Modulation of the attentional blink by on-line response selection: evidence from speeded and unspeeded task1 decisions

Two critical target stimuli (T1 and T2) were embedded in a stream of white letters shown on a black background, using a rapid serial visual presentation paradigm (RSVP, 100 msec/item). T1 was a red H or S; T2 was an X or a Y. Performance in a two-alternative discrimination on T2 was impaired when processing of T1 was required--a result often called an attentional blink (AB). In previous work, the response in Task1 has been an unspeeded and delayed response at the end of the trial. Three experiments compared performances in Task2 that depended on whether Task1 required an unspeeded delayed response or a speeded immediate response. A larger AB was found when a speeded response was required. Furthermore, in the speeded conditions, faster responses in Task1 were associated with a smaller and shorter AB effect than were slower responses. The results show that manipulations affecting a relatively late stage of processing--response selection--affect the magnitude and duration of the AB phenomenon. A new central inhibition theory is proposed to account for these results. According to this theory, the AB is similar to the psychological refractory period effect and is caused by central postponement of short-term consolidation of T2.     

Age differences in overlapping-task performance: Evidence for efficient parallel processing in older adults.

Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task I (TI) and a lexical-decision task (word or nonword) for Task 2 (T2) were used. PRP effects, response time for T2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T2 was smaller at the short SOA than at the long SOA, reflecting slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T2 in parallel with the processing of T2, at least as efficiently as younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Better to take one long or two quick looks? Independent processing of evidence from discrete visual presentations.

Should we prefer one long look to two quick looks of equal overall duration? The authors systematically compared conditions in which a circular letter array was available either for a single look of 2d ms duration (onset asynchrony [SOA] from target to mask) or for two separate looks of d ms each. On the basis of the geometry of the underlying psychometric function relating the SOA to the probability of target identification, separate activation models with peaked hazard functions predict that for short SOAs single long looks would lead to better identification performance and that this advantage decreases (and may turn into a disadvantage) with increasing SOA. These predictions were tested, confirmed, and extended in 5 letter-identification experiments that focused on the mechanism by which information extracted from single arrays is integrated across different looks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Locus of Redundant-Targets and Nontargets Effects: Evidence From the Psychological Refractory Period Paradigm.

In target detection tasks, responses are faster when displays have 2 targets (redundant-targets effect; RTE) and slower when they have no targets (nontargets effect; NTE) relative to displays with a single target. The psychological refractory period paradigm was used to localize these effects. In Experiment 1, participants classified tones as high or low and then classified letters as targets or nontargets after a short or long stimulus onset asynchrony (SOA). The magnitudes of the RTE and NTE did not depend on SOA. In Experiment 2, the order of the tasks was reversed, and at short SOAs the RTE and NTE had similar magnitudes for both tone discrimination and target detection responses. These findings suggest that the RTE and NTE arise during response selection. Interactive effects of tone pitch with the number and type of target features were also observed, and these were tentatively interpreted as synesthetic effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"The attentional blink reflects retrieval competition among multiple rapid serial visual presentation items: Tests of an interference model": Erratum.

Reports an error in "The attentional blink reflects retrieval competition among multiple rapid serial visual presentation items: Tests of an interference model" by Matthew I. Isaak, Kimron L. Shapiro and Jesse Martin (Journal of Experimental Psychology: Human Perception and Performance, 1999[Dec], Vol 25[6], 1774-1792). On p. 1778, the correct Figure 1 was inadvertently replaced in the production process with an erroneous figure. The erratum contains the corrected figure. (The following abstract of the original article appeared in record 2000-15288-019.) When people respond to a target (T1) in a rapid serial visual presentation stream, their perception of a subsequent target (T2) is impaired if the intertarget stimulus onset asynchrony is between about 100 and 500 ms. Three experiments supported the interference model's (K. L. Shapiro, J. E. Raymond, & K. M. Arnell, 1994) claim that this attentional blink reflects competition for retrieval among multiple items in visual short-term memory. Experiments 1 and 2 revealed that items appearing during the blink are named as T2 on an above-chance proportion of trials when T2 must be identified. Experiment 3 demonstrated that both the size of the blink and sensitivity to T2 reflected the number of items competing for retrieval as T2; such competition, moreover, occurred at a conceptual or categorical level rather than at a purely visual one. The relationship between the interference and alternative models of the attentional blink is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metacontrast masking in amblyopia.

