First of all, please note that it is extremely difficult and perhaps even inappropriate to try to characterize all people of a given ethnic group as having one culture. Not all African Americans have the same culture any more than all whites have the same culture. That said, scholars tend to argue that African American culture exhibits more collectivism than white culture does.
Scholars argue that African American culture influences its members to care more about the family and other groups than white culture does. African Americans are said to have more of a sense that they are all connected to one another and that what they do individually has an impact on all members of the community. It is said that African Americans tend to have stronger relationships with members of their extended families. African Americans are also more likely to use "fictive kinship" in which they see people who are not actually related to them as members of their own family.
So, scholars do argue that African American culture is more collectivist. But we must beware of making generalizations in which we portray people of any group as homogeneous.