The Köhler Effect: Why the Right Challenge Transforms a Mentoring Relationship

I have seen the Köhler Effect play out many times, long before I ever came across the research that describes it. As a mentor, and as someone who spends time on a climbing wall, I recognise the same pattern in sport, in leadership teams, and in mentoring relationships. When you place someone in an environment where their contribution truly matters, their performance lifts. They find effort they did not know they had.

In sport, the Köhler Effect describes how athlete increases effort when paired with someone stronger or providing accountability, a desire to not "let the team down". It is not about unhealthy competition. It is about responsibility and belief that their effort influences the outcome. When people feel indispensable, they raise their game.

I see the same effect every time I climb with a partner who is more technically skilled or experienced. I am an OK boulderer, but when I climb with someone who has cleaner technique or more power on steep overhangs, I sharpen my focus, commit more fully, and push through moves I would not attempt on my own. It helps when they demonstrate their route. They may have climbed it before or they can read the wall more efficiently without needing the same trial and error. Sometimes I follow their approach. Other times I realise it does not suit me, but watching them opens up new possibilities and helps me find better lines faster. I also climb harder because they are watching, because I value the shared effort, and because I want to contribute to the rhythm of the session. Their presence lifts my performance without them saying a word

That same lift happens in mentoring.

In mentoring, your role is not to overshadow, but to model showing what clarity, confidence, and structured thinking look like. When applied with care, that presence creates momentum rather than intimidation. It encourages the mentee to stretch just beyond their current capability. When a mentee steps into a relationship where their thinking, decisions, and actions genuinely shape outcomes, they engage more deeply. They prepare more. The conversation becomes sharper. Follow through becomes stronger. They lean into challenge rather than resist it.

In senior leadership mentoring, this effect is especially powerful. Many executives spend their working lives being the most capable person in the room. When they sit with a mentor who can match, challenge or exceed their strategic reasoning and problem solving, the Köhler Effect comes alive. They shift from passive discussion to active ownership. They stretch beyond their current horizon. They bring ideas and scenarios that test their own thinking. The relationship becomes a partnership that fuels growth.

To use the Köhler Effect deliberately in mentoring, three elements make the difference:Indispensability : Create conversations where the mentee’s thinking genuinely shapes the direction. Ask questions that draw out their judgement, help them test options, and reflect on consequences. When they reach their own conclusions and take ownership of the next step, they feel the responsibility and the momentum becomes theirs.

Constructive challenge: Hold a strong standard without taking control. Model clarity, calm thinking, and disciplined decision making through your questions and presence. Challenge assumptions in a way that strengthens their confidence rather than undermines it. Stretch them one step beyond what they believe they can do, while keeping them in command of the decisions.

Shared purpose: Ensure the work sits inside a clear ambition they have defined. Whether the goal is scaling the business, preparing for funding, building leadership rhythm, or improving resilience, the shared purpose keeps the sessions aligned and meaningful. It also helps them see how each decision fits into the bigger picture.

This framing keeps the mentor firmly in the facilitator space, while still allowing the Köhler Effect to work as a motivator and accelerant.

Used well, the Köhler Effect is not about pressure. It is about presence. It is about creating the same energy you feel when you stand beneath a challenging route with a stronger climber beside you. You want to rise to the moment. You want to meet the standard. You want to contribute something that matters.

In mentoring, this creates leaders who push further, think deeper, and deliver with greater consistency.