Cognitive modeling of voluntary task switching in discretionary multitasking

오형석 Graduate School, Korea University 2021 국내박사

This paper explores cognitive processes, including the development of an adaptive control of thought-rational (ACT-R) model to represent an integrated account of voluntary task switching in discretionary multitasking. Discretionary multitasking has emerged as a prevalent and important domain in research on human-computer interaction. Studies on modeling based on cognitive architectures such as ACT-R to gain insight into and predict human behavior in multitasking are critically important. However, studies on ACT-R modeling have mainly focused on concurrent and sequential multitasking, including scheduled task switching. Therefore, in this study, an ACT-R cognitive model of voluntary task switching in discretionary multitasking was developed to provide an integrated account of when and how humans decide on switching tasks. Our model contains a symbolic structure and subsymbolic equations that represent the cognitive process of task switching as self-interruption by the imposed demands and a decision to switch. In our model, self-interruptions by negative emotions emerge from imbalances between the difficulty of the ongoing task and the level of ability, and our model includes the rational decision to switch based on the ACT-R utility system. To validate our model, it was applied to an illustrative dual-task, including a memory game and a subitizing task, and the results were compared with human data. The results demonstrate that our model can provide a relatively accurate representation, in terms of task-switching percent just after the subtask, the number of task-switching during the subtask, and performance time depending on the task difficulty level; it exhibits enhanced performance in predicting human behavior in multitasking and demonstrates how ACT-R facilitates accounts of voluntary task switching. The proposed model can be used as a practical tool for evaluating aid systems in multitasking environments.

Improved cognitive control in young people with Tourette's Syndrome during task-switching

정제영 고려대학교 대학원 2009 국내석사

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by motor and vocal tics. Tics are repetitive and uncontrolled behaviours associated with the abnormality of basal ganglia and frontal lobe that lead to impaired cognitive functions. We investigated cognitive control of TS group using an oculomotor task-switching. Participants performed a peripheral conflict task and a latency task. The peripheral conflict task, task-switching consists of 2 task types (pro-saccade and anti-saccade) and 2 trial types (repetition and switch). There are 4 conditions: repeated pro-saccade trials, switched pro-saccade trials, repeated anti-saccade trials, and switched anti-saccade trials. In latency task, control task, participants were required to perform pro-saccade trials only. We found that TS group showed greater accuracy compared to control group in anti-saccade trials and switch trials in the peripheral conflict task. However there was no significant difference in reaction time between TS group and the control group. Both groups showed shorter duration and distance of eye movement in pro-saccade task than in anti-saccade task. The velocity of saccades did not exhibit the difference between groups. The results of conflict task indicate that TS group performs better than the control group in trials demanding high level of cognitive control, which is not caused by a general speed accuracy trade-off. And we found that TS group showed prolonged reaction time than control group in the control task. This result indicates that TS group perform poorer than the control group in trials performed automatically. The current study supports and extends previous findings that TS group exhibits improved cognitive control compared to age-matched controls in the task requiring high level of cognitive control and impairs the ability to perform automatic response than control group. This might be attributed to a compensatory strategy which young people with TS use to suppress tics. 투렛 신드롬은 운동 틱과 보컬 틱으로 특징지어지는 신경 발달 장애이다. 틱은 반복적이고 통제되지 않은 행동으로 대뇌 기저핵과 전두엽의 이상과 관련된다. 우리는 투렛 신드롬 집단의 인지 통제 능력을 안구운동 task-switching 과제를 사용하여 연구하였다. 실험 참가자들은 task-switching 과제와 통제 과제를 수행하였다. task-switching 과제는 두 가지 유형의 과제(pro-saccade와 anti-saccade)와 두 종류의 시행(반복과 전환), 즉 4가지의 조건으로 구성되었다: 반복 pro-saccade 시행, 전환 pro-saccade 시행, 반복 anti-saccade 시행, 그리고 전환 anti-saccade 시행. 통제 과제에서는 실험 참가자들은 pro-saccade 과제만을 수행하였다. 우리는 투렛 신드롬 집단이 통제 집단에 비해 anti-saccade 시행과 전환 시행에서 더 높은 정확성을 보인다는 것을 발견하였다. 그러나 반응 시간에 있어서 두 집단의 차이는 유의미하지 않았다. 그리고 두 집단 모두 anti-saccade 과제보다 pro-saccade 과제에서 더 빠른 눈 움직임과 더 짧은 눈 움직임 거리를 보였다. Saccade 속도는 두 집단에서 차이가 나지 않았다. Task-switching 과제의 결과는 투렛 신드롬 집단이 통제 집단보다 고차 인지 통제 능력을 필요로 하는 시행을 더 잘 수행한다는 것을 나타낸다. 그리고 이 결과는 일반적인 속도-정확성 상쇄로 나타나는 것이 아니다. 우리는 또한 통제과제에서 투렛 신드롬 집단이 통제 집단에 비해 지연된 반응시간을 보이는 것을 발견했다. 이것은 투렛 신드롬 지단이 통제집단에 비해 자동적으로 처리되는 시행에서 수행이 떨어진다는 것을 의미한다. 본 연구는 투렛 신드롬 집단이 고차 인지 통제가 요구되는 과제에서 향샹된 인지 통제 능력을 보인다는 기존 결과를 지지하고 확장한다. 그리고 투렛 신드롬 집단이 자동적 반응 수행하는 능력이 정상 집단과 비교할 때, 손상되었음을 나타낸다. 이러한 결과는 투렛 신드롬을 가진 처소년들이 틱을 억제하기 위해 사용하는 보상적인 전략에서 기인한다고 볼 수 있다.

