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University of Basel

How we make decisions.

How our memory can trick us.

Text: Martin Hicklin

When we have to make a choice, we often select the options that trigger the strongest memories. One reason for this is that weak memories tend to make us feel uncertain.

Illustrated portrait of Prof. Dr. Sebastian Gluth. (Illustration: Studio Nippoldt)
Prof. Dr. Sebastian Gluth. (Illustration: Studio Nippoldt)

When faced with decisions in everyday situations, we constantly rely on the more or less reliable memories that are drawn from our “episodic memory” system. For example, we need these when choosing a restaurant to go to lunch with our colleagues. Or if we are planning a weekend hiking trip with friends.

When this happens, different options play out before our mind’s eye, calling up memories that are either very vivid or rather faint. Interestingly, very little research has been conducted on the relationship between memory and the cognitive process of decision-making, although they are used every day. A team headed by Professor Sebastian Gluth at the Center for Decision Neuroscience at the Faculty of Psychology sets out to change this. The relationship between specific memories stored in our episodic memory and the decision-making process is Gluth’s primary research focus.

Memory bias

Some years ago, Gluth and his team investigated why certain options win over others and how objectively our memory influences our decisions. This research was not conducted in restaurants or on hiking trails, however. Instead, the tests took place on computer screens in a laboratory. Participants were first asked to evaluate different snacks and then learned to link these snacks with specific cards on the screen – similar to the well-known Matching Pairs memory game. At the end, they were asked to choose between cards without actually seeing the snack in question.

This experimental setup proved valid. A complex study with 30 participants demonstrated that the participants in this situation mostly chose the options that triggered the strongest memories. Interestingly, this was still the case even when the snack had been given a poor rating beforehand.
This effect is referred to as “memory bias”. Although the study provided empirical evidence for the presence of this effect, it did not allow to understand the mechanisms at play. In an attempt to answer this question, Gluth and his doctoral students Regina Weilbächer and Peter Kraemer tested the hypothesis that choosing an option of which you have no or very little memory is similar to choosing an uncertain option. And a lot of research has shown that uncertainty is disliked very much and tends to be avoided.

Risks taken in the face of losses

The experiment conducted by Gluth and his colleagues drew on an older, well-established observation in uncertainty research: Where there are potential gains, people prefer the safest choice and avoid lotteries and games of chance, as shown in numerous studies by teams led by psychologists Amos Tversky and Daniel Kahneman over the past few decades. Conversely, people are more likely to take risks if they are trying to avoid certain losses. Kahneman and Tversky call this phenomenon the “reflection effect”. Building on these findings and the hypothesis that uncertainty is one reason for memory bias, Gluth and his team tested the prediction that the memory bias also works in reverse when making decisions that involve potential losses.

And indeed: The experiment did show that choices based on memory with the prospect of a reward resulted in the “safe” options with strong associated memories being chosen. The very opposite occurred when it came to avoiding losses. The predictions thus proved to be correct, leading to a better understanding of the role that memory plays in decision-making where risks are involved.

This could have all manner of consequences. Older people tend to be more wary of risks than younger people when making decisions, for example. General prejudice would regard this as the result of older people being more set in their ways. Yet maybe the reason for this is the quite different and surprising explanation by dwindling memories. Although this phenomenon has not (yet) been tested and confirmed experimentally (unlike the fact of declining memory performance with age), current research by the team at the Center for Decision Neuroscience supports the strong assumption that it exists.

“In our work, we look at how we can predict decisions as accurately and detailed as possible. We target decisions on various levels of analysis,” explains Gluth. He is assistant professor and Head of the Center for Decision Neuroscience, which is one strand of the focal area in social, economic and decision psychology. “We work very closely with one another within the faculty. As the official description goes, what connects us is ‘our passion for research into human decision-making in a social and economic context’.”

Neuroscientific processes

What Gluth brings to the table is experience in neuroscientific methods such as functional magnetic resonance imaging (fMRI). This is a unique selling point. These methods are instrumental when it comes to identifying the processes inside the brain that connect with the psychological processes examined here. Gluth, however, sees this method primarily as an additional tool. These methods will, above all, help testing the validity of the decision-making models and improving them. “First and foremost, I’m a psychologist,” comments Gluth, “I’m interested in finding out how our thoughts and decision-making processes work. I’m not simply interested in knowing what this or that part of the brain does.”

To achieve maximum transparency, Gluth and his team have adhered to the golden rules of open science from the very outset. This brings about huge benefits in terms of the repeatability of the experiments and the reproducibility of the scientific results. This is why all the experiments and the planned approach is meticulously recorded in advance. Other researchers and interested parties, for example, can visit the Open Science Framework server (OSF, www.osf.io) and see immediately which hypotheses are being tested, what data form the basis of their predictions, what is known already and what the planned approach is.

Information on the recruitment and the number of participants, what measures were taken to produce statistically robust results—this, too, is made available online in advance, even the scripts for the models used to perform the calculations. This is an open invitation for constructive, creative criticism. Once a paper is ready for publication, it is first made available for peer review on a preprint server for psychological research before submission to an academic journal. Only then is the paper published, and preferably in a specialist journal that allows open access without a paywall. What more can you ask for publicly funded research.

More articles in the current issue of UNI NOVA.

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