Faculty Bibliography

14-month-old toddlers vs. 8.5-month-old crawling infants were encouraged to ascend and descend a sloping walkway (10 degrees, 20 degrees, 30 degrees, and 40 degrees). Infants in both locomotor groups overestimated their ability to ascend slopes. However, on descending trials where falling was more aversive, most toddlers switched from walking to sliding positions for safe descent, but crawlers plunged down head first and many fell at each increment. Toddlers touched and hesitated most before descending 10 degrees and 20 degrees slopes, and they explored alternative means for descent by testing out different sliding positions before leaving the starting platform. In contrast, crawlers touched and hesitated most before descending 30 degrees and 40 degrees slopes, and they never explored alternative sliding positions. In addition, we analyzed measures of locomotor skill and experience in relation to children's ability to perceive affordances. Findings indicate that children must learn to perceive affordances for locomotion over slopes and that learning may begin by fine-tuning of exploratory activity.

Arnold Gesell (1880-1961) has had an important and lasting impact on the field of developmental psychology. He is best remembered for his developmental norms, which were acquired from decades of detailed observations of infants and children and are still the basis of most early assessments of behavioral functioning. Gesell's influence as a theorist is less direct. His maturationism quickly lost favor in the intellectual climate of Piaget, behaviorism, and information-processing approaches. Nonetheless, nativism is still a dominant theme in contemporary developmental studies in the guise of neural determinism, innate knowledge, and genetic studies. Gesell is characterized as a man of paradoxes and contrasts. Although he acknowledged the contributions of the environment, he denied its agency. Although he was devoted to children and their welfare, he assigned their individuality to biological destiny. And although he remained a steadfast maturationist, he prefigured other more dynamic views of development.