摘要
在以往的研究中,类比推理时而是一种逻辑意义上的比较类推法;时而是一种推理心理的加工过程;时而是一种问题解决和学习的迁移过程。这使得该领域的研究呈现纷繁复杂的状态。然而,心理学界研究类比推理的初衷是想弄清楚科学发现和创造性思维活动所依托的核心认知机制——类比推理的心理加工机制。尽管国内外关于类比推理的研究成果已经颇为丰富,但大部分研究仍然是建立在对类比推理的传统理解之上,这种传统的理解是不利于了解这种独特的思维机制。
研究将类比推理的概念区分为广义类比推理和狭义类比推理。并认为,狭义类比推理所具有的特点,与这种创造性思维更加相符。所谓狭义类比推理(analogical reasoning, reason by analogy),是指通过类比比较发现两个不同事物间共有的本质关系,并通过比较之后的科学思维活动,产生出创新意义的成果。狭义类比推理侧重于相当难度的科学发现和创新活动,是更高层次的认知能力,是一种需要更多认知努力的由已知推导未知的心智活动。它认为发现关系固然重要,但使本质关系得以正确的运用和转换,保证创新成果的实现则更重要。我们知道,科学发现和创新活动中遇到的问题大多是复杂而模糊界定的。即便是发现了本质关系,但是要想正确的运用相似关系,得出创新成果,仍然需要具备特定的能力。这其中就包含了研究所要关注的类比推理的转换能力。
根据上述理论构想,研究对类比推理过程中涉及到的转换过程进行分类,并在分类的基础上,对与狭义类比推理关系密切的:映射转换、推理过程转换、关系结构转换这三类转换进行实验研究。
映射转换的研究结果表明:1)瑞文高级推理测验的第二组题确实要难于第一组题;被试在转换题上的得分低于非转换题上的得分,转换题的设计效果明显,且表明是否需要进行心理上的转换确实影响了被试的解题成绩;不论题目难度的高低都不影响转换与非转换之间的差异。2)存在着基于能力的映射转换,并且映射转换能力与析出关系能力之间呈中等程度的线性相关。实验可以区分出析出关系能力高、低的被试和转换能力高、低的被试。
推理过程转换的研究结果表明:1)以四卡问题为代表的假设检验的推理过程在特定的实验条件下,表现出推理过程转换的心理加工过程。2)改善问题的陈述形式,使之和样例问题一样,能够降低推理过程转换的难度,促进推理过程转换的成绩。3)多个样例归纳的图式促进同形同型或异形同型的解答,却对推理转换过程有抑制作用。
关系结构转换的研究结果表明:1)日常生活中,人们更多地使用关系结构进行检索,但表面相似性的作用仍然比较重要。2)立场偏好的情感因素影响了类比源的产生。观点立场一致的条件比观点立场不一致的条件,产生更多数量的类比源和共同的关系结构。两种条件在语义相似程度、结构转换的清楚度这两方面没有显著差异;在语义范畴类别上存在差异。3)反对与支持两种条件,在不同的实验情境下表现不同。4)结构转换模糊的被试,其产生无效类比源的可能性越大。这也意味着,这类被试关系结构的转换能力更低些。而结构转换清楚的被试,其产生有效类比源的可能性更大,这类被试关系结构的转换能力更高些。
研究的意义在于:1)提出狭义类比推理的概念,将科学发现和创造性思维当中的类比推理与其它广义意义上的类比推理概念,比如:类比迁移、类推,相区分。2)首次对类比推理加工机制中的转换过程进行分类。并对与狭义类比推理密切相关的三类转换过程进行实验研究。3)通过实验研究发现映射转换能力的存在,并将这一能力与基于知识经验的转换相区分。4)一系列的实验研究对教育和创新思维的培养有实践指导意义。
In the past study, analogy somehow be a comparative analogism, or be a machining process of reasoning psychology, or even be a transfer process of problem solving and learning. All these made the study of analogy stay in various kinds. However, psychological process mechanism of analogical reasoning, which is the core of creativity thinking, is the original intention of investigating analogical in psychology. Although the achievement of analogy reasoning both in home and abroad were abundant, a traditional understanding of analogy fails to understand this unique thinking mechanism.
