Gordon Logan

Summary

Affiliation: Vanderbilt University
Country: USA

Publications

  1. pmc Selecting a response in task switching: testing a model of compound cue retrieval
    Darryl W Schneider
    Department of Psychology, Vanderbilt University, USA
    J Exp Psychol Learn Mem Cogn 35:122-36. 2009
  2. ncbi request reprint Executive control of visual attention in dual-task situations
    G D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37240, USA
    Psychol Rev 108:393-434. 2001
  3. ncbi request reprint Working memory, task switching, and executive control in the task span procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Gen 133:218-36. 2004
  4. doi request reprint The left hand doesn't know what the right hand is doing: the disruptive effects of attention to the hands in skilled typewriting
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
    Psychol Sci 20:1296-300. 2009
  5. ncbi request reprint Very clever homunculus: compound stimulus strategies for the explicit task-cuing procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychon Bull Rev 11:832-40. 2004
  6. ncbi request reprint Still clever after all these years: searching for the homunculus in explicitly cued task switching
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Hum Percept Perform 33:978-94. 2007
  7. ncbi request reprint The time it takes to switch attention
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychon Bull Rev 12:647-53. 2005
  8. ncbi request reprint Interpreting instructional cues in task switching procedures: the role of mediator retrieval
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Learn Mem Cogn 32:347-63. 2006
  9. ncbi request reprint Out with the old, in with the new: more valid measures of switch cost and retrieval time in the task span procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychon Bull Rev 13:139-44. 2006
  10. ncbi request reprint Priming or executive control? Associative priming of cue encoding increases "switch costs" in the explicit task-cuing procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Mem Cognit 34:1250-9. 2006

