Environments can change over time, making the benefit of a choice change during deliberation. For example: the choice of what route to take into town might change depending on the weather. Image credit: Nicholas Barendregt (CC BY 4.0)
How do we make good choices? Should I have cake or yoghurt for breakfast? The strategies we use to make decisions are important not just for our daily lives, but also for learning more about how the brain works.
Decision-making strategies have two components: first, a deliberation period (when we gather information to determine which choice is ‘best’); and second, a decision ‘rule’ (which tells us when to stop deliberating and commit to a choice). Although deliberation is relatively well-understood, less is known about the decision rules people use, or how those rules produce different outcomes.
Another issue is that even the simplest decisions must sometimes adapt to a changing world. For example, if it starts raining while you are deciding which route to walk into town, you would probably choose the driest route – even if it did not initially look the best. However, most studies of decision strategies have assumed that the decision-maker’s environment does not change during the decision process.
In other words, we know much less about the decision rules used in real-life situations, where the environment changes. Barendregt et al. therefore wanted to extend the approaches previously used to study decisions in static environments, to determine which decision rules might be best suited to more realistic environments that change over time.
First, Barendregt et al. constructed a computer simulation of decision-making with environmental changes built in. These changes were either alterations in the quality of evidence for or against a particular choice, or the ‘reward’ from a choice, i.e., feedback on how good the decision was. They then used the computer simulation to model single decisions where these changes took place.
These virtual experiments showed that the best performance – for example, the most accurate decisions – resulted when the threshold for moving from deliberation (i.e., considering the evidence) to selecting an option could respond to, or even anticipate, the changing situations. Importantly, the simulations’ results also predicted real-world choices made by human participants when given a decision-making task with similar variations in evidence and reward over time. In other words, the virtual decision-making rules could explain real behavior.
This study sheds new light on how we make decisions in a changing environment. In the future, Barendregt et al. hope that this will contribute to a broader understanding of decision-making and behavior in a wide range of contexts, from psychology to economics and even ecology.
