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)     

God and perceptual evidence

I presented a substantially different version of this paper at the 1991 American Philosophical Association Central Division Meeting. William L. Rowe commented. The paper in its present form has profited considerably from Rowe's comments.     

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.     

An "Epidemic" Model of Adolescent Cigarette Smoking

The prevalence of regular smoking increases rapidly during adolescence. We applied modeling methods from the study of epidemic infectious disease to smoking behavior. Our "epidemic" models dealt with the process of transition among four states: nonsmoker (susceptible), trier (exposed), regular smoker (infected), and ex-smoker (recovered). The best fitting model was one in which the transition from nonsmoker to trier was a social contagion process where nonsmokers contacted either triers or regular smokers. All other transitions were treated as constant rate processes in which a constant proportion of eligible individuals made the transition in a given year. The recursive equation model embodying these assumptions was able to predict accurately the proportion of adolescents in each state in Grades 6–11. Our results support a "stage" model of smoking, suggesting that different psychological and physiological processes are involved in the initiation of smoking than in developing a habit of regular smoking. A possible sex difference was found in the non-contact transition between trier and smoker states, with the transition being more probable in females than in males.     

Integration of the big five and circumplex approaches to trait structure.

To integrate the 5-dimensional simple-structure and circumplex models of personality, the Abridged Big Five Dimensional Circumplex (AB5C) taxonomy of personality traits was developed, consisting of the 10 circumplexes that can be formed by pitting each of the Big Five factors against one another. The model maps facets of the Big Five dimensions as blends of 2 factors. An application to data consisting of 636 self-ratings and peer ratings on 540 personality trait adjectives yielded 34 well-defined facets out of a possible 45. The AB5C solution is compared with simple-structure and lower dimensional circumplex solutions, and its integrative and corrective potential are discussed, as well as its limitations.     

Information feedback and the learning multiple-degree-of-freedom activities

The influence of information feedback on the learning of a multiple-degree-of-freedom activity, the overhand throw, was investigated. During learning, feedback was presented in the form of knowledge of results, knowledge of performance, knowledge of performance with attention-focusing cues, or knowledge of performance with error-correcting transitional information. Across 12 practice sessions, performance was assessed with respect to both throwing distance and throwing form. Subjects provided with knowledge of performance along with transitional information demonstrated significant gains in throwing distance, compared with subjects receiving knowledge of performance or knowledge of results alone. Movement form ratings followed the same trend. Providing learners with cues to focus their attention on the relevant aspects of knowledge of performance or directly providing transitional information was a better aid to the acquisition of throwing form than providing knowledge of results or knowledge of performance alone. These results support the hypothesis that knowledge of results may not be the most potent form of feedback in multiple-degree-of-freedom activities and that knowledge of performance, when combined with additional information, can lead to significant gains in skill acquisition.     

Affect, personality, and social activity.

These studies examined relations between social activity and state and trait measures of Positive and Negative Affect. In Study 1 Ss completed scales relevant to 3-factor models of personality and a weekly mood and social activity questionnaire for 13 weeks. In Study 2 Ss completed measures of the 5-factor model of personality and a daily mood and social activity survey for 6-7 weeks. In within- and between-Ss analyses, socializing correlated significantly with state measures of Positive Affect and with trait measures of Extraversion/Positive Emotionality. These relations were relatively general across various types of positive affect and social events; however, specific types of social events also were differentially related to affect. In contrast, social activity had no consistent association with measures of Negative Affect or the other personality dimensions. The results support a temperamental view of Extraversion.