Measured the time course of visual signals arising from each eye of 4 strabismic and/or anisometropic amblyopes and 2 visually normal Ss using monoptic metacontrast masking. The amblyope Ss had 1 nonamblyopic eye, clear ocular media, and normal fundi. The method involved the brightness estimation of a high-contrast disk target whose visibility varied as a function of the stimulus onset asynchrony (SOA) of a subsequent annular mask. Results indicate that the SOA of optimal masking was delayed in the amblyopic eye compared to that of the fellow nonamblyopic eye or with normal eyes. The smaller the target, the greater was this SOA difference and the broader was the amblyopic U-shaped masking function. This finding is discussed in terms of the current model of metacontrast and represents the differential effect of the amblyopic process on human sustained and transient neurons. (French abstract) (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can Practice Overcome Age-Related Differences in the Psychological Refractory Period Effect?

Can dual-task practice remove age-related differences in the psychological refractory period (PRP) effect? To answer this question, younger and older individuals practiced 7 blocks of a PRP design, in which Task 1 (T1) required a vocal response to an auditory stimulus and Task 2 (T2) required a manual response to a visual stimulus (Experiment 1). The results showed that practice did not reduce, but rather increased, age-related differences in PRP interference. Using the trained individuals, the introduction of a less complex new T1 (Experiment 2) or a less complex new T2 (Experiment 3) with the task previously practiced reduced the PRP interference but only in older adults. The authors propose that older adults suffer from a large task-switch cost that is more sensitive to task complexity than to the amount of practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The attentional blink reflects retrieval competition among multiple rapid serial visual presentation items: Tests of an interference model.

[Correction Notice: An erratum for this article was reported in Vol 26(2) of Journal of Experimental Psychology: Human Perception and Performance (see record 2007-17423-001). On p. 1778, the correct Figure 1 was inadvertently replaced in the production process with an erroneous figure. The erratum contains the corrected figure.] When people respond to a target (T1) in a rapid serial visual presentation stream, their perception of a subsequent target (T2) is impaired if the intertarget stimulus onset asynchrony is between about 100 and 500 ms. Three experiments supported the interference model's (K. L. Shapiro, J. E. Raymond, & K. M. Arnell, 1994) claim that this attentional blink reflects competition for retrieval among multiple items in visual short-term memory. Experiments 1 and 2 revealed that items appearing during the blink are named as T2 on an above-chance proportion of trials when T2 must be identified. Experiment 3 demonstrated that both the size of the blink and sensitivity to T2 reflected the number of items competing for retrieval as T2; such competition, moreover, occurred at a conceptual or categorical level rather than at a purely visual one. The relationship between the interference and alternative models of the attentional blink is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional blink for color.

Colored letters were presented by means of rapid serial visual presentation (RSVP). Two letters (T1 and T2) were targets that required a speeded (T1) or delayed (T2) response. T1 was shown on half of the trials. Two tasks were performed in the experimental conditions. Task1 required a discrimination between 2 letters (when T1 was shown) or an indication that T1 was absent. In Experiment 1, Task2 was to detect the presence of a unique color in the RSVP stream (e.g., green in a stream of alternating red and gray). In Experiment 2, Task2 was to report the color of the first colored letter to appear in the RSVP stream. The lag between T1 and T2 in the RSVP stream was manipulated. Accuracy of color reports in Task2 was poor at shorter lags and improved as the lag was lengthened in both experiments, demonstrating an attentional blink for chromatic information. Theoretical implications of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early interference in a priming task with brief masked targets.

Priming effects were examined in 2 experiments with 216 undergraduates in which a pronunciation or lexical decision task was used. Attention was manipulated by varying the probability that prime and target would be strongly associated. Both experiments showed significant interference in the low attention condition and at the 200-msec SOA, presumably before the onset of consciously directed processing. Two subsequent experiments with 160 undergraduates used a short SOA and the low attention condition to determine the conditions under which this interference would occur by varying the interstimulus interval, target duration, and the mask. Interference occurred only when targets were brief and masked. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the role of eye movements and saccade preparation in generating auditory inhibition of return.

Examined whether the suggestion that "the eccentricity of signals which are effective in activating inhibition of return is restricted to the eccentricity to which accurate saccades can be made" is consistent with the necessary conditions for the occurrence of location-based auditory inhibition of return in a total of 24 volunteers. In 3 experiments, listeners were required to either localize or identify the 2nd of 2 successive sounds. The 1st sound and the 2nd sound could originate from either the same or different locations, and the interval between the onsets of the 2 sounds (Stimulus Onset Asynchrony, SOA) was varied. Sounds were presented out of visual range at 135 azimuth left or right. In Exp 1, localization responses were made more quickly at 100 ms SOA when the target sounded from the same location as the cue, and at 700 ms SOA when the target and cue sounded from different locations. In Exps 2 and 3, Ss monitored visual information presented directly in front of them at the same time as the auditory cue and target were presented behind them. Results indicate that in both experiments, a transition from facilitation at a brief SOA to inhibition at a longer SOA was observed for the auditory task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading aloud is not automatic: Processing capacity is required to generate a phonological code from print.

