While Americans claim they are more likely to purchase a product if the brand supports a cause, and more than 40 percent have “liked” a brand or posted on Facebook for supporting a cause, barely one in five actually put their money where their good intentions are by switching brands, paying more or purchasing more.

That’s one of the key findings in a new study co-sponsored by BlogHer, the news, entertainment and information network for women online, and the cause consumer engagement specialty at Ketchum.

“This research is significant because it contrasts what consumers actually do versus what they say they would do in reaction to a hypothetical cause marketing situation,” says Kelley Skoloda, partner and director of Ketchum’s global brand marketing practice. “In many instances, it appears cause programs have a far greater effect on brand affinity, reputation and share of voice than on sales. But the research also revealed the keys to turn talk into action.”

While only 23 percent of consumers report a change in their purchase behavior based on a cause, nearly twice that number report using social media and word-of-mouth to talk about a cause.

“The study reveals four key drivers that brands must focus on to generate consumer engagement and sales,” notes Melissa Kinch, senior vice president and associate director of Ketchum’s North American corporate practice. “These drivers are target your most passionate audience, understand what they are passionate about, include local engagement opportunities, and leverage online influencers.”

The study finds people are willing to change purchase behavior if the cause aligns with their personal passions and impacts them, their community or someone close to them.

Passion for a cause is the top reason why Americans evangelize a particular brand and the cause it supports, with 38 percent of adults saying it was the primary reason why they have written, blogged or tweeted about a brand and cause.

People want cause support to be simple and easy: 48 percent are most receptive to programs from which companies donate a portion of sales to a cause, and 38 percent want companies to make it easy to support a cause online (e.g., become a Facebook friend).

About half (46 percent) of those surveyed are motivated to buy a product from a company when it makes a donation to a local school or organization, a figure that jumps to 70 percent for older adults aged 65 to 76.

Americans are most passionate about causes supporting breast cancer initiatives (44 percent), animals (36 percent) and children’s causes (35 percent).

“The findings show consumers will purchase a product if they are passionate about the cause associated with it or if it’s important to them and their loved ones,” says Kinch. “Too often, brands focus on causes that are less relevant to consumers and later wonder why there is no impact on sales. While there’s certainly still a place for longer-term reputational cause or responsibility programs that educate customers about causes, short-term sales are clearly driven by addressing consumers’ personal passions.”

Among the international findings:
• Brazilians prefer to support a cause via email, while those in Hong Kong like to share content and information about a cause via social media.
• Hong Kongers are the most likely to post an update their Facebook page urging friends to support a cause.
• Brazilians are far more likely to turn to social media than Germans to discuss a brand’s cause and urge readers to make a purchase. Only 6 percent of Germans said they would blog or tweet about a cause, compared to 23 percent for Brazil, 16 percent for Hong Kong and 10 percent for the United States.
• While 42 percent of Americans have “liked” a brand or product on Facebook to support or learn about a cause, only 9 percent of Germans have done the same.