Journal of the acoustical Society of America, 2011
Auditory threshold is 3 to 5 dB higher when signal frequency changes from trial to trial thanwhen... more Auditory threshold is 3 to 5 dB higher when signal frequency changes from trial to trial thanwhen the same on every trial. This threshold increase can be avoided by presenting a weakcue at the same frequency as the signal at the beginning of each trial. To achieve thisimprovement, Scharf, Reeves, and Suciu (2007) showed that the cue onset must precede thesignal onset by at least 200 ms. Threshold increased as signal delay decreased from 352 to82 ms. It was unclear whether poorer detection at shorter delays was caused by sluggishnessin focusing on the correct frequency or by interference from the temporally proximate cue.We now show that the threshold at delays at least as short as 52 ms can be ascribed primarilyif not entirely to interference. The implication is that selective frequency focusing is veryrapid.
The human visual system is spatially inhomogenous, and this property should be included in models... more The human visual system is spatially inhomogenous, and this property should be included in models of visual processing. We used weighted Hermite polynomials (WHPs) to encode and to characterize such inhomogenous processing. Simulations using an order-transfer-function (OTF) defined for each WHP order, at three spatial scales, provide elegant predictions of variations in two-point resolution and detection sensitivity with retinal eccentricity, of spatial frequency discrimination, and of WHP order discrimination.
We examined whether attentional capture can occur during an attentional blink (AB). If attention ... more We examined whether attentional capture can occur during an attentional blink (AB). If attention were 'locked up' during an AB, capture should not occur. To test for capture, we varied the salience of the two targets (T1 and T2) or of a distractor. Salience was controlled by adjusting chromaticity at equiluminance to equate simple reaction times. Experiment 1 demonstrated that the extent of AB varied almost entirely with T2 salience, not with T1 salience. In Experiment 2, a salient distractor between T1 and T2 reduced the AB without affecting its temporal profile; a salient distractor after T2 had no effect on AB. We conclude that attentional capture can occur during the AB, and stimulus salience modulates, rather than overriding, the AB. Independent of the postattentional (consolidation) mechanism primarily responsible for the AB, stimulus salience affects how an attention gate is triggered (Shih, 2000).
ABSTRACT Subjects first detected a target presented at the left of fixation, and then attempted t... more ABSTRACT Subjects first detected a target presented at the left of fixation, and then attempted to report, in order, the first four items (numerals or shapes) in a stream of items presented to the right of fixation. At comparably difficult presentation rates, 10/s for numerals and 5/s for shapes, reports showed a mixture of correctly ordered items with items reported in a direction opposite to their order of presentation. Reports fit a three-parameter attention-gating model (AGM), which assumes that (1) after target detection, an attention gate opens briefly to allow items to enter visual short-term memory (VSTM), and (2) report order is determined by the attention each item receives in VSTM. Items presented either early or late in the stream tend to receive less attention and are thus reported as later than more central items. The fit to the AGM for both numerals and unlabelled shapes provides evidence that reports reflect order in short-term visual (rather than verbal) memory.
Arend and Reeves [J. Opt. Soc. Am. A 3, 1743 (1986)] described measurements of color constancy in... more Arend and Reeves [J. Opt. Soc. Am. A 3, 1743 (1986)] described measurements of color constancy in computer simulations of arrays of colored papers of equal Munsell value under 4000-, 6500-, and 10,000-K daylight illuminants.
We report an extension of those experiments to chromatic arrays spanning a wide range of Munsell values. The computer-simulated scene included a standard array of Munsell papers under 6500-K illumination and a test array, an identical array of the same papers under 4000 or 10,000 K. Observers adjusted a patch in the test array in order to match the corresponding patch in the standard array by one of two criteria. They either matched hue and saturation or they made surface-color matches, in which the test patch was made to "look as if it were cut from the same piece of paper as the standard patch." The test and the standard patches were surrounded by a single color
(annulus display) or by many colors (Mondrian display). The data agreed with those of our previous equal-value experiment. The paper matches were often approximately color constant. The hue-saturation matches were in the correct direction for constancy but were always closer to. a chromaticity match (no constancy) than to the
chromaticity required for hue-saturation constancy.
Can a release of attention from fixation help explain the saccadic 'gap effect', the shortening o... more Can a release of attention from fixation help explain the saccadic 'gap effect', the shortening of saccadic latency (SL) when the fixation spot is extinguished just before saccade target onset? Practiced observers generated SLs and button-presses to one of four 10°eccentric targets in overlap (fixation spot stays on), gap0 (fixation offsets at target onset), and gap200 conditions; in gap200, the fixation spot was removed, dimmed, expanded, or brightened 200 ms before target onset. Our data excluded speed-accuracy tradeoffs, express saccades, stimulus salience, and oculomotor readiness, while fixation offset and general warning had minor effects, leaving attention release as the default explanation. Supporting this notion, finger-press reactions to foveal probe dots presented after the fixation spot was brightened (to hold attention) were faster than those made after the spot was removed (to release attention). Varying the time from gap onset to the probe dot mapped out the time-course of the putative attentional release, which takes $140 ms.
