Lecture on Short-term Memory

Introduction

• Focus on short-term memory (STM) today.
• Future discussion on working memory as a continuation of STM.
• Short-term memory questions what people remember, differentiating between STM and long-term memory (LTM).
• Memory involves retaining, retrieving, and using information when original info is absent.

Importance of Memory

• Memory is like a time machine, allowing for information retrieval and use.
• Recommended to watch video on Clive Wearing for understanding memory importance.

Models of Memory

• Atkinson and Shiffrin Model (1968):
  • Three memory storages: Sensory memory, short-term memory, and long-term memory.
  • Information flows from sensory to STM and then to LTM through processes like rehearsal.
• Sensory Memory:
  • Holds all incoming info for seconds or fractions.
  • Includes iconic (visual), echoic (auditory), haptic (touch), gustatory (taste), and olfactory (smell) memories.
  • Can create visual illusions like persistence of vision.

Rehearsal and Control Processes

• Rehearsal:
  • A dynamic control process to transfer info from STM to LTM.
  • Involves repeating info to maintain it in STM and transfer it to LTM.
• Strategies:
  • Various strategies enhance memory by focusing attention on important info.
• Retrieval:
  • Retrieving info from LTM back to STM for use.

Experiments on Memory

• Sperling's Experiments on Sensory Memory:
  • Examined capacity of sensory memory using whole and partial report methods.
  • Found sensory memory captures more info than initially reported when cues (tones) are used.
• Peterson & Peterson on Duration of STM:
  • Used recall method to study duration of STM.
  • STM info decays over time if not rehearsed.

Capacity of Short-term Memory

• Digit Span and Change Detection Tasks:
  • Assess STM capacity, usually 5-9 items.
  • Change detection tasks involve identifying changes in visual stimuli.
• Chunking:
  • Grouping small units (letters, digits) into larger meaningful units to enhance STM capacity.
  • Relies on LTM for meaningful associations.

Short-term Memory Phenomena

• Chunking in Practice:
  • Helps recall in chess by remembering based on familiar game positions.
• Complexity Influences Capacity:
  • More complex stimuli reduce STM capacity.
  • Experiments by Alvarez and Cavanagh show less capacity for complex images.

Conclusion

• STM is limited in capacity and duration.
• Control processes like rehearsal and chunking help extend STM's effectiveness.
• Understanding STM and its processes critical for applications in learning and memory enhancement.

Quiz Questions Highlight

• Rehearsal occurs in STM: True
• Information stored in STM for 25 seconds: False
• Control processes involve attentional strategies: True
• Persistence of vision explained with fireworks example: True
• Greater info in image, fewer items in STM: False