Two closely related fish living side by side in Lake Tanganyika make similar choices when decisions are simple — but take very different approaches when decisions become more complex. The finding offers an intriguing lesson for how we think about decision-making: better decisions may not always require more thinking, but knowing what deserves our attention.
Why do two individuals faced with the same information sometimes make completely different decisions?
It is a familiar question in human psychology. But researchers studying wild fish in Lake Tanganyika have found that the answer may have as much to do with how a decision is made as with the information available.
In more than 5,000 underwater trials, researchers from the Max Planck Institute of Animal Behavior, Université Clermont Auvergne and France’s CNRS studied two closely related species of Featherfin cichlids.
When choices were straightforward, the fish behaved almost identically. But when decisions became more complicated, their approaches diverged.
One species continued to make rapid, decisive choices. The other slowed down, apparently taking multiple pieces of information into account before deciding.
The finding suggests that evolution can shape not only what animals choose, but the decision-making strategy they use to get there.
Two ways of making the same decision
The researchers studied male Aulonocranus dewindti, known as the golden featherfin, and Cyathopharynx furcifer, or blue featherfin.
Both species build elaborate sand bowers to attract females and routinely remove foreign objects from them. That natural behaviour gave the researchers a way to study decision-making in the wild without relying on artificial training.
The team placed carefully designed 3D-printed objects into the fish’s bowers and recorded which objects they removed first.
Initially, the two species showed the same preferences.
Given simple choices involving colour or size, both behaved similarly. They preferred larger objects, for example, and both showed an “oddity effect”, preferentially removing an object whose colour stood out from a group.
But when the researchers made the choices more difficult, the similarity disappeared.
One object might have the preferred colour but be smaller, while another was larger but less attractive in colour.
The blue featherfin continued to make quick choices, apparently relying on a single feature.
The golden featherfin behaved differently. It took longer to decide and did not show a clear preference between the alternatives. As the complexity of the task increased, so did the time it took to reach a decision.
The blue featherfin, meanwhile, actually became faster.
“It was crucial to study this in two well-matched species,” says first author Dr Maëlan Tomasek. “They could see the same things, they were equally motivated, and they agreed when the choices were simple. Only when we made the decisions more demanding did they suddenly diverge.”
More information doesn’t necessarily mean a better decision
The researchers then used another decision-making experiment, known in human psychology as the decoy effect, to investigate whether the slower fish were simply becoming confused.
They weren’t.
When presented with a third, inferior option, the golden featherfin largely ignored the decoy and continued to treat the two main alternatives as equally attractive.
The researchers interpret this as evidence that the fish was considering several features of the choice rather than simply responding randomly.
The result is interesting because it challenges a familiar way of thinking about intelligence.
We often assume that better decision-making means processing more information, considering more possibilities and taking more time.
But the fish suggest something more nuanced.
Sometimes the ability to focus quickly on what matters most may be advantageous. In other situations, taking more information into account may produce the better response.
Neither approach is inherently superior.
“Comparative cognition has often focused on ranking species by their cognitive aptitude, their ‘cleverness’,” says co-senior author Dr Valérie Dufour. “Our results suggest a different perspective.”
Closely related species can solve the same problem using different cognitive strategies, she says, without one strategy necessarily being better than the other.
The innovation lesson: know what deserves your attention
That distinction has an interesting resonance beyond animal behaviour.
In organisations, innovation teams and complex decision-making environments, there is often pressure to develop a single “best” way of making decisions.
Some situations demand rapid judgement. Others benefit from slowing down, challenging assumptions and weighing competing signals.
- We’ve explored a related question before: how the way we frame a task can influence the way we think, act and make decisions. [read: How to tap into your motivation when you need it]
The lesson from the fish is not that organisations should make decisions like fish. Rather, it is that decision quality may depend on matching the decision process to the problem.
When the signal is clear, additional analysis can add friction without adding value.
When several important factors are in conflict, speed may obscure something that deserves attention.
Better decisions, in other words, may not always come from thinking more. They may come from knowing what deserves to be thought about — and how much.
Different strategies, different environments
The researchers believe the difference between the two species could reflect different life experiences or evolutionary histories. More research is needed to determine its source.
Dr Alex Jordan, co-senior author at the Max Planck Institute of Animal Behavior, argues that evolution does not necessarily produce increasingly complicated ways of making decisions.
Instead, it can produce strategies that are better suited to particular environments.
“When simple solutions work, they need not be replaced by more complicated rules,” he says.
That may be the most useful finding of all.
Innovation is often associated with adding complexity: more data, more analysis, more technology and more sophisticated systems.
But sometimes the smarter solution is to identify the information that matters most and act on it quickly.
And sometimes the smarter solution is to stop, consider the competing signals and give the decision more time.
The challenge isn’t always to think more. It’s to know when to think differently.
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Iain is a writer, journalist and lecturer, and former editor of two international business magazines. Iain is now editor of Innovators Magazine, as well as the creative director for OnePoint5Media.
