Phasic Alertness and the Residual Task-Switching Cost

2005 ◽  
Vol 52 (2) ◽  
pp. 109-124 ◽  
Author(s):  
Nachshon Meiran ◽  
Ziv Chorev
Keyword(s):  
Task Switching ◽  
Target Stimulus ◽  
Switching Cost ◽  
Optimal Interval ◽  
Phasic Alertness ◽  
Goal Representation

Abstract. Participants switched between two randomly ordered discrimination tasks and each trial began with the presentation of a task cue instructing which task to execute. The authors induced phasic alertness by presenting a salient uninformative stimulus after the task cue was provided, and at variable intervals before the target stimulus was presented (Experiments 1-3) or before the task cue (Experiment 4). When the alerting stimulus preceded the target stimulus or the task cue by an optimal interval, RT was faster, indicating an alert state and the task-switching cost was reduced. These results support the suggestion of De Jong (Acta Psychologica, 1999 ) that alertness improves the overcoming of retrieval competition through improved goal representation, but also show that the effect is specific to the residual task-switching cost.

scholarly journals Control processes in voluntary and explicitly cued task switching

2014 ◽  
Vol 67 (10) ◽  
pp. 1944-1958 ◽  
Author(s):  
Michael E. J. Masson ◽  
Sarah Carruthers
Keyword(s):  
Mathematical Model ◽  
Task Switching ◽  
Target Stimulus ◽  
Task Switch ◽  
Voluntary Task Switching ◽  
Additional Task ◽  
External Cues ◽  
Additional Process ◽  
Response Time Distributions ◽  
Cue Encoding

Explicitly cued task switching slows performance relative to performing the same task on consecutive trials. This effect appears to be due partly to more efficient encoding of the task cue when the same cue is used on consecutive trials and partly to an additional task-switching process. These components were examined by comparing explicitly cued and voluntary task switching groups, with external cues presented to both groups. Cue-switch effects varied in predictable ways to dissociate explicitly cued and voluntary task switching, whereas task-switch effects had similar characteristics for both instructional groups. The data were well fitted by a mathematical model of task switching that included a cue-encoding mechanism (whereby cue repetition improves performance) and an additional process that was invoked on task-switch trials. Analyses of response-time distributions suggest that this additional process involves task-set reconfiguration that may or may not be engaged before the target stimulus is presented.

Task-Switching Methodology

2013 ◽  
Vol 221 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Ofer Rahamim ◽  
Yoav Bar-Anan ◽  
Golan Shahar ◽  
Nachshon Meiran
Keyword(s):  
Personality Traits ◽  
Task Switching ◽  
Congruency Effect ◽  
Switching Cost ◽  
Task Rule ◽  
Evaluative Processes ◽  
Goal System ◽  
And Task

In this paper, the authors review studies involving switching between an evaluative task and a nonevaluative task as a means to indirectly assess evaluative processes in the context of research of attitudes, psychopathology, and personality traits. Two task-switching indices, Switching Cost and Task Rule Congruency Effect, which represent two distinct sets of processes, have been used so far and can be assessed simultaneously. The authors suggest that using task-switching methodology as a platform provides significant methodological as well as theoretical advantages, which they attribute to the heightened involvement of the individual’s goal system, characterizing the task-switching paradigm.

Task-switching cost and repetition priming: Two overlooked confounds in the fixed-set procedure of the Sternberg paradigm and how they affect memory set-size effects

2014 ◽  
Vol 67 (10) ◽  
pp. 1871-1894 ◽  
Author(s):  
Jerwen Jou
Keyword(s):  
Task Switching ◽  
Repetition Priming ◽  
Switching Cost ◽  
Set Size ◽  
Confounding Variables ◽  
Fixed Set ◽  
Category Instance ◽  
Nonlinear Relation ◽  
Sternberg Paradigm ◽  
Set Size Effects

Subjects performed Sternberg-type memory recognition tasks (Sternberg paradigm) in four experiments. Category-instance names were used as learning and testing materials. Sternberg's original experiments demonstrated a linear relation between reaction time (RT) and memory-set size (MSS). A few later studies found no relation, and other studies found a nonlinear relation (logarithmic) between the two variables. These deviations were used as evidence undermining Sternberg's serial scan theory. This study identified two confounding variables in the fixed-set procedure of the paradigm (where multiple probes are presented at test for a learned memory set) that could generate a MSS RT function that was either flat or logarithmic rather than linearly increasing. These two confounding variables were task-switching cost and repetition priming. The former factor worked against smaller memory sets and in favour of larger sets whereas the latter factor worked in the opposite way. Results demonstrated that a null or a logarithmic RT-to-MSS relation could be the artefact of the combined effects of these two variables. The Sternberg paradigm has been used widely in memory research, and a thorough understanding of the subtle methodological pitfalls is crucial. It is suggested that a varied-set procedure (where only one probe is presented at test for a learned memory set) is a more contamination-free procedure for measuring the MSS effects, and that if a fixed-set procedure is used, it is worthwhile examining the RT function of the very first trials across the MSSs, which are presumably relatively free of contamination by the subsequent trials.

Functional Anatomy of Intensity Aspects of Attention

2003 ◽  
Vol 14 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Walter Sturm
Keyword(s):  
Right Hemisphere ◽  
Functional Anatomy ◽  
Fmri Data ◽  
Functional Networks ◽  
Top Down ◽  
Stimulus Modality ◽  
Spatial Orienting ◽  
Phasic Alertness ◽  
Co Activation ◽  
Attention System

Abstract: Behavioral and PET/fMRI-data are presented to delineate the functional networks subserving alertness, sustained attention, and vigilance as different aspects of attention intensity. The data suggest that a mostly right-hemisphere frontal, parietal, thalamic, and brainstem network plays an important role in the regulation of attention intensity, irrespective of stimulus modality. Under conditions of phasic alertness there is less right frontal activation reflecting a diminished need for top-down regulation with phasic extrinsic stimulation. Furthermore, a high overlap between the functional networks for alerting and spatial orienting of attention is demonstrated. These findings support the hypothesis of a co-activation of the posterior attention system involved in spatial orienting by the anterior alerting network. Possible implications of these findings for the therapy of neglect are proposed.

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