In this article, we provide guidance for substantive researchers on the use of structural equation modeling in practice for theory testing and development. We present a comprehensive, two-step modeling approach that employs a series of nested models and sequential chi-square difference tests. We discuss the comparative advantages of this approach over a one-step approach. Considerations in specification, assessment of fit, and respecification of measurement models using confirmatory factor analysis are reviewed. As background to the two-step approach, the distinction between exploratory and confirmatory analysis, the distinction between complementary approaches for theory testing versus predictive application, and some developments in estimation methods also are discussed.

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Structural equation modeling in practice: a review and recommended two-step approach

A Scaling Method for Priorities in Hierarchical Structures

Tested the 2-process theory of detection, search, and attention presented by the current authors (1977) in a series of experiments. The studies (a) demonstrate the qualitative difference between 2 modes of information processing: automatic detection and controlled search; (b) trace the course of the

http://psycnet.apa.org/doi/10.1037/0033-295X.84.2.127

Controlled and automatic human information processing: II. Perceptual learning, automatic attending and a general theory.

Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. How- ever, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide vari- ety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recoding of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity- limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed.

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The magical number 4 in short-term memory: a reconsideration of mental storage capacity.

Two data sources--self-reports and peer ratings--and two instruments--adjective factors and questionnaire scales--were used to assess the five-factor model of personality. As in a previous study of self-reports (McCrae & Costa, 1985b), adjective factors of neuroticism, extraversion, openness to experience, agreeableness-antagonism, and conscientiousness-undirectedness were identified in an analysis of 738 peer ratings of 275 adult subjects. Intraclass correlations among raters, ranging from .30 to .65, and correlations between mean peer ratings and self-reports, from .25 to .62, showed substantial cross-observer agreement on all five adjective factors. Similar results were seen in analyses of scales from the NEO Personality Inventory. Items from the adjective factors were used as guides in a discussion of the nature of the five factors. These data reinforce recent appeals for the adoption of the five-factor model in personality research and assessment.

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Validation of the five-factor model of personality across instruments and observers.

Past research indicates that short-term memory can be immune to the effects of proactive interference (PI). Past research also indicates that immunity to PI is found only in those circumstances where phonemic representations of to-be-remembered items are present and provide discriminative information. The first three experiments demonstrate the existence of a further boundary condition. PI is observed only if interfering and target items are subsumed by the same cue. This finding suggests that short-term recall, like long-term recall, is cue dependent. Cuing effects are further explored in two experiments that manipulate category dominance. The finding that category dominance effects parallel PI effects strongly suggests that retrieval cues play a critical role in short-term recall.

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Cuing effects in short-term recall.

Arousal and recognition memory: The effects of impulsivity, caffeine and time on task

It has recently become increasingly popular to claim that individual differences in personality are not very important sources of variation in human behavior. It has been suggested that the noncognitive traits that can be identified show very little consistency across situations, and that although the search for consistent dimensions of personality was reasonable, it has not proved to be very useful and should be abandoned.

Empirical Tests and Theoretical Extensions of Arousal-Based Theories of Personality

Two experiments were conducted in which the central variable was the addition of verbal context on the test which was not present during study. Neither study showed context to be a relevant variable. Because verbal context effects (when they do occur) are presumed to result from a change of meaning, the broader role of word meaning in recognition was examined. Studies in which homographs were used to produce a change in meaning were reviewed with the conclusion that when appropriate controls are used the effects are too small to support meaning as a major factor underlying recognition. An experiment using homographs verified the general conclusion from previous studies. A review of studies was then undertaken to determine the influence of synonym distractors on recognition scores. If word meaning is critical in word recognition, the use of synonyms of study words as new words on the recognition test should produce large decrements. The evidence available did not support this expectation, and an experiment using both within-subject and between-subject comparisons showed at best only small effects. The general conclusion was that theories of recognition in which word meaning plays a dominant role cannot be supported. It is likely that word meaning is encoded during study of lists of words but is infrequently used in making recognition decisions.

Context change and the role of meaning in word recognition.

Recent research has begun to provide support for the assumptions that memories are stored as a composite and are accessed in parallel (Tehan & Humphreys, 1998). New predictions derived from these assumptions and from the Chappell and Humphreys (1994) implementation of these assumptions were tested. In three experiments, subjects studied relatively short lists of words. Some of the lists contained two similar targets (thief andtheft) or two dissimilar targets (thief andsteal) associated with the same cue (ROBBERY). As predicted, target similarity affected performance in cued recall but not free association. Contrary to predictions, two spaced presentations of a target did not improve performance in free association. Two additional experiments confirmed and extended this finding. Several alternative explanations for the target similarity effect, which incorporate assumptions about separate representations and sequential search, are rejected. The importance of the finding that, in at least one implicit memory paradigm, repetition does not improve performance is also discussed.

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Michael S. Humphreys

Papers

Cuing effects in short-term recall.

Arousal and recognition memory: The effects of impulsivity, caffeine and time on task

Empirical Tests and Theoretical Extensions of Arousal-Based Theories of Personality

Context change and the role of meaning in word recognition.

Target similarity effects: Support for the parallel distributed processing assumptions