Identification of brief luminance decrements on parafoveal stimuli presented during smooth pursui... more Identification of brief luminance decrements on parafoveal stimuli presented during smooth pursuit improves when a spot pursuit target is surrounded by a larger random dot cinematogram (RDC) that moves with it (Heinen, Jin, & Watamaniuk, 2011). This was hypothesized to occur because the RDC provided an alternative, less attention-demanding pursuit drive, and therefore released attentional resources for visual perception tasks that are shared with those used to pursue the spot. Here, we used the RDC as a tool to probe whether spot pursuit also shares attentional resources with the saccadic system. To this end, we set out to determine if the RDC could release attention from pursuit of the spot to perform a saccade task. Observers made a saccade to one of four parafoveal targets that moved with the spot pursuit stimulus. The targets either moved alone or were surrounded by an RDC (100% coherence). Saccade latency decreased with the RDC, suggesting that the RDC released attention needed to pursue the spot, which was then used for the saccade task. Additional evidence that attention was released by the RDC was obtained in an experiment in which attention was anchored to the fovea by requiring observers to detect a brief color change applied 130 ms before the saccade target appeared. This manipulation eliminated the RDC advantage. The results imply that attentional resources used by the pursuit and saccadic eye movement control systems are shared.
Observers viewed briefly presented target dot patterns, either at low contrast without a mask (no... more Observers viewed briefly presented target dot patterns, either at low contrast without a mask (no mask, or NM) or at high contrast and followed by a long-lasting patterned mask (backward masking, or BM). Experiment 1 demonstrated independent processing of NM target dots but limited capacity processing of BM target dots. Experiments 2 and 3 showed that visual images may radically change sensitivity (d') in BM but not in NM. Results suggest that d' is reduced if the image suppresses dots relevant for the detection task, but that d' is raised if the image suppresses dots that compete for processing with those the observer must detect.
Distinguishing opponent and non-opponent detection pathways in early dark adaptation
Vision Research, 1983
Desensitization of the red-green opponent pathway was demonstrated in early dark adaptation with ... more Desensitization of the red-green opponent pathway was demonstrated in early dark adaptation with the aid of a test chosen to isolate that pathway. Isolation was achieved by requiring the observer to adjust the intensity of a foveal test light to the threshold for flicker, when the test alternated slowly between luminance-matched red and yellow fields. The luminance matches were precise enough that only an opponent pathway could mediate the flicker thresholds. Desensitization occurred after continuous light adaptation to 626 nm fields, but did not occur after adaptation to yellow fields, or if the 626 nm field was turned on and off at 2 Hz throughout adaptation. The properties of the red-green pathway measured with the flicker thresholds resemble those of the yellow-blue pathway as shown in transient tritanopla.
The probe-signal method ) was used to determine the percentage of trials in which unpracticed sub... more The probe-signal method ) was used to determine the percentage of trials in which unpracticed subjects detected (two-interval, forced-choice)a soft, expected sound as compared with an unexpected sound. Pure tones at or near an expected frequency were detected in about 90% of the trials. Tones more than one-half critical band away were detected near chance (50%). Complex sounds (a band of noise or a multitone complex) were detected better if they were inside the same critical band as the expected signal than if they were outside the band. A signal that differed spectrally from the expected sound was not detected even though it had the same low pitch, based on a common fundamental frequency. The results may mean that under some conditions focused attention alters sensitivity in the auditory system.
Journal of the acoustical Society of America, 2011
Auditory threshold is 3 to 5 dB higher when signal frequency changes from trial to trial thanwhen... more Auditory threshold is 3 to 5 dB higher when signal frequency changes from trial to trial thanwhen the same on every trial. This threshold increase can be avoided by presenting a weakcue at the same frequency as the signal at the beginning of each trial. To achieve thisimprovement, Scharf, Reeves, and Suciu (2007) showed that the cue onset must precede thesignal onset by at least 200 ms. Threshold increased as signal delay decreased from 352 to82 ms. It was unclear whether poorer detection at shorter delays was caused by sluggishnessin focusing on the correct frequency or by interference from the temporally proximate cue.We now show that the threshold at delays at least as short as 52 ms can be ascribed primarilyif not entirely to interference. The implication is that selective frequency focusing is veryrapid.
