On component analyses

Principal components analysis can be redefined in terms of the regression of observed variables upon component variables. Two criteria for the adequacy of a component representation in this context are developed and are shown to lead to different component solutions. Both criteria are generalized to allow weighting, the choice of weights determining the scale invariance properties of the resulting solution. A theorem is presented giving necessary and sufficient conditions for equivalent component solutions under different choices of weighting. Applications of the theorem are discussed that involve the components analysis of linearly derived variables and of external variables.Preparation of this article was supported in part by National Institute of Aging Grant NIA-AG03164-03 to William Meredith.     

A note on latent trait theory and Bowker's test

Bowker's test for marginal equality in contingency tables provides a familiar chi-square test to determine whether the marginal distributions are the same across two or more factors or occasions. In this note it is shown how latent trait theory provides a theoretical framework for the development and application of this test.The research reported here was supported by a grant to the senior author from the National Institute on Aging (AG03164).     

Social metrics of song learning

Five metrics of song learning are described for brown-headed cowbirds (Molothrus ater). The intent of these metrics is to capture not only the behavior of the song learner but the social context in which song learning occurs. Playback procedures, observations of mating, and acoustic and functional assessment of song content are combined to yield measures of song potency, functional validity, social dynamics, vocal flexibility, and social reactivity. Taken as a whole, the results revealed by these metrics indicate that males learn to be effective singers by attending to the social consequences of their behavior.     

Obtaining squared multiple correlations from a correlation matrix which may be singular

A theorem is presented relating the squared multiple correlation of each measure in a battery with the other measures to the unique generalized inverse of the correlation matrix. This theorem is independent of the rank of the correlation matrix and may be utilized for singular correlation matrices. A coefficient is presented which indicates whether the squared multiple correlation is unity or not. Note that not all measures necessarily have unit squared multiple correlations with the other measures when the correlation matrix is singular. Some suggestions for computations are given for simultaneous determination of squared multiple correlations for all measures.The research reported in this paper was supported by the Personnel and Training Branch of the Office of Naval Research under Contract Number 00014-67-A-0305-0003 with the University of Illinois.     

Contrasting patterns in the acquisition of spatial/temporal terms

Competing hypotheses about the acquisition of terms that refer to relationships in both time and space are tested. One hypothesis is that the language of time is acquired as a spatial metaphor; consequently, such terms will be acquired in their spatial sense first. The competing hypothesis is that differential experience with the dual senses of each term will result in different patterns of acquisition, depending upon which sense is dominant in actual usage. Comprehension of before-after, first-last, and ahead-behind by 4- to 6-year-olds was assessed in spatial, temporal, and spatial-temporal meaning tasks. Results support the second view: there is no consistent order of acquisition; the sense acquired first is the dominant sense, as determined by both linguistic evidence and empirical survey.     

Visual-word recognition thresholds for screen-fragmented names of the Snodgrass and Vanderwart pictures

The set of names corresponding to the pictures from Snodgrass and Vanderwart (1980) were screen fragmented by means of a series of procedures implemented in Microsoft QuickBasic on a Macintosh microcomputer. Words were screen fragmented by deleting blocks of pixels from their images rather than by deleting individual letters. The screen-fragmentation procedure is particularly useful for the present set of words, in which a large proportion of the names of the pictures are short (fewer than five letters). The screen-fragmentation procedure can produce any number of fragmentation levels. In the present implementation, eight levels of fragmented images were produced, to correspond to the eight levels available for the Snodgrass and Vanderwart pictures.     

Self-concept and sociometric outcomes: a comparison of only children and sibling children from urban and rural areas in the People's Republic of China.

We investigated differences in self-concept between 360 only children and 555 sibling children in the sixth grade of three urban schools and three rural schools in the People's Republic of China. Peer perceptions and teacher perceptions were also collected using sociometric measures. Self-concept was determined by the Self-Perception Profile for Children (Harter, 1985). Comparisons of sibling children and only children showed no differences on self-concept; however, urban residents had higher self-concept scores than children from rural areas, and boys scored higher than girls. No significant interaction effects between sibling status, gender, and residence were found.     

The Relationship Between Health and Human Services and the Personal Goal-Directed Activities of Persons Living with AIDS

This study evaluates the relationship between the social climate from different services and the personal goal-directed activities of 224 individuals with AIDS. The study's results supported the main hypothesis that recipient and participatory service involvement uniquely influence personal goal-directed activities, even after considering individuals with AIDS' physical symptoms, psychological distress, income, and recruitment site. Income and involvement with participatory services were both positively related to the amount of personal goal-directed activity. Longitudinal analyses suggest that personal initiative contributes to the subsequent amount of personal goal-directed activities a person pursues. These results suggest further examination of factors contributing to the selection of different service types and of the processes underlying the relationship between participatory services and positive outcomes for clients with AIDS.