Look-ahead fixations during visuomotor behavior: Evidence from assembling a camping tent.

Eye movements can support ongoing manipulative actions, but a class of so-called look ahead fixations (LAFs) are related to future tasks. We examined LAFs in a complex natural task-assembling a camping tent. Tent assembly is a relatively uncommon task and requires the completion of multiple subtasks in sequence over a 5- to 20-minute duration. Participants wore a head-mounted camera and eye tracker. Subtasks and LAFs were annotated. We document four novel aspects of LAFs. First, LAFs were not random and their frequency was biased to certain objects and subtasks. Second, latencies are larger than previously noted, with 35% of LAFs occurring within 10 seconds before motor manipulation and 75% within 100 seconds. Third, LAF behavior extends far into future subtasks, because only 47% of LAFs are made to objects relevant to the current subtask. Seventy-five percent of LAFs are to objects used within five upcoming steps. Last, LAFs are often directed repeatedly to the target before manipulation, suggesting memory volatility. LAFs with short fixation-action latencies have been hypothesized to benefit future visual search and/or motor manipulation. However, the diversity of LAFs suggest they may also reflect scene exploration and task relevance, as well as longer term problem solving and task planning.