Definitive Study Guide on Memory Phenomena

The aim is to create a comprehensive theory of memory, not just offering explanations for specific phenomena.
In the late 19th century, the first theories of memory focused on describing memory phenomena rather than fully explaining them.
- Ebbinghaus was an early contributor who attempted some explanations.
- His student Mueller studied a notable memory phenomenon called the serial position effect.

Definition: The serial position effect describes how individuals remember the first and last items in a list better than those in the middle.
Application: Commonly observed in everyday situations such as trying to memorize names at a meeting.
Example: If one meets 25 people, they tend to remember the first few and the last few names, but struggle with names in the middle.

Methodology: An experiment can be designed to present a list of 25 words to subjects one at a time.
- Each word is displayed for 5 seconds with a half-second interstimulus interval between words.
- Total time for presentation: 100 seconds - calculation: 75 seconds for the words + 25 seconds for intervals.
Recall Task: After the presentation, subjects perform a free recall task.
- Distinction: Free recall (any order) vs. serial recall (specific order).

Results show a serial position curve when plotting recall probability against the position of words.
- People tend to remember the beginning (primacy effect) and end (recency effect) of lists better than the middle.
Terms defined:
- Recency Effect: The tendency to remember the most recently presented items.
- Primacy Effect: The tendency to remember the first items more effectively.

The concepts of recency and primacy do not provide explanations; they describe observations.
Two competing explanations during the behavioral period:
- Decay Theory: Memory traces fade over time.
- Interference Theory: Earlier and later information interferes with information in the middle of a list.

Proactive Interference: Earlier learned information interferes with later learned information.
- Example: Difficulty recalling list B when it follows list A.
Retroactive Interference: Later learned information interferes with recalling earlier learned information.
- Example: Difficulty recalling list A after learning list B.

An experiment with two groups learning the same list of items at different times to assess interference.
- Group 1 learned in the morning, tested at night; Group 2 learned at night, tested in the morning.
Hypothesis: More experiences between learning and recall increases interference.
Results supported the interference explanation more than decay, challenging the notion of decay as a viable explanation.

Atkinson & Shifrin (1968) introduced a multi-store model of memory that includes:
- Sensory Register: For initial input, modality-specific stores (iconic for visual, echoic for auditory).
- Short-Term Store: Limited capacity (7±2 items), items can be rehearsed.
- Long-Term Store: Enormous capacity, information not actively rehearsed may decay over time.

Sensory information is not interpreted; raw information is registered briefly.
- Iconic and echoic stores are critical and have time limitations (approx. 0.5 seconds & 2 seconds, respectively).
Attention focuses information from the sensory store into the short-term store.

Longer duration in short-term store correlates with the likelihood of entering long-term memory,
- The first items have more rehearsal opportunity and likelihood of long-term storage.
- The last items have recency advantages in short-term storage, influencing recall probabilities.
- Items in the middle are hindered by both proactive and retroactive interference.

Activation of long-term memories occurs through retrieval processes into short-term memory.
- The model illustrates how retrieval works between memory stores and the interplay of rehearsal and interference.
Importance of practice and rehearsal highlighted for better recall and memory consolidation.

Distinction between tasks when measuring recall can affect outcomes.
- Free recall may not show the same outcomes as serial recall due to interference factors during recall.
Murray Glanzer's pivotal experiments in 1967 solidified the understanding of memory through innovative testing against interference predictions.