- Semantic memory is a component of declarative (explicit) memory that stores general world knowledge, concepts, meanings, and facts that are not tied to personal experiences.
- It encompasses information such as vocabulary, mathematical rules, historical facts, scientific principles, and the meanings of words and symbols. For example, knowing that the Earth orbits the Sun, that a dog is a type of animal, or that “justice” is an abstract concept are all instances of semantic memory.
- Unlike episodic memory, which is autobiographical and contextual, semantic memory is context-free—it does not involve remembering when or where the information was acquired.
- Semantic memory relies on a distributed network of brain regions, particularly the lateral and anterior temporal lobes, which are involved in the storage and integration of conceptual knowledge. The inferior parietal cortex and prefrontal cortex also contribute to the organization and retrieval of semantic information. While the hippocampus plays a role in the initial learning and consolidation of semantic memory, especially early in life or when new knowledge is acquired, over time the reliance shifts more toward cortical storage, making established semantic memories relatively stable and resistant to damage.
- The acquisition of semantic memory begins early in childhood as individuals learn language, categorize objects, and build mental representations of the world. It grows continuously throughout life, expanding through education, reading, social interactions, and personal exploration. Unlike episodic memory, semantic memory is not usually affected by normal forgetting as rapidly, and tends to remain intact even in aging—although specific word-finding or retrieval issues may emerge in older adults.
- Semantic memory is critical for communication, reasoning, and decision-making. It enables us to understand and use language, apply rules and concepts to novel situations, and make inferences based on general knowledge. For example, recognizing that a zebra is a mammal, even if one has never seen one in person, relies on the abstraction and categorization inherent in semantic memory.
- Impairments in semantic memory can be seen in neurodegenerative conditions such as semantic dementia or Alzheimer’s disease, where individuals may lose knowledge about words, objects, or even the function of familiar tools. Studying semantic memory has broad implications not only for neuroscience and psychology but also for artificial intelligence and education, as it highlights how abstract knowledge is structured, accessed, and applied in complex tasks.