Neural correlates of cognitive style during task switching : 과제전환에서 인지 양식 선호에 따른 신경적 상관

오윤경 경북대학교 대학원 2017 국내석사

A recent study employing the color-word Stroop task proposed that preference for Object-Spatial-Verbal cognitive style is associated with cognitive control. Based on this finding, the present study aims to find that the same cognitive style has an influence on task-switching processes. In doing so, a task-switching including the object and verbal tasks was employed, and cognitive preference scores were obtained. The neural responses were recorded by fMRI. Cognitive style preference scores, behavioral switch cost, and neural switch cost were used for analysis. For the behavioral results, in the switched condition from verbal to object task, the more prefer verbal style the higher behavioral switch costs were observed. However, the neural results identified a positive relationship between preference for object style and the neural switch cost in PCC/Precuneus and left IPS. In addition, an interaction between both cognitive style preferences was found in the same condition in angular gyrus. These findings indicated that preference for cognitive style is related to attentional resource allocation, selection and processing of target-relevant information. It suggests that preference for cognitive style is associated with cognitive control during task-switching. In the verbal task, there was no relationship between task-switching performance and cognitive style preference. 인지적 처리에 영향을 주는 개인차 요인으로 대상-공간-언어 인지양식이 제안되었다. 따라서, 본 연구에서는 여러 인지적 통제 처리를 요구하는 과제전환 패러다임을 이용하여 대상-공간-언어 인지양식이 과제전환의 수행에 주요한 개인차로 작용하는지 확인하고자 하였다. 이를 위하여 대상과제와 언어과제를 포함하는 과제전환 패러다임을 고안하고, 한국판 인지양식 설문지(K-OSIVQ)를 통해 인지양식 선호점수를 구하였다. 또한 과제를 수행하는 동안 기능적 자기공명영상을 촬영하였다. 인지적 통제처리와 인지양식의 관계를 확인하기 위해 인지양식 선호점수와 행동 전환 비용, 신경적 전환 비용 간의 상관을 분석하였다. 행동 분석 결과, 대상과제에서 방해자극을 선호할수록 과제전환이 더 느리게 수행되는 결과가 나타났다. 그러나 뇌영상 분석 결과, 대상과제에서 대상양식 선호와 신경적 전환비용의 정적 관계가 후측대상회와 쐐기앞소엽 그리고 두정간구에서 확인되었다. 또한 각회에서 신경적 전환 비용과 두 인지양식 선호 점수 간 상호작용이 발견되었다. 이는 과제전환 패러다임에서 인지적 통제가 작용하는 과제 세트 재구성에서 인지양식이 관여한다는 것을 시사한다. 언어과제에서는 과제 수행과 인지양식 선호와의 관계가 발견되지 않았다.

