However, it extends the capabilities of these modes through bit-plane animation techniques and a new, nonstandard, high-resolution graphics mode that will work with standard VGA cards and register-compatible cards. These techniques make possible a powerful animation class for managing complex animation or tachistoscopic presentations consisting of hundreds or thousands of frames. The library also combines such features as page flipping, screen blanking, video-refresh synchronization, interrupt-driven millisecond timing, interrupt-driven keyboard response collection, graphics primitives, bitmaps, and screen fonts. Utilities allow for the conversion of PCX graphics files and the creation of new screen fonts from monochrome bitmap files. The technologies and techniques underlying the library are presented along with an example program.     

Responses of schizophrenics and nonpatients to a tachistoscopic presentation of the Rorschach

Three groups of 36 subjects each, two of nonpsychiatric subjects and one of first admission schizophrenics, were administered the Rorschach tachistoscopically. Each group was subdivided into three subgroups to permit a variation in exposure times for the blots. Intervals of 200ms, 400ms, and 600ms were used; however, the differences in exposure times did not produce significant differences within any of the groups. Thus, the data were compared by groups. The results indicate no significant differences across the groups for accuracy of from (X + %). The schizophrenic group did give significantly more Special Scores related to cognitive slippage. They also gave a much higher proportion of pure form responses and substantially more card rejections than either of the nonpsychiatric groups. The results are discussed in the context of research on information processing and the early operations in the Rorschach response process.     

A tachistoscopic software system for use in remote timesharing applications

A program is described that permits the use of an Imlac PDS-1 display computer, in conjunction with a host timeshare system, as a software-controlled tachistoscope. Alphanumeric and graphic message strings are received from the host computer over a telephone line, and are then displayed for specified periods of time in sequence. The display computer records the S’s responses and reaction time and reports this information back to the host computer for recording and analysis. The system is designed so that the burden of software development for the realization of a specific experimental plan is shifted to the large-capacity host machine, and it can utilize all of the features of standard FORTRAN as implemented on the host computer system.     

Solving the rod-and-frame test in a tachistoscopic presentation: Effects of stimulus size and perceptual style

This research was undertaken to demonstrate, with correlational evidence, that presenting the rod-and-frame test (RIT) with either limited (tachistoscopic) or unlimited (Oltman’s, 1968, portable RFT) exposure time does not significantly affect the ranking of subjects. The underlying hypothesis is that the intersubject variability of performance on the portable RFT is due essentially to differences in sensitivity to the optostatic vection that appears automatically and almost immediately. Results of the tachistoscopic test show that the effect of angular size of the stimulus is similar to that described in the literature for unlimited time situations, and that subjects’ ranking is very similar regardless of the exposure time (W = .80). However, although a difference is observed between the means of low and high achievers in both types of RFT, intraindividual intertask homogeneity (correlation coefficient) is not verified in each of these subgroups. From these results, one can distinguish two processes in the RFT: the first, vections, has to do with the subject’s postural orientation and seems to playa great role in organizing interindividual differences. The second process, a more cognitive one, has a less striking effect and has to do with the selection of reference frames in perceptual organization.     

Evidence for independent parallel channels in tachistoscopic perception

This paper reviews the implications of a number of experimental results for a test between two different types of models of perceptual processing: models that assume a limitation of perceptual capacity vs models that postulate independent, parallel perceptual channels. The results of recent “detection” experiments (e.g., Estes & Taylor, 1966) have been consistent with the limited-capacity model developed by Rumelhart (1970). The same results, however, are predicted by the “ICC” independent-parallel-channels model, an extension of work by Eriksen and Spencer (1969) developed in the present paper. This model emphasizes the interaction of two factors: decisional properties of the detection task, plus perceptual confusion phenomena known to occur under tachistoscopic conditions.Two experiments relevant to a test between the ICC and Rumelhart conceptions are reported. Experiment I involved a “time-sharing” paradigm that varied the demands of two detection tasks performed within a single trial. Experiment II involved the elimination of certain perceptual confusion phenomena. The results of Expts I and II appeared consistent with the ICC model but inconsistent with the Rumelhart model. After consideration of alternative limited-capacity models, it was concluded that: (1) a decision-confusion interaction is a necessary component of information-processing models, and that (2) the ICC independent-parallel-channels model is sufficient to account for the broad spectrum of experimental results reviewed.     

