Changing your mind on cannabis

Later this year Kiwis will get a chance to decide on where they stand on legalised cannabis in a referendum to be held alongside the upcoming general election.

The Government recently announced details of its proposed recreational cannabis scheme and former Associate Minister of Health Peter Dunne wrote in Newsroom: "It is likely though that voters will be seeking clearer answers to these before they vote in the referendum. Unless such answers are forthcoming, they may yet prove to be the devil in the detail that defeats the scheme in the referendum, in that event setting off an even more unsatisfactory situation than at present.”

However, no matter how many questions are asked and what answers are provided, and in spite of the chatter on talk-radio, television, print media and social media, chances are those who are opposed to it now will still be opposed later; while those who are supportive now will remain supportive.

This is because of something called “confirmation bias”; which means, by and large, we pay attention to information that bolsters our already pre-conceived notions about things. Given that we tend to make decisions on gut feelings, we typically do not do well in terms of looking for disconfirming evidence. This is primarily because looking for disconfirming evidence is effortful rather than intuitive and does not come easily.
 

For instance, suppose you believe that cannabis use is associated with increased delinquency. Is this right or not? In order to think through this problem, you need to consider four different groups of people and the sizes of those groups: (1) Cannabis users who are delinquent; (2) Cannabis users who are not delinquent; (3) Delinquents who do not use cannabis and finally (4) Non-delinquents who do not use cannabis. But if you are already convinced cannabis use causes delinquency then you will looking for support for the first outcome.. While, if you are in favour of legalising cannabis then you will keep thinking of all the people you know who smoke pot and never commit any crimes, or all the criminals who commit crimes while high on something other than cannabis or not intoxicated at all.

But, in order to arrive at the correct answer, we need to look for the disconfirming evidence and often, we don’t. Instead, we automatically seek the evidence that confirms our existing beliefs rather than evidence that may falsify it.

There are plenty of examples of such behaviour. For instance, US researchers had 48 Stanford undergraduates who supported or opposed capital punishment look at two studies, one confirming and the other disconfirming their existing beliefs about the deterrent effects of the death penalty. As the authors expected, both groups rated the study that confirmed their own beliefs to be the more convincing and the net effect was an increase in attitude polarisation.

The authors wrote: People who hold strong opinions on complex social issues are likely to examine relevant empirical evidence in a biased manner. They are apt to accept “confirming” evidence at face value while subjecting “disconfirming” evidence to critical evaluation, and, as a result, draw undue support for their initial positions from mixed or random empirical findings.

So can we change our confirmation bias? Well, you can. And if you want to make sure you have an open mind on the cannabis issue so you make an educated vote in the referendum, then you need to start with perspective-taking. You need to ask what does the other person or other side think they know in order to support or oppose this? Don’t rule out their position as being silly or ignorant – or at least, don’t rule out everyone. Or get another person to play devil’s advocate and see if your arguments are as solid as you thought they were.

Ask yourself these questions: Have you thought through all the four variants of the problem I posed at the beginning? Do you want to change other people’s minds? Then, as far as practicable, do not demean their arguments. Point out the different sides of the problem and rather than debate abstract logical propositions, make connections to our lived experiences. Talk about specific examples of common acquaintances who use cannabis but are not criminals. Or one who has committed crime but has never smoked cannabis.

An example of ‘lived experience’ bringing change is when there was rapid change in attitudes toward gay marriage in the US in the 1980s and 1990s. Research suggests the increased support for gay marriage was driven by Americans who had gay or lesbian friends or family as well as those who had contact with out-of-the-closet gay people and lesbians.

Seeking disconfirming evidence when faced with knotty philosophical questions like these can help us arrive at better decisions. This applies to all sorts of problems in life; not just cannabis legislation.