The role of duration and rapid temporal processing on the lateral perception of consonants and vowels

This study explored the extent to which rapid temporal processing and duration contribute to the right-ear advantage (REA) and presumably left-hemisphere processing for stop consonants and the lack of clear-cut laterality effects for vowels. Three sets of synthetic stimuli were constructed: consonant vowel stimuli [ba da ga bi di gi bu du gu] of 300 msec duration (full stimuli) and two shortened stimuli consisting either of a noise burst and 40-msec transitions (40-msec stimuli), or a noise burst and 20-msec transitions (20-msec stimuli). Stimuli were presented dichotically for consonant, vowel, and syllable identification. Results indicated a significant REA for consonants in the full and 40-msec conditions and a non-significant REA in the 20-msec condition. Nevertheless, the magnitude of laterality did not change across the three conditions. These results suggest that although transition information including duration contributes to lateralization for stop consonants, it is the presence of abrupt onsets which crucially determines lateralized processing. For vowels, there was a significant REA only in the full stimulus condition, and a significant decrement in the magnitude of the laterality effect in the two shortened stimulus conditions. These results suggest that for vowel perception, it is the nature of the acoustic cue used for phonetic identification and not duration that seems to be the critical determinant of lateralization effects.     

The mean and standard deviation of the distribution of group assembly sums

An interesting problem in linear programming is the group assembly problem which is mathematically equivalent to the general transportation problem of economics. Computer programs designed for the determination of exact and approximate optimal group assemblies have been available for some time. This paper presents formulas for the mean and squared standard deviation of the distribution of all possible group assembly sums. Computational techniques are presented and the results are related to those of the analysis of variance of ak-factor problem withn levels of each factor.This research was supported in part by the United States Air Force under Project No. 7713, Task No. 77232, and Contract No. AF 18(600)-1050, monitored by the Crew Research Laboratory of the Air Force Personnel and Training Research Center. Permission is granted for reproduction, translation, publication, use, and disposal in whole and in part by or for the United States Government.     

Reinforcer devaluation in palatability-based learned flavor preferences

Rats exposed to simultaneous compounds of 1 neutral flavor with dilute (2%) sucrose and a 2nd flavor with dilute (2%) maltodextrin subsequently consumed both flavors in preference to a 3rd flavor that was never paired with a palatable taste. Brief training exposure under ad lib food and water minimized the post-ingestive effects of nutrients, emphasizing the contribution of palatability to these preferences. Devaluation of sucrose or maltodextrin by pairing with illness (Experiment 1) or sensory-specific satiety (Experiment 2) selectively reduced the preference for the flavor previously paired with the devalued reinforcer. Such reinforcer-specific devaluation effects suggest that palatability-based learned flavor preferences are under-pinned by a Pavlovian process whereby the cue flavor is associated with the taste of the concurrently consumed palatable reinforcer.     

Dual diagnosis in an Australian forensic psychiatric hospital: prevalence and implications for services

Despite a growing awareness of the unique needs of psychiatric patients with co-occurring substance abuse and dependence disorders (i.e. dual diagnosis), there is a dearth of research investigating the prevalence of dual diagnosis in forensic psychiatric populations. Similarly, little work has been done to determine the implications of dual diagnosis for forensic psychiatric patients. Patients at the Thomas Embling Hospital in Victoria, Australia, were assessed to determine the prevalence of substance abuse disorders and mental illnesses within this population. Results reveal that the majority of patients (approximately 74%) have a lifetime substance abuse or dependence disorder. Information was collected concerning patients' criminal histories and the Level of Service Inventory, Revised, was completed for each patient who participated. Results suggest that patients with both major mental illnesses and substance abuse disorders have more extensive criminal histories and demonstrate a higher level of risks and needs when compared with patients with major mental illness alone. The implications for the development and delivery of effective forensic mental health services that address both co-occurring disorders are also discussed.     

Predicting preschoolers' externalizing behaviors from toddler temperament,conflict, and maternal negativity

Rarely have researchers elucidated early childhood precursors of externalizing behaviors for boys and girls from a normative sample. Toddlers (N = 104; 52 girls) were observed interacting with a same-sex peer and their mothers, and indices of conflict-aggression, emotion and behavior dysregulation, parenting, and child externalizing problems were obtained. Results indicated that boys initiated more conflictual-aggressive interactions as toddlers and had more externalizing difficulties 2 years later, yet girls' (not boys') conflict-aggressive initiations at age 2 were related to subsequent externalizing problems. When such initiations were controlled for, emotional-behavioral undercontrol at age 2 also independently predicted externalizing problems at age 4. Moreover, the relation between conflict-aggressive initiations at age 2 and externalizing problems at age 4 was strongest for dysregulated toddlers. Finally, the relation between age 2 conflict-aggressive initiations and age 4 externalizing problems was strongest for those toddlers who incurred high levels of maternal negativity. These findings illustrate temperament by parenting connections in the development of externalizing problems.     

Cue interactions in flavor preference learning: a configural analysis

Four experiments showed that the preference normally established to a neutral flavor cue that was paired with maltodextrin was attenuated when that cue was conditioned in compound with another flavor--overshadowing. Furthermore, two experiments showed that the preference for a neutral flavor conditioned as part of a compound was further attenuated if the other element in that compound was separately paired with the reinforcer--blocking. These results stand in contrast to a number of previous compound flavor preference conditioning experiments, which have not revealed reliable cue competition effects. These discrepant findings are discussed in terms of the effects of within-compound associations and a configural perspective on potentiation. Modeling of this configural perspective predicts that a compound of two separately trained cues will elicit a similar response to the individual cues themselves--absence of summation. Two experiments confirmed this prediction.     

Effect of Color Coding on Visually Oriented Tests With Students of Different Cognitive Styles

The purpose of this study was to examine the effects that differentially coded (black and white and color) illustrations had on students (N = 117) who were classified as field dependent, field neutral, or field independent as a result of their performance on the visually oriented Group Embedded Figures Test (Witkin, Olt-man, Rashin, & Karp, 1971). Students were randomly assigned to two instructional treatments complemented by illustrations (black and white and colored). After receiving their respective treatments, students reviewed two visually oriented criterion tests. Two-way analyses of variance conducted on achievement scores indicated that field independents scored significantly higher than did field dependents on both visual tests, and differences between field-dependent and field-independent learners who received the color-coded treatments on the visual identification test were insignificant. Results indicate that field dependency is an important instructional variable and that for some types of learning objectives the process of color coding instructional materials may reduce achievement differences attributed to differences in cognitive style.