This study differs analogy from a narrow sense analogy a broad sense analogy. We think the characteristics of the narrow sense analogy will be in accord with creativity thinking. The meaning of the narrow sense analogy is the reason by analogy. It is a course that to discover the mutual essence relationship between two dissimilarity things by analogical compare, and producing innovative content fruit by the activity of science thinking after comparison. The narrow sense analogy emphasizes particularly on quite difficulty science discover and innovative activity. That is a further high level cognitive capability and the thinker's activity from known to unknown requiring more cognitive endeavor. The problems of science discovery and innovative activity were complicated and illegibility. Even we can discover the core relation, specific ability still needed. Such ability will include the analogical transduction ability that we should pay more attention.
According to the above theory assumption, this research classifies the transduction process involving in the course of analogical reasoning. Upon classification, we did the experimental investigation of three type of transduction including mapping transduction, reasoning process transduction, and relational structure transduction
The result of mapping transduction shows:1) the second group problem is more difficult than the first group problem in Reven advanced reasoning exam. The score of the transduction problem is lower than the score of the nontransduction problem. The design effect of transduction problem is obvious, the difficulty of the problem will not influence the transduction process.2)mapping transduction based on the capability is existed. It is related with the ability of the analysis induce in middling degree.
The result of reasoning process transduction shows:1) the reasoning process of the hypothesis inspection puts up the process of reasoning process.2) the statement form of the problem is the same as the statement form of the exemplar problem that can reduce the difficulty of the reasoning process and facilitate the performance of the reasoning process.3) the schema induction of many exemplar problems can facilitate the performance of the isomorphism problems, but will restrain the performance of the hetero-morphism problems.
The result of the transduction relational structure shows:1) people can retrieve by the relational structure in ordinary life, but the function of the superficial similarity is still important.2) the affective factors of standpoint preference will influence the analogy production.3) the two conditions of opposition and approval will have a different performance in different experimental state.4) the subject of fuzzy structure transduction has more chance producing the nullity analog, but the subject of clear structure transduction has more chance producing effective analog.
The meaning of the study is:1) We put forward the concept of the narrow sense analogy and distinguish the analogical reasoning in science discovery and innovation thinking from the other concept of the broad sense of analogy, such as:analogical transfer, analogism.2) We classify the transduction process in analogical reasoning process mechanism.3) We find the capability of the mapping transduction through the experimental study.4) A series of the experimental results will have practical instructive sense in the education and the cultivation of innovative thinking.
引文
陈英和,赵笑梅.类比问题解决的理论及研究.北京师范大学学报(社会科学版),2008,205(1):51-56
陈英和,赵笑梅.小学三~五年级儿童类比问题解决及策略运用发展.心理发展与教育,2007,(2):18-62
董奇.儿童创造力发展心理学.浙江教育出版社,1993.
佟秀丽.表面特征和结构特征在故事类比通达中的.心理科学进展,2004,12(6):851-859
佟秀丽.实体和初级关系(FOR)匹配的分离与结合对故事类比通达的影响.心理学报,2005,37(4):458-468
佟秀丽,莫雷,Zhe Chen,等.空间行为关系类比匹配中客体相似性的作用.心理科学,2007,30(1):10-18
冯廷勇,李宇,李红,苏缇,龙长权.3~5岁儿童表面与结构相似性类比推理的实验研究.心理科学,2006,29(5):1091-1095
姜子云.应用题相似性和图式归纳对解题迁移的影响.内蒙古师范大学学报(哲学社会科学版),2006,35(4):94-97
李宇.儿童问题类比相似性的研究进展.宁波大学学报(教育科学版),2005,27(3):21-24
刘建清.9-12岁儿童类比推理能力的发展.心理科学,1995,18(1):56-58
刘志雅,莫雷,佟秀丽.选择作业中证伪思维的影响因素.心理学报,2005,37(3):328-334
李红,冯廷勇.4~5岁儿童单双维类比推理能力的发展水平和特点.心理学报,2002,34(4):395-399
李一军,毕春斌.类比推理发展的历史及展望.决策与决策支持系统,1994,4(3):71-78
马晓清,冯廷勇,李宇,李红.从知觉分心任务看儿童类比推理能力的发展.心理学报,2008,40(9):987-993.
