@article {18925, title = {When is it better not to look ahead?}, journal = {Artificial Intelligence}, volume = {174}, year = {2010}, month = {2010/11//}, pages = {1323 - 1338}, abstract = {In situations where one needs to make a sequence of decisions, it is often believed that looking ahead will help produce better decisions. However, it was shown 30 years ago that there are {\textquotedblleft}pathological{\textquotedblright} situations in which looking ahead is counterproductive. Two long-standing open questions are (a) what combinations of factors have the biggest influence on whether lookahead pathology occurs, and (b) whether it occurs in real-world decision-making.This paper includes simulation results for several synthetic game-tree models, and experimental results for three well-known board games: two chess endgames, kalah (with some modifications to facilitate experimentation), and the 8-puzzle. The simulations show the interplay between lookahead pathology and several factors that affect it; and the experiments confirm the trends predicted by the simulation models. The experiments also show that lookahead pathology is more common than has been thought: all three games contain situations where it occurs. }, keywords = {Game-tree search, Lookahead pathology, minimax}, isbn = {0004-3702}, doi = {10.1016/j.artint.2010.08.002}, url = {http://www.sciencedirect.com/science/article/pii/S0004370210001402}, author = {Nau, Dana S. and Lu{\v s}trek,Mitja and Parker,Austin and Bratko,Ivan and Gams,Matja{\v z}} }