Exploring how apathy and compulsivity can shape decision-making

In their new preregistered research article, “The effect of apathy and compulsivity on planning and stopping in sequential decision-making,”  Jacqueline Scholl and Nils Kolling, both of Oxford University, explore how behavioral traits associated with various illnesses can affect real-world behavior when performing tasks and making complex decisions—in this case, searching for, applying to, and deciding whether to accept a new job. 

Importantly, the authors chose to publish their study as a Preregistered Research Article with PLOS Biology. In this model, authors submit a design for a confirmatory study, together with preliminary results from any exploratory investigation, for peer review. Following review and revision of the study design, research projects may be provisionally accepted for publication after the results and analysis are completed. 

Below, read excerpts from a longer interview with the authors, discussing their hypotheses and results, next steps for the research, and their decision to preregister.

Interviewer: You and your coauthors have recently published a research article in PLOS Biology, in which you use job search behavior to explore how sequential decision-making is affected by apathy and compulsion. Can you tell us at a high level what your investigation entailed, and what inspired you to pursue this line of inquiry?

JS: In the past psychology experiments aimed to be as simple as possible. However, this often misses out on many complexities that people actually need to deal with in daily life. We hypothesized that these more “real life” situations are also when psychiatric traits – like apathy –show up more clearly. Our work here is in line with a more ‘ecological approach’ which takes inspiration from real-life situations that need to be solved and uses computational modeling to capture the complexities.

The specific complexity that we were interested in here is how people plan ahead when they need to think about making a series of decisions – like searching for a job. This often entails going through a sequence of getting offers and deciding whether to accept or reject them. While we had previously investigated the brain mechanisms of the general decision making and planning processes, in this study we identified several clinical dimensions which might manifest in sequential decision making changes. For example, we hypothesized that apathy might lead people to keep searching for too long because they get ‘stuck in a rut’ (‘decision inertia’). And that compulsivity might also lead to searching for too long, but for a different reason, namely being insensitive to the costs searching entails.

NK: Another key inspiration for our study was related to introspection. Generally, decision making studies do not ask participants about their own reasoning for their behavior but fit models to their behavior instead. They do so in the belief that “actions speak louder than words”. However, when it comes to clinical changes some of those changes are about how we “feel” and think about our behavior, not just what we do. This is why it’s so exciting to look at BOTH what people do and what they think together and compare them. 

Interviewer: And why did you choose to preregister this study? What, if anything, can journals do to encourage preregistration and/or make it easier to do?

NK: When you want to combine a complex task with clinical and real-life dimensions as well as self-reflective report measures about their own behavior, you need a new analysis approach to match your ambitions. Specifically, the sheer amount of potential associations when it comes to a sophisticated cognitive model that can measure multiple cognitive features and multiple clinical dimensions means you need a way to narrow down the hypothesis space.

JS: In such a situation, it’s incredibly powerful to collect two samples as we did here with a ‘discovery sample’ (roughly 400 participants) / ‘confirmation sample’ (750 participants). A major advantage of this approach is that we could be guided by the data in generating precise hypotheses about clinical dimensions (in the discovery sample). Yet at the same time, we could avoid any potential statistical pitfalls to do with explorations (e.g. p-hacking) through pre-registration before collecting the confirmation sample. 

NK: Offering pre-registrations in well-respected journals, like PLOS Biology, is a major step forward for visibility of pre-reg studies. We hope that our study can play a role in showing other researchers how pre-reg and discovery/confirmation approaches can empower [researchers] to answer new questions with new approaches.

Interviewer: For readers who may not know, in preregistered research, authors begin by first articulating a hypothesis, study design and analytical approach, which is then submitted for peer review. In your case you actually tested three hypotheses! What was it like to receive comments so early in the process, and how do you think that early peer review may have influenced the study you conducted?

JS: For our specific case, the review process was quite similar to standard peer review because we had a sizeable ‘discovery sample’ on which it was based. In fact, in the past, the discovery sample would have been for most researchers the only sample they had in the paper. Our huge advantage now was that we could boost our confidence in the validity of the findings through the confirmation sample.

One major advantage compared to standard peer-review was that when reviewers made sensible suggestions about additional control variables to collect, we could actually implement this; rather than just thinking ‘we wished we had done that’.

NK: For other types of pre-reg studies, that are earlier in the process, a lot more feedback can go into initial design, analysis and planning, showing what a large spectrum of pre-reg reports are possible!

Interviewer: Turning back to the research itself now, you explored two traits associated with a broad range of illnesses: apathy, which can be linked to depression, brain injury, neurodegenerative disorders, and other factors; and compulsivity, which is a core feature of OCD. On the surface to someone who’s not an expert in the field, apathy and compulsivity may appear to be opposites. Why does it make sense to study them in tandem?

JS: Being able to look at different psychiatrically traits at the same time is a key advantage of the kind of large online studies we have done here. The reason that this is important is that many psychiatric traits are correlated. For example, in a sample of patients with OCD [obsessive compulsive disorder], many would also have other diagnoses. This makes controlling for related but distinct clinical dimensions key. If one instead recruits patients with only OCD, these patients would be quite unrepresentative of the overall patient population.

Taking advantage of the ease of data collection over the internet, we could get hundreds of participants to allow us to statistically dissociate the different psychiatric traits using a ‘transdiagnostic approach’. This means that, instead of splitting participants into groups according to diagnostic categories, we measured how much of each trait (e.g. apathy or compulsivity) each person has. And then in turn we could link these traits uniquely to differences in behavior (controlling for other traits).

NK: Importantly, our clinical dimensions were established empirically from questionnaire measures that covered a wide range of clinical questions/features. Thus, we can say that apathy and compulsivity are not the exact opposite from each other, as they otherwise would have been absorbed into one clinical dimension. In our study, both dimensions also appeared to lead to quite different changes. Apathy led to quite specific behavioral change in decision inertia but no corresponding change in insight. On the other hand, compulsivity came with a series of meta-cognitive or self-reported changes, but relatively little behavioral effects in our task. 

Read the full interview on Biologue!