Visual backward masking as measured by voice reaction time

Instead of using percent correct identifications or detections as the dependent variable, latency in voicing the target stimulus was measured in a backward masking paradigm. Reaction time (RT) to target letters was reliably increased when they were simultaneously encircled by a black ring mask of a size found to produce masking using an identification or detection criterion. The masking function in terms of RT was typical in shape, a decreasing function of stimulus onset asynchrony (SOA) over an interval of 150 msec. Since the target remained “on” when the mask appeared, the results are incompatible with an erasure interpretation of masking effects. Analyses of the variances of the RTs supported an interpretation of a progressive decrease in masking effects as SOA increased.     

Binaural interaction in backward masking

The binaural auditory system exhibits certain advantages over the monaural system when detecting a tonal signal in a background of masking noise. These advantages have been described in detail and are referred to as masking-level differences, or MLDs. It has been demonstrated, for example, that performance in detecting a tonal signal that has been reversed in phase at one ear relative to the other ear is about 15–17 dB better than detection of the same signal in-phase at the two ears when masked by moderately intense masking noise that is in-phase at the two ears. The explanations for this phenomenon fall into two general categories, and both types of explanations are based upon the interaction of the tonal signal and masker when they are added together. In the present paper, data are presented which indicate that an MLD of at least 4–5 dB can be obtained in a binaural masking experiment in which the offset of the tonal signal precedes the onset of the noise masker.     

Response latency,confidence, and ROCs in auditory signal detection

Response latencies were obtained from 10 Ss in auditory signal-detection experiments. The response latencies were inversely related to certainty that a signal was (or was not) presented. The S’s decision criterion was found to have an influence on response latency, which was consistent with the hypothesis that stimuli close to the current criterion elicit longer response latencies than stimuli more distant from the criterion. Comparisons among receiver operating characteristics derived from binary decisions, from the latencies of binary decisions, and from confidence ratings show that response latencies and binary decisions together yield more information about the stimulus than does the binary decision alone. However, the increment in information gained from the measurement of response latencies is in general (though not for every S) smaller than that gained by shifting from yes-no responses to a confidence-rating procedure.     

Effect of “backward” masker fringe on the detectability of pulsed diotic and dichotic tonal signals

The effects of backward masker “fringe” on performance in homophasic and antiphasic masking conditions were investigated. The results of the study indicate that (1) the presence of a backward masker fringe has only a small effect on performance in homophasic masking conditions; (2) under antiphasic masking conditions, the presence of a backward masker fringe improves performance; (3) similar to the results of studies investigating the effects of forward masker fringe, the magnitude of the improvement in performance increases as the duration of the fringe increases; and (4) the magnitude of the improvement caused by the presence of backward masker fringe is considerably smaller than the magnitude of the improvement caused by the forward masker fringe. It appears, then, that the presence of backward masker fringe may provide a baseline or reference phase similar to that which the forward fringe is presumed to provide. The presence of this reference phase after the offset of the signal apparently makes the phase shift associated with the signal-plus-noise waveform more discernible, thus leading to higher detectability. However, for reasons not yet clear, the presence of a baseline or reference phase after the offset of the signal (backward fringe conditions) does not make the signal-plus-noise phase shift as discernible as do either the presence of that same reference phase before the onset of the signal (forward fringe condition) or the presence of that same reference phase both before signal onset and after signal offset (continuous masker condition).     

Visual angle and apparent size of objects in peripheral vision

Measurements of apparent size were obtained by distance adjustment of a peripherally viewed stimulus to produce a match to a foveally viewed standard. As eccentricity increased, the peripheral stimulus was adjusted at distances of progressively greater visual angle, indicating that a continuous diminution in apparent size occurs with increased eccentricity. This effect was found to be stable for several conditions of illumination and for changes in the light adaptive state of S. Apparent size diminution and apparent distance increase were also found for familiar objects viewed in an open field.     

A signal detection analysis of the effects of hearing on the visual recognition of two-digit numbers

A signal detection measure of visual recognition was used to assess the visual recognition of two-digit numbers in three different conditions: (1) voicing of the number as it was presented visually; (2) voicing of a different number than the one presented; and (3) no voicing. The three treatment means were significantly different, with matched voicing resulting in the best performance and no voicing, in the worst. There was no evidence that the treatments differentially affected response criteria.