Hayley E. P. Lagroix

Perception of Temporal Order Is Impaired during the Time Course of the Attentional Blink.

Identification accuracy for the second of two target (T2) is impaired when presented shortly after the first (T1). Does this attentional blink (AB) also impair the perception of the order of presentation? In four experiments, three letter targets (T1, T2, T3) were inserted in a stream of digit distractors displayed in rapid serial visual presentation (RSVP), with T3 always presented directly after T2. The T1-T2 lag was varied to assess the perception of T2-T3 temporal order throughout the period of the AB. Factorial manipulation of the presence or absence of distractors before T1 and between T1 and T2 had similar effects on accuracy and on perception of temporal order. It is important to note that perception of temporal order suffered even when accuracy was unimpaired. This pattern of results is consistent with prior-entry theories of the perception of temporal order but not with episodic-integration theories. Simulations based on the Episodic Simultaneous Type, Serial Token (eSTST) model (Wyble, Bowman, & Nieuwenstein, 2009) provided excellent fits to the data except for the condition in which no distractors were presented in the RSVP stream.

The root cause of the attentional blink: First-target processing or disruption of input control?

Identification of the second of two targets (T2) is impaired when presented shortly after the first (T1). T1-based theories ascribe this attentional blink (AB) to a T1-initiated period of inattention. Distractor-based theories ascribe it to a disruption of input control caused by post-T1 distractors. The finding that an AB occurs without intertarget distractors (Nieuwenstein, Potter, & Theeuwes, Journal of Experimental Psychology: Human Perception and Performance 35:159-169, 2009) seemingly disconfirms distractor-based theories. The present experiments addressed different ways in which distractor-based theories might account for that finding. Intertarget events were varied in four experiments. Experiment 1 replicated Nieuwenstein, Potter, and Theeuwes’s findings. The next two experiments tested two ways (lack of visual stimulation, violation of expectation) in which the blank intertarget interval might cause an AB. Experiment 4 explored whether backward-masking of T1 can account entirely for the larger AB obtained with intervening distractors or whether distractors also disrupt input control. The results disconfirm predictions from distractor-based theories and support the claim of T1-based theories that T1 processing alone is sufficient for the AB. Simulations based on the eSTST (Wyble, Bowman, & Nieuwenstein, Journal of Experimental Psychology: Human Perception and Performance 35:787-807, 2009) and the B&B models (Olivers & Meeter, Psychological Research, 115, 836-863 2008) were compared. Predictions were more accurate from the T1-based theory (eSTST) than from the distractor-based theory (B&B).

The attentional blink is not affected by backward masking of T2, T2-mask SOA, or level of T2 impoverishment.

Identification of the second of two targets (T2) is impaired when presented shortly after the first (T1). This attentional blink (AB) is thought to arise from a delay in T2 processing during which T2 is vulnerable to masking. Conventional studies have measured T2 accuracy which is constrained by the 100% ceiling. We avoided this problem by using a dynamic threshold-tracking procedure that is inherently free from ceiling constraints. In two experiments we examined how AB magnitude is affected by three masking-related factors: (a) presence/absence of T2 mask, (b) T2-mask stimulus onset asynchrony (SOA), and (c) level of T2 impoverishment (signal-to-noise ratio [SNR]). In Experiment 1, overall accuracy decreased with T2-mask SOA. The magnitude of the AB, however, was invariant with SOA and with mask presence/absence. Experiment 2 further showed that the AB was invariant with T2 SNR. The relationship among mask presence/absence, SOA, and T2 SNR and the AB is encompassed in a qualitative model.

Visual search is postponed during the period of the AB: An event‐related potential study

In the phenomenon known as the attentional blink (AB), perception of the second of two rapidly sequential targets (T2) is impaired when presented shortly after the first (T1). Studies in which T2 consisted of a pop-out search array provided evidence suggesting that visual search is postponed during the AB. In the present work, we used behavioral and electrophysiological measures to test this postponement hypothesis. The behavioral measure was reaction time (RT) to T2; the electrophysiological measure was the onset latency of an ERP index of attentional selection, known as the N2pc. Consistent with the postponement hypothesis, both measures were delayed during the AB. The delay in N2pc was substantially shorter than that in RT, pointing to multiple sources of delay in the chain of processing events, as distinct from the single source postulated in current theories of the AB. Finally, the finding that the N2pc was delayed during the AB strongly suggests that attention is involved in the processing of pop-out search arrays.

