有研究發現過度的媒界多任務處理者(HMMs)在多種認知任務上較輕度的媒界多任務處理者(LMMs)表現得遜色。這表示HMMs的多種認知功能，包括工作記憶的更新及維持、選擇性的注意力及作業轉換的能力，皆次於LMMs。有研究採用有線索的作業轉換典範時，為每一個作業設置了兩個線索，從而將總的作業轉換成本拆分為與作業轉換過程中兩個連續而不同的階段相關的部份。第一部份的成本由線索的改變導致，代表使用線索把作業心向從長期記憶抽出放於工作記憶這一階段所需要的成本。第二部份的成本由作業的改變導致，代表將作業規則應用於刺激這一階段所需的成本。第二階段的成本被大多數研究者視為真正的作業轉換成本。本研究想探討的問題是過度的媒界多任務處理所影響的是哪一階段的作業轉換能力。我們採用一份網上的媒界使用問卷選出二十名HMMs及二十名LMMs來參加實驗。實驗中，被試必須完成一個雙線索對單作業的作業轉換典範，當中的兩個作業分別為一個打字作業及一個性別判斷作業。反應時上的總作業轉換成本被拆成兩個部份: (甲)作業不變而線索改變所引起的線索轉換成本，及(乙)線索轉換成本所不能解釋的剩下的作業轉換成本。我們發現HMMs的線索轉換成本顯著地高於LMMs的線索轉換成本。然而，兩組人之間的作業轉換成本並沒有顯著差異。結果表明，HMMs只在使用線索把作業心向從長期記憶拿出來放在工作記憶這一階段遜色於LMMs。 / Heavy media multitaskers (HMMs) are found to be inferior to light media multitaskers (LMMs) in cognitive functions such as updating and maintenance of working memory representations, selectively attention, and surprisingly, the ability to switch between tasks. Research on task-switching paradigm using a 2:1 mapping between cues and tasks separates the total switch cost into costs related to two distinct, serial processing stages. The first type of cost, relating to the stage of cue-driven retrieval of task-set from long-term memory into working memory, is caused by a change in the task-indicating cue. The second type of cost, relating to the stage of application of task-rules onto the stimuli, is caused by a change of the task-set and has been regarded by some as the actual task-switch cost. In the current study, we examine which stage(s) are affected by media multitasking experience. Twenty HMMs and twenty LMMs identified using an online media-use questionnaire participated in a cued task-switching experiment involving a word typing task and a face gender classification task. The overall switch cost in response time was decomposed into two components: (a) the cue-switch cost as a result of a change of the cue with the task unchanged; and (b) the task-switch cost, which represent the switch cost not accountable by the cue-switch cost. HMMs showed a significantly larger cue-switch cost than LMMs, while the task-switch cost was similar for the two groups. Results suggest that HMMs may only be inferior in the cue-driven retrieval process of task set but not in the task-rule application stage. / Detailed summary in vernacular field only. / Lui, Fai Hong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 25-28). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Chapter Chapter 1: --- Introduction --- p.1 / Media multitasking and its chronic effects --- p.1 / Effects of media multitasking on task switching ability --- p.4 / The typical task-switching paradigm --- p.5 / Task-switching paradigm using a 2:1 mapping between cues and tasks --- p.7 / Design of the current study --- p.10 / Hypotheses of the current study --- p.11 / Chapter Chapter 2: --- 2: Experiment 1: Method --- p.15 / Participants --- p.15 / Apparatus --- p.15 / Stimuli and procedure --- p.16 / Chapter Chapter 3: --- Experiment 1: Results --- p.19 / Chapter Chapter 4: --- Experiment 2 --- p.22 / Chapter Chapter 5: --- Experiment 2: Method --- p.24 / Participants --- p.24 / Apparatus --- p.24 / Stimuli and procedure --- p.24 / Chapter Chapter 6: --- Experiment 2: Results --- p.26 / Chapter Chapter 7: --- Discussions --- p.28

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Twenty-two subjects with chronic/recurrent Epstein-Barr Virus (EBV) infection were compared with 22 controls to assess cognitive dysfunction. Subjects were compared on 15 measures of cognitive functioning from the Boston Diagnostic Aphasia Examination, Perceptual Speed, Wechsler Adult Intelligence Scale-Revised, Finger Tapping Test, Stroop Test, Trail-Making Test, Wisconsin Card Sorting Test and Revised Wechsler Memory Scale. They also were compared on measures of depression including the Beck Depression Inventory, Minnesota Multiphasic Personality Inventory (MMPI) depression subscale and SCL-90-Revised depression subscale. Group differences were assessed using discriminant analysis. Only some measures were included in this analysis, i.e. percent retention on Visual Reproduction and Logical Memory subtests of the Revised Wechsler Memory Scale, differential between time scores and between error scores on conditions three and two of the Stroop Test and total number of errors and perseverative errors on the Wisconsin Card Sorting Test. The Beck Depression Inventory was included to statistically remove depression effects from cognitive performances. Remaining measures were administered for exploratory and/or comparative purposes only. Results from discriminant analysis revealed significant group differences on the Beck, but not on any cognitive measure either before or after removal of depression effects. However, direction of group differences on cognitive measures occurred as expected. Also, a post-hoc multivariate analysis of variance revealed significant group differences on MMPI scales 1, 2 and 3 with EBV subjects showing higher elevations. Significant group differences also occurred on MMPI scale 7. Two categories of explanation for results are offered. The first suggests that cognitive deficits were missed due to shortcomings in study design. Remaining hypotheses address the possibility that no cognitive deficits occur with chronic/recurrent EBV infection. Suggestion for why EBV patients complain of cognitive deficits include discussion of hysteroid tendencies and intensification of sensations by a focus on somatic processes. The usefulness of assuming a multifactorial basis for symptoms associated with chronic/recurrent EBV infection, and the importance of abandoning the either/or approach of earlier investigators to hypothesizing about etiology, are discussed.

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It was the purpose of the present study to determine the shape of the TEPR function during a dichotic shadowing task when the imposed work load is beyond the capability of the subject.It was hypothesized that as the task became increasingly difficult, the plotted functions of the maximum TEPR and words/s produced would start out small, increase rapidly, then level off or decrease reflecting the amount of information processing actually done. Ratings of subjectively perceived effort would also follow this pattern, whereas ratings of perceived task difficulty would continue to increase. Analyses were performed on mixed between-subjects and within-subjects designs using Two-way Analyses of Variance for repeated measures. The Newman-Keuls Procedure was used for all post-hoc comparisons.The results clearly demonstrated that the maximum TEPR reflects information actually being processed rather than the imposed difficulty of the task. Subjective ratings of perceived effort appear to reflect the same. The TEPR is not a good indicator of perceived task difficulty since ratings of task difficulty continued to increase after the TEPR leveled off.

Reflective eye movementa as a function of cognitive nodes were studied in English speaking and Spanish bilingual populations (N=20). A total of 40 questions were asked with the initial, lateral eye movement recorded. Questions consisted of 20 verbal-mathematical type intended to elicit right-eye movement and 20 spatial questions intended to elicit left-eye movement. A significant difference in responses was found dependent on the type of questions asked (F=114.3421,p<.001). No significant differences were obtained between the two groups.

In order to assess flexibility in acquiring and using conflicting response rules, rats with selective lesions of the NBM or sham-lesion controls were subjected to serial reversal training in a simple operant discrimination paradigm. The NBM lesion group did not differ from the control group in acquisition of the original rules; the NBM lesion group required more time to master the changes in rules in the first reversal, but not in subsequent reversals.