母一嘉,母其文.类比推理的功能性磁共振成像与主成份分析.西部医学,2008,20(1):171-176
莫雷,刘丽虹.样例表面内容对问题解决类比迁移过程的影响.心理学 报,1999,31(3):313-321
莫雷,唐雪峰.表面概貌对原理运用的影响的实验研究.心理学报,2000,32(4):399-408
莫雷,唐雪峰.事件类型的相似性对原理运用影响的实验研究.心理科学,2001,24(1):5-8
曲衍立,张梅玲.类比迁移研究综述.心理学动态,1999,8(2):1-7
邱琴.影响图式归纳和类比迁移的三因素实验研究.江西师范大学硕士学位论.2004
邱琴,胡竹菁,闵容.影响图式归纳和类比迁移的三因素实验研究.心理科学,2005,28(6):1370-1374
任洁.影响学习迁移的几个因素的实验研究.应用心理学,1996,2(1):52-58
唐慧琳,刘昌.类比推理的影响因素及脑生理基础研究.心理科学进展,2004,12(2):193-200
唐慧琳,刘昌.工作记忆对类比推理的影响.心理学探新,2006,26(4):26-31
王亚同.类比推理过程的实验研究.青海师范大学学报(社会科学版),1989,(2):102-107
王亚同.认知心理学关于类比推理的研究.青海师范大学学报(社会科学版).1991,(1):93-100
王亚同,鲁忠义.类比推理研究的有关理论.心理学动态,1998,6(2):40-45
王儒芳,李红.表面相似性类比推理问题解决中的情感效应.宁波大学学报(教育科学版),2005,27(2):35-38
徐冬溶,潘去鹤,张畅,王选.类比推理综述(上).计算机科学,1997a,24(1):8-14
徐冬溶,潘去鹤,张畅,王选.类比推理综述(上).计算机科学,1997b,24(1):8-14
刑强.样例的编码方式对问题解决迁移的影响及心理机制.心理发展与教育,2006,(2):71-75
朱新明,李亦菲.对三种认知迁移理论的述评.心理发展与教育,2001,(1):58-62
张树东,高潇怡.类比推理能力的三种发展观.心理科学,2000,(4):1-8
张向葵,王金凤.西方儿童类比推理研究的回眸与展望.教育实践与研究,1999,(5):14-15
张向葵,张雪琴,高琨,孙树勇.类比推理研究综述.心理科学,2000,23(6):725-728
张向葵,徐国庆.有关类比推理过程中的图式归纳研究综述.心理科学,2003,26:866-869
张庆林,王永明.类比迁移的三种理论.心理科学,1998,21(6):550-551
张庆林,王永明.类比迁移发生机制的研究.心理科学,1999,22(2):141-143
张晋萍.中学生一般自我效能感、认知需求和创造性的关系研究.山西大学硕士学 位论文.2004.
张卫,郭淑斌.问题解决的类比迁移.华南师范大学学报(社会科学版),1997,(6):59-64
查子秀.外国心理学中关于类比推理的一些研究.心理科学进展,1985,18-23
Anderson J R, Thompson R. Use of analogy in a production-system architecture.In:S. Vosniadou,A. Ortony. Eds. Similarity and Analogical Reasoning. Cambridge, England:Cambridge University Press,1989
Badie K, Hejazi M. Creative idea generation via passing through an intermediate space between the source and the target. Proceeding of the Workshop Program at the Fourth International Conference on Case-based Reasoning. Canada,2001.125-8.
Blanchette I, Dunbar K. Constraints underlying analogy use in a realworld context:Politics. In:M.G. Shafto and P. Langley. Eds.Proceedings of the Nineteenth Annual Conference of the Cognitive Science Society. Stanford, CA:Lawrence Erlbaum Associates,1997.867
Blanchette I, Dunbar K. How analogies are generated:The role of structural and superficial similarity. Memory & Cognition,2000,29:730-735
Bunge S A, Wendelken C, Badre D,Wagner A D. Analogical reasoning and prefrontal cortex:Evidence for separable retrieval and integration mechanisms. Cerebral Cortex,2004.
