Katherine Turner on Learning Through Experience
By Adrienne Gelpi Lomangino, Head Teacher and Research Coordinator
hate to admit it, but I love children most for what they give me. Mark Twain said that a person could live two weeks on one compliment. A child who says that they like you, the child who puts his or her hand in yours or wants to play, gives you a big compliment. If working at Bing is any indication, I’m going to live a long time.”
One of the familiar faces at Bing during her pregnancy and then with a baby strapped to her front, Katherine Turner does not have a child enrolled here, but has grown acquainted with many children as a researcher in all of the classrooms. Whether following beckoning children over the hill to see what they find so exciting or asking questions about a spaceship made of wood scraps, Katherine demonstrates her keen interest in children’s thinking.
Katherine came to the Bay Area from Montreal, where she grew up, and obtained a bachelor’s degree in developmental psychology from San Francisco State University. Her research there, under the direction of David Matsumoto, focused on how personality influences the recognition of emotions among Japanese and American college students. Now at Stanford, with John Gabrieli as her adviser, Katherine is pursuing a doctorate in developmental psychology, studying memory. She has been married for ten years and expanded her family last summer with the arrival of Indira Rose Mercedes Turner. Thus this year Katherine has grappled with the simultaneous demands of finishing her degree and being a new mother.
Katherine has collected much of her dissertation data at Bing, working with John Gabrieli on the cognitive neuroscience of implicit memory. In contrast to explicit memory, implicit memory does not require conscious remembrance of a past experience but instead uses past experience to facilitate memory, even without our awareness. To measure such facilitation, researchers examine whether participants respond faster, find tasks easier, or reach solutions with greater accuracy when they have had prior experience related to the task. The positive effect of prior experience on subsequent performance is referred to as priming.
Katherine’s studies examine the developmental course of two forms of implicit memory, perceptual priming and sensorimotor skill learning, among four-year-olds, six-year-olds, and adults. For instance, in one study, conducted with sixteen preschool children and sixteen adults, she asked participants to name line drawings of common objects and animals (e.g., lamp, ship, rabbit). Then forty-eight hours later, the participants viewed incomplete versions of the previously viewed pictures and new images. Across a series of eight partial pictures each image became increasingly complete, and Katherine examined the point at which participants could identify the picture in the series. Looking for priming, she noted the difference in how complete the picture needed to be in order for participants to identify previously viewed versus new pictures—in other words, how much having seen a picture helped participants to identify an incomplete version of it.
Adults correctly identified both previously viewed and new pictures at a less complete level than preschool children did, but Katherine found no significant difference in the magnitude of priming for the two age groups. That is, participants of both ages identified previously viewed pictures sooner than new pictures. Thus, the degree to which previous viewing of pictures facilitates memory is stable by age four.
Katherine’s second study focused on motor skills, taking the research on implicit memory in a new direction. The brain structures supporting sensorimotor learning are thought to mature later than those that support perceptual priming, reaching maturity after children enter elementary school as compared to age two. Would sensorimotor learning follow the same developmental course observed for perceptual priming?
To explore this question, Katherine used a task that required participants to touch objects on a screen. Seventeen four-year-olds, fifteen six-year-olds, and twenty-six adults observed faces as they appeared in one of four locations across the middle of a touch-sensitive computer screen. The sequence of locations in which the faces appeared involved either first-order or second-order transitions. In a first-order transition, events frequently occur in pairs, such that a face appearing in, say, the second site is typically followed by one appearing in, say, the fourth site. A second-order transition is more complex, involving triplets of events in which the first two previous locations predict the third location. Katherine examined whether participants learned these sequences as they pressed the appearing faces. She encouraged children to tickle the faces and make them laugh (touching the faces on the screen produced a laughing noise).
On the sensorimotor task, in contrast to the priming task, four-year-olds’ performances did not correspond to those of the older groups. The four-year-olds learned the first-order transitions but not the second-order transitions. In contrast, six-year-olds and adults learned both types of sequences. Katherine’s results suggest that while visual priming matures by age four, the learning of sensorimotor sequences matures later. These two types of learning rely upon different areas of the brain: the occipital neo-cortex and the fronto-striatal system, respectively. Thus, these findings provide evidence of how variations in the maturation of brain functioning influences the development of learning.
The connection between brain development and behavior deeply interests Katherine Turner. “One of the most exciting things about doing developmental research,” she says, “is that I have the opportunity to watch children’s cognitions change. This is especially true since I look at cognition from both a brain-based and a behavioral perspective. My daughter gives me new insights every day, so my cup of inspiration is overflowing.”