Research Grants

Collaborators

Detail Information

Publications61

  1. pmc Selecting a response in task switching: testing a model of compound cue retrieval
    Darryl W Schneider
    Department of Psychology, Vanderbilt University, USA
    J Exp Psychol Learn Mem Cogn 35:122-36. 2009
    ..Relations to current theorizing about response congruency effects and models of response selection in task switching are discussed...
  2. ncbi request reprint Executive control of visual attention in dual-task situations
    G D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37240, USA
    Psychol Rev 108:393-434. 2001
    ..The theory accounts for concurrence cost, set-switching cost, crosstalk between tasks, and the modulation of crosstalk by task set...
  3. ncbi request reprint Working memory, task switching, and executive control in the task span procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Gen 133:218-36. 2004
    ..The results suggest there is no trade-off between storage and task switching, which supports some theories of executive control and challenges others...
  4. doi request reprint The left hand doesn't know what the right hand is doing: the disruptive effects of attention to the hands in skilled typewriting
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
    Psychol Sci 20:1296-300. 2009
    ..This produces the disruption...
  5. ncbi request reprint Very clever homunculus: compound stimulus strategies for the explicit task-cuing procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychon Bull Rev 11:832-40. 2004
    ..The results suggest that subjects responded to the compound of the cue and the target rather than switching task set between trials...
  6. ncbi request reprint Still clever after all these years: searching for the homunculus in explicitly cued task switching
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Hum Percept Perform 33:978-94. 2007
    ..This article is a response to S. Monsell and G. A. Mizon's challenge that highlights empirical problems with their evidence and reports an experiment that challenges critical assumptions of their theoretical account...
  7. ncbi request reprint The time it takes to switch attention
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychon Bull Rev 12:647-53. 2005
    ..The model fits suggest that cue encoding took 67-74 msec and attention switching took 76-101 msec...
  8. ncbi request reprint Interpreting instructional cues in task switching procedures: the role of mediator retrieval
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Learn Mem Cogn 32:347-63. 2006
    ..The results are discussed in terms of the role of mediators in interpreting instructional cues...
  9. ncbi request reprint Out with the old, in with the new: more valid measures of switch cost and retrieval time in the task span procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychon Bull Rev 13:139-44. 2006
    ..This measure was more valid than the RT in the memory span condition of Experiment 1, which was used in the original report...
  10. ncbi request reprint Priming or executive control? Associative priming of cue encoding increases "switch costs" in the explicit task-cuing procedure
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Mem Cognit 34:1250-9. 2006
    ....
  11. ncbi request reprint What it costs to implement a plan: plan-level and task-level contributions to switch costs
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Mem Cognit 35:591-602. 2007
    ..Experiment 4 showed that memory load had no effect on switch costs. The results are discussed in terms of the interaction between plan-level and task-level processing in the implementation of plans...
  12. ncbi request reprint Cumulative progress in formal theories of attention
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37203, USA
    Annu Rev Psychol 55:207-34. 2004
    ..The review describes the classical similarity-choice and signal-detection theories and relates them to current theories of categorization, Garner tasks, visual search, cuing procedures, task switching, and strategy choice...
  13. ncbi request reprint An instance theory of attention and memory
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Psychol Rev 109:376-400. 2002
    ..Attention selects objects by categorizing them; objects are categorized by attending to them. ITAM incorporates each of its ancestors as a special case, so it inherits their successes...
  14. ncbi request reprint Subitizing and similarity: toward a pattern-matching theory of enumeration
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Psychon Bull Rev 10:676-82. 2003
    ..An analysis based on multidimensional scaling suggested that numerosity could be retrieved accurately for displays of 1-3 dots, but not for displays of 4-10 dots...
  15. ncbi request reprint Parallel memory retrieval in dual-task situations: II. Episodic memory
    G D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37240, USA
    J Exp Psychol Learn Mem Cogn 27:668-85. 2001
    ..This priming is inconsistent with discrete serial retrieval and consistent with parallel retrieval...
  16. ncbi request reprint Simon-type effects: chronometric evidence for keypress schemata in typewriting
    Gordon D Logan
    Department of Psychology, Nashville, Tennessee 73203, USA
    J Exp Psychol Hum Percept Perform 29:741-57. 2003
    ..The results are consistent with D. E. Rumelhart and D. A. Norman's (1982) theory of typewriting...
  17. ncbi request reprint Clever homunculus: is there an endogenous act of control in the explicit task-cuing procedure?
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    J Exp Psychol Hum Percept Perform 29:575-99. 2003