The human visual system is spatially inhomogenous, and this property should be included in models... more The human visual system is spatially inhomogenous, and this property should be included in models of visual processing. We used weighted Hermite polynomials (WHPs) to encode and to characterize such inhomogenous processing. Simulations using an order-transfer-function (OTF) defined for each WHP order, at three spatial scales, provide elegant predictions of variations in two-point resolution and detection sensitivity with retinal eccentricity, of spatial frequency discrimination, and of WHP order discrimination.
We examined whether attentional capture can occur during an attentional blink (AB). If attention ... more We examined whether attentional capture can occur during an attentional blink (AB). If attention were 'locked up' during an AB, capture should not occur. To test for capture, we varied the salience of the two targets (T1 and T2) or of a distractor. Salience was controlled by adjusting chromaticity at equiluminance to equate simple reaction times. Experiment 1 demonstrated that the extent of AB varied almost entirely with T2 salience, not with T1 salience. In Experiment 2, a salient distractor between T1 and T2 reduced the AB without affecting its temporal profile; a salient distractor after T2 had no effect on AB. We conclude that attentional capture can occur during the AB, and stimulus salience modulates, rather than overriding, the AB. Independent of the postattentional (consolidation) mechanism primarily responsible for the AB, stimulus salience affects how an attention gate is triggered (Shih, 2000).
ABSTRACT Subjects first detected a target presented at the left of fixation, and then attempted t... more ABSTRACT Subjects first detected a target presented at the left of fixation, and then attempted to report, in order, the first four items (numerals or shapes) in a stream of items presented to the right of fixation. At comparably difficult presentation rates, 10/s for numerals and 5/s for shapes, reports showed a mixture of correctly ordered items with items reported in a direction opposite to their order of presentation. Reports fit a three-parameter attention-gating model (AGM), which assumes that (1) after target detection, an attention gate opens briefly to allow items to enter visual short-term memory (VSTM), and (2) report order is determined by the attention each item receives in VSTM. Items presented either early or late in the stream tend to receive less attention and are thus reported as later than more central items. The fit to the AGM for both numerals and unlabelled shapes provides evidence that reports reflect order in short-term visual (rather than verbal) memory.
Arend and Reeves [J. Opt. Soc. Am. A 3, 1743 (1986)] described measurements of color constancy in... more Arend and Reeves [J. Opt. Soc. Am. A 3, 1743 (1986)] described measurements of color constancy in computer simulations of arrays of colored papers of equal Munsell value under 4000-, 6500-, and 10,000-K daylight illuminants.
We report an extension of those experiments to chromatic arrays spanning a wide range of Munsell values. The computer-simulated scene included a standard array of Munsell papers under 6500-K illumination and a test array, an identical array of the same papers under 4000 or 10,000 K. Observers adjusted a patch in the test array in order to match the corresponding patch in the standard array by one of two criteria. They either matched hue and saturation or they made surface-color matches, in which the test patch was made to "look as if it were cut from the same piece of paper as the standard patch." The test and the standard patches were surrounded by a single color
(annulus display) or by many colors (Mondrian display). The data agreed with those of our previous equal-value experiment. The paper matches were often approximately color constant. The hue-saturation matches were in the correct direction for constancy but were always closer to. a chromaticity match (no constancy) than to the
chromaticity required for hue-saturation constancy.
Can a release of attention from fixation help explain the saccadic 'gap effect', the shortening o... more Can a release of attention from fixation help explain the saccadic 'gap effect', the shortening of saccadic latency (SL) when the fixation spot is extinguished just before saccade target onset? Practiced observers generated SLs and button-presses to one of four 10°eccentric targets in overlap (fixation spot stays on), gap0 (fixation offsets at target onset), and gap200 conditions; in gap200, the fixation spot was removed, dimmed, expanded, or brightened 200 ms before target onset. Our data excluded speed-accuracy tradeoffs, express saccades, stimulus salience, and oculomotor readiness, while fixation offset and general warning had minor effects, leaving attention release as the default explanation. Supporting this notion, finger-press reactions to foveal probe dots presented after the fixation spot was brightened (to hold attention) were faster than those made after the spot was removed (to release attention). Varying the time from gap onset to the probe dot mapped out the time-course of the putative attentional release, which takes $140 ms.
