An ‘EPIC’ on Multitasking

Jason Baer

Multitasking

• Used very often in practical settings• Reveals fundamentals of an information processing system• Fundamental facts of multitasking and how they should be

interpreted is under debate• Executive-process interactive control (EPIC) as a framework for

formulating models• Many features of EPIC's perceptual/motor capabilities have been later

incorporated into the ACT-R, CLARION, and other cognitive architectures

Multitasking Theories

• Generally focus on the existence of a finite set of mental resources• How multiple tasks consume these resources• Global single channel• Perceptual bottleneck• Response-selection bottleneck• Movement-production bottleneck• Unitary-resource theory• Multiple-Resource Theory

• To address the diverse controversy• Develop a computational model• Describe perceptual-motor process• Analyze executive processes

Multitasking Theories

• Generally focus on the existence of a finite set of mental resources• How multiple tasks consume these resources• Global single channel• Perceptual bottleneck• Response-selection bottleneck• Movement-production bottleneck• Unitary-resource theory• Multiple-Resource Theory

• To address the diverse controversy• Develop a computational model• Describe perceptual-motor process• Analyze executive processes

Characteristics of EPIC

• 5 Heuristics1.Integrated information-processing architecture.2.Production-system formalism.3.Omission of limited processing-capacity assumption.4.Emphasis on task strategies and executive processes.5.Detailed treatment of perceptual-motor constraints.

• Parsimonious production system• Information processing architecture

Modeling Human Performance With EPIC• Ensuring that single-

task performance ‘fits’ the model• Multiple-task

performance is managed by executive processes and scheduling algorithms

The Simulations

• These models seem effective at displaying patterns of reaction times and psychological refractory-period phenomena• The simulations allow them to manipulate task priority, task

presentation time, difficulty of task, and difficulty in response selection; all major components of multitasking• Under simulations of these tasks, the model appears to show

promise, allowing some detailed interpretation of these particular task characteristics• Since there are so many simulations presented by the authors, I

elected to just skip to the shortcomings

Additions to the model• Continued deferment of Task 2• Determined by how ‘conservative’ a person is during performance

• Expanded gaze variation in uncertainty• Symmetric deferment under uncertainty