An Impression-Driven Model of Candidate Evaluation Author(s): Milton Lodge, Kathleen M. McGraw, Patrick Stroh Source: The American Political Science Review, Vol. 83, No. 2 (Jun., 1989), pp. 399-419 Published by: American Political Science Association Stable URL: http://www.jstor.org/stable/1962397 Accessed: 23/02/2010 11:56 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=apsa. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. American Political Science Association is collaborating with JSTOR to digitize, preserve and extend access to The American Political Science Review. http://www.jstor.org AN IMPRESSION-DRIVENMODEL OF CANDIDATE EVALUATION MILTON LODGE KATHLEEN M. McGRAW PATRICK STROH State Universityof New York Stony Brook T e describeand test two process models of candidateevaluation. The memory-basedmodel holds that evaluations are dependent on the mix of pro and con informationretrieved from memory. The impression-drivenmodel holds that eval- uations are formed and updated "on-line"as informationis encountered. The results provide evidencefor the existenceof stereotypingand projectionbiases that renderthe mix of evidenceavailable in memorya nonveridicalrepresentation of the informationto which subjectswere exposed. People do not rely on the specific candidateinformation available in memory. Rather,consistent with the logic of the impression-drivenprocess- ing model, an "on-line"judgment formed when the informationwas encounteredbest predicts candidate evaluation. The results raise both methodologicaland substantive challenges to how political scientists measure and model the candidate evaluation process, O ur primaryaim because citizens are exposed to informa- is to develop and test two competitive tion (be it party affiliation, character,or models of the candidateevaluation proc- policy stances)over an extendedperiod of ess. We focus on information,our general time, and some of that informationmust perspective being the information-proc- be stored in, and retrieved from, long- essing approach identified with Herbert term memory when an evaluationor vote Simon (1981, 1985; Newell and Simon is necessary. 1972). All contemporarypolitical science Despite the lack of explicit attentionto models of vote choice are information- memory in contemporaryvoting models, processing models in that candidate eval- they appearto share the common implicit uation is treated as a function of the mix assumption that the direction and of information (e.g., Brody and Page strength of candidate evaluation is in 1972; Campbell et al. 1960; Enelow and large part determinedby the "evidence" Hinich 1985; Kelley 1983; Kelley and availablein memory. Forexample, Kelley Mirer 1974; Lazarsfeld, Berelson, and and Mirer (1974) state the case for a Gaudet 1944). However, none of them memory-basedmodel of vote choice: 'The provide an accounting of the memory voter canvasses his likes and dislikes of processes involved in candidate evalua- the leading candidatesand major parties tion. Yet memory processesare criticalto involved in an election. Weighing each understanding candidate evaluation, like and dislike equally, he votes for the AMERICAN POLITICAL SCIENCE REVIEW VOLUME 83 NO. 2 JUNE 1989 American Political Science Review Vol. 83 candidatetoward whom he has the great- problems found to undermineseriously est numberof net favorableattitudes" (p. the veridicall"and "representative"mem- 574). ory modelsrelates to cognitiveconstraints This memory-basedmodel of evalua- in the processingof information;that is, tion makestwo criticalassumptions about memoryoften reflectsone's prior expecta- human informationprocessing. First, the tions, with the bulk of the empiricalevi- information recalled by respondents is dence strongly implicatingthe impact of thought either to be a more or less veridi- prior beliefs on attention and memory cal representationof the informationthey processes (Fiskeand Taylor 1984). A sec- were actually exposed to (Kelley 1983) ond issue we considerfocuses on evalua- or-more reasonably-to reflect the sa- tive constraintsin the processingof new lient information they were exposed to information. Is the evidence culled from plus what they "reasonably"inferred memory a reflection of rationalization about the candidates(Conover and Feld- processesthat serve to "fit"the evidenceto man 1986; Granberg1985). Second-and "match"one's current evaluation of the from our perspectivemost critically-the candidate?Again, the empiricalevidence model assumes that citizens base their documentsan evaluativebias in informa- evaluationon the evidenceretrieved from tion processing, the basic finding being memory. Moreover, the methodologies that people are prone to recall evidence used to assess the validity of candidate that is consistent with current attitudes evaluation models also reflect the impor- (Chaikenand Stangor1987). tance of memory. The reliance on re- In additionto problemsrelated to mem- sponses to the Survey Research Center ory per se, we are concerned with the (SRC) open-ended like-dislike questions judgmentprocess itself: How do citizens and candidate issue proximity scales re- use whatever informationis available in flects assumptions that (1) the citizen is memory to inform an evaluation?To ex- willing and able to conduct a search for aminememory processes as they apply to relevant informationin memory, (2) this candidate evaluation, we consider two search will generate a veridical or (more competing information-processing plausibly) a representativesample of the models: the memory-basedmodel of the informationto which the citizen was ex- judgment process and the "on-line,"or posed, and (3) this available information impression-driven, model (Hastie and is then used to inform an evaluation and Park 1986; Lichtensteinand Srull 1987). vote choice. We test the validity of these assump- Memory-basedprocessing. The memory- tions by examiningtwo importantaspects based model of candidate evaluation of the memory-judgmentrelationship as aligns with common sense in positing a appliedto the process of candidateevalu- positive relationship between memory ation. The first aspect deals with memory and judgment.When a personis calledon retrieval processes: How much of what to make an evaluation, whether at the kind of candidateinformation do citizens ballot box or in reply to an interviewer's retrievefrom memory?The key question request,it is reasonableto assumethat the being, Is the "configuration"of evi- overall evaluation is based upon the ac- dence representedin long-term memory tual mix of pro and con evidenceavailable a veridical mapping or (more plausi- in memory. Commonsense, unfortunate- bly) a representativesample of informa- ly, is a fallible guide. A great deal of tion to which the citizen was exposed, or research indicates that there is typically is memory for a political candidate sub- little or no relationshipbetween the blend ject to systematic biases? One class of of pro and con informationavailable in 400 CandidateEvaluation memory and the direction or strengthof haps, for the paucity of specifics in the evaluation (see Hastieand Park1986 for a SRC open-ended like-dislike questions review). Apparently, memory-based (Gant and Davis 1984). evaluation is too cognitively taxing, rely- Forthe memory-basedmodel of evalua- ing on the effortfulretrieval of specificin- tion, a summaryjudgment is thought to formation from long-term memory, the be "computed"from the specific memory weighing of evidence, and then the com- traces recalledat the time the assessment putation of a summary evaluation, all is called for. To the extent that this repre- common complaints leveled against ra- sents an accurateportrayal of the evalua- tional choice models in generaland issue tion process, it is arduous, time-consum- voting models in particular (Herstein ing, and unreliable,requiring more effort 1981). and attentional resources than all but Downsian man could or would be willing Impression-drivenprocessing. Given the to expend. On the other hand, the on-line failure to find unequivocal support for model of the judgmentprocess is psycho- memory-basedprocessing, a second class logically realisticin proposing that when of models has been proposed. Impression- asked to voice an opinion, people typical- driven, or "on-line,"processing occurs ly retrievetheir summary evaluation from when a judgmentis made as relevant in- memory, only dredgingup specificmem- formationis encountered.A key concept ory traces when pressed to give reasons in understandingthe on-line model of why