Taxometric analyses of sexual orientation and gender identity

Taxa are nonarbitrary classes whose existence is an empirical question and not a matter of mere semantic convenience. Taxometric procedures detect whether numerical relations between purported indicators of conjectured taxa bear the hallmarks of true taxa. On the basis of theoretical considerations, the current study tested whether taxa underlie sexual orientation and related measures of gender identity. Two taxometric procedures, maximum covariance, making hits maximum (MAXCOV) and mean above minus below a cut (MAMBAC), were applied to Kinsey Scales and measures of childhood gender nonconformity and adult gender identity in a sample of nearly 5,000 members of the Australian Twin Registry. Results suggest that latent taxa underlie these measures. About 12-15% of men and 5-10% of women belong to latent taxa associated with homosexual preference. These percentages are greater than those of individuals who report homosexual preference, however, and hence it appears that an appreciable proportion of individuals in these taxa have heterosexual preference. An understanding of the origins of these latent taxa may be important to understanding the development of sexual orientation and gender identity.     

Motivational state regulates the content of learned flavor preferences

Rats acquired a preference for an aqueous odor (almond) presented in simultaneous compound with sucrose. Separate presentations of saccharin reduced this preference in rats with ad-lib access to food during training or at test, but not in rats that were hungry during both training and test. In contrast, separate presentations of sucrose reduced the preference for the almond irrespective of deprivation state during training and test. We interpret the results to mean that a hungry rat forms odor-taste and odor-calorie associations, and its motivational state on test determines which of these associations controls the preference. In contrast, a rat that is not hungry during training only forms an odor-taste association, and its performance on test is independent of its level of hunger.     

Variation among developmental dyslexics: evidence from a printed-word-learning task

A word-learning task was used to investigate variation among developmental dyslexics classified as phonological and surface dyslexics. Dyslexic children and chronological age (CA)- and reading level (RL)-matched normal readers were taught to pronounce novel nonsense words such as veep. Words were assigned either a regular (e.g., "veep") or an irregular (e.g., "vip") pronunciation. Phonological dyslexics learned both regular and exception words more slowly than the normal readers and, unlike the other groups, did not show a regular-word advantage. Surface dyslexics also learned regular and exception words more slowly than the CA group, consistent with a specific problem in mastering arbitrary item-specific pronunciations, but their performance resembled that of the RL group. The results parallel earlier findings from Manis, Seidenberg, Doi, McBride-Chang, & Petersen [Cognition 58 (1996) 157-195] indicating that surface dyslexics and phonological dyslexics have a different profile of reading deficits, with surface dyslexics resembling younger normal readers and phonological dyslexics showing a specific phonological deficit. Models of reading and reading disability need to account for the heterogeneity in reading processes among dyslexic children.     

Some characteristics of auditory spatial attention revealed using rhythmic masking release

The tuning of auditory spatial attention with respect to interaural level and time difference cues (ILDs and ITDs) was explored using a rhythmic masking release (RMR) procedure. Listeners heard tone sequences defining one of two simple target rhythms, interleaved with arhythmic masking tones, presented over headphones. There were two conditions, which differed only in the ILD of the tones defining the target rhythm: For one condition, ILD was 0 dB and the perceived lateral position was central, and for the other, ILD was 4 dB and the perceived lateral position was to the right; target tone ITD was always zero. For the masking tones, ILD was fixed at 0 dB and ITDs were varied, giving rise to a range of lateral positions determined by ITD. The listeners' task was to attend to and identify the target rhythm. The data showed that target rhythm identification accuracy was low, indicating that maskers were effective, when target and masker shared spatial position, but not when they shared only ITD. A clear implication is that at least within the constraints of the RMR paradigm, overall spatial position, and not ITD, is the substrate for auditory spatial attention.     

Describing the Acquisition of Determiners in English: A Growth Modeling Approach

This paper, based on naturalistic data, describes the acquisitional course and use of the articles a and the in young English-speaking children (18-61 months), with special emphasis on the role of individual variation. A growth modeling approach to the data reveals that children's individual acquisition schedules are similar in trend, but vary in the rate at which they omit determiners at a given point of time. This picture suggests that an analysis that presumes homogeneous development will seriously misrepresent the fluctuations between and within individuals. Interestingly, this variation does not reflect a variation in children's abilities to use determiners correctly-irrespective of the rate in which they used determiners, children seldom used determiners incorrectly. The analysis also reveals that children's optional omission of determiners in obligatory contexts, beginning at 18 months of age, gradually decreases on average by 3-4% a month until 36 months of age, and thereafter plunges by a factor of 10 to an average of 0.3% per month. At 36 month of age the majority of children use determiners at a near-mastery level (Brown, 1973). These findings provide a useful framework for theorizing about possible mechanisms underlying the nature of early language development pre- and post-36 months of age.     