The present experiments tested the claim that phonological recoding occurs "automatically" by assessing whether it uses central attention in the context of the psychological refractory period paradigm. Task 1 was a tone discrimination task and Task 2 was reading aloud. The joint effects of long-lag word repetition priming and stimulus onset asynchrony (SOA) were underadditive in Experiment 1, suggesting that an early component of lexical processing does not use central attention. In contrast, nonword letter length and grapheme-phoneme complexity yielded additive effects with SOA in Experiments 2, 3, and 4, suggesting that assembled phonology uses central attention. Further, orthographic neighborhood density also yielded additive effects with SOA in Experiments 5, 6, and 7, suggesting that lexical contributions to phonological recoding use central attention. Taken together, the results of these experiments are inconsistent with the widespread claim that phonological codes are assembled and/or addressed automatically. It is suggested that "automaticity" should be replaced by accounts that make more specific claims about how processing unfolds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Loci of signal probability effects and of the attentional blink bottleneck.

To investigate the locus of signal probability effects and the influence of stimulus quality on this locus, the authors manipulated probability in Task 2 of a psychological refractory period (PRP) paradigm. The effect was additive with stimulus onset asynchrony (SOA) when the target was not masked but underadditive with decreasing SOA when the target was masked. Even with masking, however, a range of probabilities had effects additive with SOA. The results suggest loci of stimulus probability before the PRP bottleneck as well as at or after the bottleneck. A second issue addressed was the locus of interference in the attentional blink (AB). The AB was larger when the probability of the first of 2 targets was lower. The results lead to the conclusion that one cause of the AB effect is a locus at least as late as the PRP bottleneck. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delayed Attentional Engagement in the Attentional Blink.

Observers often miss the 2nd of 2 visual targets (first target [T1] and second target [T2]) when these targets are presented closely in time; the attentional blink (AB). The authors hypothesized that the AB occurs because the attentional response to T2 is delayed by T1 processing, causing T2 to lose a competition for attention to the item that follows it. The authors investigated this hypothesis by determining whether the AB is attenuated when T2 is precued. The results from 4 experiments showed that the duration and magnitude of the AB were substantially reduced when T2 was precued. The observed improvement in T2 report did not occur at the expense of T1 report, suggesting that processing of T1 was already completed or was at least protected when the cue was presented. The authors conclude that, during the AB, there is a delay between detection and the selection of target candidates for consolidation in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cortical dynamics of lateral inhibition: Metacontrast masking.

The dynamic properties of a neural network model of visual perception, called the boundary contour system, explain characteristics of metacontrast visual masking. Computer simulations of the model, with a single set of parameters, demonstrate that it accounts for 9 key properties of metacontrast masking: Metacontrast masking is strongest at positive stimulus onset asynchronies (SOAs); decreasing target luminance changes the shape of the masking curve; increasing target duration weakens masking; masking effects weaken with spatial separation; increasing mask duration leads to stronger masking at shorter SOAs; masking strength depends on the amount and distribution of contour in the mask; a second mask can disinhibit the masking of the target; such disinhibition depends on the SOA of the 2 masks; and such disinhibition depends on the spatial separation of the 2 masks. No other theory provides a unified explanation of these data sets. Additionally, the model suggests a new analysis of data related to the SOA law and makes several testable predictions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modularity beyond perception: Evidence from the PRP paradigm.

