電視廣播大學(xué)廣告心理學(xué)復(fù)習(xí)題參考資料小抄.doc

考試題型：單項(xiàng)選擇；填空；名詞解釋；簡答；案例分析。卷面分?jǐn)?shù)100分，占總分70%；平時(shí)分?jǐn)?shù)占總分30%，包括：課堂作業(yè)及課后作業(yè)注意：有些題是要舉例的，這個(gè)沒有統(tǒng)一答案，給大家寫上該內(nèi)容在書上的頁數(shù)，大家看完書理解了自己舉例。廣告心理學(xué)復(fù)習(xí)題1. 廣告心理學(xué)的研究對象和基本研究內(nèi)容是什么?研究對象：消費(fèi)者與廣告活動(dòng)互相作用過程中產(chǎn)生的心理現(xiàn)象及其存在的心理活動(dòng)規(guī)律研究內(nèi)容：傳播心理，說服心理，相關(guān)環(huán)境影響因素以及廣告心理效果測定，品牌心理。2. 簡述廣告心理學(xué)的產(chǎn)生和發(fā)展過程。產(chǎn)生：1879年德國心理學(xué)家馮特就建立第一個(gè)心理學(xué)實(shí)驗(yàn)室，標(biāo)志著科學(xué)心理學(xué)的誕生。1895年，美國明尼蘇達(dá)大學(xué)心理實(shí)驗(yàn)室的H.蓋爾率先采用問卷法，研究消費(fèi)者對廣告及廣告商品的態(tài)度和看法，他的研究是廣告心理學(xué)方面最早的研究。1901年起兩年內(nèi)美國西北大學(xué)的心理學(xué)家W.D.斯科特發(fā)表12篇有關(guān)廣告心理的文章，1903年將自己有關(guān)廣告心理學(xué)的研究結(jié)果匯集出版，書名為廣告原理，此書的出版標(biāo)志著廣告心理學(xué)的誕生。1908年德國心理學(xué)家敏斯特伯格出版廣告心理學(xué)，1912年發(fā)表心理學(xué)與經(jīng)濟(jì)生活一書。發(fā)展過程：基本的心理學(xué)理論影響到心理學(xué)的每一個(gè)領(lǐng)域，包括廣告心理學(xué)。第一次世界大戰(zhàn)后，社會(huì)心理學(xué)家對說服等心理學(xué)問題繼續(xù)進(jìn)行了很多研究，取得突出的發(fā)展。這些研究成果廣泛應(yīng)用于廣告實(shí)踐，從而促進(jìn)了廣告心理學(xué)的發(fā)展。20世紀(jì)40年代后，對消費(fèi)者深層動(dòng)機(jī)的探討引起人們極大的興趣。20世紀(jì)50年代人本主義心理學(xué)的需要層次理論為廣告心理學(xué)中消費(fèi)者需要的研究提供了基礎(chǔ)。20世紀(jì)60年代后，受認(rèn)知心理學(xué)影響，廣告心理學(xué)研究領(lǐng)域內(nèi)的認(rèn)知研究越來越多，研究技術(shù)手段也大大提高。我國廣告心理學(xué)研究起步較晚，受西方研究取向的影響比較大。20世紀(jì)80年代末90年代初，我國臺(tái)灣出版的一些廣告心理學(xué)書籍對廣告心理的研究起到促進(jìn)作用。3. 學(xué)習(xí)廣告心理學(xué)的意義有哪些？廣告可以激發(fā)消費(fèi)者的購買動(dòng)機(jī)并提供相關(guān)信息廣告創(chuàng)意、廣告設(shè)計(jì)需要把握消費(fèi)者的心理行為特征準(zhǔn)確的把握消費(fèi)者的價(jià)值觀和消費(fèi)行為特征需要采用科學(xué)的心理學(xué)研究方法4. 具備什么特征的廣告對受眾的吸引力大？大幅面廣告、廣告方式采用活動(dòng)或者變化的、彩色的廣告、恰當(dāng)?shù)奈恢?、新異性、有趣的信息、符合受眾的消費(fèi)需要、懸念廣告5. 注意的特點(diǎn)和功能？特多：指向性和集中性功能：選擇功能、維持功能、調(diào)節(jié)功能。6. 從心理學(xué)的角度分析，為什么好的懸念廣告能起到好的廣告效果？制造懸念引起受眾的好奇心，使得他們對廣告從被動(dòng)狀態(tài)轉(zhuǎn)為主動(dòng)狀態(tài)，讓他們主動(dòng)去注意懸念的結(jié)果。7. 什么是感覺閾限？什么是閾下知覺廣告？感覺閾限（sensory threshold），用于測量感覺系統(tǒng)感受性大小的指標(biāo)，用剛能引起感覺的刺激量來表示?？煞譃榻^對感覺閾限和差別感覺閾限兩類。 8. 閾下知覺廣告和植入式廣告（例如隱含在電影或電視畫面中的廣告）的區(qū)別是什么？植入式廣告視覺器官雖然可以接收到閃過的消息（能夠意識(shí)到），但是由于廣告閃現(xiàn)速度太快，或刺激強(qiáng)度太弱或太強(qiáng)，人們往往認(rèn)識(shí)不到這是廣告，從而在不知不覺中接受了廣告。而閾下知覺廣告是人們意識(shí)不到自己看到了。9. 有哪些因素影響知覺的解釋？在廣告中可以怎樣加以應(yīng)用？舉例說明。影響因素：經(jīng)驗(yàn)因素、情緒因素、態(tài)度因素。應(yīng)用：45頁人們利用經(jīng)驗(yàn)進(jìn)行感知。有時(shí)在知覺事物時(shí)，可能不會(huì)看到事物的全部，但是人們一樣可以做出正確的感知。知覺過程中的推論。人們在知覺過程中會(huì)進(jìn)行推論，利用這種現(xiàn)象制作的廣告往往也會(huì)收到意想不到的效果。10. 舉例說明知覺特性在廣告中的應(yīng)用。43頁11. 記憶過程包含哪幾個(gè)環(huán)節(jié)？記憶系統(tǒng)是由哪幾個(gè)部分組成的？包含識(shí)記、保持和提取三個(gè)環(huán)節(jié)。記憶系統(tǒng)是由感覺記憶、短時(shí)記憶和長時(shí)記憶組成。12. 廣告播放一遍很難讓人記住，重復(fù)播放多了又惹人煩。從心理學(xué)角度分析廣告重復(fù)的積極作用和消極作用。積極作用：不斷的重復(fù)廣告在一定程度上說明該產(chǎn)品仍是富有競爭力的，能夠給消費(fèi)者以信心，同時(shí)，能夠幫助消費(fèi)者識(shí)記廣告中的信息，并且保持對這些信息的記憶。消極作用：過度重復(fù)鑒于沒有新的內(nèi)容而導(dǎo)致厭倦的產(chǎn)生。隨著重復(fù)次數(shù)的繼續(xù)增加，以致于把認(rèn)知活動(dòng)轉(zhuǎn)移到其他無關(guān)的信息，其結(jié)果難以產(chǎn)生態(tài)度的改變，甚至導(dǎo)致消極態(tài)度。 