Load and similarity in tactile working memory Emil Holmer1, Mikael Heimann2, & Mary Rudner1 1
Linnaeus Centre HEAD, Department of Behavioural Sciences and Learning, Linköping University, Sweden
2
Division of Psychology and Department of Behavioural Sciences and Learning, Linköping University, Sweden
Background
Methods • Participants: • 18 (1 male) teenagers, mean age 17.8 (SD = 0.99) • Non-verbal cognitive ability (standardized score 8.3, SD = 2.9) and verbal working memory (standardized score 8.8, SD = 1.4) at expected levels (WAIS-IV, Wechsler, 2010) • Experimental tactile working memory task • Design: load (four levels: three, four, five, or six items to remember) by similarity (two levels: similar or dissimilar items). • Materials: 3D-printed tiles (40x35 mm), all but one patterned. One set of tiles was prepared for each level of similarity across the four levels of load (sets at load three items, in Figure 1). • Procedure: Within sets, tiles were presented one by one in a fixed order (see Figure 2). • Dependent variable: Proportion of tiles placed in the correct position in a sequence.
Results • Performance (Figure 3): similar < dissimilar at the lowest (3 items, p = .01) and highest (6 items, p = .03) levels of load, and marginally significant at the second to last level (5 items, p = .07) • Correlations: no associations between the proportion of tiles placed in the correct position across all sets and non-verbal cognitive ability or verbal working memory (ps > .10)
Conclusions and future directions • For tactile WM, the similarity effect may vary across load or materials • Lack of correlations with visual/verbal cognitive tasks indicate that tactile working memory might involve specific perceptual and/or higher level cognitive mechanisms • Interactions between load and similarity should be followed up in future studies of tactile WM, as well as effects of interferences (e.g., verbal, visual, or tactile) • Future studies should also investigate how tactile WM is characterized in individuals who rely on tactile exploration of the world • How to effectively present different types of tactile materials in experiments is an important issue to deal with in future studies
Contact information:
[email protected] 4th International Conference on Cognitive Hearing Science for Communication 18-21 June 2017, Linköping, Sweden
3 items Similar 3 items Dissimilar Figure 1. Examples from the lowest level of of memory load (3 items) in the tactile working memory task.
1. Explore each tile (n = 3, 4, 5, or 6) for 2 seconds
2. Answer question
How many tiles in set?
3. Get back all tiles in set arrange in correct order
4. Example of response 3
2
1
Figure 2. Steps in administration of each set of tiles in the tactile working memory task.
100
Similar
Dissimilar
90 80 70
Proportion correct, %
• The tactile modality is the main channel for communication for individuals with combined visual and auditory impairment • Studies of tactile working memory indicate effects of load and verbal/visual interference • In this pilot study, we investigated whether the canonical similarity effect generalizes to tactile working memory
60 50 40 30 20 10 0 3
4 5 Number of items (i.e. tiles) to remember
6
Figure 3. The proportion of tiles placed in the correct position in a sequence for trials of similar and dissimilar tiles. Error bars represent +/- one standard error.
Acknowledgements Thanks to pupils at Curt Nicolin Gymnasiet for preparation of test materials: Emil Andersson, Viktor Andersson, Alexander Carlsson, Lukas Ceasar, Johan Frid, Ramsey Haider, Edvin Hultgren, Aleksandra Koprivica, Denis Nokic, Albin Olsson, Martin Rosén, Pierre Vallin, Tim Wahlberg, Lennon Wikner, and Emil Wåhlander.
