Making better choices when your brain is tired

Research has consistently shown that judges tend to make harsher decisions later in their decision sessions, with approval rates dropping substantially before breaks and returning to higher levels after rest periods as demonstrated in a study of Israeli parole board decisions. This effect isn't limited to the legal system – it impacts executive decision-making across industries.

Your brain processes thousands of decisions daily. By day's end, the neurological machinery responsible for weighing options, forecasting outcomes, and managing risk operates at diminished capacity. The conventional response? Push through. Power through. Muscle through.

Yet elite performers recognize that decision fatigue isn't about willpower, it's about neurological resource allocation. They don't make better decisions when tired; they architect decision environments that preserve cognitive capital for what truly matters.

In this issue, we'll decode the neuroscience of decision fatigue, examine how it silently compromises leadership effectiveness, and introduce evidence-based protocols for maintaining decision quality when others falter.

The neurobiology of decision degradation

When your prefrontal cortex — the neurological CEO — faces prolonged cognitive demands, several biological mechanisms compromise decision quality. Glucose depletion reduces available energy for executive function. Dopamine fluctuations alter risk assessment capabilities. Cortisol accumulation narrows thinking aperture.

Research shows that executives facing decision fatigue are more likely to select default options and less likely to pursue innovative alternatives as described in studies on decision fatigue and heuristic analyst forecasts

Your 5pm brain is neurologically different from your 9am brain when it comes to decision quality.

To counteract these shifts, consider the following four evidence-based protocols designed to preserve executive function and improve decision-making under cognitive strain:

Decision batching

Context-switching between decisions has a measurable cognitive cost. According to research from the University of California, Irvine, it can take over 23 minutes to return to your original task after being interrupted. By grouping similar decisions (hiring decisions, financial approvals, strategic planning), you eliminate transition costs and leverage specialized neural networks optimized for specific decision types.

What you can do:

Block your calendar for homogeneous decision types. Reserve 90-minute windows for single-category decisions rather than addressing them as they arise.

Energy zoning 

Match decision types to your natural energy patterns. Research indicates that complex decisions show improvement when made during personal peak cognitive hours, while routine decisions show less significant variation throughout the day.

What you can do:

Audit your energy patterns for one week. Note peak mental clarity times, then ruthlessly protect these windows for decisions with the highest cognitive demands and greatest organizational impact.

Pre-made decision frameworks 

Before fatigue strikes, design decision architecture that your exhausted future self will navigate. Decision matrices provide a structured method for comparing different alternatives against weighted criteria, helping to make objective, transparent decisions even under cognitive constraints.

What you can do:

Create standardized templates for your most common decision types, including explicit criteria, weighting factors, and acceptable outcome ranges.

Decision arbitrage 

Not all decisions deserve equal cognitive investment. Advanced executives calculate the cognitive ROI of different decision types and strategically invest their limited decision-making resources where returns are highest.

What you can do:

Classify decisions into three tiers based on reversibility, impact scope, and uncertainty level. Systematize or delegate Tier 3 (low-impact) decisions, conserving resources for Tier 1 (high-impact) choices.

Quick wins

📖 Book recommendation: 

Thinking in Bets by Annie Duke

Former poker champion Duke provides a framework for making decisions under uncertainty that acknowledges the role of luck versus skill, essential perspective for fatigue-proofing your choices.

⏱️ Routine hack:

The "10/10/10" rule for tough calls

Before making any significant decision while fatigued, ask yourself: How will I feel about this choice in 10 minutes? 10 months? 10 years? This temporal distancing technique activates different neural networks and counters decision fatigue's present bias.

🧠 Mindset shift:

"Every yes is a no to something more important" 

Decision fatigue is about making too many decisions. Recognize that your decision-making capacity is finite and preserve it accordingly.

The reset revolution

Tobi Lütke, Shopify's CEO, implements decision arbitrage through his "trust battery" system, a concept he's discussed publicly in several interviews that has become central to Shopify's organizational culture.

Lütke's trust battery approach treats decision authority as dynamic, fluctuating based on demonstrated judgment quality.

The concept works like an actual battery - when two people begin working together, their trust battery starts at around 50%.

Each interaction either charges or depletes this battery, with charging happening when someone delivers on promises and depleting when they don't follow through. What makes this system unique is how it creates objective language for discussing trust.

At Shopify, decision rights flow toward those with fully charged trust batteries. As Lütke explains:

"If your cell phone is 80% charged, you're not worried about finding a charger... What people want to do in a company is get to the 80% or 100% level in the area that they run. You gain full autonomy this way." 

This creates natural accountability as team members know their decisions must continually earn trust.

Most importantly, this system enables Lütke to schedule high-stakes decisions only after recovery blocks, recognizing that decision quality varies based on cognitive state. The trust battery framework provides a structured way to track how mental state affects decision outcomes. When someone new joins Shopify, they understand that their trust battery begins at 50% - they're given the benefit of the doubt, but must actively build trust through demonstrated performance.

This creates what Lütke calls "a marketplace for good judgment" rather than static hierarchical decision structures, allowing decision authority to flow naturally to those who consistently demonstrate good judgment while preserving cognitive resources for the company's most consequential choices.

This week, conduct your own decision arbitrage experiment. Identify and isolate your three highest-impact decisions for the coming days. Block 30 minutes of your peak cognitive time to address each one specifically, removing all distractions and applying the frameworks outlined above.

Then ask yourself: What decisions do you regret making under fatigue? Which decisions truly deserve your peak cognitive resources?

The quality of your decisions ultimately determines the quality of your leadership. Your exhausted 5pm brain may be inevitable, but making critical decisions with that brain is entirely optional.