Final answer:
Martha's son is having difficulty with cognitive flexibility, which is the ability to switch thought processes to adapt to new rules. This is part of normal cognitive development in young children, which is fostered by play that involves sorting and categorization.
Step-by-step explanation:
Martha's son is demonstrating difficulties with cognitive flexibility, which is the ability to transition thoughts between two different concepts—in this case, sorting by color and sorting by shape. This is a common development stage for children as they learn to adapt their thought processes. Cognitive flexibility is a vital skill that children develop during play, as it allows them to switch between different rules and expectations, which is necessary for adapting to new situations. Through play, such as sorting cards or fitting shape-specific pegs into the corresponding holes, children like Martha's son learn about organizing and categorizing information, which are aspects of cognitive development.
Since Martha's son is a toddler, he is still building upon his cognitive abilities, which includes understanding object permanence and the development of fine motor skills. These aspects are crucial for children throughout the toddler stage to interact with their environment effectively and start building the framework for logical and mathematical reasoning skills.