The experiments reported in this thesis attempted to directly study the process of look-ahead during problem solving. Recent work has suggested that interface manipulations that increase look-ahead during problem solving lead to improvements in performance. However, evidence has been indirect, and there have been few attempts specifically made to quantify look-ahead span, changes that may occur over time and possible interactions with the task environment. An initial experiment required users to specify 3 moves in advance while solving the 8-puzzle. The strict enforcing of look-ahead by even a small number of moves was unsuccessful in terms of improving problem performance. In fact, results indicated that such move enforcement may negatively affect performance. Subsequent experiments, using both the 8-puzzle and Water Jars problems, provided participants with a motivation to plan using a Scoreboard system that rewarded greater planning and look-ahead. Results found this approach to be more viable, as the interface appeared to support the opportunistic planning behaviour frequently undertaken by participants. Across a series of experiments, increased look-ahead led to more efficient problem solving performance compared to controls, while leaving total time to solution unaffected. Look-ahead span increased to approximately 11 steps when transforming the same start-state to a goal-state over trials on the 8-puzzle. When a new solution path had to be generated for each new problem start-state, look-ahead still increased over trials, but only to a span of approximately 4 steps. This look-ahead span was also observed during Water Jars performance when the Scoreboard manipulation was present. A manipulation of 'system response time' (SRT) on Water Jars problems also led to improved performance but indicated an adaptation to the manipulation, leading to a lesser impact of SRT than previous manipulations. The results are discussed in relation to existing studies of planning, performance and the role that look-ahead may have in future studies of problem solving.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:583742 |
| Date | January 2006 |
| Creators | Chambers, Stephen R. |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/54259/ |
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