One of the earliest meme-tastic moments for Justin Trudeau, the yoga-posing, quantum computing-explaining, wheelchair-assisting Canadian prime minister, was the image of his gender-split, racially diverse cabinet. Making good on an earlier promise, Trudeau introduced a cabinet in November that had 15 men and 15 women. Pictures of the diverse group -- combined with Trudeau's drop-the-mic "because it's 2015" explanation -- went viral online, projecting an image that seemed to encapsulate a new chapter of governing from the young Liberal leader.

During a town hall with MSNBC host Rachel Maddow on Monday night, Hillary Clinton was asked whether she too would pledge to have a Cabinet that's half women and half men. She didn't outright say yes. But she effectively said she planned to do so, saying "Well, I am going to have a Cabinet that looks like America, and 50 percent of America is women, right?" The news followed reports last week that women will be on her short list of vice-presidential running mates, and earlier this month, Clinton called a gender diverse Cabinet something that "is certainly my goal."

But while Trudeau may have rightly said he created a gender diverse cabinet because it's time -- and Hillary may plan to have one that looks like America -- this is about a lot more than timing or optics. Yes, diversity has been shown over and over again to result in better decision making. Yes, a half-female Cabinet would be radical and historic.

But it's also likely to be much more effective. To get the better decision-making results that come from diverse teams, the women and minorities in the group first have to be heard, and research has shown that it's often not until a "critical mass" of women on a team is reached that they're able to make real contributions that improve governing.

Research on corporate boards offers the analogy. A frequently cited study from 2006 examined how many women needed to be on a board for women to make a difference. Based on interviews with female directors, CEOs and corporate secretaries, researchers Vicki Kramer, Alison Konrad and Sumru Erkut found that it took having at least three women for them "to create a critical mass where women are no longer seen as outsiders" and can influence the discussions in substantial ways.

When there is only one woman on a board, the researchers found in their interviews, she's seen as a token member who represents the "woman's point of view" and can be excluded from social events. Add a second woman and things improve, but "women and men are still aware of gender in ways that can keep the women from working together as effectively as they might."

Get to at least three female members, however, and "suddenly having women in the room becomes a normal state of affairs," the researchers write. "Women start being treated as individuals with different personalities, styles and interests. Women’s tendencies to be more collaborative but also to be more active in asking questions and raising different issues start to become the boardroom norm."

It's not the only research to find that mere token representation by women isn't enough for diversity to really make an impact. A study of German firms, for instance, found that it's only after a board reaches 30 percent women that diversity is associated with higher firm performance. Meanwhile, a recent study of the minutes from board meetings of companies in Israel found that when there are at least three directors of each gender, the boards were much more active in their discussions and more likely to replace underperforming CEOs.

Of course, a presidential Cabinet and a corporate board are two different beasts: One advises the president and acts as her senior team, the other supervises the chief executive and has the power to fire him. They're also somewhat different sizes. The typical corporate board has 11 members; the president's Cabinet has 16 official members and another seven that have Cabinet-level rank.

Still, they are both groups of high-powered leaders who act, in some sense, as advisers, and must work together in a group where gender dynamics are sure to play out. Reaching a critical mass of diverse team members, rather than just having token representation, isn't just something that will make for good photo opportunities, or underscore a leader's feminism. It's a key factor in helping the women leaders in the group be heard, treated as more than token representatives and have real influence over critical decisions by the group.

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