Final answer:
Proactive interference does not illustrate the brain becoming specialized through exposure to common stimuli; it describes the challenge in learning new information due to existing memories, in contrast to pruning, discrimination between language sounds, and the cross-race effect.
Step-by-step explanation:
The psychological phenomenon that does not illustrate the principle of our brains becoming specialists based on routine exposure to common stimuli is proactive interference. Proactive interference describes the difficulty in learning new information because of already existing information. This contrasts with:
- Pruning, which is where the brain eliminates unused synaptic connections, enhancing the efficiency of neural transmissions related to frequently encountered stimuli.
- Discrimination between language sounds, which is a skill that develops as infants are repeatedly exposed to their native language, leading them to become adept at distinguishing its phonemes.
- The cross-race effect, where individuals are better at recognizing faces of their own race compared to faces of other races, likely due to more frequent exposure to same-race faces.
Each of these phenomena exemplifies the brain's specialization in processing frequently encountered stimuli, with proactive interference representing a contrasting process where prior learning hampers new memory formation.