The new study tested how fetuses in nearly 100 pregnant women responded to a specific stimulus, in this case, a “vibroacoustic stimulation,” which is a very low sound that makes a vibration. The researchers observed the reaction using an ultrasound. When the fetus first receives the stimulation, it is startled. But after repeated trials of the same stimulation, 30 seconds apart, the fetus gets used to the sound and doesn’t react.
Called habituation (the same process found in adults by which we grow accustomed to sensory stimuli – odors, sounds, etc), this learned response was noted to last up to four weeks in the babies at 34 weeks development. The researchers believe the babies can habituate earlier than 30 weeks if the correct stimuli is used.
Even a more liberal definition of personhood views consciousness of things external to oneself (such as the ability to feel pleasure or pain) as an indicator. Not only did the babies tested feel the vibration, they were able to respond in an increasingly intelligent manner through the use of memory. These findings further demonstrate that this pre-natal human development is earlier than previously thought.
Those who hold a developmental view of personhood will have two options: deny the results or merely admit that the process advances more rapidly than supposed. In actuality, it highlights one of the weaknesses of the developmental view: Subjective criteria making the final determination of personhood.
By establishing subjective criteria for personhood, the door is opened for further steps such as euthanasia, infanticide, and elimination of the physically and mentally impaired. (In fact, some have gone so far as to propose such measures.)
The value of an individual should not be based upon such ambiguous determinants, but upon the value of life found in the unique cell formed at conception. This human dignity that should be afforded to all people, both born and unborn.