Businesses, take note: An underserved and poorly understood consumer group is poised to become a driving force in economic and business development, by virtue of sheer numbers and rising globalization.

They are subsistence consumers—people in developing nations like India who earn just a few dollars a day and lack access to basics such as education, health care and sanitation.

As these consumers gain access to income and information over the next decade, their combined purchasing power, already in the trillions of dollars, likely will grow at higher rates than that of consumers in industrialized nations. The lesson for multinational companies: Understanding and addressing the needs of the world’s poorest consumers is likely to become a profitable, as well as a socially responsible, strategy.

A characteristic associated with low-income consumers, and one that has major implications for doing business with them, is that many struggle with reading and math. Like the 14% of Americans estimated to be functionally illiterate in a U.S. government survey, subsistence consumers have difficulty reading package labels, store signs or product-use instructions, or subtracting the purchase price of an item from cash on hand—all of which hampers their ability to put their limited incomes to best use.

Our research shows that low-literacy consumers process market information and approach purchasing decisions differently than other groups of shoppers. As a result, companies may have to alter marketing practices such as packaging, advertising, pricing, store signage and the training of retail-store employees in order to communicate with them more effectively and win their business.

Here is what we learned from our studies on low-literacy, low-income consumers in the U.S. and subsistence consumers in developing markets, and our recommendations on how marketers can improve the value these groups get from product purchase and use.

CONCRETE THINKING

One of the key observations we made is that low-literacy consumers have difficulty with abstract thinking. These individuals tend to group objects by visualizing concrete and practical situations they have experienced.

They exhibited what science would call a low grasp of abstract categories—tools, cooking utensils or protein-rich foods, for example—which suggests low-literacy consumers may have difficulty