1. Semantic Overlap in Dual-Task Performance: Evidence for a Specific Deficit in Old Age
Aging Effects in Dual-Task Performance Are Insulated Against Semantic Deficits
François Maquestiaux(1) Elise Gémonet(1) Morgan Laboureau(1) & Eliot Hazeltine(2)
(1) Université Bourgogne Franche-Comté - (2) University of Iowa
Background
Learning to perform two tasks at once without interference is very difficult, due to the presence of a stubborn central attentional limitation (e.g., Tombu & Jolicoeur, 2004). Learning a dual-task skill becomes even more difficult as people age (e.g., Strobach et al., 2012).
Main Questions
Does semantic overlap between two tasks influence the difficulties encountered when learning to perform two tasks at the same?
Are older adults more affected when there is a more and more semantic overlap between the tasks, that is when the central representations are more semantically related?
Method
Semantic
Overlap
Participants
12 younger adults (M = 22.3 yo) / 15 older adults (M = 67.6 yo) No
Procedure
3 types of blocks
Single-task blocks: VM task only, AV task only
Mixed single-task blocks: VM task OR AV task
Dual-task blocks: VM task AND AV task
10 blocks per session
4 single-task blocks
3 mixed single-task blocks
3 dual-task blocks
8 training sessions
Weak
Strong
Results
Visual-Manual Task
Younger Adults Older Adults
Auditory-Vocal Task
Younger Adults Older Adults
Age x Semantic Overlap, F < 1
Age x Semantic Overlap x Training session, F < 1
Age x Semantic Overlap, F(2, 21) = 8.20, p < .01
Specific age deficit in the strong overlap condition
Age x Semantic Overlap x Training session, F(14,147) = 2.53, p < .01
 Practice attenuates but not eliminates the specific age deficit
None of the reported interactions was qualified by type of blocks
(single vs. dual)
Visual-Manual Task
Dual-Task Costs (Dual – Single)
Auditory-Vocal Task
Dual-Task Costs (Dual – Single)
Much larger DT costs with age (167 vs. 83 ms), F(1, 21) = 4.25, p = .052
Reduction of DT costs with training, F(7, 147) = 8.58, p < .001
No other effect was significant
Much larger DT costs with age (286 vs. 137 ms) , F(1, 21) = 7.78, p < .05
Reduction of DT costs with training, F(7, 147) = 11.49, p < .001
No other effect was significant
Discussion
Clearly, older adults experienced a specific deficit on one task in the strong semantic overlap condition. However, this semantic deficit did not aggravate dual-task performance. However, the difficulty associated with semantically-related tasks did not lead to increased dual-task costs. The absence of semantic central interference suggests that the central limitation responsible for dual-task interference functions independently of the content of what is centrally processed.