When did we start to believe it was highly efficient and productive to run short back-to-back meetings every 30 minutes for 8 hours a day? Or very long meetings crammed full of agenda items? Or meetings starting and finishing in the wee hours? When did we start to believe that humans are machines operating on an inexhaustible supply of energy?

The reality is that every day human beings work with a limited supply of mental energy – and when it is gone our ability to make thoughtful decisions and contributions is significantly compromised. Intuitively we all know that – it’s what we’ve experienced. The mere act of making a decision, let alone a smart decision about a complex issue, feels much harder when we are running on empty. But did you know that “cognitive depletion” starts to happen long before we are exhausted? Every choice we make and every act of “self-regulation” (e.g. biting our tongue instead of bursting into anger), takes mental energy. They deplete our mental store. The problem is that while we recognise the end game (mental exhaustion), we have no internal warning system to alert us to the corrosive impact of cognitive depletion on decisions made along the way. Our decisions are compromised – we’re less flexible, less innovative (more likely to default to what we’ve always done before) and we make mistakes – but we think we doing just fine.

As part of her book, “Which two heads are better than one? How diverse teams create breakthrough ideas and make smarter decisions”, Juliet Bourke recently reviewed current research on cognitive depletion – or “capacity bias” – to understand its operation in theory and practice, as well as remedial strategies. While research is relatively new in this space, Bourke found a strong connection between cognitive depletion and one’s ability to connect with diverse people and understand diverse perspectives. It’s not a virtuous cycle. Diversity requires cognitive energy – to really listen to and comprehend a different way of seeing the world and to regulate personal behaviours. And when one is cognitively depleted it is even more difficult to attend and process diverse ideas. Bourke’s view is that attention to cognitive depletion is a missing element in the diversity of thinking conversation.

Compromised decisions

Compromised decision making is the conclusion that Tel Aviv University Professor Shai Danziger, and his colleagues reached after reviewing 1,112 judicial rulings conducted over ten months by eight judges, at two parole boards and in four prisons. Judges pride themselves on their capacity to make evidence-based decisions and to apply established rules of evidence that are designed to minimise subjectivity and maximise objectivity. So it came as a shock to the judges – and the researchers – to discover that their decisions about releasing prisoners on parole were also strongly influenced by when each case was considered.

Danziger found that, 64.2% of prisoners were likely to have their parole request rejected, unless the prisoner was listed as the first case of the day, the first case after morning tea, or the first case after lunch. In those circumstances, the likelihood of success jumped up to 65%. From that high point, with every subsequent decision, the likelihood of success was reduced, and fell away dramatically for the second or third decision after morning tea or lunch.

Why the connection between timing and the decision outcome? Danziger suggested that making a decision to release a felon back into the community, or to reduce their parole conditions, is an inherently risky decision. The easier decision is to maintain the status quo. Hence, with every decision, a judge’s mental energy was slightly depleted, leaving him or her with slightly less energy to devote to the next risky case. Even more importantly, the impact of that depletion was to render the judge less likely to think critically, and more likely to default to the status quo and reject the application. It is a sobering study.

President Obama’s choices

The real and present danger of cognitive depletion is, quite seriously, why United States President, Barack Obama, only wears grey and blue suits.

“I’m trying to pare down decisions. I don’t want to make decisions about what I’m eating or wearing. Because I have too many other decisions to make. You need to focus your decision-making energy. You need to routinise yourself. You can’t be going through the day distracted by trivia,” says Obama, whose decisions require an enormous level of attention.

“Nothing comes to my desk that is perfectly solvable. Otherwise someone else would have solved it.”

Obama’s decision-making context may lie at the extreme end of the spectrum, but the situation for decisions made by senior leaders cannot be far behind. Indeed, 2015 research by Deloitte of 3,300 leaders across 106 countries, found that 74% rated their organisations as “complex” or “very complex” .

For leaders making complex decisions, cognitive depletion is a real problem, causing people to lose more and more of their capacity for thoughtful behaviours and decisions. Eventually, cognitive exhaustion hits and people revert to what Kahneman would call “System One Thinking”: automatic, fast, intuitive and emotional. As a consequence, people are less likely to undertake the complex work of compromise, more likely to take the path of least resistance, and much less likely to engage with, and make use of, diverse thinking.

Making a change

So how can leaders protect and improve their cognitive energy? Psychologists often use the analogy that cognitive energy is like a muscle: people can train themselves to strengthen that muscle, motivate themselves to use the muscle, conserve its use until strictly necessary and keep it in peak form. Although research into combating cognitive depletion is relatively new, early findings suggest that it can be:

1. Conserved: by minimising the expenditure of energy on trivial decisions (like what to eat each day).

2. Topped-up: in the short-term taking breaks between meetings and giving people regular glucose (which the brain relies upon for energy) can act to replenish depleted energy stores. Ultimately however, the store will be depleted.

3. Rallied: what is left of mental energy can be rallied to the cause of paying attention if people are encouraged to remember the merit of their decision and accountability for the outcome. Rallying however, is only effective for a final burst of energy (to stimulate effort to cross the finishing line).

4. Slightly extended: when people practise regular small acts of self-control it helps to build their pool of mental energy (although this has an obvious ceiling). One example the researchers found was the daily practice of noticing and replacing slouching with non-slouching.

Final words

Easily said and yet hard to do: taking up these changes requires a fundamental re-orientation to the way leaders “manage” complexity and ever increasing demands for their time and energy. Squishing in one more meeting, taking one more late night phone call, inserting another difficult decision into a packed meeting agenda – all of these strategies are heading in the wrong direction if the research on cognitive depletion holds true.

To date much of the research has considered complex and intense decision making. When diversity is also taken into account – be that dealing with diverse stakeholders or accessing and understanding diverse information – the challenge level is raised even higher. Why? Because preliminary research reveals an interaction between diversity and cognitive depletion. Put simply: paying attention to diversity is hard and accelerates cognitive depletion. More worryingly, cognitive depletion amplifies the impact of biases. So if leaders and their teams want to make even smarter decisions, and see diversity as part of the solution, considering strategies to mitigate cognitive depletion has to be part of the strategy.

This is Bourke’s central argument: without attention to capacity biases, the potential value created through diversity of thinking will be constrained. Why? Because people will have less energy to connect with diverse people (and will therefore revert to familiar networks), to listen to diverse ideas (preferring to listen to what’s already known) and to undertake the important work of perspective taking, mental agility and compromise (all critical for forming a new idea). Bourke not only highlights the importance of paying attention to cognitive depletion per se, she makes the compelling case that cognitive capacity is a focal part of the diversity of thinking story.

For further information see Bourke, J. (2016) Which two heads are better than one? How diverse teams create breakthrough ideas and make smarter decisions, Australian Institute of Company Directors.

[1] Danziger, S., & Ward, R. (2010). Language changes implicit associations between ethnic groups and evaluation in bilinguals Psychological Science, 21 (6), pp. 799-800;

[2] Lewis, M., (2012) Obama’s way Vanity Fair, October 2012;

[3] Deloitte (2015) Global Human Capital Trends 2015: Leading in the new world of work, p.88