Browsing by Author "Tian, Yingxue"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    The Domain-Specificity of Serial Order Short-Term Memory
    (2018-04-11) Tian, Yingxue; Fischer-Baum, Simon
    The capacity to remember a sequence of items is critical to various cognitive functions, including short-term memory (STM). The information in a sequence is at least twofold, including item-identity and the serial order of items. In both the verbal and nonverbal domains, it is well established that the STM capacity supporting serial order information dissociates from item-identity information. The research in this thesis addresses whether the serial order STM capacity is shared for sequences in different content domains. One hypothesis is that there are domain-specific serial order STM capacities exclusive to distinct domains, whereas an alternative hypothesis is that one general serial order STM capacity is being recruited for sequences in different domains. Although various studies have explored the domain-generality of serial order STM capacity, a conclusive result has not been reached. In the thesis, I examine these two hypotheses from an individual difference perspective. The two hypotheses were operationalized by manifest variables from four sequence matching tasks with verbal stimuli (letters and words) and nonverbal stimuli (locations and arrows). Participants had to decide whether two six-item sequences were identical. Non-identical trials differed either by a single item identity or by a transposition of two adjacent items, and they presumably were supported by item and serial order STM capacity, respectively. Accuracy was used to manifest individual differences at detecting item and order changes in STM at the behavioral level. With nested model comparison, the domain-specific model represented by distinct item and serial order STM capacities in both domains best fits the data from 153 participants. On this basis, the current study supports the hypothesis that serial order STM capacity is domain-specific.
  • Thumbnail Image
    Item
    The spatialization of working memory: Multilevel modeling and network neuroscience approaches
    (2022-08-12) Tian, Yingxue; Fischer-Baum, Simon
    Daily life is filled with activities that require holding sequences in memory for a short period of time. It has been proposed that this process is supported by the spatialization of working memory (WM), whereby items are maintained on a mental whiteboard with earlier items in the sequence localized towards the left and later items localized towards the right. Support for this hypothesis comes from a behavioral phenomenon – the Spatial Position Association of Response Codes (SPoARC) effect – in which participants are faster to make judgments about items earlier in a sequence with their left hand, and faster to make judgments about items later in a sequence with their right hand. The research in this dissertation addresses the behavioral underpinnings and neural correlates of the SPoARC effect from an individual differences perspective. For the behavioral underpinnings, I investigated the relationship between the SPoARC effect, different WM capacities, and different aspects of spatial attention using a multilevel modeling approach. A larger SPoARC effect was found to be associated with a higher capacity to maintain item information in spatial WM, and in turn, was conducive to a higher capacity to maintain serial order information in verbal WM; but there was no relationship with other spatial attention capacities. For the neural correlates, I examined the mesoscale network modularity with graph theory analysis on resting-state functional connectivity. A less modular, more interactive organization of the neural regions that mediate verbal serial order WM and spatial processing (spatial attention or spatial WM) were beneficial to a larger SPoARC effect. The findings elucidate the spatial processing involved in the SPoARC effect and extend the mechanistic understanding of the previous theoretical model. This research underscores the importance of using different methodological approaches to reach a converging theoretical framework. The cognitive and neurobiological profiles of the SPoARC effect and its implication for serial order maintenance in WM are discussed.