Fig 4. For the 2 subjects, GC and LI, number of correct vocal tact responses in the 8-trial transfer of function test conducted with Pair 2 and Pair 3 (Set 1), Pair 4, Pair 5, and Pair 6 (Set 2), and on the 36-trial vocal behavior transfer test with all 12 arbitrary stimuli from Set 1 and Set 2.