In 1832, the Great Reform Act confirmed the exclusion of women from the electorate. In 1973, the Matrimonial Clauses Act confirmed the exclusion of same-sex couples from marriage. Thankfully, these exclusions were repealed in 1928 and 2013 respectively. The law evolves, and necessarily so.

Yet all of these changes have taken place slowly, and in the face of the pervasive resistance to change known as status quo bias: A cognitive error where one option is incorrectly judged to be better than another simply because it represents the status quo.

Several studies have confirmed the ubiquity of this effect. In the famous ‘mug experiment’, students were asked to fill out a questionnaire, and then rewarded with either a mug or a large chocolate bar. After receiving the gifts, they were then offered the chance to exchange their gift for the respective other option. Approximately 90% declined.  As soon as the ‘status quo’ was established either a mug or chocolate, students were happy to retain their original gift.

Though the choice of gift seems trivial, the  consequences of giving an undue bonus to the status quo can be significant: People fail to move their existing investments to more lucrative options, for example, or are resistant to changing their long-term medication for a more effective alternative.

The bias also exerts a powerful influence over the formulation and interpretation of the law. Consider the criminalisation of marijuana use in the Misuse of Drugs Act 1971 and the paucity of legal restraints on the adult consumption of alcohol and tobacco. Given the relative societal costs of these substances, this state of affairs makes seemingly little sense, and we have reason to suspect that status quo bias may be part of the problem.

One way to check is via the Reversal Test, a heuristic developed by philosophers Nick Bostrom and Toby Ord. The test posits that when a proposal to change a certain parameter is thought to have bad overall consequences, one should consider a change to the same parameter in the opposite direction. If this is also thought to have bad overall consequences, then the onus is on those who reach these conclusions to explain why our position cannot be improved through changes to this parameter. If they are unable to do so, then we have reason to suspect that they suffer from status quo bias.

The parameter at hand with drug laws is the criminalising of substances that pose a threat to public health and safety. Those who believe that we should not decriminalise marijuana should therefore consider if they would endorse a shift in the other direction; namely criminalising substances of similar or greater toxicity (such as alcohol), and imposing stronger penalties on transgressors. This position seems unlikely to be either popular or justifiable on public health grounds.

The Reversal Test is also illuminating when applied to other areas of law: If intensive factory farming, 40-hour working weeks, and labelling non-nationals “illegal” were not established norms, would we find that they should be?

Thorough its invisibility and ubiquity, the status quo bias is a silent threat to legislative  progress. Departing from the status quo where necessary, and recognising and resisting the  bias where it arises, will surely result in wiser, better motivated, and more responsive legislation.


Kahneman, D., & Tversky, A. (1984). Choices, values, and frames. American psychologist, 39(4), 341.

Gilovich, T., Griffin, D., & Kahneman, D. (Eds.). (2002). Heuristics and biases: The psychology of intuitive judgment. Cambridge University Press.

Bostrom, N., & Ord, T. (2006). The Reversal Test: Eliminating Status Quo Bias in Applied Ethics*. Ethics, 116(4), 656-679. Chicago.

Samuelson, W., & Zeckhauser, R. (1988). Status quo bias in decision making. Journal of risk and uncertainty, 1(1), 7-59.