Contrast Dependent Knowledge Development in Contrast Supported Scientific Observation

Knowledge of contrasts between phenomena can influence how people think and reason about them, so learning contrasts is important in school science. Building knowledge through a process of construction is a common framework through which school science is taught. However, telling phenomena apart through differentiation also plays an important role in learning and may be underused as a teaching framework. An effective way to learn contrasts is to use them to perceptually differentiate similar-looking phenomena presented side-by-side. However, little is known about the persistence/usefulness of knowledge generated during perceptual differentiation over short periods of time and its usage in student reasoning within an argument. This study addresses this issue through the use of a sample “ID activity” in which participants are shown a side-by-side presentation of two species and asked to identify them using two sets of contrasts. Student thinking was monitored through the collection of 10 student think-alouds. Results show that once a contrast statement is made it is repeated. These initial observations and repeats coalesce to form the students contrast dependent knowledge of the species. This shows that not only is perceptual knowledge persistent over long periods time, as established in previous studies, but it persists within a short activity. Furthermore, in most instances the restatements are used as a part of rebuttal within an argument. Understanding the nature of knowledge gained from contrast-supported scientific observation has implications for the usage of contrast activities in school science