Effects of external and internal task-switching upon idea generation performance

석경영 서울대학교 대학원 2016 국내석사

Multi-tasking pervades in our daily lives. We are handling more than two tasks at the same time. In a situation where more than two tasks are to be carried out within a set amount of time, there are mainly two reasons why a person switches from one task to another. In one instance, switching occurs because of external circumstances regardless of the intent of performers, such as the close of the set time. In the other, switching occurs because the performer gets bored or can no longer concentrate on the task. This study was carried out to examine how these two types of task switching affect idea generation. Two idea generation tasks were presented to different groups under various conditions. For each task participants were allowed to use for 12 min. In the control group (n=25), participants were instructed to tackle the two tasks one at a time (Task A then Task B). There were two experimental conditions: in the external task switching condition, participants were obliged to alternate the two tasks sequentially for 12 min each (Task A, Task B, Task A, Task B); In the internal switch condition, participants were allowed to switch the two tasks whenever they want to within 24 minutes for each task. The number and the quality of the ideas were rated by two graders who were not informed about the purpose of the study. The results showed that the quality of the ideas was lower for the external task switching condition than that for the control condition. However, the performance of the internal task switching group was superior to that of the control condition. Subsequent analysis showed that the increase in the number of switching resulted in lower performance even in case of the group who were given the choice when to switch. In conclusion, the results showed that performance improves when task switching choice is allowed but that too many switches have a negative influence on performance. Possible applications of these results were discussed.

Cognitive flexibility in response-contingent task-switching

Lee, Kibbum Graduate School, Yonsei University 2019 국내석사

우리가 여러가지 과제들을 연달아 수행하게 될 때, 과제와 과제 간의 전환이 일어나게 된다. 과제 전환(task-switching)이 일어나게 되면 인지 과정에 있어 전환에 필요한 추가적인 자원으로 인해 전환 비용(switch cost)이 발생하게 된다. 인지적 유연성(cognitive flexibility)은 이전 연구들이 여러가지 단서를 사용하여 맥락 단서 효과를 보여준 것과 동일하게 과제 전환에서도 암묵적인 학습이 가능함을 보여준다 (예: Braem과 Egner, 2018). 실험 1에서는 전환이 더 높은 확률로 발생할 경우 더 낮은 확률로 전환되는 조건에 비해 더 낮은 전환 비용이 발생하여 보다 빠른 반응속도를 보일 것으로 예측하였다. 이어 연구 2에서는 반응 수반적인 확률을 다른 방식으로 연합하여 해당 반응에 연합된 과제 전환이 아닌 특정 과제 자체를 학습하도록 수정하여 연구를 진행하였고, 결과적으로 높은 확률 조건에서 전환 비용이 낮아짐을 확인하였다. 결과적으로 전환 조건이 반응에 수반되는 경우에는 전환 비용이 낮아지지 않았지만 과제의 종류가 반응에 수반되는 경우에는 전환 비용이 낮아진 것을 알 수 있었다. 확률을 조작하는 조건을 다르게 하여 암묵적 학습을 통한 반응 수반성에 대해 더 구체적인 연구가 필요할 것으로 보인다. 또한 인지적 유연성을 나타내는 뇌영역에 대한 인지신경학적 연구를 통해 반응 수반적 확률을 조작하면 인지적인 처리를 통해 효율적인 인지 처리와 유연한 사고가 가능한지 알아볼 수 있을 것으로 기대한다. When we do multiple tasks in a serial manner, it requires switching between tasks. When such a task-switching happens, it accompanies a switch cost which demonstrates the cognitive process resulting from additional resource required for a change in cognition. If someone is more agile in task-switching, it can be considered as flexible cognition, whereas if higher switch cost is involved, the person may be considered as fixated in cognition (Chrysikou, 2019). According to recent studies, cognitive flexibility can be learned implicitly, as previous studies using different cues show how contextual cueing could be applied in task-switching (e.g., Braem & Egner, 2018). In Experiment 1, we predicted that higher probability of switch (75%) will bring about decreased switch cost, or faster RT, in subsequent trials, compared to trials after lower probability of switch (25%). If switch cost could be reduced after higher probability of switch, it would show that implicit learning can improve performance. As a result, however, there was no difference between two levels of switch probability. In Experiment 2, response-contingent probability was applied in a different unit, and the subsequent task was displayed in high or low probability according to the response. As a result, faster RT (i.e. lower switch cost) was observed in higher probability condition compared to lower probability condition. As a conclusion, the switch cost was modified in higher switch probability trials only when one implicitly learned response-contingent task conditions, and not for response-contingent switch conditions. More detailed manipulation of probability may bring about strategic usage of implicit learned knowledge on response contingency. Further studies on neural correlates of cognitive flexibility and executive function will benefit the future application as more people are paying attention to maintaining good cognitive abilities in old age.

