Listeners' discrimination of real and human-imitated animal sounds

To determine if listeners can accurately distinguish between real and human-imitated animal sounds, a total of 165 recorded sounds (55 real and 110 human-imitated) of cats, cows, dogs, pigs, and sheep were randomly arranged on a master tape and presented to 30 listeners for discriminative judgments. Results indicate that, in general, listeners can accurately discriminate real from human-imitated animal sounds. Suggestions for future research are discussed.     

Rhythm and the timing of movement sequences

Summary Many motor skills involve a sequence of movements phased over a period of time. The present study investigated the importance of rhythmic timing structures in the acquisition and control of a serial key-pressing task. Four groups of subjects received extensive practice on 9-element finger sequences varying in the form of the inherent temporal structure. Following a training period, the stability of the various timing patterns was examined by requiring subjects to perform the key-pressing task concurrently with a verbal memory task. The memory task involved reporting back a sequence of visually-presented words with a lag of one word. A comparison was made of performance on the two tasks under dual task and control (single task) conditions. The results suggested that natural rhythmic timing structures require less attention for production than unnatural temporal patterns. A breakdown of the temporal patterns into within-group and between-group intervals showed that patterns containing within-group intervals that related as 1:1 or 1:2 evidenced good stability under dual-task conditions. These results were taken as support for the suggestion by Fraisse (1946) that the perception and production of rhythms can be understood by an internal representation that allows only two distinct durations that relate as 1:2. Furthermore, it was suggested that relative timing may become an invariant property of motor program representation only in those instances in which the timing sequence completely fits the internal timing structure.     

The influence of a history of romance on judgments and responses to a complaint of sexual harassment

Results indicated that a female complainant was seen as less innocent and an accused male less guilty when they had previously been romantically involved. As a consequence, decision makers felt it was more appropriate to be lenient in responding to the accused. Also, as demonstrated in previous research, male and female decision makers differed in their judgments and responses to a complaint of sexual harassment. These results have implications for organizational policies concerning workplace romance and for training people to deal with complaints of sexual harassment.Partial support for this study was provided by a Saint Mary's Senate research grant. The authors thank an anonymous reviewer for the helpful comments on an earlier version of the paper.     

Performance asymmetries and coupling dynamics in the acquisition of multifrequency bimanual coordination

Sixteen right-handed participants without formal musical training performed a rhythmic multifrequency coordination task for several hours over a one-week period. Two groups were studied with respect to the assignment of hand to frequency: 1L:2R, in which the preferred right hand performed the higher frequency, and 2L:1R in which the non-preferred left hand performed the higher frequency. Performance asymmetries in terms of relative phase stability were initially expected and confirmed. The 1L:2R pattern was more stable than 2L:1R. It has been suggested that performance asymmetries result from asymmetrical coupling between the limbs as influenced by handedness. This study examined whether the acquisition of 2L:1R, the less stable of the two patterns, required the formation of asymmetrical coupling such that the faster hand would exert a greater forcing on the slower hand than vice versa, a supposition put forth in many studies of bimanual polyrhythmic tapping. The present data provide quantitative evidence that, in terms of stability (as quantified by relative phase uniformity, transition pathways, and lead-lag relations), handedness asymmetries, as well as acquired asymmetries, can be captured by low-dimensional dynamics consisting of symmetric and asymmetric coupling terms. Received: 18 November 1996 / Accepted: 6 May 1997     

Pigeons' spatial memory: factors affecting delayed matching of key location.

The delayed-matching-to-sample procedure was modified to study pigeons' spatial memory. Nine pecking keys, arranged as a three-by-three matrix, served as the spatial cues. Trials began with a brief "ready" stimulus (dimming of the houselight). Then a randomly chosen key was lit briefly as a sample. After a short delay the sample key was lit again along with one of the other eight keys. A peck at the key that had served as the sample produced grain reinforcement, where as a peck to the other key produced only the intertrial interval. After delayed matching of key location was learned, the effects of sample and delay duration, number of keys illuminated as sample and comparisons, and organization of three-key samples were studied. Matching accuracy decreased as sample duration decreased, delay increased, the number of locations serving as samples increased, the number and proximity of comparisons increased, and when the three-key samples were "discontinuous" rather than "lines".     

Comparison of extra- and within-stimulus prompting to teach prepositional discriminations to preschool children with developmental disabilities

Journal of Behavioral Education -     

Comparison of extra- and within-stimulus prompting to teach prepositional discriminations to preschool children with developmental disabilities

This study compared extra-stimulus to within-stimulus prompts in teaching children with developmental disabilities to discriminate the prepositional concepts In and On. Five preschool-aged children who had difficulty discriminating verbal instructions participated. Extra-stimulus prompts involved modeling, gestures, positioning, and auditory cues which did not form part of the target discrimination. Within-stimulus prompts manipulated the volume and intonational pattern of the verbal stimuli. Four children did not learn the discrimination with extra-stimulus prompting. All four of these children, plus a fifth child who did not have prior experience with extra-stimulus prompting, reached criterion in the within-stimulus prompting condition. The success of the within-stimulus prompts may be related to their enhancing phonetic differences between the verbal stimuli.     

Diagnostic Accuracy of Memory Measures in Alzheimer’s Dementia and Mild Cognitive Impairment: a Systematic Review and Meta-Analysis

With an increasing focus on biomarkers in dementia research, illustrating the role of neuropsychological assessment in detecting mild cognitive impairment (MCI) and Alzheimer’s dementia (AD) is important. This systematic review and meta-analysis, conducted in accordance with PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) standards, summarizes the sensitivity and specificity of memory measures in individuals with MCI and AD. Both meta-analytic and qualitative examination of AD versus healthy control (HC) studies (n = 47) revealed generally high sensitivity and specificity (≥ 80% for AD comparisons) for measures of immediate (sensitivity = 87%, specificity = 88%) and delayed memory (sensitivity = 89%, specificity = 89%), especially those involving word-list recall. Examination of MCI versus HC studies (n = 38) revealed generally lower diagnostic accuracy for both immediate (sensitivity = 72%, specificity = 81%) and delayed memory (sensitivity = 75%, specificity = 81%). Measures that differentiated AD from other conditions (n = 10 studies) yielded mixed results, with generally high sensitivity in the context of low or variable specificity. Results confirm that memory measures have high diagnostic accuracy for identification of AD, are promising but require further refinement for identification of MCI, and provide support for ongoing investigation of neuropsychological assessment as a cognitive biomarker of preclinical AD. Emphasizing diagnostic test accuracy statistics over null hypothesis testing in future studies will promote the ongoing use of neuropsychological tests as Alzheimer’s disease research and clinical criteria increasingly rely upon cerebrospinal fluid (CSF) and neuroimaging biomarkers.