10.5 Variability

• People are willing to pay substantial amounts of money to reduce the variability in their life
• Users are capable of adapting to varying situations
• Goodman and Spence (1981)
• Subjects took more advantage of fast response time by making their subsequent commands immediately and balancing the time lost in waiting for slower responses
• Modest variations in response time (plus or minus 50% of the mean) appear to be tolerable
• It may be useful to slow down unexpected fast responses