Catrambone R. Reinvestigating the effects of surface and structural+ featureson analogical access. In:M. G. Shafto, P. Langley. Eds. Proceedings of the Nineteenth Annual of the Cognitive Science Society. Stanford, CA:Lawrence Erlbaum Associate,1997.90-95
Catrambone R,Holyoak K J. Overcoming contextual limitations on problem solving transfer. Journal of Experimental Psychology:Learning, Memory, and Cognition,1989,15:1147-1156
Carbonell J G. Learning by analogy:Formulating and generalizing plans from past experience. In:R. S. Michalski, J. G. Carbonell,T.M. Mitchell. Eds. Maching learning:An artificial intelligence approach. PaltoAlto CA:Tioga,1983.137-161
Cheng P W, Holyoak K J. Pragmatic reasoning schemas. Cognitive Psychology, 1985,17:391-416
Chen Z. Children's analogical problem solving:The effects of superficial structural and procedual similarity. Journal of Experimental Child Psychology,1996,62:410-431
Chen Z. Analogical problem solving:A hierarchical analysis of procedural similarity. Journal of Experimental Psychology:Learning, Memory and Cognition,2002,28:81-98
Chen Z. Learning to align relations:the role of feedback and self-explanation. Child Development,2005
Clement C A, Gentner D. Systematicity as a selection constraint in analogical mapping. Cognitive Science,1991,15:89-132
Dario D. Salvucci John R. Anderson,1999
Dreistadt R. An analysis of the use of analogies and metaphors in science. Journal of Psychology,1968,68:97-116
Dunbar K. How scientists really reason scientific reasoning in real-world laboratories. In:Sternberg R J,Davidson J E.Eds.The Nature of Insight. Cambridge, MA:MIT Press,1995.365-395
Dunbar K. How scientists think:On-line creativity and conceptual change in science. In:T. B. Ward, S. M. Smith, S. Vaid. Eds. Conceptual structures and processes:Emergence, Discovery and Change. Washington DC:APA Press,1997.461-493
Evans T G. A program for the solution of geometric-analogy intelligence test questions.In:M. Minsky. Ed. Semantic information processing. Cambridge, MA:MIT Press,1968.271-353.
Falkenhainer B,Forbus K D, Gentner D.The structure-mapping engine Algorithm and examples. Artificial Intelligence,1989,41:1-63
Forbus K D, Gentner D, Law K. MAC/FAC:Amodel of similarity-based retrieval. Cognitive Science,1995,19:141-205
Gentner D,Toupin C.Systematicity and surface similarity in the development of analogy. Cognitive Science,1986,10:277-300
Gentner D. Metaphor as structure mapping:the relational shift.Child Development,1988,59:47-59
Gentner D. The mechanisms of analogical learning. In:S. Vosniadou, A. Ortony. Eds. Similarity and Analogical Reasoning. Cambridge, England Cambridge University Press,1989.
Gentner D. Structure-mapping:A theoretical framework for analogy. Cognitive Science,1983, (7):155-170
Gentner D. Analogy. IN:R. A. Wilson, F. C. Keil. Eds. The MIT encyclpedia of the cognitive science. Cambridge, MA:MIT Press,1999
Gentner D,Wolff P.Metaphor and knowledge change. In:E. Dietrich & A. Markman. Eds. Cognitive dynamics:Conceptual change in humans and machines.Mahwah, NJ:LEA,2000.295-342
Gentner D.Analogical reasoning, Psychology of.2002.106-112
Gentner D. Why we're so smart. In:D. Gentner,S.Goldin-Meadow,Eds. Language in mind:Advances in the study of language and thought. Cambridge, MA:MIT Press,2003.195-235
Gentner D.Spatial cognition in apes and humans. TRENDS in cognitive science,2007,11(50):192-194
Gentner D,Bowdle B, Wolff P, Boronat C. Metaphor is like analogy. In: Centner D, Holyoak K J, Kokinov B N. Eds. The analogical mind:Perspectives from cognitive science. Cambridge MA, MIT Press,2001.199-253
Gentner D,Clement C.1988.Evidence for relational selectivity in the interpretation of analogy and metaphor. In:G. H. Bower. Ed. The psychology of learning and motivation:Advances in research and theroy.New York:Academic Press,1988.307-358
Gentner D, Holyoak K, KokinovB.The Place of Analogy in Cognition. In:Gentner,D.,Holyoak, K. and Kokinov,B. (Eds)Analogy:Perspectives from Cognitive Science. Cambridge, MA:MIT Press,2001,1-19