13. 舉例說明廣告該如何重復(fù)才能起到積極效果。根據(jù)學(xué)習(xí)過程的“先多后少”和遺忘過程的“先快后慢”的特點(diǎn)，對于廣告發(fā)布的時(shí)間重復(fù)間隔應(yīng)采用“先短后長”的策略最為合適。根據(jù)“先短后長”的策略，廣告電話重復(fù)內(nèi)容就要有變化，具有不同創(chuàng)意的廣告更易被受眾記住。比如香奈兒廣告，他的香水始終展現(xiàn)的是高貴優(yōu)雅的形象，雖然在電視、雜志也經(jīng)?？吹?，但是他的廣告創(chuàng)意卻是不斷變化的，每次都給人耳目一新的感覺。14. 怎樣利用記憶規(guī)律來提高廣告效果？舉例說明 65頁廣告的重復(fù)策略。把廣告信息編碼組塊。增加對象維度。 利用漢語特點(diǎn)組織編碼。15. 表象和想象的區(qū)別和聯(lián)系是什么？創(chuàng)造想象和再造想象有什么區(qū)別？表象是在知覺的基礎(chǔ)上產(chǎn)生的，構(gòu)成表象的材料來自過去知覺過的內(nèi)容。想象是新形象的創(chuàng)造，想象的內(nèi)容往往出現(xiàn)在現(xiàn)實(shí)以前，或者是現(xiàn)實(shí)中不可能出現(xiàn)的事物。對已有表象進(jìn)行加工改造而形成新形象的過程就是想象。所以想象是在記憶表象的基礎(chǔ)上產(chǎn)生，是對記憶表象的進(jìn)一步加工。再造想象是根據(jù)詞語的描述或者圖示，在頭腦中形成與之相符合或者相仿的新形象的過程。而再造想象不依據(jù)現(xiàn)場的描述，獨(dú)立創(chuàng)造新形象的過程，再造想象具有首創(chuàng)性、獨(dú)立性和新穎性的特點(diǎn)。16. 舉例說明廣告中的創(chuàng)造想象。 77頁17. 什么是聯(lián)覺？什么是聯(lián)想？聯(lián)想和聯(lián)覺在廣告中的作用是什么？聯(lián)覺是感覺相互作用的一種特殊表現(xiàn)， 由一種已經(jīng)產(chǎn)生的感覺，引起另一種感覺的心理作用。聯(lián)想是由當(dāng)前感知的事物回憶起另一種有關(guān)的事物，或者由想起的一種事物聯(lián)想起有關(guān)的另一種事物。聯(lián)想的作用：廣告可以利用人們的聯(lián)想，使廣告的時(shí)間 和空間在人們的心理上得以擴(kuò)大和延伸。聯(lián)覺的作用：聯(lián)覺現(xiàn)象用于廣告設(shè)計(jì)當(dāng)中，可以讓受眾從視覺的畫面中“聽見”、“聞到”、“接觸到”、“嘗到”什么，從聽到的聲音中“看到”、“聞到”、“接觸到”、“嘗到”什么，這樣就在一定程度上突破了媒體的局限性，給受眾帶來跟豐富的體驗(yàn)。18. 態(tài)度有哪些結(jié)構(gòu)成分？廣告商如何使受眾形成或改變對某種產(chǎn)品的態(tài)度？態(tài)度是由情感、認(rèn)知和行為構(gòu)成的綜合體。改變情感成分（經(jīng)典調(diào)節(jié)反射、激發(fā)對廣告本身的情感、更多接觸）、改變行為成分、改變認(rèn)知成分，是常用的策略和方法（改變信念、增加新的信念、改變權(quán)重）19. 態(tài)度改變的ELM模型的基本觀點(diǎn)是什么？ELM理論認(rèn)為，品牌卷入程度是決定信息如何被加工處理以及態(tài)度如何改變的關(guān)鍵因素。高卷入程度能導(dǎo)致一條通向態(tài)度改變的“中樞路徑”，在中樞路徑中，態(tài)度改變是消費(fèi)者認(rèn)真考慮和綜合信息的結(jié)果。在此過程中，消費(fèi)者主動(dòng)考慮廣告的信息來源、商標(biāo)產(chǎn)品等，收集和檢驗(yàn)過去的有關(guān)體驗(yàn)，分析判斷廣告商品性能等，最后作出綜合的評價(jià)。而低卷入程度只能導(dǎo)致一條通向態(tài)度改變的“邊緣路徑”。這時(shí)消費(fèi)者只是對所獲得的信息進(jìn)行粗淺的處理，并依據(jù)信息中的一些顯而易見的線索形成對品牌或者店鋪的印象。從態(tài)度改變的效果來看，中樞路徑所引起的態(tài)度變化比邊緣路徑要持久，中樞路徑所形成的態(tài)度可能比邊緣路徑形成的態(tài)度預(yù)測后來的行為要好。20. 如何增強(qiáng)廣告的說服力？提高信息源的可信度、提供雙面貓信息、給消費(fèi)者以積極的情感體驗(yàn)21. 如何根據(jù)消費(fèi)者的需要制定廣告訴求策略？滿足消費(fèi)者的優(yōu)勢需要根據(jù)不同消費(fèi)群體的興趣點(diǎn)選擇廣告訴求點(diǎn)把握需要的動(dòng)態(tài)特征根據(jù)競爭對手的廣告主題選擇適當(dāng)?shù)膹V告訴求點(diǎn)22. 什么是廣告的理性訴求？為什么獨(dú)特賣點(diǎn)說屬于理性訴求？該如何尋找獨(dú)特賣點(diǎn)？在廣告中突出自己商品所具有的特性及優(yōu)越性，提出事實(shí)或進(jìn)行特性比較，通過展示商品的固有特性、用途和使用方法等，提供關(guān)于商品的事實(shí)性信息而使消費(fèi)者形成一定的品牌態(tài)度，這種廣告訴求方式即是理性訴求，這種廣告策略被稱為“硬銷售”。USP的基本前提是將消費(fèi)者視為理性思維者，認(rèn)為他們在做出購買決策時(shí)追求利益最大化。由此出發(fā)，廣告應(yīng)建立在理性訴求上，宣傳能帶給消費(fèi)者的實(shí)際利益。也就是說，對準(zhǔn)消費(fèi)者的需要，承諾提供給他們實(shí)惠，同時(shí)給出這種承諾的事實(shí)性支持理由，以回答消費(fèi)者的疑問。第一，每一則廣告必須向消費(fèi)者傳達(dá)一個(gè)消費(fèi)主張，這個(gè)主張必須讓消費(fèi)者明白“買這樣的商品，你會(huì)得到什么樣的特殊利益”。第二，這一主張必須是競爭對手做不到或者沒有、無法提出的，在品牌和訴求方面是獨(dú)一無二的。第三，這一主張必須聚焦在一個(gè)點(diǎn)上，集中強(qiáng)力打動(dòng)、感染和吸引消費(fèi)者來 購買廣告商品。23. 制約廣告理性訴求效果的因素有哪些？與商品有關(guān)的因素。產(chǎn)品的生命周期與同質(zhì)化程度。