Does consolidation of visuospatial sequence knowledge depend on eye movements?

Abstract

In the current study, we assessed whether visuospatial sequence knowledge is retained over 24 hours and whether this retention is dependent on the occurrence of eye movements. Participants performed two sessions of a serial reaction time (SRT) task in which they had to manually react to the identity of a target letter pair presented in one of four locations around a fixation cross. When the letter pair 'XO' was presented, a left response had to be given, when the letter pair 'OX' was presented, a right response was required. In the Eye Movements (EM) condition, eye movements were necessary to perform the task since the fixation cross and the target were separated by at least 9° visual angle. In the No Eye Movements (NEM) condition, on the other hand, eye movements were minimized by keeping the distance from the fixation cross to the target below 1° visual angle and by limiting the stimulus presentation to 100 ms. Since the target identity changed randomly in both conditions, no manual response sequence was present in the task. However, target location was structured according to a deterministic sequence in both the EM and NEM condition. Learning of the target location sequence was determined at the end of the first session and 24 hours after initial learning. Results indicated that the sequence learning effect in the SRT task diminished, yet remained significant, over the 24 hour interval in both conditions. Importantly, the difference in eye movements had no impact on the transfer of sequence knowledge. These results suggest that the retention of visuospatial sequence knowledge occurs alike, irrespective of whether this knowledge is supported by eye movements or not.

Figure 1. Research method.

(A) Example of two consecutive trials in the no eye movements (NEM) and the eye movements (EM) condition. Participants had to respond to the identity of the target letter pair “XO” or “OX”; “XO” required a left response, “OX” a right one. In the NEM condition, target and distractors (“YQ” or “QY”) were presented close to the fixation cross and were displayed for 100 ms, after which only the fixation cross remained on the screen. The next trial started 400 ms (RSI) after a response was given. In the EM condition, target and distractors were widely separated and remained on the screen until participants responded. In both conditions, target identity, and hence manual responses, changed randomly, while target location was structured according to a deterministic sequence. In the current example, target location 1 (above the fixation cross) was followed by target location 2 (right from the fixation cross). (B) Overview of the design, which was similar in the NEM and the EM condition. T  =  trained blocks, U  =  untrained blocks.

Figure 2. Performance per block for the no eye movements (NEM) and eye movements (EM) condition.

In panel (A), mean median reaction times are presented. In panel (B), mean (untransformed) error rates are presented. In Session 1, the trained sequence changed to an untrained sequence in Block 13 (U13). In Session 2, the trained sequence changed to an untrained sequence in Blocks 2 (U2) and 5 (U5). Error bars denote standard errors of the mean. Note: some of the data (i.e., the data of the first session of the participants in the NEM condition) were included in our paper previously published in Experimental Psychology .

Figure 3. Reaction time (RT) performance on trained and untrained blocks in Session 1 and 2 for the no eye movements (NEM) and the eye movements (EM) condition.

(A) Mean median RTs for trained Blocks 12-14 of Session 1 and trained Blocks 1-3 of Session 2 per condition. (B) Mean median RTs for untrained Block 13 of Session 1 and untrained Block 2 of Session 2 for both conditions. Error bars denote standard errors of the mean.