    ..The results suggest that the explicit task-cuing procedure does not require an endogenous act of control...
  18. doi request reprint Cognitive illusions of authorship reveal hierarchical error detection in skilled typists
    Gordon D Logan
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Science 330:683-6. 2010
    ..This dissociation suggests two error-detection processes: one sensitive to the appearance of the screen and the other sensitive to keystrokes...
  19. pmc Automatic and controlled response inhibition: associative learning in the go/no-go and stop-signal paradigms
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN 37203
    J Exp Psychol Gen 137:649-72. 2008
    ..Thus, the results suggest that the two paradigms are not equivalent because they allow different kinds of response inhibition...
  20. pmc Proactive adjustments of response strategies in the stop-signal paradigm
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Hum Percept Perform 35:835-54. 2009
    ..Furthermore, the results show that subjects can make proactive response-strategy adjustments on a trial-by-trial basis, suggesting a flexible cognitive system that can proactively adjust itself in changing environments...
  21. doi request reprint Automaticity of cognitive control: goal priming in response-inhibition paradigms
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN, USA
    J Exp Psychol Learn Mem Cogn 35:1381-8. 2009
    ..Stop performance was slower for GO than for ### or STOP. These findings suggest that task goals can be primed and that response inhibition and executive control can be influenced by automatic processing...
  22. doi request reprint Do you know where your fingers have been? Explicit knowledge of the spatial layout of the keyboard in skilled typists
    Xianyun Liu
    Vanderbilt University, Nashville, Tennessee 37203, USA
    Mem Cognit 38:474-84. 2010
    ..The two experiments suggest that skilled typists have poor explicit knowledge of key locations. The results are interpreted in terms of a model with two hierarchical parts in the system controlling typewriting...
  23. ncbi request reprint Voluntary task switching: chasing the elusive homunculus
    Catherine M Arrington
    Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN 37203, USA
    J Exp Psychol Learn Mem Cogn 31:683-702. 2005
    ..The degree to which task switching procedures capture top-down versus bottom-up processes may depend on the extent of environmental support provided by the procedure...
  24. pmc Influence of history on saccade countermanding performance in humans and macaque monkeys
    Erik E Emeric
    Center for Integrative and Cognitive Neuroscience, Vanderbilt Vision Research Center, Department of Psychology, Vanderbilt University, 301 Wilson Hall, 111, 21st Avenue South, Nashville, TN 37203, USA
    Vision Res 47:35-49. 2007
    ....
  25. doi request reprint The target of task switching
    Darryl W Schneider
    Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
    Can J Exp Psychol 64:129-33. 2010
    ..In four experiments that varied the degree to which words and images were mixed together, no differences in switch costs were observed. These results support the idea that categorical target representations are central to task switching...
  26. ncbi request reprint Retrieving information from a hierarchical plan
    Darryl W Schneider
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Learn Mem Cogn 33:1076-91. 2007
    ..In tandem, the empirical data and modeling work provide deeper insight into the representation of and access to information in memory that comprises a plan for guiding behavior...
  27. doi request reprint How to stop and change a response: the role of goal activation in multitasking
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Hum Percept Perform 34:1212-28. 2008
    ....
  28. doi request reprint Long-term aftereffects of response inhibition: memory retrieval, task goals, and cognitive control
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Hum Percept Perform 34:1229-35. 2008
    ..On the basis of these findings, the authors concluded that cognitive control can rely on both memory retrieval and executive processes...
  29. doi request reprint Object-based attention in Chinese readers of Chinese words: beyond Gestalt principles
    Xingshan Li
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Psychon Bull Rev 15:945-9. 2008
    ..Because there were no bottom-up factors that distinguished the words, these results showed that objects defined by subjects' knowledge--in this case, lexical information--can also constrain the deployment of attention...
  30. doi request reprint Episodic contributions to sequential control: learning from a typist's touch
    Matthew J C Crump
    Department of Psychology, Vanderbilt University, Wilson Hall, 111 21st Avenue South, Nashville, TN 37203, USA
    J Exp Psychol Hum Percept Perform 36:662-72. 2010
    ..The finding that recent episodic experience with typing particular words and letters influences skilled typing performance holds widespread implications for theories of typing, sequence learning, and motor control...
  31. doi request reprint Contextual control over task-set retrieval
    Matthew J C Crump
    Department of Psychology, Vanderbilt University, 633 Wilson Hall, 111 21st Ave South, Nashville, TN 37203, USA
    Atten Percept Psychophys 72:2047-53. 2010
    ..We discuss the notion that contextual information provides rapid, unconscious control over the extent to which prior task-set representations are retrieved in the service of guiding online performance...
