In order to achieve his purpose of affecting readers' emotions, Steinbeck integrated the stories he heard from people into his novel by using the intercalary chapter technique. He alternates these intercalary chapters that tell the story of all migrant workers with plot chapters about the fictional Joad family.
You may recognize connections between the interviews you listened to earlier and some of the stories you'll read in The Grapes of Wrath.
Take a look at how Steinbeck echoes real life in his literary nonfiction chapters.
Interview excerpt The Grapes of Wrath excerpt
"We sold what household things we had . . ."1 "In the little houses the tenant people sifted their belongings and the belongings of their fathers and of their grandfathers."4
"Mom and Dad drove the Model T truck loaded to the hilt with stuff . . ."2 "[T]hen frantically they loaded up the cars and drove away . . ."5
"And it was just the way that people gave to each other that helped us through the toughest times."3 "[T]hey shared their lives, their food, and the things they hoped for . . ."6