購買風(fēng)險(xiǎn)水平。商品的吸引力。與消費(fèi)者有關(guān)的因素。消費(fèi)者對有關(guān)商品的知識(shí)和經(jīng)驗(yàn)。消費(fèi)者的社會(huì)經(jīng)濟(jì)地位。消費(fèi)者的購買預(yù)期。消費(fèi)者的個(gè)性心理特點(diǎn)。24. 情感廣告是如何起到說服作用的？情感廣告是說服作業(yè)具體表現(xiàn)在積極地情感反應(yīng)會(huì)導(dǎo)致對廣告中品牌/商品的積極態(tài)度?？梢酝ㄟ^直接的方式和間接的方式起到作用。直接作用方式。是指積極或消極的情感直接造成態(tài)度的變化。經(jīng)典條件反射作用過程。對客體積極態(tài)度是可以通過經(jīng)典條件化引起的。社會(huì)學(xué)習(xí)。借助于觀察和模仿，即通過廣告中人物的活動(dòng)和情感體驗(yàn)使自己得到同樣的體驗(yàn)和感受，而廣告中的人物的活動(dòng)和情感體驗(yàn)是同使用或不使用特定的產(chǎn)品聯(lián)系在一起的。間接作用方式。情感通過對信息加工過程的影響，間接的影響態(tài)度的變化。情感對信息加工規(guī)程的影響，一種表現(xiàn)是當(dāng)呈現(xiàn)的信息同受眾的情感體驗(yàn)一致時(shí)，人們對呈現(xiàn)信息的回憶成績要比對不一致信息回憶的更好。另一種表現(xiàn)是，在信息加工程度上對于令人振奮的說服信息，積極的情感體驗(yàn)者比消極的情感體驗(yàn)者了解的更多。而令人沮喪的說服信息則相反。25. 廣告中常見的情感類型有哪些？舉例說明。 142頁美感、親熱感、幽默感、害怕感26. 廣告怎樣使用懼怕訴求才能取得好效果？當(dāng)懼怕訴求引起的恐懼程度很低時(shí)，不足以使被說服者產(chǎn)生較大的心理壓力，說服效果不好。如果懼怕或者威脅的訴求太強(qiáng)，可能激發(fā)消費(fèi)者知覺防御機(jī)制，從而導(dǎo)致他們對面臨的問題產(chǎn)生回避反應(yīng)，拒不接受說服信息，也不會(huì)產(chǎn)生好的說服效果。一般情況下，中等強(qiáng)度的威脅說服效果最好。27. 什么是廣告的心理效果？如何測評廣告的心理效果？廣告的心理效果也稱廣告的接觸效果。是指廣告呈現(xiàn)之后使接受者產(chǎn)生的各種心理效應(yīng)，包括對受眾在知覺、記憶、理解、情緒情感、動(dòng)機(jī)與行為等諸多心理特征方面的影響。這是廣告效果最核心的部分，對它的測定最能反映出廣告宣傳效力的大小。廣告的心理效果測定，包括消費(fèi)者對廣告信息的注意、星期、情緒、記憶、理解、信任、欲望、行動(dòng)等心理活動(dòng)的不同側(cè)面，概括起來說，就是要了解消費(fèi)者的態(tài)度和行為反應(yīng)。測量的主要項(xiàng)目有：注意度、知名度、理解度、記憶度、信任度、購買動(dòng)機(jī)、視聽率、行動(dòng)率等。實(shí)際上，對廣告的心理效果的測定，在事前、事中、事后測評中都要涉及，這也反映出他在廣告效果測定中的重要地位。28. 什么是品牌的識(shí)別特征？品牌的外部識(shí)別特征有哪些？品牌的內(nèi)部識(shí)別特征有哪些？試舉例說明。 173頁品牌的識(shí)別性特征是指品牌名稱、標(biāo)識(shí)物等符號(hào)系統(tǒng)帶來的外在特征。企業(yè)通過品牌整體規(guī)劃和設(shè)計(jì)所獲得的品牌符號(hào)具有特殊的個(gè)性和強(qiáng)烈的視覺沖擊力,以幫助目標(biāo)受眾來區(qū)別本產(chǎn)品和其他產(chǎn)品。 外部特征：品牌名稱、標(biāo)識(shí)、吉祥物、形象代言人和其他視覺特征。內(nèi)部特征：價(jià)值觀、信仰、情感和其他個(gè)性特點(diǎn)，統(tǒng)稱為品牌個(gè)性。29. 什么是品牌的美譽(yù)度？如何利用情感的遷移來增強(qiáng)品牌的美譽(yù)度？美譽(yù)度是大眾對商品品質(zhì)或者企業(yè)特質(zhì)的反映。這種反映是在認(rèn)知的基礎(chǔ)上，一方面形成積極信念（相信這種商品或這個(gè)企業(yè)會(huì)給自己提供某種利益），同時(shí)又伴有美好的情感體驗(yàn)（好感度），產(chǎn)生了積極的評價(jià)。美譽(yù)度是引發(fā)認(rèn)牌購買的直接動(dòng)力。一是借助于他人的良好聲譽(yù)來提高品牌的美譽(yù)度，“名人廣告”和“名人品牌”就是與這個(gè)途徑相應(yīng)的市場策略；二是利用成熟品牌的聲譽(yù)來創(chuàng)建新品牌，這種從已有的核心品牌而來的擴(kuò)展或延伸，即通常所說的“品牌延伸”。30. 品牌的忠誠度體現(xiàn)在哪些方面，如何測量品牌的忠誠度？主要體現(xiàn)在認(rèn)牌購買的行為模式中。測量在選擇商品的順序、購買比例、重復(fù)購買和品牌的偏好。31. 品牌的知名度、美譽(yù)度和忠誠度三者之間的關(guān)系如何？舉例說明。 181頁品牌態(tài)度發(fā)展的第一步，是部分品牌從眾多品牌中進(jìn)入到消費(fèi)大眾“了解”的行列，從而獲得了知名度。其中的一些又進(jìn)一步深化，使人們相信它們能夠提供某種或某些利益，因而對它們產(chǎn)生依賴和好感。這樣它們便獲得了美譽(yù)度，成為“可接受”的 品牌。購買后的消費(fèi)或使用，使消費(fèi)者感到滿意，從而獲得正強(qiáng)化，形成對品牌的忠誠，產(chǎn)生了認(rèn)牌購買，即“再購買”或“持續(xù)購買”，即忠誠度。32. 網(wǎng)絡(luò)廣告有哪些常見的形式？旗幟廣告、圖標(biāo)廣告、文字鏈接、電子郵件廣告、新聞組廣告、網(wǎng)上問卷調(diào)查、關(guān)鍵字廣告、互動(dòng)游戲式廣告、壁紙廣告、彈出廣告、通欄廣告、巨型廣告。33. 與傳統(tǒng)的媒體廣告相比，網(wǎng)絡(luò)廣告的優(yōu)劣如何？傳播范圍極大、非強(qiáng)迫性傳送資訊、受眾數(shù)量可準(zhǔn)確統(tǒng)計(jì)、靈活的實(shí)時(shí)性、強(qiáng)烈 交互性與感官性。請您刪除一下內(nèi)容，O(_)O謝謝！