Final answer:
Ian uses 'chunking' by breaking his social security number into segments to make it easier to remember. This memory strategy leverages the limited capacity of working memory by organizing information into more manageable units for recall.
Step-by-step explanation:
When Ian reports his social security number as "999-99-1111", he is using a memory strategy known as chunking. This strategy involves organizing information into manageable bits or groups, making it easier to remember. Rather than recalling a continuous string of numbers, breaking them down into smaller groups allows for easier retention and recall.
Chunking is especially useful in remembering sequences of numbers, such as phone numbers or social security numbers, as it caters to the limited capacity of our short-term memory, usually referenced to as the "magic number" 7 plus or minus 2. However, more recent research suggests that working memory capacity may be closer to 4 plus or minus 1, reinforcing the usefulness of chunking for effective recall.
In this context, chunking is the correct answer, as Ian is breaking the larger 9-digit number into smaller pieces to enhance memory recall by fitting within the working memory's limited capacity.