| The purpose of this study was to investigate the construct validity of vocabulary tests and the nature of verbal ability by integrating findings and theories of cognitive psychology with those of differential psychology. The study included three kinds of measurements: an experimental faceted vocabulary test, reference ability tests, and a verbal exposure questionnaire. The faceted vocabulary test was used to study sources of difficulty in vocabulary test performance and how these sources of difficulty affect the relations between vocabulary tests and other ability measures.;The experimental task was a 3 x 3 x 3 x 2 faceted vocabulary test. The facets were word abstractness (concrete, medium, abstract), word frequency (low, medium, high), item type (vague recognition, accurate recognition, definition), and blocks (two parallel blocks). The item-type facet included two contrasts: definition vs. recognition items, and vague- vs. accurate-recognition items. The reference battery included tests of general mental ability, verbal ability, spatial ability, memory span, and closure speed. The verbal exposure questionnaire assessed frequency and time spent in reading, writing, doing homework, and viewing television. Subjects were 74 high school seniors selected to represent the bivariate distribution of verbal and spatial ability in a reference population of high school students.;The results indicated that vocabulary item difficulty increased with word abstractness, word infrequency, when item format required more precise word knowledge, and when the item required definition as opposed to recognition of the word. The results also suggested that partial concepts are prevalent in young adults and that word acquisition is a gradual process. Many words could be recognized vaguely but not accurately, or defined vaguely but not accurately, or recognized but not defined.;The following findings point to the role of reasoning processes in the acquisition or definition of words: (a) some responses indicated that subjects could give correct examples of how the word was used in sentences but inferred incorrect defining features; (b) students with low reasoning ability had major difficulties in the inference process during the definition stage; (c) the reasoning composite related to vocabulary measures at the lower end of the vocabulary distribution but not at the higher end. This suggests that a certain level of reasoning ability is necessary for effective extraction of word meaning. Above this level, reasoning ability makes little difference in performance on vocabulary tests; (d) vocabulary items that required the student to do more than merely recognize the correct meaning of a word had higher correlations with reasoning than recognition vocabulary items.;Verbal ability as represented by reading comprehension and reading vocabulary tests was best measured by frequent or medium-frequency words rather than by rare words. On the other hand, difficult recognition vocabulary tests such as advanced vocabulary tests seemed to measure mainly sources of difficulty due to infrequent words--sources that were related to individual differences in verbal exposure.;The results also suggest that students with poor verbal-sequential skills had particular difficulties with abstract words. Students with relatively little verbal exposure had particular difficulties with rare words, students with poor reasoning skills had major difficulties with definition items, and students with high spatial ability had an advantage in the acquisition or definition of concrete words. The roles of exposure and interest variables in the acquisition of vocabulary and other verbal knowledge were also discussed. |