2016年中央電大期末復(fù)習(xí)考試小抄大全，電大期末考試必備小抄，電大考試必過小抄Acetylcholine is a neurotransmitter released from nerve endings (terminals) in both the peripheral and the central nervous systems. It is synthesized within the nerve terminal from choline, taken up from the tissue fluid into the nerve ending by a specialized transport mechanism. The enzyme necessary for this synthesis is formed in the nerve cell body and passes down the axon to its end, carried in the axoplasmic flow, the slow movement of intracellular substance (cytoplasm). Acetylcholine is stored in the nerve terminal, sequestered in small vesicles awaiting release. When a nerve action potential reaches and invades the nerve terminal, a shower of acetylcholine vesicles is released into the junction (synapse) between the nerve terminal and the effector cell which the nerve activates. This may be another nerve cell or a muscle or gland cell. Thus electrical signals are converted to chemical signals, allowing messages to be passed between nerve cells or between nerve cells and non-nerve cells. This process is termed chemical neurotransmission and was first demonstrated, for nerves to the heart, by the German pharmacologist Loewi in 1921. Chemical transmission involving acetylcholine is known as cholinergic. Acetylcholine acts as a transmitter between motor nerves and the fibres of skeletal muscle at all neuromuscular junctions. At this type of synapse, the nerve terminal is closely apposed to the cell membrane of a muscle fibre at the so-called motor end plate. On release, acetylcholine acts almost instantly, to cause a sequence of chemical and physical events (starting with depolarization of the motor endplate) which cause contraction of the muscle fibre. This is exactly what is required for voluntary muscles in which a rapid response to a command is required. The action of acetylcholine is terminated rapidly, in around 10 milliseconds; an enzyme (cholinesterase) breaks the transmitter down into choline and an acetate ion. The choline is then available for re-uptake into the nerve terminal. These same principles apply to cholinergic transmission at sites other than neuromuscular junctions, although the structure of the synapses differs. In the autonomic nervous system these include nerve-to-nerve synapses at the relay stations (ganglia) in both the sympathetic and the parasympathetic divisions, and the endings of parasympathetic nerve fibres on non-voluntary (smooth) muscle, the heart, and glandular cells; in response to activation of this nerve supply, smooth muscle contracts (notably in the gut), the frequency of heart beat is slowed, and glands secrete. Acetylcholine is also an important transmitter at many sites in the brain at nerve-to-nerve synapses. To understand how acetylcholine brings about a