The Dimension Action (DA) model asserts that the visual system is modular, and that each task involves multiple-response mechanisms rather than a unitary-response selection mechanism. The model has been supported by evidence from single-task interference paradigms. We use the psychological refractory period paradigm and show that dual-task performance can also be explained by the DA model. In 6 experiments we contrasted predictions from the DA model with predictions from the Response Selection Bottleneck (RSB; Pashler, 1994) model asserting that dual-task limitations are due to a unitary-response selection mechanism. Task 1 in all experiments was a tone discrimination task. In Experiments 1 to 3, Task 2 was a variation of either the Stroop or the flanker tasks. Experiments 4 to 6 manipulated response selection directly. The results showed that response selection effects can be underadditive in some conditions and additive in others depending on the modular nature of the response effect. Together, the results support the existence of an underlying modular architecture as proposed by the DA model and pose serious difficulties for the RSB model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The demonstration of short-term consolidation

In a dual-task paradigm, a visual display (T1) containing characters (letters or symbols) was presented first, followed by an auditory signal (T2) at various stimulus-onset asynchronies (SOAs). A speeded response to T2 was required. When the information in T1 had to be recalled later, response times to T2 (RT2) were elevated at short SOAs and decreased as SOA was increased. The effects on RT2 were larger when there were more items to be remembered. We interpreted the results as evidence that encoding information into short-term memory (STM) involves a distinct process, which we call short-term consolidation (STC). The results suggested that STC has limited capacity and that it requires central processing mechanisms. Additional evidence suggested that no memory for T1 was formed in STM when STC was not engaged.     

Adaptation reveals multiple levels of representation in auditory stream segregation.

When presented with alternating low and high tones, listeners are more likely to perceive 2 separate streams of tones (“streaming”) than a single coherent stream when the frequency separation (Δ?) between tones is greater and the number of tone presentations is greater (“buildup”). However, the same large-Δ? sequence reduces streaming for subsequent patterns presented after a gap of up to several seconds. Buildup occurs at a level of neural representation with sharp frequency tuning. The authors used adaptation to demonstrate that the contextual effect of prior Δ? arose from a representation with broad frequency tuning, unlike buildup. Separate adaptation did not occur in a representation of Δ? independent of frequency range, suggesting that any frequency-shift detectors undergoing adaptation are also frequency specific. A separate effect of prior perception was observed, dissociating stimulus-related (i.e., Δ?) and perception-related (i.e., 1 stream vs. 2 streams) adaptation. Viewing a visual analogue to auditory streaming had no effect on subsequent perception of streaming, suggesting adaptation in auditory-specific brain circuits. These results, along with previous findings on buildup, suggest that processing in at least 3 levels of auditory neural representation underlies segregation and formation of auditory streams. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative theories of metacontrast masking.

In metacontrast masking, the effect of a visual mask stimulus on the perceptual strength of a target stimulus varies with the stimulus-onset asynchrony (SOA) between them. As SOA increases, the target percept first becomes weaker, bottoms out at an intermediate SOA, and then increases for still larger SOAs. As a result, a plot of target percept strength against SOA produces a U-shaped masking curve. Theories have proposed special mechanisms to account for this curve, but new mathematical analyses indicate that it is a robust characteristic of a large class of neurally plausible systems. The author describes 3 quantitative methods of accounting for the U-shaped masking effect and analyzes previously published mathematical models of masking. The models produce the masking curve through mask blocking, whereby a strong internal representation of the target blocks the mask's effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stop-reaction time and the internal clock

In a stop-reaction-time (stop-RT) task, a subject is presented with a regular, isochronous sequence of brief signals separated by a constant time interval, or stimulus onset asynchrony (SOA). His/her task is to press a response key as fast as possible when the sequence stops. As the sequence unfolds, an internal representation of the SOA duration builds up. Stop-RT is assumed to be triggered when an internal clock, operating as an "alarm clock," reaches a time criterion. Criterion setting is contingent upon variability in the SOA's internal representation. In Experiment 1A, stop-RT was measured for isochronous sequences of brief tones, light flashes, and also sequences of tones and flashes presented in regular alternation (tone-light-tone ...). Stop-RT was a linear function of SOA duration (ranging from 250 to 1,000 msec), regardless of modality, supporting a "central-clock" hypothesis. On the other and, taken together, the results of Experiments 1A, 1B, 2, and 3 suggest that no internal representation of the bimodal (tone-light) SOA of alternating sequences builds up. Indeed, an alternating sequence is physically equivalent to two interlaced isochronous subsequences, one auditory and one visual. So, two internal representations, one for the auditory (tone-tone) and one for the visual (light-light) SOA, could build up, and two time criteria running "in parallel" could thus support stop-RT. To provide a critical test of parallel timing, stop-RT was measured for bimodal 5:3 polyrhythms formed by the superposition of auditory and visual isochronous sequences that had different SOA durations (Experiment 4). Parallel timing accounted for a large proportion of variance in polyrhythmic stop-RT data. Overall findings can be accounted for by assuming a functional architecture of an internal clock in which pulses emitted by a central pacemaker are available in parallel with two modality-specific switch-accumulator "timing modules."