Final answer:
Short-term memory (STM) is a limited capacity storage system that holds information for a short duration before it is either consolidated into long-term memory or forgotten. The capacity of STM was previously thought to be 7±2 items but has been updated to 4±1 items according to more recent research. Factors like acoustic versus visual encoding and decay or interference can impact STM retention.
Step-by-step explanation:
Short-Term Memory (STM)
Short-term memory (STM) is part of the working memory system and is responsible for temporarily holding small amounts of information accessible for a short period of time. George Miller's seminal research from 1956 suggested that STM can retain on average 7 pieces of information, plus or minus 2, a concept often referred to as the 'magic number' 7±2. However, modern studies by Cowan in 2010 indicate that this capacity may actually be closer to 4±1 items.
STM engages in various types of encoding, with acoustic encoding (hearing) being slightly more effective than visual encoding (seeing). This is one reason why people may recall numbers better than letters; numbers are more frequently encoded acoustically. Furthermore, Baddeley and Hitch's model of working memory includes different components for handling specific types of information, which affects how information is processed and transferred to long-term memory.
The functional duration of STM is relatively short, lasting approximately 15 to 30 seconds before the information is either consolidated into long-term memory (LTM) or forgotten. LTM, unlike STM, is believed to have an unlimited capacity to store information indefinitely. The organization and retrieval of memories in LTM are complex processes influenced by factors like associativity and suggestibility.
Memory trace decay and interference (such as proactive interference) play crucial roles in STM retention. The classic study by Peterson and Peterson using trigrams demonstrated that memory trace decay occurs around 18 seconds if not rehearsed. This decay coupled with interference can affect the accuracy and duration of short-term memory retention.