1. Presentation for the Class of 2008
Vigilance and
Sustained Attention
P.A. Hancock
Presentation for the Class of 2008
Human Factors II EXP 6257
January 31st, 2008
Department of Psychology s Institute for Simulation and Training
University of Central Florida
Orlando, FL 32826

2. Mackworth was the founder of modern vigilance research, a term he took from the neurologist, Sir Henry Head. His
original experimental research was triggered by WW II concerns for radar
operators looking for submarines out
over the Bay of Biscay. His original
monograph on the topic, republished
in Sinako’s text, still represents the best introduction to the area.
Mackworth was the first to formally identified the ‘vigilance decrement function’ which remains pertinent to all operations in automated and semi-automated systems today. His work on stress effects was also pivotal. He worked at the APU Cambridge for part of his career, as did many other influential scientists who have had a fundamental impact on applied human performance theory. Others include Broadbent, Poulton, Baddeley, Wilkinson, etc.
Norman Mackworth

3. The Vigilance Decrement

4. Inhibition theory (behaviorism)
Theories of Vigilance
Inhibition theory (behaviorism)
Expectancy Theory
Arousal Theory
Resource Theory

5. Raja Parasuraman has long-standing research programs in two areas, human factors and cognitive neuroscience. The first concerns human performance in human-machine systems, particularly with respect to the influence of automation and computer technology on attention, memory, and vigilance. His second area of research is the cognitive neuroscience of attention, where he has conducted studies using information-processing paradigms, event-related brain potentials and functional brain imaging (PET, fMRI), both in normal populations and in relation to aging and Alzheimer’s disease. He also has a research thrust in the molecular genetics of cognition, specifically attention and working memory. Finally, he has recently combined his interests in human factors (ergonomics) and cognitive neuroscience by developing the field of neuroergonomics, which he defines as the study of brain and behavior at work.
Raja Parasuraman

6. The Vigilance Taxonomy
Task Type: Simultaneous vs. Successive
Modality: Visual vs. Auditory
Source Complexity: Single vs. Multiple
Event Rate: Slow vs. Fast
Revisions of the taxonomy by See, Howe, Warm, & Dember (1995).
Sensitivity decrement can occur in SIM as well as SUC tasks, and at low as well as high event rates.
Sensory vs. cognitive tasks should be added to the classification system.
These may differ according to the types of processing required to distinguish signals from non-signals.
This dimension interacts with SIM/SUC: In a SIM task, the decrement correlates positively with event rate for cognitive tasks but negatively for sensory. The reverse was found for SUC tasks.
The “cognitive increment” will occur in SIM tasks at low event rates.
They found the decrement was not significantly moderated by modality, regularity, p(signal), spatial uncertainty, and KR.

8. Psychophysics of Vigilance
First Order Factors:
Immediate physical properties of the stimulus
Modality
Signal Salience (Conspicuity)
Event Rate
Second Order Factors:
Characteristics of the stimulus inferred by the observer based on experience with the task
Signal Uncertainty (Spatial & Temporal)

9. Psychophysics of Vigilance: Modality

10. Psychophysics of Vigilance: Event Rate

11. Psychophysics of Vigilance: Signal Salience

12. Psychophysics of Vigilance: Signal Duration

13. Overall Workload as a Function of Periods of Watch

14. Weighted Frustration as a Function of Periods of Watch

15. Workload and Performance
Event Rate
Time
Modality
Task Type
Source Complexity
Perf -
A>V
SIM >SUC
or SIM<SUC WL +
+/0
A=V
T x C/0
Note. A= Auditory Task; V= Visual Task
SIM = Simultaneous Task; SUC = Successive Task
T x C = interaction between task type and display complexity

16. Workload and Performance
Signal
Salience
P(S)
KR/cueing
Spatial uncertainty
Temporal Uncertainty
Perf +
+/0(KR) - WL ?
-/0(both)

17. Task-Based Stress and Performance
Event Rate
Time
Modality
Task Type
Source Complexity
Perf -
A>V
SIM >SUC
or SIM<SUC
Perceived Stress +
A < V
SUC>SIM? ?
+ manipulation increases values on the dependent measure
manipulation decreases values on the dependent measure
0 manipulation has no significant impact on dependent measure
Note. A= Auditory Task; V= Visual Task
SIM = Simultaneous Task; SUC = Successive Task
T x C = interaction between task type and display complexity

18. Task-Based Stress and Performance
Signal
Salience
P(S)
KR/cueing
Spatial uncertainty
Temporal Uncertainty
Perf +
+/0(KR) -
Perceived Stress ?
- (KR)
0 ?(cueing)

19. DSSQ Distress Task Engagement Worry Tense Arousal Energetic Arousal
Hedonic Tone
Confidence & Control
Task Engagement
Energetic Arousal
Motivation
Concentration
Worry
Self-focused Attention
Self-Esteem
Task-related Cognitive Interference
Task-irrelevant Cognitive Interference
Task engagement, distress, and worry are secondary factors derived from the primary factors listed below them.

20. Pre- and Post-Vigil Scores for the DSSQ Scales
Scores were calculated by computing z-scores using normative means and standard deviations obtained from Matthews et al., 1999 (cited in ch. 1 of Hancock & Desmond)

21. DSSQ standard scores as a function of time on task and stimulus modality. The task required temporal discrimination.

22. Configural Displays and Vigilance
Input 1
Input 2
Output
Configural Bar Graph Display
Integration Task
Focused Attention Task
Neutral Event
Critical Signal

23. Configural Displays and Vigilance
Input 1
Input 2
Output
Non-Configural Bar Graph Display
Integration Task
Focused Attention Task
Neutral Event
Critical Signal

24. Configural Displays and Vigilance
Input 1
Input 2
Output
Object Configural Display
Integration Task
Focused Attention Task
Neutral Event
Critical Signal

25. A' Periods of Watch (6-min)
Sensitivity as a function of periods of Watch for the integration task 1
0.98
0.96
0.94
0.92 A'
0.9
conint
0.88
nonint
objinit
0.86
0.84
0.82
0.8 1 2 3 4
Periods of Watch (6-min)

26. Periods of Watch (6-min)
Sensitivity as a function of periods of Watch for the focused attention task 1
0.98
0.96
0.94
0.92 A'
0.9
conf
0.88
nonf
objf
0.86
0.84
0.82
0.8 1 2 3 4
Periods of Watch (6-min)

27. Periods of Watch (6-min)
Response Bias as a function of periods of Watch for the integration task 1
0.9
0.8
0.7
0.6
Response Bias
0.5
conint
0.4
nonint
objinit
0.3
0.2
0.1 1 2 3 4
Periods of Watch (6-min)

28. Periods of Watch (6-min)
Response Bias as a function of periods of Watch for the focused attention task 1
0.9
0.8
0.7
0.6
conf
Response Bias
0.5
nonf
objf
0.4
0.3
0.2
0.1 1 2 3 4
Periods of Watch (6-min)

29. Overall Workload as a Function of Display Type