Editing Stimulus modality (section)

===Sound stimuli and human fetuses===
A number of studies have shown that a human fetus will respond to sound stimuli coming from the outside world.<ref name=Sontang>{{Cite journal | last1 = Sontag | first1 = L. W. | title = Changes in the Rate of the Human Fetal Heart in Response to Vibratory Stimuli | doi = 10.1001/archpedi.1936.01970150087006 | journal = Archives of Pediatrics & Adolescent Medicine | volume = 51 | issue = 3 | pages = 583–589 | year = 1936 }}</ref><ref name=Forbes>{{Cite journal | last1 = Forbes | first1 = H. S. | last2 = Forbes | first2 = H. B. | doi = 10.1037/h0071872 | title = Fetal sense reaction: Hearing | journal = Journal of Comparative Psychology | volume = 7 | issue = 5 | pages = 353–355 | year = 1927 }}</ref> In a series of 214 tests conducted on 7 pregnant women, a reliable increase in fetal movement was detected in the minute directly following the application of a sound stimulus to the abdomen of the mother with a frequency of 120 per second.<ref name=Sontang />