variety of effects in different cells it is necessary to understand membrane receptors. In post-synaptic membranes (those of the cells on which the nerve fibres terminate) there are many different sorts of receptors and some are receptors for acetylcholine. These are protein molecules that react specifically with acetylcholine in a reversible fashion. It is the complex of receptor combined with acetylcholine which brings about a biophysical reaction, resulting in the response from the receptive cell. Two major types of acetylcholine receptors exist in the membranes of cells. The type in skeletal muscle is known as nicotinic; in glands, smooth muscle, and the heart they are muscarinic; and there are some of each type in the brain. These terms are used because nicotine mimics the action of acetylcholine at nicotinic receptors, whereas muscarine, an alkaloid from the mushroom Amanita muscaria, mimics the action of acetylcholine at the muscarinic receptors. Acetylcholine is the neurotransmitter produced by neurons referred to as cholinergic neurons. In the peripheral nervous system acetylcholine plays a role in skeletal muscle movement, as well as in the regulation of smooth muscle and cardiac muscle. In the central nervous system acetylcholine is believed to be involved in learning, memory, and mood. Acetylcholine is synthesized from choline and acetyl coenzyme A through the action of the enzyme choline acetyltransferase and becomes packaged into membrane-boundvesicles. After the arrival of a nerve signal at the termination of an axon, the vesicles fuse with the cell membrane, causing the release of acetylcholine into thesynaptic cleft. For the nerve signal to continue, acetylcholine must diffuse to another nearby neuron or muscle cell, where it will bind and activate areceptorprotein. There are two main types of cholinergic receptors, nicotinic and muscarinic. Nicotinic receptors are located at synapses between two neurons and at synapses between neurons and skeletal muscle cells. Upon activation a nicotinic receptor acts as a channel for the movement of ions into and out of the neuron, directly resulting indepolarizationof the neuron. Muscarinic receptors, located at the synapses of nerves with smooth or cardiac muscle, trigger a chain of chemical events referred to as signal transduction. For a cholinergic neuron to receive another impulse, acetylcholine must be released from the receptor to which it has bound. This will only happen if the concentration of acetylcholine in the synaptic cleft is very low. Low synaptic concentrations of acetylcholine can be maintained via a hydrolysis reaction catalyzed by the enzyme acetylcholinesterase. This enzyme hydrolyzes acetylcholine into acetic acid and choline. If acetylcholinesterase activity is