Figure 5. Pulse and chirp response fields predicted by the best 4-feature, 3-feature and 2-feature model.

(A) The pulse response field of the best 4-feature model shows highest phonotactic scores for patterns that are accumulated in an oval bounded by pulse periods of 30 and 45 ms and pulse duty cycles of 0.4 and 0.7. The pulse response fields of the best 3-feature model (B) and the best 2-feature model (C) are clearly independent of the pulse duty cycle and show an extension on the diagonal defined by a pulse period of 40 ms. The chirp response field of the best 4-feature model (D) and the best 3-feature model (E) are qualitatively similar and reveal best scores for patterns with chirp durations and pauses between 200 and 300 ms. The best 2-feature model predicts highest scores for patterns with a chirp pause between 100 and 250 ms, irrespective of the chirp duration (F). Circles indicate experimentally measured phonotactic scores.