icture the following scenario: a developmental psychologist is investigating a very young research participant’s perceptual capacities and ability to learn from experience. First, she plays a loud sound near the participant’s ear. She notes that the participant moves vigorously in response and concludes that the participant can hear the sound. Now she continues to play the same tone, over and over. As everyone else in the lab gets tired of repeatedly hearing the same sound, so, apparently, does the participant, who responds less and less to the repetitions of the sound and eventually does not react to it at all. Has the participant learned to recognize the sound, or just gone to sleep? To find out, the researcher next presents a different sound, to which the participant responds vigorously. The participant seems to have recognized a difference between the new sound and the old one, suggesting that the participant has experienced some simple learning. Wanting to see if the participant can learn something more complex, and in a natural setting, the researcher sends the participant home, asking the participant’s mother to read aloud from a Dr. Seuss book for several minutes each day for six weeks. The idea is to see whether the participant later shows any recognition of the passages that were read. But before the researcher can test the participant again, something quite important happens: the participant is born!

This scenario is not at all fanciful. Indeed, as you will discover later in this chapter, it is an accurate description of a fascinating and informative study that helped to revolutionize the scientific understanding of prenatal development (DeCasper & Spence, 1986). As you will also discover in this chapter, researchers have been asking many questions about the sensory and learning capabilities of fetuses. They have been finding that while in the womb, fetuses can detect a range of stimuli coming from the outside world, and that they can learn from these experiences and be affected by them after birth.

In this chapter, we will examine the extraordinary course of prenatal development—a time of astonishingly rapid and dramatic change. In addition to discussing the normal processes involved in prenatal development, including fetal learning, we will consider some of the ways in which these processes can be disrupted by environmental hazards. We will also examine the birth process and what the infant experiences during this dramatic turning point, as well as some of the most salient aspects of neonatal behavior. Finally, we will outline issues associated with premature birth.

In our discussion of the earliest periods of development, most of the themes we described in Chapter 1 will play prominent roles. The most notable will be nature and nurture, as we emphasize how every aspect of development before birth results from the continual interplay of biological and environmental factors. The active child theme will also be featured, because the activity of the fetus contributes in numerous vital ways to its development. In fact, as you will see, normal prenatal development depends on certain fetal behaviors. Another theme we will highlight is the sociocultural context of prenatal development and birth. There is substantial cultural variation in how people think about the beginning of life and how they handle the birth process. The theme of individual differences comes into play at many points, starting with sex differences in survival rates from conception on. The continuity/discontinuity theme is also prominent: despite the dramatic contrast between prenatal and postnatal life, the behavior of newborns shows clear connections to their behavior and experience inside the womb. Finally, the theme of research and children’s welfare is central to our discussion of how poverty can affect prenatal development and birth outcomes, as well as to our description of intervention programs designed to foster healthy development for preterm infants.