When it comes to figuring out why so many millennials haven’t started investing, the majority of advisors and the financial industry have it all wrong, according to a new study.

While conventional wisdom paints a picture of millennials as aggressive, knowledgeable and confident when it comes to investing, new research finds that the majority of millennials lack confidence in financial decision-making and show little interest in robo-advisors. Moreover, despite coming of age in a digital world, they prefer to work face to face with a financial professional.

The report from the CFA Institute and Finra Investor Education, entitled “Uncertain Futures: 7 Myths about Millennials and Investing," essentially turns common wisdom about millennial investors on its head, which is a dicey proposition considering the generation stands to inherit a whopping $40 trillion.

"This study dismisses many of the assumptions that are commonly held about millennials and why many of them are not investing," said Finra Foundation President Gerri Walsh. "These findings help us better understand the needs and wants of millennials to further enhance investor education efforts that will engage millennials in the financial markets."

As it turns out, there are actually three subsets of millennials—those with no investment accounts, those with only retirement accounts and those with taxable investment accounts (most of this group also owned retirement accounts)—and they have very different goals and habits, according to the study.

"By providing insights into investment preferences and concerns, this research can help financial professionals engage and better serve the needs of the next generation of investors, ”said Bjorn Forfang, deputy CEO of the CFA Institute.

These were among the study's findings:

• When it comes to working with a financial professional, 58 percent of millennials say they prefer to work face to face.
• Millennials who do invest more often start when they are young, before age 21.
• Innovations in investment products and services currently hold limited appeal for millennials.
• Forty-six percent of millennials with investment accounts cited parents and family as key factors in their decision to start investing.

The survey also debunks the following myths about millennials and their investing behavior:

Myth 1: Millennials have lofty financial goals. Contrary to conventional wisdom, millennials expect to retire at the age of 65. Non-investing millennials have very modest financial goals and are focused on surviving month to month. In contrast, the financial goals of millennials with taxable accounts mirror those of Gen Xers and baby boomers, such as "saving enough to retire when I want and live comfortably."

Myth 2: Income and debt are the key barriers to investing. While income and debt are important, 39 percent of millennials without taxable investment accounts state that not having enough knowledge about investing is also an important barrier.

Myth 3: Millennials are overconfident in general, so they are probably overconfident about investing. Far from being overconfident, only 21 percent of non-investing millennials and millennials with only retirement accounts are very or extremely confident about making investment decisions. This figure increases to 47 percent for millennials with taxable accounts.

Myth 4:  Millennials are skeptical of the financial services industry and by extension, financial professionals. Nearly three quarters (72 percent) of millennials working with a financial professional are very or extremely satisfied with their financial professional. Only 15 percent of millennials not working with a financial professional cite lack of trust as a reason.

Myth 5: Millennials overestimate the investable assets needed to work with financial professionals. In fact, millennials underestimate the investable assets needed to work with a typical financial professional. Twenty percent of millennials believe there is no minimum amount needed to work with a financial professional. About six in 10 believe a financial professional would work with them if they had $10,000 or less to invest. Millennials also lack guideposts for pricing financial advice. Forty-two percent of millennials do not know what financial professionals charge for their services. When asked to estimate, they guess high: 77 percent believe financial professionals charge 5 percent or more of assets under management.

Myth 6: Millennials gravitate toward electronic communication and robo-advisors. Despite their affinity for technology, 58 percent of millennials prefer to work face to face with a financial professional, on par with baby boomers (60 percent) and Gen Xers (58 percent). Only 16 percent of millennials show strong interest in using robo-advisors.

Myth 7: Millennials are all the same and have similar investing attitudes and behaviors. Advisors should not think of millennials as a monolithic entity. For example, urban millennials are 50 percent more likely than rural millennials to own taxable investment accounts. Thirty-three percent of male millennials are extremely or very confident in their financial decision-making, compared to only 23 percent of female millennials. Twenty-eight percent of white millennials have taxable accounts compared with 20 percent of African-American millennials.

The findings should help interested advisors begin to decode the elusive millennial generation. "Investment professionals who take time to demonstrate that client interests are paramount can expect to earn the trust of millennial clients," said  Forfang.