Administration of inhalation anesthetics to small animals: Some problems and solutions

Some problems inherent in administering inhalation anesthetics to small laboratory animals in studies of memory consolidation are discussed. A simple and inexpensive apparatus which has been designed to eliminate some of these problems is described.     

Linear dependence in multiple correlation work

The problem in multiple correlation work of nonsense results attributable to linear dependence of variables, which has been discussed by Ragnar Frisch in relation to economic data, is presented from the standpoint of its significance in psychological research. It is shown that a symmetric correlation determinant with unity in the diagonal cells can vanish only when there is a first-order or partial correlation of unity between one pair of the variables. On the basis of this result, it is argued that the problem should be expected to cause less difficulty in the field of psychology than in economics and that psychologists should be able to avoid the pitfall by bringing to bear their knowledge of the variables with which they are working.     

The relation between results obtainable with raw and corrected correlation coefficients in multiple factor analysis

This paper presents three theorems concerning the relation between results with obtained and corrected correlation coefficients in the Thurstone method of multiple factor analysis. (1) The rank of the correlational matrix, and thus the number of factors involved, is unaffected by correcting the obtained coefficients for attenuation. (2) The communality of a variable when the obtained coefficients have been corrected for attenuation is equal to the communality with obtained coefficients divided by the reliability coefficient of the variable. (3) The relationship is shown between the factorial matrix of a correlational matrix of raw correlation coefficients and the factorial matrix of a correlational matrix of corrected correlation coefficients, and a method of obtaining either of these factorial matrices from the other is indicated.     

Sampling theory in item analysis

Since item values obtained by item analysis procedures are not always stable from one situation to another, it follows that selection of items for validity or difficulty is sometimes useless. An application of Chi Square to testing homogeneity of item values is made, in the case of theUL method, and illustrative data are presented. A method of applying sampling theory to Horst's maximizing function is outlined, as illustrative of author's observation that the results of item analysis by any of various methods may be similarly tested.     

Some properties of the communality in multiple factor theory

Several theorems concerning properties of the communaltiy of a test in the Thurstone multiple factor theory are established. The following theorems are applicable to a battery ofn tests which are describable in terms ofr common factors, with orthogonal reference vectors.1. The communality of a testj is equal to the square of the multiple correlation of testj with ther reference vectors.2. The communality of a testj is equal to the square of the multiple correlation of testj with ther reference vectors and then—1 remaining tests. Corollary: The square of the multiple correlation of a testj with then—1 remaining tests is equal to or less than the communality of testj. It cannot exceed the communality.3. The square of the multiple correlation of a testj with then—1 remaining tests equals the communality of testj if the group of tests containsr statistically independent ests teach with a communality of unity.4. With correlation coefficients corrected for attenuation, when the number of tests increases indefinitely while the rank of the correlational matrix remains unchanged, the communality of a testj equals the square of the multiple correlation of testj with then—1 remaining tests.5. With raw correlation coefficients, it is shown in a special case that the square of the multiple correlation of a testj with then—1 remaining tests approaches the communality of testj as a limit when the number of tests increases indefinitely while the rank of correlational matrix remains the same. This has not yet been proved for the general case.The author wishes to express his appreciation of the encouragement and assistance given him by Dr. L. L. Thurstone.     

Application of a self‐management intervention to improve data recording of educational care providers

The present study evaluated the effects of a self‐management intervention on scheduled data recording by classroom instructors at a school for children with intellectual disability and neurodevelopmental disorders. In a multiple baseline design across two classrooms, the instructors recorded student data according to an established protocol at the school and based on earlier training they had received. During intervention, the instructors self‐monitored implementation of data recording procedures that were prompted by a signal from an automated count‐down timer. The self‐management intervention increased scheduled data recording by participants in both classrooms to 90–100%, and these results were maintained at 1‐ and 2‐month follow‐up assessments. These findings add to the small literature concerning self‐managed approaches to training and performance improvement, extend application within educational settings, and suggest practical advantages for supporting competencies of care providers.     

The recollective qualities of adolescents’ and adults’ narratives about a long-ago tornado

The recollective qualities of autobiographical memory are thought to develop over the course of the first two decades of life. We used a 9-year follow-up test of recall of a devastating tornado and of non-tornado-related events from before and after the storm, to compare the recollective qualities of adolescents’ (n?=?20, ages 11 years, 11 months to 20 years, 8 months) and adults’ (n?=?14) autobiographical memories. At the time of the tornado, half of the adolescents had been younger than age 6. Nine years after the event, all participants provided evidence that they recall the event of the tornado. Adults also had high levels of recall of the non-tornado-related events. Adolescents recalled proportionally fewer non-tornado-related events; adolescents younger than 6 at the time of the events recalled the fewest non-tornado-related events. Relative to adolescents, adults produced longer narratives. With narrative length controlled, there were few differences in the recollective qualities of adolescents’ and adults’ narrative reports, especially in the case of the tornado; the recollective qualities were stronger among adolescents older at the time of the events. Overall, participants in both age groups provided evidence of the qualities of recollection that are characteristic of autobiographical memory.     

Semantic and spatial factors in environmental memory

Reaction time (RT) in simple categorization tasks was predicted to vary as a function of the relatedness among environmental items. Differences in RT were interpreted as reflecting differences in proximity or strength of associations in environmental memory. In Experiment 1, subjects sorted names of familiar local buildings according to which seemed to go together. Hierarchical cluster analysis revealed major clusters whose members were related in function and, within these, smaller clusters of buildings related by spatial proximity. In Experiment 2, subjects responded “Yes” if two items on a trial were both local buildings and “No” if one item was local and one nonlocal. Subjects responded significantly faster to pairs taken from the cluster analysis that were related by both spatial proximity and function than they did to unrelated pairs or pairs related in function only. In Experiment 3, a free-associaton task identified related pairs of spatially proximate, functionally dissimilar environmental items. In Experiment 4, RTs to these pairs did not differ from RTs to pairs of spatially proximate, functionally dissimilar items or from RTs to pairs unrelated functionally and spatially. Spatial proximity and functional similarity together contribute to the organization in memory of buildings in the physical environment.     

Differential cerebral involvement in perceiving Chinese characters: levels of processing approach

Three experiments were designed to determine the accuracy and latency with which right-handed Chinese university students (12 females and 12 males) recognized Chinese characters in the left and right visual half-fields (VHFs). The experiments varied in the "depth" of processing required. Experiment 1 was a lexical decision task in which the configuration of the stimulus (a real Chinese character or the mirror image of a real character) determined whether the grapheme was an actual character. Experiment 2 required phonological processing; i.e., subjects had to decide whether a character (or a foil) matched the sound of an orally presented Chinese character. Experiment 3 required semantic processing; i.e., subjects had to decide if a character (or a foil) belonged to a particular semantic category. In each experiment, single characters were presented unilaterally for 150 msec. There was a significant right VHF superiority for accuracy scores for Experiments 2 and 3 but not for Experiment 1. None of the experiments yielded significant visual asymmetries in reaction time. The results do not support previous claims of orthography-specific laterality, but instead show that laterality effects for morphemic stimuli vary with the orthographic, phonological, and semantic processing demands of the task.