inhibited, the synaptic concentration of acetylcholine will remain higher than normal. If this inhibition is irreversible, as in the case of exposure to many nerve gases and some pesticides, sweating, bronchial constriction, convulsions, paralysis, and possibly death can occur. Although irreversible inhibition is dangerous, beneficial effects may be derived from transient (reversible) inhibition. Drugs that inhibit acetylcholinesterase in a reversible manner have been shown to improve memory in some people with Alzheimers disease. abstract expressionism, movement of abstract painting that emerged in New York City during the mid-1940s and attained singular prominence in American art in the following decade; also called action painting and the New York school. It was the first important school in American painting to declare its independence from European styles and to influence the development of art abroad. Arshile Gorky first gave impetus to the movement. His paintings, derived at first from the art of Picasso, Mir, and surrealism, became more personally expressive. Jackson Pollocks turbulent yet elegant abstract paintings, which were created by spattering paint on huge canvases placed on the floor, brought abstract expressionism before a hostile public. Willem de Koonings first one-man show in 1948 established him as a highly influential artist. His intensely complicated abstract paintings of the 1940s were followed by images of Woman, grotesque versions of buxom womanhood, which were virtually unparalleled in the sustained savagery of their execution. Painters such as Philip Guston and Franz Kline turned to the abstract late in the 1940s and soon developed strikingly original stylesthe former, lyrical and evocative, the latter, forceful and boldly dramatic. Other important artists involved with the movement included Hans Hofmann, Robert Motherwell, and Mark Rothko; among other major abstract expressionists were such painters as Clyfford Still, Theodoros Stamos, Adolph Gottlieb, Helen Frankenthaler, Lee Krasner, and Esteban Vicente. Abstract expressionism presented a broad range of stylistic diversity within its largely, though not exclusively, nonrepresentational framework. For example, the expressive violence and activity in paintings by de Kooning or Pollock marked the opposite end of the pole from the simple, quiescent images of Mark Rothko. Basic to most abstract expressionist painting were the attention paid to surface qualities, i.e., qualities of brushstroke and texture; the use of huge canvases; the adoption of an approach to space in which all parts of the canvas played an equally vital role in the total work; the harnessing of accidents that occurred during the process of painting; the glorification of the act of painting