Effects of category diversity on learning,memory, and generalization

In this study, we examined the effect of within-category diversity on people's ability to learn perceptual categories, their inclination to generalize categories to novel items, and their ability to distinguish new items from old. After learning to distinguish a control category from an experimental category that was either clustered or diverse, participants performed a test of category generalization or old-new recognition. Diversity made learning more difficult, increased generalization to novel items outside the range of training items, and made it difficult to distinguish such novel items from familiar ones. Regression analyses using the generalized context model suggested that the results could be explained in terms of similarities between old and new items combined with a rescaling of the similarity space that varied according to the diversity of the training items. Participants who learned the diverse category were less sensitive to psychological distance than were the participants who learned a more clustered category.     

Operant psychology goes to the fair: Marian and Keller Breland in the popular press, 1947-1966

Marian and Keller Breland pioneered the application of operant psychology to commercial animal training during the 1940s and 1950s. The Brelands' story is relatively unknown in the history of behavior analysis. Using information from the Breland-Bailey papers, this paper describes the development and activities of Animal Behavior Enterprises (ABE), the Brelands' animal training business. We also review popular press coverage of the Brelands between 1947 and 1966 to investigate the level of public exposure to ABE-trained animals and to the principles and methods of operant psychology. An examination of 308 popular print articles featuring the Brelands indicates that there was public exposure of behavior analysis through the popular press coverage of ABE-trained animals. Furthermore, the expansion of operant methods to the marine mammal and bird training industries can be linked to the Brelands' mass media exposure.     

Newborn screening for fragile X syndrome

Newborn screening for fragile X syndrome (FXS) is technically possible, and in the relatively near future accurate and inexpensive screening technologies are likely to be available. When that happens, will America's public health system adopt newborn screening for fragile X syndrome? This article addresses this issue by first placing screening for FXS in the context of the history and current status of newborn screening policy and practice. Lack of a proven medical treatment may stand as a barrier to newborn screening, but strong arguments can be made that early intervention provides important services for identified newborns and their families. Furthermore, other arguments could be used to justify newborn screening, including informed reproductive risk, medically necessary information, and consumer demand. Fragile X syndrome is offered as a prototype for many of the issues that will face society as more genetic disorders are discovered and new technologies for screening are developed.     

ANALYSIS OF WORK GROUP PRODUCTIVITY IN AN APPLIED SETTING: APPLICATION OF A TIME SERIES PANEL DESIGN

We provide a demonstration of a time series panel analysis applied under typical field research conditions characterized by (a) a small number of groups (b) all of which experience an intervention (thus there is no traditional control group), and (c) perform noncomparable tasks. The time series techniques allow a direct test of Naylor, Pritchard, and Ilgen's (1980) theory of behavior in organizations applied to work group productivity in a large-scale study of work groups conducted by Pritchard and colleagues (1989). The responses of 5 work groups to priority scores for 37 indicators of productivity over 23 months were used to predict month-by-month changes in productivity for each of the 37 group products. The results show that group productivity improvements can be explained by feedback including priority scores derived from nonlinear contingency functions of the productivity indicators. Furthermore, groups differed in their response to priority feedback. Goal setting positively affected productivity gain consistently across work groups, after the effects of priority feedback and the interaction of work groups with priority feedback were accounted for. Implications for group performance strategies and appropriate applications of the time series panel analysis are discussed.     

ON THE EFFECTS OF NONCONTINGENT DELIVERY OF DIFFERING MAGNITUDES OF REINFORCEMENT

We conducted a parametric analysis of response suppression associated with different magnitudes of noncontingent reinforcement (NCR). Participants were 5 adults with severe or profound mental retardation who engaged in a manual response that was reinforced on variable-ratio schedules during baseline. Participants were then exposed to NCR via multielement and reversal designs. The fixed-time schedules were kept constant while the magnitude of the reinforcing stimulus was varied across three levels (low, medium, and high). Results showed that high-magnitude NCR schedules produced large and consistent reductions in response rates, medium-magnitude schedules produced less consistent and smaller reductions, and low-magnitude schedules produced little or no effect on responding. These results suggest that (a) NCR affects responding by altering an establishing operation (i.e., attenuating a deprivation state) rather than through extinction, and (b) magnitude of reinforcement is an important variable in determining the effectiveness of NCR.