Distinct contributions of explicit and implicit memory processes to weight prediction when lifting objects and...

Area of Science:

• Cognitive Neuroscience
• Human Motor Control
• Memory Systems

Background:

• Weight predictions are crucial for both motor actions (lifting) and perceptual judgments.
• Previous research suggests distinct mechanisms underlie these two types of weight predictions.
• Declarative memory (explicit recall) and nondeclarative memory (implicit learning) are proposed to play differential roles.

Purpose of the Study:

• To investigate the differential reliance on declarative and nondeclarative memory in weight predictions for lifting versus perceptual judgment.
• To compare the adaptability of these weight predictions in younger adults and older adults, who have age-related differences in declarative memory.

Main Methods:

• Participants repeatedly lifted size-weight or material-weight inverted objects.
• Lift forces and perceptual weight judgments (size-weight/material-weight illusion) were measured.
• The adaptability of lifting forces and the attenuation of illusions were assessed in younger and older adults.

Main Results:

• Weight judgments, reflected by illusion magnitude changes, correlated positively with implicit memory, suggesting nondeclarative memory reliance.
• Updating of lifting forces did not differ between age groups.
• Within older adults, successful updating of lifting forces correlated with working memory performance, indicating declarative memory involvement.

Conclusions:

• Weight predictions for perceptual judgments are primarily supported by nondeclarative memory resources.
• Weight predictions for lifting actions appear to rely on declarative memory resources, particularly working memory.
• These findings provide evidence for distinct memory system involvement in motor and perceptual weight processing.