為了探討注意力與年齡因素對計時行為的影響，本實驗選用事前知道計時派典（prospective paradigm）與不涉及人為時間單位之知識的計時複製方式。針對注意力的因素，本研究採用雙重作業以操弄注意力資源集中或分散，檢測其對計時作業的影響。另針對年齡的因素，本研究比較低年級小學生、高年級小學生、及大學生成人三種不同年齡組的受試。 本研究利用四種計時作業，針對三個不同年齡層的受試進行對兩種不等的時距計時資料收集。計時作業及年齡因子的實驗設計採受試者間設計，而時距因子則採受試者內設計。研究結果發現（1）低年級組的計時準確性較高年級組或成人組差；（2）受試在雙重作業的計時表現的確較單一作業差，這個計時受干擾的結果，在複雜的雙重作業又較在簡單雙重作業明顯，且年紀愈小的受試所受干擾影響愈大；（3）三年齡層受試在雙重作業中皆有低估目標時距的現象，其中以低年級在複雜雙重作業中的低估程度最明顯；（4）低年級組的計時能力之穩定性較高年級或成人組低；（5）在無需對不斷出現之無意義刺激作偵測反應時，三年齡受試的計時準確性未受影響。 這些結果顯示計時的誤差的確隨著注意力需分派於非時間作業的增加，受試所複製的時距也隨之縮短。這項由於注意力分散所致的計時誤差在國小低年級組最明顯，但隨著年齡的成長及腦發展愈臻成熟，這項影響效果愈趨式微，致使計時的表現愈正確。 關鍵詞：時間複製、年齡與發展、雙重作業、注意力、小學生、純量計時 / The purpose of this study was to investigate the effects of the attention and age on time estimation based on the prospective timing paradigm. Four timing tasks, with different degrees of attentional requirement, were utilized to test timing of reproducing the target intervals in three groups of different ages including the lower-grade (M= 7.5 years), higher-grade (M= 11.2 years) elementary school students and adult (M= 20.1 years). The subjects in this work were asked to estimate a stimulus duration lasting for 7 or 14 s, during which they are required to either do or do not perform a concurrent non-temporal task. Thus, the experimental design for the present study was mixed with between-subject factors (age and task) and a within-subject factor (target interval). The results showed (1) the lower-grade children performed less accurate than the higher-grade children; (2) all subjects had worse timing performance in the dual-task condition than the single-task or control condition, which effect was most evident in the lower-grade children; (3) all subjects reproduced shorter interval as compared to the target interval, which effect was most apparently observed from the dual-task for the lower-grade children; (4) the lower-grade children had less reliability in timing; and (5) the effect of age on the single-task and control condition is not significant. Together, these data indicate that concurrent non-temporal task cause temporal reproduction shorter, especially under high attention demand in lower-grade children. In addition to the influence by the task complexity, the accuracy of timing estimation depends on the age. Keywords: time reproduction、age and development、dual task、attention、elementary school student、Scalar expectancy theory(SET)

區辨性增強低頻反應作業 (differential reinforcement of low-rate responding task, DRL task) 為一與時間相關聯之操作式制約行為作業，該作業常用於計時行為、行為抑制功能、或抗焦慮與抗憂鬱症等藥物之行為藥理研究的探討。雖然DRL作業是一種實驗室常用的動物行為模式，但是對於上述行為或藥理機制的探討往往缺乏一致性的解釋，其中可能的原因為DRL作業的行為同時包含了計時與行為抑制的成份。針對上述問題，本研究將以DRL行為作業為研究主題，探討作業習得歷程之神經機制。首先根據DRL作業之行為內涵，將作業的習得分為行為抑制與計時先後表現的兩個階段；並依據過去的研究文獻整理出的八個與行為抑制和計時表現相關之大腦區塊，以c-Fos免疫組織化學染色法探討行為抑制和計時的神經機制。實驗結果發現受試於行為抑制的表現階段，其眶眼皮質、內側前額葉皮質、與海馬CA1區域的c-Fos表現量較高；而在計時行為的表現階段，除了和行為抑制有關的三個大腦區塊外，尚有前扣帶迴、紋狀體、與齒狀迴呈現c-Fos表現量增加的現象。綜合以上結果，DRL-10秒作業於學習初期所進行的行為抑制可能和前額葉皮質與海馬體的神經互動有關；而學習較末階段的計時表現，則可能需要前額葉皮質、紋狀體、與海馬等三處較多的次級區域的組織加入，形成神經網路的方式支援之。 / Differential reinforcement of low-rate responding (DRL) task was an operant conditioned behavior based on temporal contingency. This task has been widely used to investigate the behavioral components of timing and behavioral inhibition, which is frequently used for pharmacological screening of anxiolytic and antidepressant drugs. Despite of being widely used as an animal behavioral model in the laboratory, but the performance of the DRL task was varied and inconsistent when the drug test conducted. One way to encounter this problematic issue is to differentiate the distinct behavioral components of DRL task and correlate the involved neural substrates, which was the theme investigated in the present study. This study first characterized the acquisition process of the DRL-10 sec task into behavioral inhibition and the timing stages, and then assessed the c-Fos levels by immunohistochemistry in the eight brain areas that potentially involved in behavioral inhibition and the timing processes. Regarding the stage of behavioral inhibition, significant increases in c-Fos-positive neurons were observed in the orbitofrontal cortex (OFC), the medial prefrontal cortex (mPFC), and the hippocampal CA1 area. At the stage of the timing being acquired, c-Fos immunohistochemical activity was highly expressed in the anterior cingulated cortex (ACC), OFC, mPFC, the dorsolateral striatum (dlS), the dentate gyrus (DG), and the hippocampal CA1 area. Together, these results showed that the functioning dual paths between the hippocampus CA1 and the prefrontal cortex (OFC and mPFC) are critically essential for developing the appropriate performance via behavioral inhibition in the early-stage of the DRL task and with three other areas (ACC, dlS, and DG) being recruited, an anatomical circuitry connecting prefrontal/striatal/hippocampal structures were involved in the acquisition of interval timing toward the later establishment of the DRL behavior.