itself as a means of visual communication; and the attempt to transfer pure emotion directly onto the canvas. The movement had an inestimable influence on the many varieties of work that followed it, especially in the way its proponents used color and materials. Its essential energy transmitted an enduring excitement to the American art scene. Science and technology is quite a broad category, and it covers everything from studying the stars and the planets to studying molecules and viruses. Beginning with the Greeks and Hipparchus, continuing through Ptolemy, Copernicus and Galileo, and today with our work on the International Space Station, man continues to learn more and more about the heavens. From here, we look inward to biochemistry and biology. To truly understand biochemistry, scientists study and see the unseen bystudying the chemistry of biological processes. This science, along with biophysics, aims to bring a better understanding of how bodies work from how we turn food into energy to how nerve impulses transmit.analytic geometry, branch ofgeometryin which points are represented with respect to a coordinate system, such asCartesian coordinates, and in which the approach to geometric problems is primarily algebraic. Its most common application is in the representation of equations involving two or three variables as curves in two or three dimensions or surfaces in three dimensions. For example, the linear equationax+by+c=0 represents a straight line in thexy-plane, and the linear equationax+by+cz+d=0 represents a plane in space, wherea, b, c,anddare constant numbers (coefficients). In this way a geometric problem can be translated into an algebraic problem and the methods of algebra brought to bear on its solution. Conversely, the solution of a problem in algebra, such as finding the roots of an equation or system of equations, can be estimated or sometimes given exactly by geometric means, e.g., plotting curves and surfaces and determining points of intersection. In plane analytic geometry a line is frequently described in terms of its slope, which expresses its inclination to the coordinate axes; technically, the slopemof a straight line is the (trigonometric) tangent of the angle it makes with thex-axis. If the line is parallel to thex-axis, its slope is zero. Two or more lines with equal slopes are parallel to one another. In general, the slope of the line through the points (x1,y1) and (x2,y2) is given bym= (y2-y1) / (x2-x1). The conic sections are treated in analytic geometry as the curves corresponding to the general quadratic equationax2+bxy+cy2+dx+ey+f=0, wherea, b, fare constants anda, b,andcare not all zero. In solid analytic geometry the orientation of a straight line is given not by one slope but by its direction