Short-term memory (STM), often associated with working memory, has several key limitations:
-
Capacity: Short-term memory typically has a limited capacity. According to George A. Miller's classic research, the average number of items that can be held in STM is about 7±2 (Miller's Law). However, the exact number can vary among individuals and can be influenced by factors such as chunking, where information is grouped into larger units.
-
Duration: Information in short-term memory is fleeting and tends to last from about 15 to 30 seconds without rehearsal. This means that if the information is not actively maintained (for example, through repetition), it can quickly be lost.
-
Interference: Short-term memory is susceptible to interference, which means that new information can displace or disrupt the retention of existing information. This can happen due to the introduction of similar or distracting stimuli.
-
Encoding Limitations: Short-term memory primarily encodes information acoustically (by sound) rather than semantically (by meaning), which can lead to difficulties when similar-sounding items are presented or when trying to remember abstract concepts.
-
Attention: The effectiveness of short-term memory is highly dependent on attention. If a person's attention is divided, the ability to encode new information into STM can be severely impaired.
-
Contextual Dependency: Short-term memory can also be affected by contextual factors. Information encoded in a particular context might be harder to retrieve if that context is altered.
These limitations highlight the fragility of short-term memory and its dependence on various cognitive processes for maintaining and manipulating information.