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- Johansson, Roger, et al.
(författare)
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Eye movements play an active role when visuospatial information is recalled from memory
- 2012
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Ingår i: Journal of Vision. ; 12:9
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Konferensbidrag (refereegranskat)abstract
- Abstract in Undetermined Whilst it has been established that spontaneous eye movements occur with visual imagery and that they are comparable with those from an original scene inspection (e.g., Brandt & Stark, 1997; Johansson, Holsanova, & Holmqvist, 2006), the exact purpose of these eye movements has been a hot topic of debate (cf., Ferreira et al., 2008; Richardson et al., 2009). Do they have an active and functional role in memory retrieval or are they merely an epiphenomenon? In a recent study we reported that when eye movements were prohibited for participants who orally described pictures from memory, their recollections became altered and impaired (Johansson, Holsanova, Dewhurst, & Holmqvist, (in press). Journal of Experimental Psychology: Human Perception and Performance). The current study was designed as a follow-up, aiming to uncover exactly how imposing different eye movements on participants affects memory retrieval processes. Eye movements were recorded from participants who recalled properties and spatial arrangements of sets of objects under four different manipulations: (1) free viewing on a blank screen; (2) gazing at a fixation cross; (3) looking at an area which was matched with the original locations of the objects to be recalled; (4) looking at an area which did not match the original locations of the objects to be recalled. By restricting eye movements in different ways during recall, we demonstrate the sensitivity of retrieval performance to specific eye movement manipulations. Results provide evidence that eye movements do have an active and supportive role when visuospatial information is recalled by highlighting the circumstances under which a visual memory is hampered. Additionally, findings suggest that the influence of "eye movements to nothing" is primarily related to the processing and retrieval of spatial information.
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| 2. |
- Dewhurst, Richard, et al.
(författare)
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How task demands influence scanpath similarity in a sequential number-search task
- 2018
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Ingår i: Vision Research. - : Elsevier BV. - 1878-5646 .- 0042-6989. ; , s. 9-23
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Tidskriftsartikel (refereegranskat)abstract
- More and more researchers are considering the omnibus eye movement sequence—the scanpath—in their studies of visual and cognitive processing (e.g. Hayes, Petrov, & Sederberg, 2011; Madsen, Larson, Loschky, & Rebello, 2012; Ni et al., 2011; von der Malsburg & Vasishth, 2011). However, it remains unclear how recent methods for comparing scanpaths perform in experiments producing variable scanpaths, and whether these methods supplement more traditional analyses of individual oculomotor statistics. We address this problem for MultiMatch (Jarodzka et al., 2010; Dewhurst et al., 2012), evaluating its performance with a visual search-like task in which participants must fixate a series of target numbers in a prescribed order. This task should produce predictable sequences of fixations and thus provide a testing ground for scanpath measures. Task difficulty was manipulated by making the targets more or less visible through changes in font and the presence of distractors or visual noise. These changes in task demands led to slower search and more fixations. Importantly, they also resulted in a reduction in the between-subjects scanpath similarity, demonstrating that participants’ gaze patterns became more heterogenous in terms of saccade length and angle, and fixation position. This implies a divergent strategy or random component to eye-movement behaviour which increases as the task becomes more difficult. Interestingly, the duration of fixations along aligned vectors showed the opposite pattern, becoming more similar between observers in 2 of the 3 difficulty manipulations. This provides important information for vision scientists who may wish to use scanpath metrics to quantify variations in gaze across a spectrum of perceptual and cognitive tasks. © 2018 Elsevier Ltd
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| 3. |
- Dewhurst, Richard, et al.
(författare)
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It depends on how you look at it: Scanpath comparison in multiple dimensions with MultiMatch, a vector-based approach
- 2012
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Ingår i: Behavior Research Methods. - : Springer Science and Business Media LLC. - 1554-3528.
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Tidskriftsartikel (refereegranskat)abstract
- Eye movement sequences---or scanpaths---vary depending on stimulus characteristics and task (Foulsham \& Underwood, 2008; Land, Mennie, \& Rusted, 1999). Common methods for comparing scanpaths, however, are limited in their ability to capture both the spatial and temporal properties of which a scanpath consists. Here we validate a new method for scanpath comparison based on geometric vectors, which compares scanpaths over multiple dimensions retaining positional and sequential information (Jarodzka, Holmqvist, \& Nyström, 2010). `MultiMatch' was tested in two experiments and pitted against ScanMatch (Cristino, Mathôt, Theeuwes, \& Gilchrist, 2010), the most comprehensive adaptation of the popular Levenshtein method. Experiment 1 used synthetic data, demonstrating the greater sensitivity of MultiMatch to variations in spatial position. In experiment 2 real eye movement recordings were taken from participants viewing sequences of dots, designed to elicit scanpath pairs with commonalities known to be problematic for algorithms (for example, when one scanpath is shifted in locus, or fixations fall either side of an AOI boundary). Results illustrate the advantages of a multidimensional approach, revealing how two scanpath differ. For instance, if one scanpath is the reverse copy of another the difference is in direction but not the position of fixations; or if a scanpath is scaled down, the difference is in the length of saccadic vectors but not overall shape. As well as having enormous potential for any task in which consistency in eye movements is important (e.g. learning), MultiMatch is particularly relevant for "eye movements to nothing" in mental imagery research and embodiment of cognition, where satisfactory scanpath comparison algorithms are lacking.
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| 4. |
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| 5. |
- Foulsham, Thomas, et al.
(författare)
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Comparing scanpaths during scene encoding and recognition: A multi-dimensional approach
- 2012
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Ingår i: Journal of Eye Movement Research. - 1995-8692. ; 5:4:3, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedComplex stimuli and tasks elicit particular eye movement sequences. Previous research has focused on comparing between these scanpaths, particularly in memory and imagery research where it has been proposed that observers reproduce their eye movements when recognizing or imagining a stimulus. However, it is not clear whether scanpath similarity is related to memory performance and which particular aspects of the eye movements recur. We therefore compared eye movements in a picture memory task, using a recently proposed comparison method, MultiMatch, which quantifies scanpath similarity across multiple dimensions including shape and fixation duration. Scanpaths were more similar when the same participant's eye movements were compared from two viewings of the same image than between different images or different participants viewing the same image. In addition, fixation durations were similar within a participant and this similarity was associated with memory performance.
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