Cross-task congruency sequence effect in a predictable task-switching context

이지은 Graduate School, Korea University 2022 국내석사

불합치 시행 이후에 합치 시행 이후에 비해 합치 효과가 줄어드는 순차 합치 효과는 인지 통제의 대표적인 지표로, 인지 통제의 범위를 결정하는 요인을 알아내기 위해 많은 연구자들은 서로 다른 과제 사이의 순차 합치 효과를 연구해왔다. 과제 집합 설명은 과제 지시에 따라 형성된 과제 집합이 인지 통제의 범위를 결정한다고 주장하나, 억제 설명은 과제-무관련 자극 차원을 억제하는 방식으로 일어나는 통제 기제를 강조해왔다. 본 연구는 과제 전환이 예측 가능한 상황에서 서로 다른 두 과제 사이의 순차 합치 효과가 과제-관련 자극 차원에 기반한 과제 집합에 의해 결정되는지, 혹은 과제-무관련 차원에 의해 결정되는지 알아보고자 한다. 실험 1부터 3까지는 두 과제 사이에 공유되는 요소를 바꿔가며 두 과제를 두 시행마다 전환해 제시하였다. 실험 4는 두 시행마다 과제를 바꾸면서도 매 시행마다 자극이 제시되는 방향을 바꾸어 시행 간 자극이나 반응 중 어떠한 반복도 없게 하였다. 두 개의 다른 과제 간 순차 합치 효과는 과제-무관련 자극 차원을 공유하는 실험 1, 3, 4에서만 나타났다. 하지만 과제-관련 자극 차원만 공유하는 실험2의 두 과제 사이에서는 순차 합치 효과가 발견되지 않았다. 이러한 결과는 순차 합치 효과가 두 과제가 과제 전환 비용으로 대표되는 과제 간 유사성에 의해 결정되지 않는다는 것을 보여준다. 두 과제가 과제-관련 자극 차원을 공유하는지의 여부보다 과제-무관련 자극 차원이 인지 통제의 범위를 결정한다. 또한 운동 시간에서만 발견되는 순차 합치 효과는 인지 통제가 반응 실행 후 과제-무관련 차원에 의한 반응을 억제하는 방식으로 작동한다는 것을 보여준다. The sequential modulation of conflict between two different tasks has been investigated to examine the factor determining the scope of cognitive control involved in the congruency sequence effect (CSE), the phenomenon of the congruency effect being smaller after incongruent trials than after congruent trials. The present study examined whether the CSE being transferred across two tasks in a predictable task-switching context is determined by the task sets established based on the task-relevant stimulus dimension or by the inhibition of the task-irrelevant stimulus dimension. The task set account suggests the task set formed on a basis of task instructions as a factor determining the boundary of control. In contrast, the inhibition account emphasizes that the control mechanism triggered by conflict operates by suppressing the task-irrelevant stimulus dimension, suggesting the task-irrelevant stimulus dimension as a critical factor determining the boundary of control. Two different tasks alternated on every second trials in Experiments 1 to 3, while the shared component of the two tasks changed across the experiments. In Experiment 4, two tasks alternated after two trials, with the orientation of each task alternating on every trial to remove any confounding effect of repetition priming. The sequential modulation of the congruency effect between two tasks was evident in Experiments 1, 3, and 4, all of which shared the task-irrelevant stimulus dimension, regardless of the amount of task-switching cost. However, the congruency effects of the two tasks sharing only the task-relevant stimulus dimension were not sequentially modulated in Experiment 2. These results suggest that whether the CSE occurs between two tasks does not depend on the similarity between the task sets, while the magnitude of similarity is indexed by the task-switching cost. Rather, the task-irrelevant stimulus dimension determines the scope of control, regardless of whether two tasks shared the task-relevant stimulus dimension. Moreover, the congruency sequence effects observed during the response movement times indicates that the control operates in a way to inhibit the task-irrelevant response activation after response initiation.

