We conducted two experiments designed to examine whether animations of algo
rithms would help students learn the algorithms more effectively. Across th
e two studies we used two different algorithms - depth-first search and bin
omial heaps - and used two different subject populations - students with li
ttle or no computer science background and students who were computer scien
ce majors - and examined whether animations helped students acquire procedu
ral and conceptual knowledge about the algorithms. The results suggest that
one way animations may aid learning of procedural knowledge is by encourag
ing learners to predict the algorithm's behavior. However, such a learning
improvement was also found when learners made predictions of an algorithm's
behavior from static diagrams. This suggests that prediction, rather than
animation per se, may have been the key factor in aiding learning in the pr
esent studies. These initial experiments served to highlight a number of me
thodological issues that need to be systematically addressed in future expe
riments in order to fully test the relationship between animation and predi
ction as well as to examine other :possible benefits of animations on learn
ing. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.