  32. doi request reprint Hierarchical control and skilled typing: evidence for word-level control over the execution of individual keystrokes
    Matthew J C Crump
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Learn Mem Cogn 36:1369-80. 2010
    ..This suggests that word-level information causes parallel activation of constituent keystrokes, consistent with hierarchical processing. The role of hierarchical processing in typing and routine action is discussed...
  33. pmc Intact associative learning in patients with schizophrenia: evidence from a Go/NoGo paradigm
    Austin A Woolard
    Department of Psychiatry, Vanderbilt University, 1601 23rd Avenue South, Nashville, TN 37212 3133, USA
    Schizophr Res 122:131-5. 2010
    ..In the present study, we investigated the effect of associative learning during a Go/NoGo task in healthy controls subjects and patients with schizophrenia...
  34. doi request reprint Warning: This keyboard will deconstruct--the role of the keyboard in skilled typewriting
    Matthew J C Crump
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Psychon Bull Rev 17:394-9. 2010
    ..We argue that the expert knowledge mediating action control emerges during online interaction with the physical environment...
  35. ncbi request reprint Defining task-set reconfiguration: the case of reference point switching
    Darryl W Schneider
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Psychon Bull Rev 14:118-25. 2007
    ..We discuss how our approach can be generalized to define reconfiguration more clearly in other task-switching situations...
  36. ncbi request reprint Testing the semantic differential as a model of task processes with the implicit association test
    Maggie J Xiong
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Mem Cognit 34:1452-63. 2006
    ....
  37. ncbi request reprint Task switching versus cue switching: using transition cuing to disentangle sequential effects in task-switching performance
    Darryl W Schneider
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Learn Mem Cogn 33:370-8. 2007
    ..Methodological and theoretical implications of these findings for research on task switching are discussed...
  38. ncbi request reprint Priming cue encoding by manipulating transition frequency in explicitly cued task switching
    Darryl W Schneider
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychon Bull Rev 13:145-51. 2006
    ..Interpretations of our findings based on automatic priming from memory retrieval of past transitions and strategic priming from transition expectancies are discussed...
  39. ncbi request reprint Modeling task switching without switching tasks: a short-term priming account of explicitly cued performance
    Darryl W Schneider
    Departmentof Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Gen 134:343-67. 2005
    ....
  40. ncbi request reprint Episodic and semantic components of the compound-stimulus strategy in the explicit task-cuing procedure
    Catherine M Arrington
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Mem Cognit 32:965-78. 2004
    ..We found the same effects with all target set sizes. The results are consistent with use of a semantic compound-stimulus strategy...
  41. ncbi request reprint The cost of a voluntary task switch
    Catherine M Arrington
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Psychol Sci 15:610-5. 2004
    ..These results show costs associated with a voluntary task switch, when subjects must actively control the choice of the task to be performed...
  42. ncbi request reprint Repetition priming mediated by task similarity in semantic classification
    Maggie J Xiong
    Vanderbilt University, Nashville, Tennessee 37209, USA
    Mem Cognit 31:1009-20. 2003
    ..Consistent with the transfer-appropriate processing framework, repetition priming in semantic classifications was highly task specific, decreasing with increasing distance between classification scales...
  43. ncbi request reprint Inhibitory control in mind and brain: an interactive race model of countermanding saccades
    Leanne Boucher
    Department of Psychology, Vanderbilt University, Nashville, TN 37221, USA
    Psychol Rev 114:376-97. 2007
    ....
  44. ncbi request reprint Hierarchical control of cognitive processes: switching tasks in sequences
    Darryl W Schneider
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    J Exp Psychol Gen 135:623-40. 2006
    ..These findings resonate with past research on motor programs and serial memory and provide new insights into the concepts of task set and control...
  45. pmc Balancing cognitive demands: control adjustments in the stop-signal paradigm
    Patrick G Bissett
    Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
    J Exp Psychol Learn Mem Cogn 37:392-404. 2011
    ..This suggests that more global manipulations encompassing many trials affect post-stop-signal adjustments...
  46. pmc Models of response inhibition in the stop-signal and stop-change paradigms
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Neurosci Biobehav Rev 33:647-61. 2009
    ..We present evidence that favors the independent horse-race model but also some evidence that challenges the model. We end with a discussion of recent models that elaborate the role of a stop process in inhibiting a response...
  47. ncbi request reprint After-effects of goal shifting and response inhibition: a comparison of the stop-change and dual-task paradigms
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Q J Exp Psychol (Hove) 61:1151-9. 2008
    ....
  48. pmc Response inhibition in the stop-signal paradigm
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
