Long-term representational costs of overloading working memory

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human Memory

Background:

• Emerging evidence suggests that working memory (WM) capacity limitations can impact long-term memory (LTM) encoding.
• Theories of memory often assume relatively automatic gist encoding, but this may have boundaries.

Purpose of the Study:

• To investigate whether overloading working memory (WM) during encoding impairs long-term memory (LTM) retrieval of gist and details.
• To determine if this effect extends to older adults and persists under intentional learning conditions.

Main Methods:

• Experiment 1: Tested LTM gist retrieval in two older adult samples (n=40 each) with varying WM load during encoding.
• Experiment 2: Assessed LTM gist retrieval in young (n=81) and older (n=40) adults under intentional learning with overloaded WM at encoding.

Main Results:

• LTM gist retrieval was reduced in older adults when objects were encoded in sets exceeding WM capacity.
• Both young and older adults showed impaired LTM gist retrieval when WM was overloaded during intentional long-term learning.

Conclusions:

• Overloading working memory (WM) at encoding significantly impairs long-term memory (LTM) gist retrieval, even for older adults and under intentional learning.
• These findings challenge the universality of automatic gist encoding and suggest a boundary condition for memory theories.