The attentional blink: a structural or strategic limitation of the attentional system?
Year: 2010
Type: dissertation
Abstract: The Attentional Blink could be considered as a blind spot in perceptual awareness. This phenomenon results in a marked difficulty to identify the second of two sequential targets, that are presented in a close temporal contiguity, when these are embedded in a Rapid Serial Visual Presentation stream of distractors. The critical temporal window duration of this effect (within 200-600 ms after the presentation of the first target) depends on the time needed from the central processing of the first target. It is interesting to underly that when the temporal interval between the targets is equal to, or shorter then, 100 ms, the Attentional Blink disappears, namely the second target is identified without impairment. This effect is known as Lag-1 sparing in the sense that the second target results spared from the Attentional Blink. Crucial to the present research is the aim to investigate the role of the nature of processing carried out on targets in the Lag-1 sparing phenomenon. In a first series of experiments, 0, 1, or 2 digits (and in one case 0, 1, 2 letters) were embedded with equal probability in Rapid Serial Visual Presentation streams of letter distractors (and in one case in streams of digit distractors). In two experiments (i.e., the first and the third) participants were asked to identify the digits in some blocks of trials and to count the digits in others blocks. In one experiment (i.e., the second) the target to identify or counting were letters and the digits were distractors. In one experiment (i.e., the fourth) the counting task was replaced with a digit-sum task. In the last experiment (i.e., the fifth) the counting task was replaced by a counting task of the digits of a given parity sub-class (odd vs. even digits). Lag-1 sparing was always evident when the participants when the task was the explicit identification of the target digits. Lag-1 sparing was evident when participants were required to sum 2 digits or to count digits of a prespecified parity subclass (e.g., count just even digits). The effect was abolished when participants were asked to count the digits independent on their parity subclass. These results suggest that the occurrence of Lag-1 sparing depends on the type of mental representation that have to be generated on the basis of the target and task information. A numbers of researchers have emphatized the role of distractors intervening between successive targets as the primary determinant of the Attentional Blink. These authors argued that this phenomenon is abolished when 3 or more targets are displayed in a condition of contiguity in rapidly presented serial sequences. In a second series of experiments the present investigation delves deeper into the Lag-1 sparing issue. A multi-targets Rapid Serial Visual Presentation paradigm was employed in which 1-, 2-, 3- digit targets were embedded among letter distractors. Across the series of three experiments both, the numbers of presented targets and the temporal lag between them were manipulated. Evidence of an Attentional Blink was found in each experiment, namely targets that followed the first one in these sequences presented an impairment in the identification task, when the probability of a given target report was condizionalized on a correct response to the preceding targets. These results support and reinforce the notion that some form of capacity limitation in the encoding of targets plays a fundamental role in the elicitation and modulation of the Attentional Blink effect.
Author: Patrik Pluchino
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W75196906