By Dr Tanya Finnie

I once chose to live with a family of four in a two-room home in Soweto.

At the time, I thought I understood South Africa. I had grown up there. I understood Apartheid. I knew inequality existed and had strong views about the injustice of it.

Yet knowing something exists and experiencing life from inside it are two very different things.

Living in Soweto challenged assumptions I didn’t even know I had. Things I had considered normal suddenly looked different. Other things I had interpreted from a distance made much more sense when I was close enough to understand the context.

It taught me something that has stayed with me throughout my career.

We all make assumptions. The dangerous ones are the assumptions we don’t realise we’re making.

Leadership Assumptions Are Everywhere

Workplaces run on assumptions.

We assume the confident person is competent.

We assume the quiet person has nothing to add.

We assume someone who asks lots of questions doesn’t understand.

We assume the person who works late is committed.

We assume eye contact signals honesty. Speed signals capability. Directness signals confidence.

Then we build decisions around those assumptions.

Who gets hired. Who gets promoted. Who gets invited into important conversations. Who is considered leadership material. Most of the time, nobody announces the assumption. It simply becomes part of how things work around here.

When an Assumption Becomes “Common Sense”

This is where things get interesting. Spend long enough inside one organisation and its assumptions begin to feel like facts.

“That’s just how our clients expect us to behave.”

“You need a certain personality to succeed here.”

“Senior leaders need executive presence.”

“Our people prefer coming into the office.”

“They’re not quite ready for leadership.”

Perhaps. But how do we know?

I regularly challenge people in workshops to separate what they know from what they have assumed. It’s surprisingly difficult. Assumptions become particularly powerful when several people share them. Once enough people believe something, it starts to look like common sense. And common sense is heavily influenced by culture.

Culture Changes What We Assume

Having lived and worked across different countries, I’ve learnt to be suspicious of the phrase “that’s obvious.” Obvious to whom?

In one culture, a good employee may challenge the boss openly. Somewhere else, doing exactly that could be deeply disrespectful.

One leader values initiative and expects people to act without asking permission. Another interprets the same behaviour as overstepping authority.

Even concepts such as professionalism, respect, punctuality, confidence and good communication carry cultural assumptions. This becomes particularly important in multicultural workplaces because people can be following completely different unwritten rules while believing theirs are perfectly normal.

That’s where cultural intelligence becomes practical. It gives us the ability to notice our own lens before judging someone else’s behaviour through it.

Assumptions Become Systems

One leadership assumption probably won’t transform an organisation. Repeated assumptions can.

Imagine a workplace where senior leaders unconsciously associate confidence with speaking quickly and decisively. People who communicate that way are noticed. They get more airtime. Their ideas receive more attention. They’re given stretch opportunities.

Eventually they’re promoted. A few years later, leadership looks remarkably similar.

Nobody deliberately designed it that way.Yet a system has emerged.

Now think about the employee who prefers to reflect before contributing, speaks English as an additional language, comes from a culture where interrupting senior people is inappropriate, is neurodivergent, or simply communicates differently.

Their capability hasn’t changed. The system’s interpretation of capability has. This is why workplace assumptions deserve far more attention than they usually receive.

The Problem With Good Intentions

Most leaders I work with genuinely want to make fair decisions. That’s important. It also doesn’t protect us from assumptions. In fact, believing ourselves to be fair can sometimes make assumptions harder to spot because we stop looking for them.

I’ve certainly caught myself doing it. Working across cultures doesn’t make you immune to bias. If anything, it keeps reminding you how easy it is to misread behaviour when you don’t understand the context. Curiosity helps.

So does being willing to discover that your first interpretation was wrong. That takes a particular kind of leadership confidence. Going to court and saying you did not mean for someone to get hurt, does not absolve you from responsibility. Intention alone is simply not good enough.

What Are Your Assumptions Costing You?

Leadership assumptions have commercial consequences. Think about recruitment.

A candidate doesn’t make much eye contact and the interviewer decides they lack confidence.

Someone has an unfamiliar accent and their expertise is unconsciously assessed differently.

A candidate’s career has taken an unconventional route and their experience feels harder to compare.

Another doesn’t immediately build rapport with the panel and gets described as “not quite the right fit.”

These decisions can feel completely rational in the moment.

Yet organisations may be filtering out precisely the difference they claim they want.

The same thing happens after people are employed. Ideas are missed. Talent is overlooked. People learn which version of themselves receives approval and adapt accordingly.Eventually organisations wonder why everybody at senior level thinks similarly.

A Simple Assumption Test for Leaders

There’s a question I use frequently in my work:

What else could be true?

Someone is quiet in a meeting. Perhaps they’re disengaged.

What else could be true?

They may be processing. They may disagree. They may be waiting for the leader to finish. They may have learnt from experience that challenging this particular person goes badly. They may come from a culture where speaking before senior people feels inappropriate. They may simply be tired.

You don’t need to know which explanation is correct. You need enough curiosity to realise your first explanation may not be.

Another useful question is:

What evidence do I actually have?

Those two questions can slow down surprisingly poor decisions.

Where Human Systems Come Into It

This is one of the areas I’m exploring through Human Systems. Organisations tend to look at individual behaviour because it’s visible.

Someone isn’t contributing.

Someone isn’t performing.

Someone isn’t leadership material.

Someone doesn’t fit.

Human Systems asks us to widen the lens. What assumptions are shaping how that behaviour is being interpreted? What behaviours does the organisation reward? Who created those expectations? Who finds them easy to navigate? And who is spending considerable energy learning rules nobody ever explained?

Once you start looking at organisations this way, workplace culture becomes much easier to see. It lives in everyday decisions.

Human Systems Insight

Assumptions are unavoidable. We’re human. Our brains constantly use previous experience to interpret what is happening around us.

The leadership risk begins when an assumption quietly becomes a decision. And when the same assumptions influence enough decisions, they eventually become part of the system.

That’s when “how we’ve always done things” deserves a closer look.

Back to Soweto

Living in Soweto didn’t suddenly make me understand everybody else’s experience. That would be another assumption.

What it gave me was proximity. I saw things I couldn’t see from where I had been standing before. I saw how people shared communal toilets and water and thus creating a culture of sharing and trust. Their first instinct was not: I have so little, why should I share? That lesson has probably influenced my work more than I realised at the time.

When something about another person’s behaviour doesn’t make sense to me, I’ve learnt to become curious about what I might be missing. Leaders don’t need to experience every culture, identity or life circumstance represented in their workforce. That’s impossible.

They do need to recognise that where they are standing affects what they can see.

Final Reflection

Think about one person at work who frustrates you. Someone you find difficult, disengaged, overly direct, too quiet, resistant or simply “not quite right”.

Now ask yourself: What have I decided about this person that I don’t actually know?

The answer might be uncomfortable. Good. There may be something worth learning there.