שאלה | Which of the following is false for signature whistle development?

Which of the following is false for signature whistle development?

		During the Smolker&Pepper study, the three males continued to use their signature whistle from infancy
		An infant appears to copy a whistle that it only heard rarely and then uses a slightly modified version as its own signature whistle.
		Captive dolphins develop signature whistles that match acoustic features of the trainers’ whistles
		During the Smolker&Pepper study, the three males steadily converged towards a common whistle contour