An improved technique for monitoring fixation in tachistoscopic tasks

A monocular lens mounted behind a stimulus screen was used to monitor fixation in a tachistoscopic recognition task. This technique was found superior to the often used “sideview technique” and as accurate as the method involving identification of a fixation stimulus. It was found that the “telescope technique” is preferable in those studies where presentation of a fixation stimulus might interfere with recognition or report of the experimental stimulus.     

Hemispheric differences for semantically and phonologically primed nouns: A tachistoscopic study in normals

Normal individuals performed two matching tasks. In one task, semantic processing, synonyms had to be recognized. Half the stimuli were picturable and half were nonpicturable nouns. In this task, recognition of picturable synonyms was found to have hemifield symmetry, whereas recognition of nonpicturable synonyms yielded a left-hemisphere superiority, indicating that semantic matching itself did not reveal equal performance of both hemispheres. It is concluded that picturable synonyms might be recognized either by processes of visual imagery, which pertain to right-hemisphere function, or by their phonological or phonic features, which are processed by the left hemisphere. The other task, shown in previous research to exhibit a left-hemisphere superiority, was to decide if two nouns (homophones) were equally pronounced. Here a distinct left-hemisphere advantage was revealed.     

A tachistoscopic study of hemispheric processing in stuttering and nonstuttering children

Hemispheric processing, expressed as mean reaction time to various visual stimuli presented to the left and right visual fields, was investigated in eighteen stuttering and nonstuttering children. Tachistoscopic procedures were used to present linguistic stimuli (words and nonwords) as well as nonlinguistic stimuli (familiar and unfamiliar geometric figures) to the visual fields. Subjects responded by pressing a telegraph key when they perceived a real word or a familiar geometric figure. They were to make no response when they perceived nonwords or unfamiliar geometric figures. Faster reaction times were taken as an index of the most efficient or dominant hemisphere for a given task. No significant differences were found in mean reaction times for groups, visual fields, type of task, nor any of their interactions. Likewise, the data on accuracy also did not suggest that a larger proportion of stutters responded more accurately when linguistic stimuli were presented to the right hemisphere. Based on mean reaction times and on accuracy data, the stuttering and nonstuttering children performed with similar efficiencies and processing patterns.     

Sex in lateralized tachistoscopic word recognition

Although a generalized sex difference in lateralization appears to be established, a review of the literature pertaining to lexical tachistoscopic tasks suggests a dissociation by method: females show reduced visual field asymmetries relative to males in lexical decision and naming, but not in word recognition. Here 14 recognition experiments from the author's laboratory are subjected to meta-analysis, and the literature review is confirmed. There is no sex difference is visual field asymmetry for the task, although an overall field difference is found and statistical power is high to find the interaction. Possible reasons for the discrepancy with lexical decision and naming findings are discussed. One possibility is that stress on reaction time in those tasks produces a complex interaction between sex, activation/arousal, and hemispheric differences, which is not found when a less speeded method is used.     

Studies of letter identification using qualitative error analysis: effects of speed stress, tachistoscopic presentation, and word context

In Experiment 1 subjects named letters under a response deadline chosen so that an appreciable number of errors would be produced. The stimulus confusions were analyzed via the same mathematical models of stimulus recognition that have been applied to the confusion matrices generated in tachistoscopic experiments. Both the Luce choice model and the informed guessing model (a new model having a simple and elegant process interpretation) provided excellent fits to the data. The parameter values of the informed guessing model changed in logical and interpretable ways with changes in the response deadline. In Experiment 2 a direct comparison was made of the types of errors produced in the data-limited tachistoscopic situation and the resource-limited response deadline situation. It was found that, relative to the response deadline task, identification in the tachistoscopic task is much more likely to be based on partial information. In Experiments 3 and 4 the same research methodology was applied to the problem of the effect of a word context on letter perception. The methodology allowed this problem to be addressed in the context of both response deadline and tachistoscopic tasks. Several advantages of the methodology for investigating other issues of interest to cognitive psychologists are discussed.