"I think there was another discussion that was happening in a separate arena that was around high performing teams - bringing the right people together - and that was also talking about diversity, but it wasn't talking about demographic diversity; it was talking about different people's skills and those kinds of things.
"Diversity 3.0 is bringing those things together and saying: how do demography and thinking differences relate to each other? Do they relate to each other?"
The Sydney-based partner spent two years unpicking the connection between diversity and performance. The result is Which Two Heads Are Better Than One? How Diverse Teams Create Breakthrough Ideas and Make Smarter Decisions, published this year by the Australian Institute of Company Directors.
As the book heads into its second printing, Bourke talks of the "Noah's Ark" approach which she says was typical of diversity 2.0 - "I'll have two of those and two of those". That approach was simplistic, she says.
Instead, she starts from a base of diverse thinking, before layering on the benefits that gender and racial differences add.
Opening up the floor to different angles on a problem cuts down on mistakes, she argues. In fact, by trying to work out a solution on your own or with someone similar to you, you're building in an error rate of 30 per cent, Bourke says.
Homogeneity leads to errors because you just don't see enough of the problem.
"Homogeneity leads to errors because you just don't see enough of the problem." But add in more perspectives - ideally between five and eight - and you're more likely to come to the right result.
She looked at how people solve problems, finding there were six approaches - outcomes, options, people, process, risk or evidence - with all six needed for good decision making.
"And then what I found was you not only get to this 100 per cent accuracy, you also get this 20 per cent innovation.
"It's not just spotting your blindspots, but actually you can get breakthrough ideas." Unfortunately, leadership teams tend to be dominated by people who focus on the outcomes they want and the options they will use to get there, she says.
Bourke also discovered an unexpected benefit of adding more diversity of thinking to leadership lineups - people outside the team have more confidence in the decision that is made.
"So there's three elements to the value proposition: one, you stop making as many mistakes; secondly, you get some breakthrough ideas; and thirdly, you get this 'followship'."
Demographic diversity ensures that good ideas get an airing in the first place. "When you have a group of people who are gender-balanced - somewhere 50:50 or 40:60 - you tend to have more psychological safety in the group and you tend to have more 'turn taking' in the conversation.
"That means someone who is a little bit left of field, there's more likelihood that their voice will be included.
"So gender has this really interesting effect on the group dynamic; it's more collaborative.
"If you have single-sex groups they tend to be more tribal and people don't want to speak up and contradict the group."
Bourke also found that racial diversity within a team triggers curiosity.
"People see someone who is visually racially diverse and they think 'oh, you must know something that I don't' so they start to ask more questions, listen more closely and process the information."
Bourke is the first to admit that introducing greater overall diversity into teams isn't easy.
"I try to listen to people more closely and I try and hear: how do they like to solve problems?
"And what I'm looking for is someone who thinks differently than I do, and now I've got a framework to understand what 'think differently' means.
"It's not introversion or extroversion - that's a style difference.
"I'm actually looking for: are they more process oriented because I'm not very process oriented; are they more risk oriented, because I'm not risk oriented.
"I want the people to complement, play to their strengths, rather than be a clone."
For a start, your biases will get in the way.
When Bourke looked for strategies to help deal with blindspots, all she found was "be aware".
"I was really looking for considered research on what actually makes a difference." She discovered three biases that together fed into unconscious bias: connectivity bias - always connecting with similar people; informational bias - seeking out and valuing information that confirms our point of view; and capacity bias - managing decision-making energy to ensure you can adequately consider diversity of thinking.
Bourke says the main thing she learned through all her research was that diversity was not a natural state of affairs - we instinctively lean towards what we know.
