According to the source material, what does a lack of downstream effects in an initial impairment suggest about the relationship between cognitive processes A and B?

• A. Process A is not an essential precursor of Process B
• B. Process A directly causes Process B
• C. Process B is irrelevant to Process A
• D. They are both essential precursors of each other

Answer: (A)

A lack of downstream effects from an initial impairment means Process A is not a necessary precursor for Process B. In a processing sequence, if A were required for B, an impairment in A would disrupt or impair B as a downstream consequence. Seeing no such effect indicates B can operate without A, perhaps via parallel routes or alternative inputs. This pattern aligns with A not being an essential precursor to B, rather than suggesting A directly causes B, that B is irrelevant to A, or that they must both be essential precursors of each other.