Why does interleaving improve math learning? The contributions of discriminative contrast and distributed practice

Area of Science:

• Cognitive Psychology
• Educational Psychology
• Learning Sciences

Background:

• Interleaved practice, where study items from different categories are mixed, improves test performance over blocked practice (studying items category by category).
• The underlying mechanisms for this benefit are debated, with two prominent hypotheses: discriminative-contrast and distributed-practice.

Purpose of the Study:

• To investigate why interleaved practice enhances learning.
• To test the discriminative-contrast hypothesis versus the distributed-practice hypothesis.

Main Methods:

• Participants practiced calculating the volume of geometric shapes under different conditions: blocked practice, interleaved practice, and remote-interleaved practice (mixing with unrelated problems).
• Experiment 2 introduced a remote-blocked condition to further isolate the effects of interleaving versus blocking.

Main Results:

• Interleaved practice outperformed blocked practice, but remote-interleaved practice showed no advantage over standard interleaved practice in Experiment 1.
• Experiment 2 confirmed that remote-interleaved practice was superior to remote-blocked practice, supporting the distributed-practice hypothesis.

Conclusions:

• The findings suggest that the benefits of interleaved practice are primarily due to the spaced or distributed nature of learning, rather than solely due to enhanced discrimination between categories.
• Distributed practice, where learning is spread out over time, appears to be the key factor driving performance improvements observed with interleaved study schedules.