cosines, , , and , the cosines of the angles the line makes with thex-, y-,andz-axes, respectively; these satisfy the relationship 2+2+2= 1. In the same way that the conic sections are studied in two dimensions, the 17 quadric surfaces, e.g., the ellipsoid, paraboloid, and elliptic paraboloid, are studied in solid analytic geometry in terms of the general equationax2+by2+cz2+dxy+exz+fyz+px+qy+rz+s=0. The methods of analytic geometry have been generalized to four or more dimensions and have been combined with other branches of geometry. Analytic geometry was introduced by RenDescartesin 1637 and was of fundamental importance in the development of thecalculusby Sir Isaac Newton and G. W. Leibniz in the late 17th cent. More recently it has served as the basis for the modern development and exploitation ofalgebraic geometry. circle, closed plane curve consisting of all points at a given distance from some fixed point, called the center. A circle is a conic section cut by a plane perpendicular to the axis of the cone. The term circle is also used to refer to the region enclosed by the curve, more properly called a circular region. The radius of a circle is any line segment connecting the center and a point on the curve; the term is also used for the length r of this segment, i.e., the common distance of all points on the curve from the center. Similarly, the circumference of a circle is either the curve itself or its length of arc. A line segment whose two ends lie on the circumference is a chord; a chord through the center is the diameter. A secant is a line of indefinite length intersecting the circle at two points, the segment of it within the circle being a chord. A tangent to a circle is a straight line touching the circle at only one point, the point of contact, or tangency, and is always perpendicular to the radius drawn to this point. A circle is inscribed in a polygon if each side of the polygon is tangent to the circle; a circle is circumscribed about a polygon if all the vertices of the polygon lie on the circumference. The length of the circumference C of a circle is equal to (see pi) times twice the radius distance r, or C=2r. The area A bounded by a circle is given by A=r2. Greek geometry left many unsolved problems about circles, including the problem of squaring the circle, i.e., constructing a square with an area equal to that of a given circle, using only a straight edge and compass; it was finally proved impossible in the late 19th cent. (see geometric problems of antiquity). In modern mathematics the circle is the basis for such theories as inversive geometry and certain non-Euclidean geometries. The circle figures significantly in many cultures. In religion and art it frequently symbolizes heaven, eternity, or the universe.