Gentner D,Rattermann M. Language and the career of similarity. In S. A. Gelman, J. P. Byrnes. Eds. Perspectives on thought and language: Interrelations in development. CambridgeUniversity Press,1991.225-277
Gentner D, Rattermann M J, Forbus K D. The roles of similarity in transfer: Separating retrievability from nferential soundness.Cognitive Psychology,1993,25:524-575
Gentner D,Toupin C. Systematicity and surface similarity in the development of analogy. Cognitive Science.1986,10:277-300
Gick M L, Holyoak K J. Analogical problem solving. Cognitive Psychology, 1980,12:306-355
Gick M L, Holyoak K J. Schema induction and analogical transfer. Cognitive Psychology,1983,15:1-38
Goswami U. Analogical reasoning and cognitive development. In: H.Reese, Ed. Advances in child development and behavior, CA:Academic Press,1996.92-135
Goswami U. Analogical reasoning in children. In:D. Gentner, K. J. Holyoak,B. N. Kokinov.Eds.The analogical mind:Perspectives from cognitive science. Cambridge, MA:MIT Press,2001.437-470
Grudin J.Processes of verbal analogy solution.Journal of Experimental Psychology:Human Perception and Performance,1980,6:67-74
Harford G S. Analogical reasoning and conceptual complexity in cognitive development. Human Development,1992,35:193-217
Halford G S.Children's Understanding:The development of mental models.Hillsdale,NJ:Lawrence Erlbaum,1993 Hesse M.Models and analogies in science.Nore Dame,In:Notre Dame University Press,1966.
Holyoak K J.The pragmatics of analogical transfer. The Psychology of Learning and Motivation,1985,19:59-87
Holyoak K J. Pragmatic versus syntactic approaches to training deductive reasoning. Cognitive Psychology,1986,18:293-328.
Holyoak K J, Koh K. Surface and structural similarity in analogical transfer. Memory&Cognition.1987,15(4):332-340
Holyoak K,Morrison R. The Cambridge Handbook of Thinking and Reasoning. Cambridge University Press,2005
Holyoak K J, Thagard P. Analogical mapping by constraint satisfaction. Cognitive Science,1989,13:295-355
Holyoak K J, Thagard P. A computational model of analogical problem solving.In:S. Vosniadou, A. Ortony. Eds. Similatity and analogical reasoning. New York:Cambridge University Press,1989,242-266
Holyoak K J,Thagard P.Mental leaps:Analogy in creative thought. Cambridge, MA:MIT Press,1995.
Hummel J E,Holyoak K J. A Symbolic-Connectionist Theory of Relational Inference and Generalization. Psychological Review,2003,110(2):220-264
Hummel J E,Holyoak K J. Relational Reasoning in a Neurally Plausible Cognitive Architecture. Current Directions in Psychological Science,2005,14(3):154-157
Hummel J E, Holyoak K J. Distributed representations of structure:A theory of analogical access and mapping. Psychological Review,1997,104: 427-466
Holland J,Holyoak K J,Nisbett R,et al.. Induction:Processes of inference, Learning, and discovery. Cambridge, MA:MIT Press.
Johnson-Laird P N.Legrenzi P,Legerenzi M S. Reasoning and a sense of reality.British Journal of Psychology,1972,63:395-400
Kambiz Badie.Creative idea generation via interpretative approach to analogical reasoning. Kybernetes,2002,31 (9/10):1210-1219
Keane M T. On retrieving analogues when solving problems. Human Experimental Psychology,1987,15:332-340
Keane M T, Brayshaw M. The incremental analogical machine:A computational model of analogy. In:D. Sleeman. Ed. European working session on learning. London:Pitman,1988.53-62
Keane M T. Incremental analogizing:Theory and model. In:Gilhoody K J, Keane M T, Logie R et al.. Eds. Lines of Thinking:Reflections on the Psychology of Thought. Vol.Wiley,1990.
Keane M T. Adaptation as a selection constraint on analogical mapping. Proceedings of the Sixteenth Annual Conference of the Cognitive Science Society. Hillsdale, NJ:Erlbaum,1992
Keane M T, Ledgeway T, Duff S. Constraints on analogical mapping:A comparison of three models. Cognitive Science,1994,18:387-438.
