When Should We Want to be Last? And when’s a good time to see the dentist?

When Should We Want to Be Last? Exploring Sequence Biases

A version of this article appears in my book, Twisted Logic: Puzzles, Paradoxes, and Big Questions. (Chapman and Hall/CRC Press, 2024).

THE CELEBRITY TALENT CONTEST

An actor, a singer, a presenter, a reality star, a comedian, a tennis player, and an assortment of other vaguely familiar faces, line up to compete for the title of best celebrity dancer. This is the well-established format of what is called ‘Strictly Come Dancing’ in the UK or ‘Dancing with the Stars’ in the US. The prize is the coveted glitterball trophy.

But how much of their success in the competition is to do with their Waltz, Foxtrot, and Charleston, and how much is it literally down to the luck of the draw?

A study published in 2010 by Lionel and Katie Page looked at public voting at the end of episodes of a singing talent contest and found that singers who appeared later in the running order received a significantly higher share of the public vote than those who had preceded them.

This was explained as a ‘recency effect’ meaning that those performing later are more recent in the memory of people who were voting. Interestingly, a different study, of wine tasting, suggested that there is in that arena a significant ‘primacy effect’ which favours the wines that people taste first (as well, to some extent, as last).

Testing for Bias

What would happen if the evaluation of each performance was carried out immediately after each performance instead of at the end? Surely this would eliminate the benefit of going last as there would be equal recency in each case? The problem in implementing this is that the public need to see all the performers before they can choose which of them deserves their vote.

In addition to the public vote, however, Strictly Come Dancing (or Dancing with the Stars in the US) includes a score awarded by a panel of expert judges immediately after each performance. There should in theory be no recency effect in this expert evaluation – because the next performer does not take to the stage until the previous performer has been scored, and so there is no ‘last dance’ advantage in the expert scores.

I decided to look at this using a large data set of every performance ever danced on the UK and US versions of the show – going right back to the debut show in 2004. The findings, published with two co-authors in the journal, Economics Letters, proved very surprising and counter-intuitive.

Last Shall be First

Contrary to expectations, we found the same sequence order bias by the expert panel judges – who voted after each act – as by the general public, who voted after all performances had concluded.

We applied a range of statistical tests to allow for the difference in quality of the various performers and as a result we were able to exclude quality as a reason for the observed effect. This worked for all but the opening spot of the night, which we found was generally filled by one of the better performers.

So the findings matched the 2010 study in demonstrating that the last performance slot should be most prized, but we also found that the first to perform also scored better than expected. This resembles a J-curve where the first and later performing contestants disproportionately gained higher expert panel scores. You certainly don’t want to go second!

Although we believe the production team’s choice of opening performance may play a role in the first performer effect, our best explanation of the key sequence biases is as a type of ‘grade inflation’ in the expert panel’s scoring. In particular, we interpret the ‘order’ effect as deriving from studio audience pressure – a little like the published evidence of unconscious bias exhibited by referees in response to spectator pressure. The influence on the judges of increasing studio acclaim and euphoria as the contest progresses to a conclusion is likely to be further exacerbated by the proximity of the judges to the audience.

When the votes from the general public are used to augment the expert panel scores, the biases observed in the expert panel scores are amplified.

In summary, the best place to perform is last and second is the least successful place to perform.

The implications of this are worrying if they spill over into the real world. Is there an advantage in going last (or first) into the interview room for a job – even if the applicants are evaluated between interviews? What about the order in which your examination script appears in the pile that is being marked?

Hungry Judge Effect

A related study, published in the Proceedings of the National Academy of Science, found that experienced parole judges granted freedom about 65% of the time to the first prisoner to appear before them on a given day, and the first after lunch – but to almost nobody towards the end of a morning session. The paper speculates that breaks may serve to replenish mental resources by providing “rest, improving mood or by increasing glucose levels in the body”. It’s also been termed the ‘hungry judge effect’. Linked to this is the concept of decision fatigue, the idea that decision-making and good judgment declines in the wake of making too many decisions without a break.

So the research confirms what has long been suspected – that the order in which things happen can make a big difference. Combined with decision fatigue there are clear implications for everyday strategy, whenever you have a choice in the matter – such as when to make that appointment with the dentist or doctor, or when to ask for a pay rise or even a date!

CONCLUSION: LEARNING SOME LESSONS

If you learn just one thing from this, it’s that life is not always about what you do, or even how you do it, but when you do it. Now think about that appointment with the dentist. Do you really want to be last in before lunch? Consider the ‘hungry judge effect’ and apply it to the dentist and add a touch of decision fatigue into the equation. What’s your answer?

As a tip it is probably up there with the big ones! The bigger story is that there really is a lot we can learn from published research that can improve our health, happiness, and everyday lives. It’s just a matter of knowing where to look and applying the lessons. Besides, it can be a whole lot of fun!