"It's One Thing After Another": Supporting the Management of Frequent and Nested Interruptions in High-Tempo Multi-Agent Operations

Panesar, Karanvir Singh University of Michigan ProQuest Dissertations & Th 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The growing number of semi-autonomous machine agents in many safety-critical application domains brings with it an increase in the frequency with which human supervisory controllers need to interrupt ongoing tasks and lines of reasoning to handle unexpected and/or time-critical problems and requests. These disruptions may occur at inopportune times, such as being interrupted again immediately after completing a previous interrupting task (serial interruption) or while still handling a previous interruption (nested interruption). Frequent interruptions can lead to errors and delays which threaten safety in time-sensitive event-driven domains such as aviation and medicine. Successful teaming of operators with multiple machine agents therefore requires a better understanding of, and support for attention allocation and interruption management (IM). The goals of this dissertation were to 1) identify and analyze the challenges that operators encounter at various stages of interruption management (IM) when handling frequent and nested interruptions, and 2) develop and evaluate a set of candidate displays to address the observed challenges.To this end, three human-subject experiments were conducted. The first two experiments focused on identifying the difficulties faced by operators when detecting, interpreting, and switching between frequent and nested interruptions in a supervisory command and control task. Frequent and nested interruption notifications were less likely to be acknowledged, compared to less frequent and non-nested ones. Participants also struggled with the appropriate scheduling of incoming tasks and took longer to switch to nested interrupting tasks of higher urgency, compared to both single and serial interruptions. The longer switch time resulted from delays at the earlier stages of detection and interpretation of notifications as well as a resistance to switch away from the ongoing task, even for highly urgent interrupting tasks. In the third and final study, two candidate displays were developed and tested to address issues with poor scheduling of pending tasks. The first display involved automatic sorting of incoming task notifications by level of urgency; the second candidate consisted of a color- and location-based visualization of the relative urgency levels for the ongoing and interrupting task to support task prioritization and switching. The visualization of relative task urgency improved overall performance, led to decision-making accuracy, and resulted in more efficient prioritization of ongoing and interrupting tasks. At the same time, it involved a greater risk of failing to notice misclassifications made by imperfectly reliable automation.The theoretical contribution of this research is a better understanding of the process of interruption management. More specifically, challenges and performance breakdowns experienced in the detection, interpretation, and integration of frequent and nested interruptions were identified. In contrast to what is suggested by current IM models, our findings show that interruption management is not a linear process, but one where behavior and performance at one stage depends on anticipated and experienced difficulties at both earlier and subsequent stages. In addition to identifying and analyzing challenges with handling frequent interruptions, this work also addresses said challenges and provides empirically based guidance on the design of interruption-resilient interfaces. From an applied perspective, findings from this line of work will help reduce the attentional demands and improve the safety and performance of human-machine teams, and the well-being of human operators in a variety of complex event-driven application domains like aviation and healthcare.

운전 중 IVIS 조작 상황에서 과제의 난이도와 Motor cue가 과제 전환과 운전 주행에 미치는 영향

유은현 연세대학교 대학원 2018 국내석사

As information technology is more actively incorporated into automobiles, the role of IVIS(In-Vehicle Infotainment System) is becoming increasingly important as the main medium that provides convenience and entertainment for the drivers. However, using the infotainment systems while driving requires task switching between two tasks, as it involves attending to two visual resources simultaneously. We simulated a setting where participants have to drive while interacting with the infotainment system and examined how task difficulty and motor cues impact driver’s task-switching and driving performance, specifically whether the effect of motor cues differ depending on the task difficulty. For the infotainment display, we used two types of number array depending on the congruency between the digit repetition and the chunking unit, while task difficulty was manipulated by the size of the touch-keys. Participants were instructed to dial two numbers on the screen while we recorded the dialing time, lateral position, inter-key press intervals, and steering wheel control. We found that dialing time and lateral position was affected by task difficulty, while the type of number array had no effect. However, the inter–key press intervals between chunked numbers and the steering wheel movement both increased when participants had to dial an incongruent number array, which indicates that if number digits are repeated, chunking is ignored by the drivers. Our findings indicate that in a dual-task condition, motor cues offset the effect of chunking and that motor cues can effectively signal the timing for task switching. 최근 자동차와 IT 기술의 융합으로 차량 내 인포테인먼트 시스템이 운전자에게 편의 및 오락 기능을 제공하며 역할이 중요해지고 있다. 하지만 운전과 인포테인 먼트 시스템을 조작하는 것은 동시에 시각 리소스를 요구하는 과제로 과제를 전환 하며 수행해야 한다. 따라서 본 연구는 운전 중 인포테인먼트 시스템 조작 상황에 서 조작 과제의 난이도와 motor cue 가 과제 전환과 운전 주행능력에 미치는 영향 과 함께, motor cue 의 효과가 조작 과제의 난이도 수준에 따라 차이가 있는지 보 고자 하였다. motor cue 와 조작 과제 난이도의 효과를 살펴보기 위해 반복되는 숫 자가 청크 단위와 일치하는지에 따라 두 종류의 번호를 사용하였으며, 터치 키의 크기로 난이도 수준을 조절했다. 실험에서 참가자들은 모의 주행을 하며 스크린에 번호를 입력하도록 지시받았고, 과제 수행 중 번호 입력시간, 차선 유지능력, 숫자 키 입력 시간 간격과 핸들 움직임을 측정했다. 그 결과, 난이도 수준에 따라 운전 주행 능력과, 번호 입력 시간의 차이가 유의미했고, 번호 종류에 따른 차이는 나타 나지 않았다. 하지만 Incongruent 번호 입력 시, 청크로 구분된 두 숫자를 입력하는 시간의 간격과 핸들 움직임이 크게 증가하였다. 이는 반복된 숫자가 청크로 구분되어도 청크를 무시하고 한 번에 입력하였음을 나타낸다. 종합하면, 다중 과제 상황에서 청크 단위는 motor cue 에 의해 상쇄되며 과제 전환 시점을 결정하는 데 에 motor cue 의 효과가 있음을 시사한다.

