April 14
 Past Friday: One hour of presentations (panel OK) in lieu of
this class. Turn in short commentary for grade.
 Comments?
 Questions about design project? Data collection?
 IDEO website
 Fatigue and Circadian Rhythms
 Example quiz questions
 Performance effects
 Measuring Workload
Two Reasons You May
Feel Sleepy
Melatonin Factoids
The Hormone Melatonin
Adenosine
http://thebrain.mcgill.ca/flash/a/a_11/a_11_m/a_11_m_cyc/a_11_m_cyc.html
http://thebrain.mcgill.ca/flash/i/i_03/i_03_m/i_03_m_par/i_03_m_par_cafeine.html
Stress Effects on Cognition
How does fatigue affect performance?
The Yerkes-Dodson Law
 High & low stress/arousal can lead to impaired
performance by reducing resource availability
Novice or
Expert or
Stress Effects on Cognition
 If your attention is reduced, information
processing in cognitive capacity will suffer.
The Yerkes-Dodson Law:
Tunneling &
lapsing can
occur here
Fatigue Effects on Cognition
 attentional lapses
 some slowing of information processing
Attention & working memory are
compromised.
Reduced Attentional Resources Cause…
 Lapses in attention
 Slowing of information processing
 Information not processed as ‘deeply’
 Attentional narrowing/tunneling
 “Satisficing”
 Task shedding
 Reliance on automated performance
 Reliance on schemas/templates
Stress Effects on Cognition
 High Arousal or Preoccupation
 Reduced attentional capacity
 Attentional tunneling
 Perceptual
 Working memory
 Reduced working memory capacity
 Less effective memory storage & recall
Compromised: Attention, Working Memory, Retrieval from Long Term Memory
Hancock & Warm’s Model of
Stress Effects on Performance
Stress is operationalized as level of arousal
A - physiological function
B - behavior/performance
C - subjective comfort
D - normative zone
Hancock, P.A. & Szalma, J.L. (2006). Stress and Neuroergonomics. In: R. Parasuraman and M. Rizzo (Eds.),