Spatial clustering and hierarchical coding in immediate serial recall

Lillo, Carlo De; Lesk, Valerie E.

doi:10.1080/09541440902757918

Cited by 14 publications

(26 citation statements)

References 28 publications

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“…In this experiment we observed beneficial effects of clustering similar to those observed in other studies (De Lillo, 2004; De Lillo and Lesk, 2010). We found that clustering had a beneficial effect in both sequences with a long and with a short path.…”

Section: Discussionsupporting

confidence: 91%

“…The RT patterns reported for structured sequences (Bor et al, 2003; De Lillo, 2004; De Lillo and Lesk, 2010) and the fMRI results of Bor et al (2003) suggest that the detection and use of structure in Corsi sequences determines the formation of specific forms of hierarchical representation that contribute to efficient recall quite apart from other effects of path characteristics. Nevertheless, considering the possible contribution of all these factors, it is important to assess their relative role in SSR.…”

Section: Introductionmentioning

confidence: 96%

“…One of the most important issues to address in relation to SSR, as identified by a recent eminent review (Hurlstone et al, 2014) and as further elaborated below, is the characterization of the organizational factors that can contribute to accurate SSR (e.g., Kemps, 1999, 2001; Bor et al, 2003; De Lillo, 2004; Busch et al, 2005; Parmentier et al, 2005; Rossi-Arnaud et al, 2005; Parmentier and Andrés, 2006; Parmentier et al, 2006; Ridgeway, 2006; Imbo et al, 2009; De Lillo and Lesk, 2010). …”

Section: Introductionmentioning

confidence: 99%

“…Some studies (De Lillo, 2004, 2012; De Lillo and Lesk, 2010) have emphasized the notion that the understanding of the effects of organizational factors in SSR is of interest apart from the assessment of memory span per se . They proposed that with the irregular spatial arrangement of the items in Corsi-type tasks and randomly selected sequences of block tapping (see Berch et al, 1998 for examples of Corsi displays and criteria for selecting sequences that have been used in the literature), it is impossible to isolate the effect of particular organizational factors and interpret them in relation to the memory representation that they afford.…”

Section: Introductionmentioning

confidence: 99%

“…Further evidence for the hierarchical representation of clustered Corsi sequences has been provided by showing that a component of this initial RT is proportional to the number of clusters in which sequences are segregated and RTs at cluster boundaries that are proportional to the number of items within each cluster (De Lillo and Lesk, 2010). …”

Section: Introductionmentioning

confidence: 99%

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Spatio-Temporal Structure, Path Characteristics, and Perceptual Grouping in Immediate Serial Spatial Recall

2016

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Immediate serial spatial recall measures the ability to retain sequences of locations in short-term memory and is considered the spatial equivalent of digit span. It is tested by requiring participants to reproduce sequences of movements performed by an experimenter or displayed on a monitor. Different organizational factors dramatically affect serial spatial recall but they are often confounded or underspecified. Untangling them is crucial for the characterization of working-memory models and for establishing the contribution of structure and memory capacity to spatial span. We report five experiments assessing the relative role and independence of factors that have been reported in the literature. Experiment 1 disentangled the effects of spatial clustering and path-length by manipulating the distance of items displayed on a touchscreen monitor. Long-path sequences segregated by spatial clusters were compared with short-path sequences not segregated by clusters. Recall was more accurate for sequences segregated by clusters independently from path-length. Experiment 2 featured conditions where temporal pauses were introduced between or within cluster boundaries during the presentation of sequences with the same paths. Thus, the temporal structure of the sequences was either consistent or inconsistent with a hierarchical representation based on segmentation by spatial clusters but the effect of structure could not be confounded with effects of path-characteristics. Pauses at cluster boundaries yielded more accurate recall, as predicted by a hierarchical model. In Experiment 3, the systematic manipulation of sequence structure, path-length, and presence of path-crossings of sequences showed that structure explained most of the variance, followed by the presence/absence of path-crossings, and path-length. Experiments 4 and 5 replicated the results of the previous experiments in immersive virtual reality navigation tasks where the viewpoint of the observer changed dynamically during encoding and recall. This suggested that the effects of structure in spatial span are not dependent on perceptual grouping processes induced by the aerial view of the stimulus array typically afforded by spatial recall tasks. These results demonstrate the independence of coding strategies based on structure from effects of path characteristics and perceptual grouping in immediate serial spatial recall.

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Section: Discussionsupporting

confidence: 91%