Cognitive control and incidental memory interactions : contrast between excitatory and inhibitory control

이혜진 Graduate School, Korea University 2021 국내박사

Incidental memory indicates information encoded without intention. Still, information needs to be attended to be better remembered. As the human attention system can either enhance or reduce information processing, this control of attention determines the precision of incidental memory. Distinguishing between excitatory and inhibitory control of attention is important as prior studies reported contrasting findings of each modulating incidental memory. Whereas studies using a Stroop task demonstrated that excitatory attentional control to enhance the processing of task-relevant information facilitated memory, studies using a stop-signal task showed that inhibitory control to suppress motor responses impaired memory. While the contrasting results implied distinguishable neural mechanisms, the extent of influence each has on information processing and thus how they would interact were unknown. Hence, the task paradigm of testing incidental memory for stimuli encountered during various cognitive control tasks was used. First, incidental memory for images and words encountered during a task-switching paradigm was measured. Prior studies using the paradigm demonstrated that attentional control determined memory selectivity because having better memory for targets over distractors was significantly disturbed when attentional control was impaired by the lagging process of updating task sets in switching to another task. However, due to inconsistent prior study findings that a bottom-up factor of task-switching alternatively accounted for the switch-induced reduction in memory selectivity, experiments were conducted to test for both accounts. Results demonstrated that even when the bottom-up factor was controlled, attentional control determined memory selectivity. Results further implied that the locus of excitatory attentional control facilitating incidental memory was at a particular stage of information processing that precedes response selection. In contrast, inhibitory control of response inhibition was previously suggested not to be confined to the late response stage but to impair cognitive processes that precede the stage. Accordingly, to examine if response inhibition would also impair excitatory attentional control, their interactions were examined by measuring incidental memory for images encountered during a combined Stroop/stop-signal task. Results showed that inhibitory control overrode excitatory control, such that whereas response inhibition impaired memory, excitatory attentional control did not facilitate memory. This suggested that inhibitory control to suppress motor responses pervasively impairs cognitive processes that take place during early to intermediate stages including excitatory attentional control. In addition to excitatory and inhibitory control contrastively modulating incidental memory performance, they further differ in the extent of influence exerted on information processing. While a hierarchical interaction of top-down control directing attentional distribution determines the precision of incidental memory, the contrasts of excitatory and inhibitory control in implementing the hierarchical interaction imply different underlying neural mechanisms although their influence is interactive rather than additive to incidental memory.

Enhancing mobile interaction with smartphone cover

최고은 서울대학교 대학원 2017 국내석사

Most smartphones support multi-tasking with several means to switch between apps (e.g., a “recent apps” button or a “back” button). However, switching between apps is cumbersome when one has to do it frequently—for example, when notifications keep interrupting one’s current task. We introduce Peek-a-View, a fully transparent flipping screen cover that can reduce task switching overhead by providing an additional virtual screen space for subtasks. We assessed its feasibility in handling notifications. Upon receiving a notification, users can peek into the content of the notification without actually switching apps by slightly lifting the cover. If necessary, users can completely flip the cover to switch to the app that fired the notification. Two user studies showed that flipping and peeking interaction provided improved performance and proved to be useful for tasks that involve subtasks. Also, we propose cover interaction input modalities based on cover angles. Two type events; state change which supports discrete flip cover state and angle movement which changes value continuously when changing a flip cover angle; can be extended in future researches.