Symmetry and the Hebb repetition effect

Two experiments used the Hebb procedure to investigate the effect of repetition on the immediate serial recall of visuospatial information characterised by symmetry. An adapted version of the Corsi block task was employed to present supra-span symmetrical sequences (Rossi-Arnaud et al., 2006). In Experiment 1 participants had to recall both the order and the position of the cells. Results showed that the recall performance was significantly higher for sequences with vertical than for those with diagonal or horizontal symmetry. However, there was no Hebb effect. Experiment 2 required participants to remember only the order of the dots. In this condition, a significant Hebb effect was obtained for diagonal and horizontal paths, while the recall of sequences with vertical symmetry showed the same increase over repeated and non-repeated sequences. Results are discussed in terms of the role of perception and long-term memory in the immediate recall of structured block sequences.