A possible fifth stage of cognitive development that characterizes adult thinking is known as:

Postformal thought is characterized by a more nuanced understanding of problems and reasoning that goes beyond the formal operational stage, which typically encompasses abstract thinking and logic. In postformal thinking, adults are able to recognize that the world is not always black and white; they often see it as a more complex, subjective reality where answers can be context-dependent.

This stage acknowledges the importance of emotional and social factors in decision-making and problem-solving, suggesting that mature reasoning involves understanding that different situations may demand different kinds of thought processes. Individuals in this stage are often able to integrate contradictory ideas and think in ways that are more flexible and pragmatic, which is reflective of real-world complexities.

The other stages mentioned do not encompass these adult characteristics. Concrete operational thought is focused on logical thinking about concrete events, while formal operational thought deals with abstract concepts but doesn’t include the flexibility seen in postformal thought. Preoperational thought relates to early childhood cognitive development and is characterized by symbolic thinking but lacks the logical reasoning seen in older children and adults. Thus, the unique features of postformal thought make it a fitting candidate for a potential fifth stage of cognitive development, specifically related to adult reasoning.