Another dimension for assessment of speech-sound discrimination: latency of response.

The relationship of speech-sound-discrimination skills and speed of responding was investigated by presenting monosyllabic nouns in three different listening conditions to a total of 72 nursery, kindergarten, and first-grad children divided into three equal-sized groups. Speed of responding was related to the age of subjects, accuracy of responding, and context of presentation of stimulus items. There was a consistent decrease in latency of responding as age increased. Error responses had greater response latencies than correct responses. Response latencies for different contexts of presentation of stimulus items were longest for the paired-comparison context and shortest for the carrier-phrase context. Speed of responding could be considered as an additional parameter when evaluating speech-sound-discrimination skills.     

Delayed temporal discrimination in pigeons: A comparison of two procedures

A within-subjects comparison was made of pigeons' performance on two temporal discrimination procedures that were signaled by differently colored keylight samples. During stimulus trials, a peck on the key displaying a slanted line was reinforced following short keylight samples, and a peck on the key displaying a horizontal line was reinforced following long keylight samples, regardless of the location of the stimuli on those two choice keys. During position trials, a peck on the left key was reinforced following short keylight samples and a peck on the right key was reinforced following long keylight samples, regardless of which line stimulus appeared on the correct key. Thus, on stimulus trials, the correct choice key could not be discriminated prior to the presentation of the test stimuli, whereas on position trials, the correct choice key could be discriminated during the presentation of the sample stimulus. During Phase 1, with a 0-s delay between sample and choice stimuli, discrimination learning was faster on position trials than on stimulus trials for all 4 birds. During Phase 2, 0-, 0.5-, and 1.0-s delays produced differential loss of stimulus control under the two tasks for 2 birds. Response patterns during the delay intervals provided some evidence for differential mediation of the two delayed discriminations. These between-task differences suggest that the same processes may not mediate performance in each.     

Atypical central auditory speech-sound discrimination in children who stutter as indexed by the mismatch negativity

PurposeRecent theoretical conceptualizations suggest that disfluencies in stuttering may arise from several factors, one of them being atypical auditory processing. The main purpose of the present study was to investigate whether speech sound encoding and central auditory discrimination, are affected in children who stutter (CWS).MethodsParticipants were 10 CWS, and 12 typically developing children with fluent speech (TDC). Event-related potentials (ERPs) for syllables and syllable changes [consonant, vowel, vowel-duration, frequency (F0), and intensity changes], critical in speech perception and language development of CWS were compared to those of TDC.ResultsThere were no significant group differences in the amplitudes or latencies of the P1 or N2 responses elicited by the standard stimuli. However, the Mismatch Negativity (MMN) amplitude was significantly smaller in CWS than in TDC. For TDC all deviants of the linguistic multifeature paradigm elicited significant MMN amplitudes, comparable with the results found earlier with the same paradigm in 6-year-old children. In contrast, only the duration change elicited a significant MMN in CWS.ConclusionsThe results showed that central auditory speech-sound processing was typical at the level of sound encoding in CWS. In contrast, central speech-sound discrimination, as indexed by the MMN for multiple sound features (both phonetic and prosodic), was atypical in the group of CWS. Findings were linked to existing conceptualizations on stuttering etiology.Educational objectives: The reader will be able (a) to describe recent findings on central auditory speech-sound processing in individuals who stutter, (b) to describe the measurement of auditory reception and central auditory speech-sound discrimination, (c) to describe the findings of central auditory speech-sound discrimination, as indexed by the mismatch negativity (MMN), in children who stutter.     

Relationship between scores on developing cognitive abilities test and scores on medical college admissions test for nontraditional premedical students

The relationship of students' performance on the Developing Cognitive Abilities Test (DCAT), a test of scholastic aptitude, and their subsequent performance on the Medical College Admission Test (MCAT) were examined for 122 nontraditional premedical students who participated in a medical educational preparatory program. A stepwise multiple regression analysis produced moderate, though significant multiple correlations among subscores on the two tests. While there were a few exceptions, for the most part all of the subscores on the Developing Cognitive Abilities Test made a significant contribution to the regression equation in the prediction of scores on MCAT subtests. Implications for the value of the Developing Cognitive Abilities Test as an admissions tool as well as providing direction for possible intervention are discussed.     

Fading procedures and conditional discrimination in children

A discrimination reversal task followed by a conditional discrimination problem was administered to children (age range 36 to 107 months). A fading procedure was used during the discrimination reversal training of some subjects and other subjects were trained by a traditional procedure. More subjects trained by the fading procedure performed without errors during training and more subjects in the traditional group solved the conditional discrimination problem.     

