HOW DO WE REMEMBER? IMPLICATIONS FOR LEARNING DEEP TIME

Deep time is a critical component to comprehension of geology, but there is repeated evidence that introductory geology students lack an understanding of this concept (e.g., Trend, 2001). In an effort to better address this problem, it may be help to bridge research on memory and geology education. Psychologically, different memory systems exist that support learning. Learners access different memory systems depending on both the content covered and their prior experiences.

The declarative memory system (e.g., what humans use to remember their house number) has two subsets: episodic and semantic. Episodic memory is primarily based on experiences from the past to inform the future. Semantic memory is based on remembering content that is decontextualized. For example, adding 2+2 (semantic) does not require context for how, why, or where you learned it (episodic). Much of what we want students to remember falls in the semantic memory category (e.g., different time eras). But to assist our students with learning, it can be helpful to provide some of the context to help students situate their understanding of the content. Previous work on understanding students’ conceptions of deep time used the episodic memory as a foundation for the theoretical framework (e.g., Montagnero, 1996). From this work, there is evidence that time comprehension is somewhat a function of age, as students get older their ability to represent longer and longer time periods increases (Dodick & Orion, 2003).

We argue that to understand deep time, our students need for their semantic and episodic memory systems to work together. Students need assistance with the experience of deep time (episodic) through ‘trail of time’ activities (Semken et al., 2009); but they also need a rich foundation of interconnected facts and details (semantic), which they can use to support their lack of real experience of deep time. We propose that helping our students examine time by tapping the semantic and episodic memory systems, we may be able to help student comprehension of deep time. By helping students to become experts in one aspect of time (e.g., examining how sediments move in a stream in order to extrapolate to larger time frames using direct experience and deliberate connections to the content), we can take a more holistic approach toward supporting student comprehension.