Unique sudden onsets capture attention even when observers are in feature-search mode

Two sources of attentional capture have been proposed: stimulus-driven (exogenous) and goal-oriented (endogenous). A resolution between these modes of capture has not been straightforward. Even such a clearly exogenous event as the sudden onset of a stimulus can be said to capture attention endogenously if observers operate in singleton-detection mode rather than feature-search mode. In four experiments we show that a unique sudden onset captures attention even when observers are in feature-search mode. The displays were rapid serial visual presentation (RSVP) streams of differently coloured letters with the target letter defined by a specific colour. Distractors were four #s, one of the target colour, surrounding one of the non-target letters. Capture was substantially reduced when the onset of the distractor array was not unique because it was preceded by other sets of four grey # arrays in the RSVP stream. This provides unambiguous evidence that attention can be captured both exogenously and endogenously within a single task.

Questioning the goal-switching account of the AB: comment on Ferlazzo et al. (2007)

ABSTRACT Identification of the second of two targets (T2) is impaired when presented less than about 500 ms after the first (T1; Attentional Blink: AB). Although the AB is known to be remarkably robust across many manipulations, [Ferlazzo, F., Lucido, S., Di Nocera, F., Fagioli, S., & Sdoia, S. (2007). Switching between goals mediates the attentional blink effect. Experimental Psychology, 54, 89–98; Ferlazzo, F., Faglioli, S., Sdoia, S., & Di Nocera, F. (2008). Goal-completion processes affect the attentional blink. European Journal of Cognitive Psychology, 20, 697–710] found it to be substantially attenuated when the observers were set to accomplish a single goal (e.g. reporting the sum of the T1 and T2 digits) instead of a dual goal (reporting T1 and T2 separately). The larger AB obtained with the dual-goal set was ascribed to the attentional switch necessitated by the goal-switch between T1 and T2. This conclusion is questionable on three grounds: non-equivalent scoring procedures across conditions, range of inter-target lags, and unreliability of the baseline level. These issues were addressed in the present study. Contrary to Ferlazzo et al.’s conclusions, we found no AB attenuation in the single-goal, relative to the dual-goal condition.

Transition From Feature-Search to Singleton-Detection Strategies in Visual Search: The Role of Number of Target-Defining Options.

When searching for a uniquely colored target in an RSVP stream of homogeneously colored nontarget items, observers can use singleton-detection and/or feature-search modes. Using an attentional-capture paradigm, we varied systematically (a) the number of possible target colors from 1 to 4 and (b) the presence or absence of a colored ring surrounding the nontarget item displayed 200 ms before the target. When present, the ring was either the same color as 1 of the possible targets (color-match), or an irrelevant color (color-mismatch). Capture was measured as the impairment in target identification accuracy when the ring was present relative to when it was absent. Greater capture in the color-match than in the color-mismatch condition was regarded as evidence of feature-search mode. Capture in the color-mismatch condition was regarded as evidence for singleton-detection mode. We show that, as the number of target colors is increased, the relative prominence of feature-search mode decreases, and that of singleton-detection mode increases correspondingly. This novel finding shows that, when both feature-search and singleton-detection modes are possible, at least some degree of feature-search mode is used until the number of possible target-defining colors reaches about 4. This suggests that the weight assigned to singleton-detection mode increases, and that assigned to feature-search mode decreases correspondingly, as the difficulty of maintaining the target-defining features in mind is increased.

Are accuracy and reaction time equivalent measures of the attentional blink

Perception of the second of two rapidly sequential targets (T1, T2) is impaired when presented soon after the first (attentional blink; AB). AB magnitude is indexed by the difference between performance at short and long inter-target lags. Conventionally, T2 performance is assessed using accuracy as the dependent measure. An inherent problem with this measure, often encountered in AB experiments, is the 100% response ceiling. For example, Visser (2007) reported greater AB magnitude with hard than with easy T1 tasks. That conclusion is questionable, however, because the two functions converged to the ceiling, thereby confounding the effect of T1 difficulty with the ceiling constraint. To avoid this problem, we used reaction time (RT) as the dependent measure and found AB magnitude to be invariant with T1 difficulty (Experiment 1). One interpretation of this result is that the invariance seen with RT would also obtain with accuracy but for the response ceiling. This implies equivalence of the two measures, which is not always the case (Santee & Egeth, 1982). In Experiment 2, we checked the equivalence of RT and accuracy measures of the AB using the phenomenon of lag-1 sparing, which refers to the finding that T2 performance is relatively unimpaired when T2 comes directly after T1 (Lag 1). Using accuracy, Visser et al. (1999) found lag-1 sparing only when T1 and T2 were presented in the same spatial location. Lag-1 deficit occurred otherwise. We replicated Visser et al.s finding with accuracy; with RT as the dependent measure, however, lag-1 deficit occurred even when T1 and T2 were presented in the same location. This pattern of results suggests that RT and accuracy are not always equivalent measures of the underlying processes involved in the AB. Therefore, RT may not be a good way of avoiding the ceiling problem inherent in accuracy measures. Meeting abstract presented at VSS 2015.