Identification of brief luminance decrements on parafoveal stimuli presented during smooth pursui... more Identification of brief luminance decrements on parafoveal stimuli presented during smooth pursuit improves when a spot pursuit target is surrounded by a larger random dot cinematogram (RDC) that moves with it (Heinen, Jin, & Watamaniuk, 2011). This was hypothesized to occur because the RDC provided an alternative, less attention-demanding pursuit drive, and therefore released attentional resources for visual perception tasks that are shared with those used to pursue the spot. Here, we used the RDC as a tool to probe whether spot pursuit also shares attentional resources with the saccadic system. To this end, we set out to determine if the RDC could release attention from pursuit of the spot to perform a saccade task. Observers made a saccade to one of four parafoveal targets that moved with the spot pursuit stimulus. The targets either moved alone or were surrounded by an RDC (100% coherence). Saccade latency decreased with the RDC, suggesting that the RDC released attention needed to pursue the spot, which was then used for the saccade task. Additional evidence that attention was released by the RDC was obtained in an experiment in which attention was anchored to the fovea by requiring observers to detect a brief color change applied 130 ms before the saccade target appeared. This manipulation eliminated the RDC advantage. The results imply that attentional resources used by the pursuit and saccadic eye movement control systems are shared.
Observers viewed briefly presented target dot patterns, either at low contrast without a mask (no... more Observers viewed briefly presented target dot patterns, either at low contrast without a mask (no mask, or NM) or at high contrast and followed by a long-lasting patterned mask (backward masking, or BM). Experiment 1 demonstrated independent processing of NM target dots but limited capacity processing of BM target dots. Experiments 2 and 3 showed that visual images may radically change sensitivity (d') in BM but not in NM. Results suggest that d' is reduced if the image suppresses dots relevant for the detection task, but that d' is raised if the image suppresses dots that compete for processing with those the observer must detect.
Distinguishing opponent and non-opponent detection pathways in early dark adaptation
Vision Research, 1983
Desensitization of the red-green opponent pathway was demonstrated in early dark adaptation with ... more Desensitization of the red-green opponent pathway was demonstrated in early dark adaptation with the aid of a test chosen to isolate that pathway. Isolation was achieved by requiring the observer to adjust the intensity of a foveal test light to the threshold for flicker, when the test alternated slowly between luminance-matched red and yellow fields. The luminance matches were precise enough that only an opponent pathway could mediate the flicker thresholds. Desensitization occurred after continuous light adaptation to 626 nm fields, but did not occur after adaptation to yellow fields, or if the 626 nm field was turned on and off at 2 Hz throughout adaptation. The properties of the red-green pathway measured with the flicker thresholds resemble those of the yellow-blue pathway as shown in transient tritanopla.
The probe-signal method ) was used to determine the percentage of trials in which unpracticed sub... more The probe-signal method ) was used to determine the percentage of trials in which unpracticed subjects detected (two-interval, forced-choice)a soft, expected sound as compared with an unexpected sound. Pure tones at or near an expected frequency were detected in about 90% of the trials. Tones more than one-half critical band away were detected near chance (50%). Complex sounds (a band of noise or a multitone complex) were detected better if they were inside the same critical band as the expected signal than if they were outside the band. A signal that differed spectrally from the expected sound was not detected even though it had the same low pitch, based on a common fundamental frequency. The results may mean that under some conditions focused attention alters sensitivity in the auditory system.
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Papers by A. Reeves
We report an extension of those experiments to chromatic arrays spanning a wide range of Munsell values. The computer-simulated scene included a standard array of Munsell papers under 6500-K illumination and a test array, an identical array of the same papers under 4000 or 10,000 K. Observers adjusted a patch in the test array in order to match the corresponding patch in the standard array by one of two criteria. They either matched hue and saturation or they made surface-color matches, in which the test patch was made to "look as if it were cut from the same piece of paper as the standard patch." The test and the standard patches were surrounded by a single color
(annulus display) or by many colors (Mondrian display). The data agreed with those of our previous equal-value experiment. The paper matches were often approximately color constant. The hue-saturation matches were in the correct direction for constancy but were always closer to. a chromaticity match (no constancy) than to the
chromaticity required for hue-saturation constancy.
We report an extension of those experiments to chromatic arrays spanning a wide range of Munsell values. The computer-simulated scene included a standard array of Munsell papers under 6500-K illumination and a test array, an identical array of the same papers under 4000 or 10,000 K. Observers adjusted a patch in the test array in order to match the corresponding patch in the standard array by one of two criteria. They either matched hue and saturation or they made surface-color matches, in which the test patch was made to "look as if it were cut from the same piece of paper as the standard patch." The test and the standard patches were surrounded by a single color
(annulus display) or by many colors (Mondrian display). The data agreed with those of our previous equal-value experiment. The paper matches were often approximately color constant. The hue-saturation matches were in the correct direction for constancy but were always closer to. a chromaticity match (no constancy) than to the
chromaticity required for hue-saturation constancy.