    Trends Cogn Sci 12:418-24. 2008
    ....
  49. ncbi request reprint STOP-IT: Windows executable software for the stop-signal paradigm
    Frederick Verbruggen
    Department of Psychology, Vanderbilt University, Nashville, Tennessee 37203, USA
    Behav Res Methods 40:479-83. 2008
    ..STOP-IT and ANALYZE-IT are completely based on free software, are distributed under the GNU General Public License, and are available at the personal Web sites of the first two authors or at expsy.ugent.be/tscope/stop.html...
  50. ncbi request reprint A memory-based account of automatic numerosity processing
    Jessica M Choplin
    Vanderbilt University, Nashville, Tennessee, USA
    Mem Cognit 33:17-28. 2005
    ..This finding suggests that size congruity effects can be produced without comparison algorithms...
  51. ncbi request reprint Stopping eye and hand movements: are the processes independent?
    Leanne Boucher
    Vanderbilt University, Nashville, Tennessee 37203, USA
    Percept Psychophys 69:785-801. 2007
    ..The probability and latency of signal respond eye and hand movements corresponded to predictions of Logan and Cowan's (1984) race model applied to each effector independently...
  52. ncbi request reprint Converging evidence for a fronto-basal-ganglia network for inhibitory control of action and cognition
    Adam R Aron
    Department of Psychology, University of California, San Diego, La Jolla, California 92093, USA
    J Neurosci 27:11860-4. 2007
  53. ncbi request reprint Restraint and cancellation: multiple inhibition deficits in attention deficit hyperactivity disorder
    Russell Schachar
    Psychiatry Research Unit, Department of Psychiatry, Brain and Behavior Programme, Research Institute, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario, Canada
    J Abnorm Child Psychol 35:229-38. 2007
    ..We conclude that ADHD is associated with deficits in both restraint and cancellation subcomponents of inhibition...
  54. ncbi request reprint The development of selective inhibitory control across the life span
    Anne Claude Bedard
    The Hospital for Sick Children, Toronto, Canada
    Dev Neuropsychol 21:93-111. 2002
    ..Findings are discussed in regard to the decay and maturation of selective inhibitory control across the life span...
  55. ncbi request reprint Reduced response readiness delays stop signal inhibition
    Wery P M van den Wildenberg
    Department of Psychology, Developmental Psychology, University of Amsterdam, The Netherlands
    Acta Psychol (Amst) 111:155-69. 2002
    ..These findings were taken to suggest that reduced readiness gives rise to more forceful responses that are then more difficult to inhibit...
  56. ncbi request reprint Horse-race model simulations of the stop-signal procedure
    Guido P H Band
    Department of Psychology, Faculty of Psychology, Leiden University, PO Box 9555, 2300 RB Leiden, The Netherlands
    Acta Psychol (Amst) 112:105-42. 2003
    ..The simulations indicate that, under most conditions, the latency, but not variability, of response inhibition can be reliably estimated...
  57. ncbi request reprint Parallel response selection in dual-task situations
    Scott Watter
    Department of Psychology, McMaster University, Hamilton, ON, Canada
    Percept Psychophys 68:254-77. 2006
    ..Accommodating these data while preserving the essential bottleneck character of RSB theory may be possible but may also alter the very nature of the bottleneck itself...
  58. ncbi request reprint Separating cue encoding from target processing in the explicit task-cuing procedure: are there "true" task switch effects?
    Catherine M Arrington
    Lehigh University
    J Exp Psychol Learn Mem Cogn 33:484-502. 2007
    ..Implications for the authors' past modeling of task-switching performance are discussed...
  59. doi request reprint Short-term aftereffects of response inhibition: repetition priming or between-trial control adjustments?
    Frederick Verbruggen
    Department of Experimental Psychology, Ghent University
    J Exp Psychol Hum Percept Perform 34:413-26. 2008
    ..Based on these results, we suggest that the aftereffects of successful response inhibition are primarily due to repetition priming, although there was evidence for between-trial control adjustments when inhibition failed...
  60. pmc Inhibitory attentional control in patients with frontal lobe damage
    Mariana Dimitrov
    Cognitive Neuroscience Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bldg 10, Room 5C205, 10 Center Drive, MSC 1440, Bethesda, MD 20892 1440, USA
    Brain Cogn 52:258-70. 2003
    ..The data suggest that the specific inhibitory processes evaluated by these two tests are, in general, spared in patients with focal frontal lobe lesions or frontal lobe degeneration...
  61. ncbi request reprint Evidence for an error monitoring deficit in attention deficit hyperactivity disorder
    Russell J Schachar
    Brain and Behavior Program, Research Institute, and Department of Psychiatry, University of Toronto, The Hospital for Sick Children, Toronto, Canada
    J Abnorm Child Psychol 32:285-93. 2004
    ....

Research Grants3

  1. Modeling the Role of Priming in Executive Control
    Gordon Logan; Fiscal Year: 2009
    ..The first aim will establish the validity of the model, the second will establish its limits and set the stage for a general model of executive control. ..
  2. Modeling the Role of Priming in Executive Control
    Gordon Logan; Fiscal Year: 2007
    ..The first aim will establish the validity of the model, the second will establish its limits and set the stage for a general model of executive control. ..