Читать книгу Infants and Children in Context - Tara L. Kuther - Страница 222

In addition to their capacity to learn by habituation, infants are born with a second powerful tool for learning. They can learn through association. Classical conditioning entails making an association between a neutral stimulus and an unconditioned stimulus that triggers an innate reaction. Eventually, the neutral stimulus (now conditioned stimulus) produces the same response as the unconditioned stimulus.

Newborns demonstrate classical conditioning. For example, when stroking the forehead was paired with tasting sugar water, 2-hour-old infants were conditioned to suck in response to having their heads stroked (Blass, Ganchrow, & Steiner, 1984). Let’s look at this example more closely. Sugar water is an unconditioned stimulus, as it naturally evokes the unconditioned response of sucking in infants. Touching or stroking the forehead yielded no response from the 2-hour-old infants; it was a neutral stimulus. When the researcher paired the neutral stimulus (stroke) with the unconditioned stimulus (sugar water), infants soon showed the conditioned response. That is, they associated the stroking with sugar water and thereby responded to the stroke with sucking movements.

Similarly, Lipsitt and Kaye (1964) paired a tone with the presentation of a nipple to 2- and 3-day-old infants. Soon, the infants began to make sucking movements at the sound of the tone. Sleeping neonates can be conditioned to respond to a puff of air to the eye (Tarullo et al., 2016). Even premature infants can demonstrate associative learning, although at slower rates than full-term infants (Herbert, Eckerman, Goldstein, & Stanton, 2004). Research with chimpanzee fetuses has shown that they display classical conditioning before birth (Kawai, 2010). It is likely that the human fetus can as well. Although classical conditioning is innate, neurological damage can hinder infants’ abilities to learn by association. Infants with fetal alcohol syndrome (FAS) require much more time than other infants to associate eye blinking with external stimuli, such as sounds (Cheng et al., 2016).

Newborns tend to require repeated exposures to conditioning stimuli because they process information slowly (Little, Lipsitt, & Rovee-Collier, 1984). As infants grow older, classical conditioning occurs more quickly and to a broader range of stimuli. For example, in a classic study, Watson and Raynor (1920) paired a white rat with a loud banging noise to evoke fear in an 11-month-old boy known as Little Albert. Repeated pairings of the white rat with the loud noise made Albert cry even when the rat was presented without the noise. In other words, Little Albert was conditioned to associate the neutral stimulus with the conditioned stimulus. Albert demonstrated fear in response to seeing the rat, indicating that emotional responses can be classically conditioned. Our capacities to learn through classical conditioning are evident at birth—and persist throughout life.