Magic number 7+-2

The Magic Number 7±2 cognitive bias refers to the idea that the average human's working memory can hold around seven items (plus or minus two). This concept originates from a famous paper by psychologist George A. Miller in 1956, suggesting the limitations of human cognitive capacity, particularly regarding processing and remembering information.

How it works

Working memory is the part of short-term memory responsible for temporarily holding and manipulating information. The Magic Number 7±2 implies that when people attempt to retain information beyond this range, they start losing parts of it. The theory posits that our cognitive processing capabilities facilitate the grouping, or 'chunking,' of information into smaller, more memorable sets.

Examples

For instance, when trying to remember a phone number, individuals often divide the sequence into smaller groups (e.g., '123-456-7890' rather than a continuous string). Similarly, in grocery shopping, instead of recalling each item individually, people might categorize them into sections like 'fruits' or 'dairy products'.

Consequences

This cognitive limitation affects various areas where individuals need to recall complex information, such as multitasking or learning. It impacts decision-making processes, where people might oversimplify their choices due to memory constraints, leading to biases in judgments and inefficiencies in information processing.

Counteracting

To mitigate this bias, techniques such as chunking information and utilizing mnemonic devices can help increase memory retention. Also, using external aids like notes, lists, or digital tools to offload the cognitive load improves accurate information handling. Training and cognitive exercises can also expand working memory capacity.

Critiques

Some critics argue that Miller's original paper overstates the universality of this cognitive limit, noting exceptions and varying results across different population groups and settings. Furthermore, individual differences, such as expertise or familiarity with the information, can alter one's memory capacity.

Fields of Impact

Also known as

Relevant Research

• The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information

  Miller, G. A. (1956)

  Psychological Review, 63, 81-97

• 51-57

  Cowan, N. (2010). The magical mystery four: How is working memory capacity limited, and why? Current Directions in Psychological Science, 19 (1)

• 829-839

  Baddeley, A. (2003). Working memory: looking back and looking forward. Nature Reviews Neuroscience, 4 (10)