Keane M T. What makes an analogy difficult?The effects of order and causal structure on analogical mapping. Journal of Experimental Psychology:Learning, Memory and Cognition,1997,23(4):946-967
Kroger J K, Saab F W, Fales C L. et al.. Recruitment of anterior dorsolateral prefrontal cortex in human reasoning:A parametric study of relational complexity. Cerebral Cortex,2002,12:477-485
Kokinov B N.Analogy is like cognition:Dynamic, emergent, and context-sensitive. In:K. J. Holyoak, D. Gentner, B. Kokinov. Eds. Advances in analogy research:Integration of theory and data from the cognitive, computational, and neural sciences. Sofia, Bulgaria:NBU. Press,1998
Luo Q,Perry C, Peng D, et al..The neural substrate of analogical reasoning:An FMRI study. Cognitive Brain Research,2003,17:527-534
Lopez A, Atran S, Coley J D, Medin D L, Smith E E. The tree of life:Universal and cultural features of folkbiological taxonomies and inductions. Cognitive Psychology,1997,32:251-295
Markman A B.Constrains on analogical inference.Cognitive Science,1997,21:373-418
Markman A B, Gentner D. Structure mapping in the comparison process. American Journal of Psychology,2000,113(4):501-538
Markman A B, Gentner D. Thinking. Annu. Rev. Psychol.,2001,52:223-47.
Novick L R, Holyoak K J. Mathematical problem solving by analogy. Journal of Experimental Psychology:Learning, Memory, and Cognition,1991,17: 398-415
Osherson D N, Smith E E, Wilkie O, Lopez A, Shafir E. Category based induction. Psychological Review,1990,97:185-200
Proffitt J B, Coley J D, Medin D L. Expertise and Category-Based Induction. Journal of Experimental Psychology:Learning, Memory, and Cognition, 2000,26(4):811-828
Piaget J, Montangero J, Billeter J. Les Correlates. In:J. Piaget. Ed. Abstraction Reflechissssante. Paris:Press Universitairres de France,1977.
Pierce K,Crain R.The source of children's errors during nonisomorphic analogical transfer. Journal of Experimental Child Psychology,1996,62:102-130
Reitman W. Cogniton and thought. New York:Wiley,1965.
Ross B H. This is like that:The use of earlier problems and the separation of similarity effects. Journal of Experimental-Psycholgoy:Learning, Memory and Cognition,1987,13:629-639
Ross B H. Distinguishing types of superficial similarities:Different effects on the access and use of earlier problems. Journal of Experimental Psychology:Learning, Memory and Cognition,1989,15(2):456-468
Ross B H,Kilbane M C. Effects of principle explanation and superficial similarity on analogical mapping in problem solving. Journal of Experimental Psychology:Learning,Memory and Cogniton,1997,23(2):427-440
Salvucci D D,Anderson J R. Analogy. In:J. R. Anderson,C. Lebiere. Eds.The Atomic Components of Thought. Hillsdale, NJ:Lawrence Erlbaum Associates,1998a:343-383
Shepard R N. Attention and the metric structure of the stimulus spare. Journal of Mathematical Psychology,1964,1(1):54-87
Spearman C.The nature of intelligence and the principles of cognition. London, UK:Macmillan,1923.
Simon D,Krawczyk D C, Holyoak K J. Construction of Preferences by constraint satisfaction. Psychological Science,2004,15(5):331-336
Simon D, Pham L B, Quang A L, Holyoak K J. The Emergence of Coherence Over the Course of Decision Making. Journal of Experimental Psychology:Learning, Memory, and Cognition,2001,27(5):1250-1260
Sternberg R J. Component processes in analogical reasoning. Psychological Review,1977,84(4):353-378
Thagard P. Explanatory coherence. Behavioral and Brain Sciences, 1989,12:435-502
Thagard P, Holyoak K J, Nelson G, Gochfeld D. Analog retrieval by constraint satisfaction. Artificial Intelligence,1
Thagard P. Coherence in thought and action. Cambridge, MA:MIT Press,2000
Tversky A. Features of similarity. Psychological Review,1977,84(4):327-352
Wason P C.Reasoning about rule. Quarterly Journal of Experimental: Psychology,1968,20:273-281
Wharton C M,Holyoak K J, Downing P E. Below the surface analogical similarity and retrieval competition in reminding. Cognitive Psychology,1994,26:64-101
Winston P H. Learning and reasoning by analogy. Communications of the ACM,1986,23,689-703
Zhang S, Markman A B. Overcoming the early entrant advantage:The role of alignalble and nonalignalble difference. Journal of Marketing Research,1998,35:413-426