Chronometric Evidence for Central Postponement in Temporally Overlapping Tasks
DOI: 10.1080/14640748908402351
archive: archived pipeline: cataloged verified
Get this paper ↗ (DOI — opens at the source; we link to it, we don't host it)
Summary
This study investigates the mechanisms underlying dual-task interference when two tasks are performed in rapid succession, specifically testing whether a central processing bottleneck or capacity-sharing better explains response delays. The authors address the theoretical debate between postponement models, which posit that certain cognitive stages require exclusive access to a single mechanism, and capacity-sharing models, which suggest that limited resources are divided between tasks, slowing both. The research aims to provide decisive chronometric evidence for a central bottleneck located at the decision or response-selection stage. The experimental design employed an overlapping tasks paradigm where participants performed two classification tasks: identifying the pitch of an auditory tone (Task 1) and classifying a visual letter (Task 2). Stimulus onset asynchronies (SOAs) of 50, 100, and 400 milliseconds were used. Two variables affecting Task 2 were manipulated: stimulus intensity (expected to affect early perceptual processing) and stimulus repetition (expected to affect central response selection). Experiment 1 instructed subjects to respond to the first stimulus as quickly as possible. Experiment 2 introduced a "grouping" instruction, encouraging subjects to emit both responses in close temporal proximity to test if strategic response coupling altered the underlying interference patterns. The results strongly supported the postponement model with a bottleneck at the decision/response-selection stage. In Experiment 1, the effect of stimulus intensity on the second response time (RT2) was significantly reduced in the dual-task condition compared to the single-task condition, demonstrating underadditivity. This indicates that delays in early perceptual processing were masked by the wait for the central bottleneck. Conversely, the effect of stimulus repetition on RT2 was additive across single- and dual-task conditions, indicating that response-selection processes could not overlap with Task 1. The RT2-SOA function exhibited a slope near -1, consistent with the bottleneck waiting for Task 1 completion. In Experiment 2, encouraging response grouping dramatically slowed the first response (RT1) and made it sensitive to Task 2 difficulty variables, but it did not alter the pattern of factor effects on RT2. This confirmed that the central postponement process remained the primary source of interference regardless of response strategy. These findings provide robust evidence against capacity-sharing models and support the existence of a central processing bottleneck in human cognition. The study demonstrates that while early perceptual stages and late motor execution can proceed in parallel, the central stage of decision and response selection is serial. This has significant implications for understanding the architecture of human attention and for designing systems requiring rapid human-machine interaction, as it clarifies that dual-task costs arise from specific sequential constraints rather than general resource depletion.
Key finding
Dual-task interference is best explained by a central postponement model with a bottleneck at the decision/response-selection stage, as evidenced by underadditive effects of perceptual variables and additive effects of response-selection variables on second-task response times.
Methodology
lab_experiment
Sample size: 36
Provenance
The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via openalex_abstract on 2026-05-08.
| Stage | Outcome | Tool | Model | Prompt | Attempts | Completed |
|---|---|---|---|---|---|---|
| discover | success | — | — | — | 1 | 2026-05-07 |
| archive | success | canonical_url | — | — | 7 | 2026-06-06 |
| extract | success | cached | — | — | 3 | 2026-06-10 |
| clean | success | clean | — | — | 1 | 2026-06-04 |
| chunk | success | chunk | — | — | 1 | 2026-06-04 |
| embed | success | embed | Qwen/Qwen3-Embedding-8B | — | 1 | 2026-06-04 |
| enrich | success | openalex | — | — | 2 | 2026-05-08 |
| promote | success | — | — | — | 1 | 2026-05-07 |
| summarize | success | llm | qwen3.6-27b-prismaquant | summ-v5 | 2 | 2026-06-10 |
| tag | success | vector_similarity | — | — | 15 | 2026-06-11 |
| verify | success | — | — | — | 2 | 2026-06-10 |
Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.
Topics
Ranked by relevance to this paper. Hover a topic for its definition.
Information type
What kind of knowledge this paper contributes, grouped by family — independent of topic (what it is about) and method (how it was studied).
- Empirical Findings: behavioral performance data