REASONING ABOUT SEQUENCES OF SPATIAL EVENTS: HOW DO GEOLOGISTS KNOW WHAT HAPPENED FIRST?

A skill that most geologists possess is the ability to assess the temporal sequence of events that produced the present state from the spatial arrangement of outcrops, map patterns, or cross-sections. Geologists report combining multiple field observations with prior knowledge to mentally animate a sequence of transformations that correspond to geological events (sedimentation, folding, etc.). The skills used to interpret geological structures (e.g., unconformities) as temporal sequence may be generally applicable. We designed a working memory task to further investigate this skill. Participants (N=21) were presented with pairs of color splotches in a “Pollock-style” painting, in which one splotch of paint may overlap another. Using the spatial and visual information provided by the pairs, participants were asked to recall the order the different colors were painted on a blank canvas. In half of the sequences, two of the colors had an ambiguous order (e.g., one cannot determine which of the two colors was painted first). Along with completing the visual sequencing task, participants also completed two working memory tasks, Automated Reading Span, which assesses verbal working memory capacity, and Automated Symmetry Span, which assesses spatial working memory capacity. One objective was to see if visual sequencing ability is related to verbal or spatial working memory capacity. Not surprisingly, results indicated that as more colors were added to the paintings, the participants’ accuracy decreased. There were two unexpected results. First, 51 % of students had difficulty completing the task when three colors were used. Second, investigation of the errors revealed that many had trouble detecting ambiguity in the ambiguous trials. Performance on the visual sequencing task significantly correlated to performance on the Automated Reading Span (r=.58) and on the Automated Symmetry Span (r=.64). Potential implications are: 1) That educators may be able to use students’ performance on established working memory tasks to determine who will have difficulty with the visual sequencing skill out in the field; 2) The effects of training spatial working memory may transfer to visual sequencing ability; and 3) Understanding ambiguity is difficult for students, and potentially merits being addressed pedagogically.