Recording from single neurons in the brain has shown that neurons responding to specific types of stimuli are often clustered in specific areas. These results support the idea of .......

The question states that neurons for "specific types of stimuli" are "clustered in specific areas." This means that different parts of the brain are specialized to handle different kinds of information or tasks.

• a. Dissociation: This refers to a situation where damage to one part of the brain impairs one function but not another, suggesting separate neural pathways. While related to brain function, it's not the direct idea supported by neurons for specific stimuli being clustered.
• b. Cortical association: This term typically refers to the association areas of the cerebral cortex, which integrate information from different sensory and motor areas. It doesn't specifically describe the clustering of neurons for particular stimuli.
• c. Localization of function: This is the principle that specific functions or abilities are controlled by specific, distinct areas of the brain. The observation that neurons responding to specific stimuli are clustered in particular regions is direct evidence for this principle.
• d. The information processing approach: This is a broad theoretical framework that views the mind as processing information in stages, similar to a computer. While brain activity underlies information processing, the clustering of neurons for specific stimuli is a more specific anatomical and functional observation, directly supporting the idea of specialized brain regions.

The clustering of neurons for specific stimuli in specific areas is a direct example of different brain regions having specialized roles, which is the definition of localization of function.

The final answer is $\boxed{\text{c. localization of function}}$.