Confirming the latent structure and base rate of schizotypy: a taxometric analysis.

Meehl's (1962, 1990) model of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous and that a "schizogene" determines membership in a latent class, or taxon (Meehl & Golden, 1982). The authors sought to determine the latent structure and base rate of schizotypy. They applied Meehl's (1973; Meehl & Golden, 1982) MAXCOV-HITMAX taxometric analytic procedures to a subset of items from the Perceptual Aberration Scale (PAS; Chapman, Chapman, & Raulin, 1978), a prominent psychometric index of schizotypy, derived from a randomly ascertained nonclinical university sample (N = 1,093). The results, in accordance with Meehl's conjectures, strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a general population taxon base rate of approximately .10.     

Some consequences of stimulus variability on speech processing by 2-month-old infants.

The present study explores how stimulus variability in speech production influences the 2-month-old infant's perception and memory for speech sounds. Experiment 1 focuses on the consequences of talker variability for the infant's ability to detect differences between speech sounds. When tested with high-amplitude sucking (HAS) procedure, infants who listened to versions of a syllable, such as [symbol: see text], produced by 6 male and 6 female talkers, detected a change to another syllable, such as [symbol: see text], uttered by the same group of talkers. In fact, infants exposed to multiple talkers performed as well as other infants who heard utterances produced by only a single talker. Moreover, other results showed that infants discriminate the voices of the individual talkers, although discriminating one mixed group of talkers (3 males and 3 females) from another is too difficult for them. Experiment 2 explored the consequences of talker variability on infants' memory for speech sounds. The HAS procedure was modified by introducing a 2-min delay period between the familiarization and test phases of the experiment. Talker variability impeded infants' encoding of speech sounds. Infants who heard versions of the same syllable produced by 12 different talkers did not detect a change to a new syllable produced by the same talkers after the delay period. However, infants who heard the same syllable produced by a single talker were able to detect the phonetic change after the delay. Finally, although infants who heard productions from a single talker retained information about the phonetic structure of the syllable during the delay, they apparently did not retain information about the identity of the talker. Experiment 3 reduced the range of variability across talkers and investigated whether variability interferes with retention of all speech information. Although reducing the range of variability did not lead to retention of phonetic details, infants did recognize a change in the gender of the talkers' voices (from male to female or vice versa) after a 2-min delay. Two additional experiments explored the consequences of limiting the variability to a single talker. In Experiment 4, with an immediate testing procedure, infants exposed to 12 different tokens of one syllable produced by the same talker discriminated these from 12 tokens of another syllable.(ABSTRACT TRUNCATED AT 400 WORDS)     

Whole words and decoding for short-term learning: comparisons on a "talking-computer" system.

Low-and average-ability readers in first and second grade studied a list of 36 words using a "talking-computer" system. The system highlighted and simultaneously pronounced orthographic units in the words when the children touched the words with a light pen. During two training sessions, the computer presented four groups of 9 words each, one group as whole words, one in syllabic units, one in subsyllabic units, and one as single grapheme-phoneme units. All children learned the least words with single grapheme-phoneme units, having had the greatest difficulty blending the units into words during training. The other presentation units did not differ significantly from each other for most students on post-testing. However, the low first-grade readers learned fewer words segmented and presented by subsyllables than by syllable or word units, but only for multisyllabic words. Monosyllabic words were blended and learned as easily with onset-rime segmentation as with whole word units, for all children.     

Inaccurate reporting and inappropriate variables: a reply to Vecchio's (1990) examination of cognitive resource theory.

In an article in the Journal of Applied Psychology, Vecchio (1990) purported to test cognitive resource theory (Fiedler, 1986; Fiedler & Garcia, 1987). We present evidence that Vecchio's article seriously misrepresented previous work on cognitive resource theory and also contained several flaws in methodology that call into question his conclusions regarding the validity of cognitive resource theory.     

Information Load: A Test of an Inverted-U Hypothesis with Hourly and Salaried Employees

We surveyed 714 hourly and 516 salaried employees of a midwestern telephone company to test the effects of information load on work-related outcomes. Using curvilinear regression analyses, we found support for our hypothesis that employees are less satisfied with outcomes as the load of information deviates positively or negatively from some level. We also predicted, and found, that this quadratic function was more prevalent in the hourly group than in the salaried group. Implications, future research directions, and limitations of the present study are discussed.