Eye movements as indicator of solution knowledge in anagram solving

The current study attempted to replicate the results of Ellis et al. (2011) in an extended way. In the original study Ellis et al. demonstrated that eye movements may indicate the solution knowledge prior to response. They compared viewing times on the distractor letter vs. solution letters. Viewing time on distractor letter started decreasing since several seconds prior to response both in insight and non-insight trials. We added two additional parameters of anagrams: solution-word frequency and frequency of cooccurrence (“agglutination”) of the distractor letter with the solution letters. Low-frequency words and/or stimuli with high agglutinating distractor were solved less often and longer than others, with the effect of distractor type only for the low-frequency words. Eye-tracking data analysis revealed that either in insight and non-insight trials distractor did not differ from solution letters in the first half of the solving process, but had fewer viewing time in the second half of the solving process. In the more difficult stimuli (by solution- word frequency and distractor type) distractor was revealed later than in easier ones or did not differ at all. Eye-tracking data on viewing time on distractor vs. solution letters were in accordance with the Ellis et al.’s results and the anagram difficulty factors.

Visuospatial Perceptual Sequence Learning and Eye Movements

We examined perceptual sequence learning by means of an adapted serial reaction time task in which eye movements were unnecessary for performing the sequence learning task. Participants had to respond to the identity of a target letter pair (“OX” or “XO”) appearing in one of four locations. On the other locations, similar distractor letter pairs (“QY” or “YQ”) were shown. While target identity changed randomly, target location was structured according to a deterministic sequence. To render eye movements superfluous, (1) stimulus letter pairs appeared around a fixation cross with a visual angle of 0.63°, which means that they appeared within the foveal visual area and (2) the letter pairs were presented for only 100 ms, a period too short to allow proper eye movements. Reliable sequence knowledge was acquired under these conditions, as responses were both slower and less accurate when the trained sequence was replaced by an untrained sequence. These results support the notion that perceptual sequence learning can be based on shifts of attention without overt oculomotor movements.