HIBAR: Effects of acetaminophen on risk taking (with virtual balloons)

HIBAR re-analysis risk taking

Had I Been A Reviewer.

Ruben C. Arslan https://rubenarslan.github.io (Center for Adaptive Rationality, Max Planck Institute for Human Development, Berlin)https://www.mpib-berlin.mpg.de/en/staff/ruben-arslan
An analogue of the Balloon Analogue Risk Task (BART). From the [Internet Archive Book Images](https://www.flickr.com/photos/internetarchivebookimages/14760892026/)

Figure 1: An analogue of the Balloon Analogue Risk Task (BART). From the Internet Archive Book Images

Update March 4, 2021

I exchanged a few emails with Baldwin Way. After two responses, he stopped replying.

Several of my concerns below are not allayed by his responses, and I’m further concerned that Way does not seem motivated to fix unambiguous errors (non-public preregistration that was not frozen, deviation from preregistered analysis) or respond to a critic. His final sentence to me was that I should try running acetaminophen studies myself, but given the presented evidence, I currently feel like this would be a waste of time.

Original post

A journalist is calling me later today to talk about this recently published paper, so I read it.

Although I have a research interest in risk taking, I had not read the recent flurry of papers that link acetaminophen (paracetamol/Tylenol) to various psychological outcomes.

Here’s the abstract of the paper:

Acetaminophen, an analgesic and antipyretic available over-the-counter and used in over 600 medicines, is one of the most consumed drugs in the USA. Recent research has suggested that acetaminophen’s effects extend to the blunting of negative as well as positive affect. Because affect is a determinant of risk perception and risk taking, we tested the hypothesis that acute acetaminophen consumption (1000 mg) could influence these important judgments and decisions. In three double-blind, placebo-controlled studies, healthy young adults completed a laboratory measure of risk taking (Balloon Analog Risk Task) and in Studies 1 and 2 completed self-report measures of risk perception. Across all studies (total n = 545), acetaminophen increased risk-taking behavior. On the more affectively stimulating risk perception measure used in Study 2, acetaminophen reduced self-reported perceived risk and this reduction statistically mediated increased risk-taking behavior. These results indicate that acetaminophen can increase risk taking, which may be due to reductions in risk perceptions, particularly those that are highly affect laden.

Well, because of my own research and studies like Frey et al. 2017, I have my doubts that changes on the BART will generalize to changes in real world risk taking. I think it’s a somewhat silly task, where the optimal behaviour is to inflate several balloons 64/128 times (unlike real balloons, the balloon has a 1/128 chance of bursting at the first press, which goes to 100% chance of bursting at the 128th press). In the study, they played this task for “imaginary money”, which they “lost” when the balloon burst, so high scores mainly mean people pressed a button a lot of times. Unsurprisingly, people rarely “pump” (press a button) the optimal number of times, perhaps because it is boring to do so. Ironically, the BART is in wide use, because it is supposed to measure the affectively-laden side of risk taking (rather than supposedly even more boring lotteries). To be honest, I would not bet money that the BART even predicts how much air people put in a real balloon, let alone bigger life choices.

They also look at self-reported perceptions of risk on the DOSPERT and in a inventory by Finucane, finding mixed results.

But before asking whether the results will generalize to real world behavior, I should first try to judge whether the results are even likely to replicate.

An initial overview doesn’t inspire confidence:

I emailed the last author, Baldwin Way, to get access to the preregistration, which he granted (the link still isn’t public).

As it turns out:

I emailed the last author some questions to ask for explanations of some of these deviations.

Doing some further digging, I found that the first author’s master’s thesis reports a third study that tested whether these effects extended to ibuprofen (but not the study 2 reported here).

To my mind, the empirical evidence isn’t very strong and it’s unfortunate that the authors’ studies left open several researcher degrees of freedom, making it hard to take their p values at face value.

I don’t know if this study is characteristic of the broader literature (see here for a critical take), but I think if I avoid paracetamol in the future, the liver damage will weigh heavier on my mind than the supposed psychological effects.

If someone wants to do further research on this, especially with undergraduates, I’d recommend asking them whether they drank the night before or are in other pain. We would not want to claim that paracetamol affects real world risk taking, when it really just affects whether we’re willing to hear a loud bang while hungover.

Further reading:


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Text and figures are licensed under Creative Commons Attribution CC BY 4.0. Source code is available at https://github.com/rubenarslan/rubenarslan.github.io, unless otherwise noted. The figures that have been reused from other sources don't fall under this license and can be recognized by a note in their caption: "Figure from ...".


For attribution, please cite this work as

Arslan (2020, Sept. 23). One lives only to make blunders: HIBAR: Effects of acetaminophen on risk taking (with virtual balloons). Retrieved from https://rubenarslan.github.io/posts/2020-09-23-hibar-effects-of-acetaminophen-on-risk-taking/

BibTeX citation

  author = {Arslan, Ruben C.},
  title = {One lives only to make blunders: HIBAR: Effects of acetaminophen on risk taking (with virtual balloons)},
  url = {https://rubenarslan.github.io/posts/2020-09-23-hibar-effects-of-acetaminophen-on-risk-taking/},
  year = {2020}