How many decisions have you made so far today? Feeling tired? You may not be surprised to learn that a decision-charged day will leave you mentally-fatigued and progressively worsen your decision-making ability. But did know you that this worsening takes place in a systematic way? As a rule, the greater the fatigue, the more the decision-maker will opt for the choice that is mentally the least demanding, namely the default or the status-quo. This means it is possible to predict what people will choose based solely on the number of decisions they have already made.
Research concerning what is known as ‘choice fatigue’ has been far-reaching. For example, court judges hearing parole cases are much more likely to grant parole at the start of the day or after a break. The greater the time elapsed since the last break, the greater the likelihood that they opt for the default – namely sending the prisoner back to jail. Another study concerned German car buyers who had to choose equipment for their new vehicle from a lengthy list of options. Here too, the greater the choice, the greater the reliance on default options. Even voting decisions are influenced by choice fatigue. In California, for example, the 2010 gubernatorial elections coincided with ballots for the US Senate and House of Representatives; the state’s Attorney-General, Treasurer, Controller and various other state officials; the Supreme Court and Court of Appeals; and a good half-dozen propositions, including the controversial Proposition 19, which concerned the legalisation of marijuana in California. Research at Stanford University showed that the position of a proposition on the ballot sheet influenced the likelihood the elector would vote ‘no’, equivalent to maintaining the status-quo , or abstain. Lowering the proposition 10 places on the ballot sheet increases the no-votes and abstentions by between 1.3 and 0.7 percentage points. In some cases, this difference is within the winning margin.
Sadly parole prisoners cannot decide when the judge takes a break. However, we can generally try to shield ourselves from the costly decision-making errors that result from choice fatigue if we know where the pitfalls are. For example, a shrewd car dealer will ensure that high-margin default options appear later in the sequence or among choices where there are many alternatives. Generally, it is probably best to make important or performance-relevant decisions after a break.
 Danziger, Leva & Avbnaim-Pesso (2011). Extraneous factors in judicial decisions. PNAS
 Levav et al. (2010). Order in product customization decisions: Evidence from field experiments. Journal of Political Economy.
 In California, at least. ‘No’ does not necessarily represent the status quo in other states.
 Augenblick & Nicholson (2011). Choice Fatigue: The effect of making previous choices on decision-making context on decision-making in a voting context.