Differences in immediacy between traditional and nontraditional students

Reported differences between 83 traditional and 44 nontraditional college students on immediacy were nonsignificant.     

Errorless establishment of visual discrimination using fading procedures

A visual discrimination task involved presenting a triangle briefly as a sample. When it was withdrawn, this triangle and two others differing slightly in degree of rotation were presented in different positions, with S required to locate the sample that had been presented. Discrimination proved difficult for preschool children. When only the correct triangle was illuminated, discrimination was readily established. The brightness difference between correct and incorrect matches was gradually faded out by increasing the intensity of the incorrect matches, until they were equal in brightness to the correct match. The discrimination established by brightness difference was maintained in its absence, thereby transferring stimulus control from brightness to form, in an almost errorless sequence.     

Frequency discrimination: assessing global-level and element-level units in memory

Subjects' knowledge of how often various events occur was used to assess the retention of memory units for word-like strings of letters. A series of strings was presented at one of three exposure durations. Within the series, the frequencies of occurrence of different strings and of the letters composing the strings were varied orthogonally. At relatively long exposure durations, subjects could discriminate the frequency of occurrence for both strings and their constituent letters. The formation of global-level (string) memory units was indicated by judgments of string frequency being unaffected by either the frequencies of their component letters or experimental conditions (brief exposures) that prohibited accurate judgment of letter frequency. Although judgments of letter frequency were sometimes biased by the frequency of the strings containing the letters, the success with which the judgments discriminated different levels of letter frequency did not depend on the activation of string-level memory units. Furthermore, subjects' frequency judgments for letters were not predictable from their recall of the strings containing the letters. These results, which could not be explained by Tversky and Kahneman's (1973) "availability heuristic," provided evidence for the formation of element-level (letter) memory units. A converging experiment established that element-level frequency information could be abstracted from words as well as nonwords, and further, that this information was stored in long-term memory.     

Relationship between two aspects of perfectionism and obsessive-compulsive symptoms

In this study was investigated the relationship between two aspects of perfectionism (Concern over Mistakes and Personal Standards) and obsessive-compulsive symptoms. College students (57 men and 193 women: M age = 19.5 yr., SD = 1.9) majoring in psychology were from introductory psychology classes and a psychological assessment practice class. They completed the Padua Inventory, which assesses obsessive-compulsive symptoms, and the subscales of Concern over Mistakes and Personal Standards of the Frost Multidimensional Perfectionism Scale, which assess the tendency to be concerned about making mistakes and the tendency to set excessively high standards, respectively. Multiple regression analysis indicated that only the Concern over Mistakes scores predicted significantly all Padua Inventory subscale scores. Perhaps only being concerned over making mistakes may be associated with obsessive-compulsive symptoms. The tendency to set high standards was not strongly correlated with obsessive-compulsive symptoms. Further, the relationship between setting high standards and having obsessive-compulsive symptoms reported in previous studies may be spurious. Further work is required to untangle these associations.     

The discrimination of two racial samples

Nineteen different anthropometric measures were obtained on all members of each of two racial groups. A procedure was developed and applied to the data to give maximum differentiation between the groups. The method is applicable wherever we have a large number of independent variables and a dependent variable. In such cases, the conventional methods for determining multiple regression constants are very laborious. An iteration method is presented which is more rapid than any with which the writers are familiar. The method selects in sequence those variables which together yield the largest multiple correlation with the criterion. At each step in the procedure, rapid estimates of the regression weights and the multiple correlation at that point are available.     

A comparison of method-of-adjustment and forced-choice procedures in frequency discrimination

Reported estimates of the frequency difference limen (DL) for tones show considerable variability. To determine the extent that the differences are dependent on psychophysical method, three estimates of the DL at 1,000 Hz were obtained from the same subjects for each of three psychophysical procedures. The three estimates were: (1) the standard deviation of final settings in a methbd of adjustment, (2) the average of several reversals in an adaptive two-interval forced-choice procedure, and (3) the 76%-correct point in a two-interval forced-choice procedure using constant stimuli. The two forced-choice procedures yielded very similar DLs. The adjustment procedure yielded significantly smaller estimates. Possible reasons for the different values produced by adjustment procedures and the nature of the underlying decision process are discussed.     

Fakability of two different role-play methodologies for assessing assertion.

The fakability of two methodologically different role-play tests of assertion was examined, 30 undergraduates low in assertiveness were tested and retested on the Behavioral Assertiveness Test--Revised and the Idiographic Role-play Test. Half of the testees were instructed to fake assertion during the second testing. Analysis indicated that both tests were fakable; however, testees reported more difficulty faking the latter test than the former. The detection of faking may be possible, particularly on role-play tests employing an idiographic methodology.