Algorithms for fast and precise computation of the normal integral

Five highly accurate algorithms that evaluate the normal distribution function are presented. The algorithms, which are based on either numerical integration or series expansions, are explicated, and applications of Simpson’s rule are discussed. Computer programs that implement the algorithms were compared with respect to accuracy and speed. The programs attain from 11- to 15-decimal-place accuracy in finding one-tailed areas of the normal curve, and most execute very quickly. Recommendations are made for selection of algorithms and programs to approximate the normal distribution.     

Access to attitude-relevant information in memory as a determinant of persuasion: The role of message attributes

Recipients with access to attitude-relevant information in memory were thought to draw on these beliefs and prior experiences to evaluate the validity of message arguments. Consistent with this idea, persuasion for these recipients was largely a function of the perceived validity of message content: Messages containing high-quality arguments were more persuasive than messages containing lowquality arguments, whereas variations in a structural attribute of the message (its length) proved to have little impact on opinion change. In contrast, people who tend to retrieve little attitude-relevant information were believed to be less able to evaluate the validity of message arguments in terms of information accessed from memory. Instead, it was anticipated that they would base their opinion judgments on a more superficial analysis of persuasion cues, focusing on attributes like message length. Consistent with this reasoning, these recipients were more persuaded by long than short messages. Recipients with moderate levels of retrieval functioned much like the high-retrieval subjects.     

The prevalence of nightmares and their independence from anxiety

Although several studies have examined the prevalence of nightmares and their relationship to anxiety, this is the first to have used daily dream logs, rather than retrospective self-reports, to monitor nightmare frequency. 220 undergraduates were administered self-report measures of anxiety and for 2 weeks recorded the number of their nightmares in logs. 47% of Ss reported at least one nightmare during the study period. The dream logs yielded an estimated mean annual nightmare frequency of 23.6, which is 2.5 times as great as the estimate yielded by retrospective reports (p less than .01). Nightmare frequency and anxiety were uncorrelated. The findings indicate that nightmares are more prevalent than has been reported, and their frequency unrelated to self-reported anxiety.     

An Hebrew language version of the Stroop test

We present normative data from a Hebrew language version of the Stroop color-word test. In this sample of college-educated Israeli young adults, 18 women and 28 men with a mean age of 28.4 yr. completed a Hebrew language Stroop test. When compared with 1978 English language norms of Golden, Hebrew speakers were slower on color-word reading and color naming, similar on naming the color of incongruently colored names of colors, and showed less interference. Slowed color-word reading and color-naming may reflect the two-syllable length of the Hebrew names for one-syllable length English language colors; reduced interference may reflect the exclusion of vowels in much Hebrew printing and subjects' ability to provide competing, nonconflicting words while naming the color of words in which the hue and the lexical content do not match.     

Auditory and phonetic levels of processing in speech perception: neurophysiological and information-processing analyses.

Two new experimental operations were used to distinguish between auditory and phonetic levels of processing in speech perception: the first based on reaction time data in speeded classification tasks with synthetic speech stimuli, and the second based on average evoked potentials recorded concurrently in the same tasks. Each of four experiments compared the processing of two different dimensions of the same synthetic consonant-vowel syllables. When a phonetic dimensions was compared to an auditory dimension, different patterns of results were obtained in both the reaction time and evoked potential data. No such differences were obtained for isolated acoustic components of the phonetic dimension or for two purely auditory dimensions. Together with other recent evidence, the present results constitute additional converging operations on the distinction between auditory and phonetic processes in speech perception and on the idea that phonetic processing involves mechanisms that are lateralized in one cerebral hemisphere.     

When are semantic targets detected faster than visual or acoustic ones?

Duration-discrimination data from an experiment using empty auditory intervals in a two-alternative forced-choice paradigm are presented. The observed functional relationship between standard deviation of the psychometric density function and stimulus duration is shown to be fit significantly better by a Weber’s law model of duration discrimination than by Creelman’s counter model. Both models fail to predict the rapid rise in the Weber fraction observed for durations longer than about 2 sec. However, the Weber’s law model, based on a generalization of Weber’s law, accurately predicts the initial drop in the Weber fraction for very short durations and the observed constancy of the Weber fraction for durations up to 2 sec.     

Speed-accuracy tradeoff functions in choice reaction time: Experimental designs and computational procedures

The existence of tradeoffs between speed and accuracy is an important interpretative problem in choice reaction time (RT) experiments. A recently suggested solution to this problem is the use of complete speed-accuracy tradeoff functions as the primary dependent variable in choice RT ,experiments instead of a single mean RT and error rate. This paper reviews and compares existing procedures for generating empirical speed-accuracy tradeoff, functions for use as dependent variables in choice RT experiments. Two major types of tradeoff function are identified, and their experimental designs and computational procedures are discussed and evaluated. Systematic disparities are demonstrated between the two tradeoff functions in both empirical and computer-simulated data. Although all existing procedures for generating speed-accuracy tradeoff functions involve empirically untested assumptions, one procedure requires less stringent assumptions and is less sensitive to sources of experimental and statistical error. This procedure involves plotting accuracy against RT over a set of experimental conditions in which subjects’ criteria for speed vs. accuracy are systematically varied.     

Parallel processing of auditory and phonetic information in speech discrimination

Recent experiments using a variety of techniques have suggested that speech perception involves separate auditory and phonetic levels of processing. Two models of auditory and phonetic processing appear to be consistent with existing data: (a) a strictserial model in which auditory information would be processed at one level, followed by the processing of phonetic information at a subsequent level; and (b) aparallel model in which auditory and phonetic processing could proceed simultaneously. The present experiment attempted to distinguish empirically between these two models. Ss identified either an auditory dimension (fundamental frequency) or a phonetic dimension (place of articulation of the consonant) of synthetic consonant-vowel syllables. When the two dimensions varied in a completely correlated manner, reaction times were significantly shorter than when either dimension varied alone. This “redundancy gain” could not be attributed to speed-accuracy trades, selective serial processing, or differential transfer between conditions. These results allow rejection of a completely serial model, suggesting instead that at least some portion of auditory and phonetic processing can occur in parallel.     

A mental-health locus of control scale

The purpose of this study was to develop and seek initial validation of a mental- health locus of control scale. Twenty-six mental-health professionals rated each of the 14 statements of a previously-designed mental-health service request form along a 5-point locus of control scale. Six of the 14 items met the study's criteria for inclusion in the mental-health locus of control scale. Discriminant validity of the scale was provided by a study demonstrating that psychotic patients were more external in their perceived locus of control than were a nonpsychotic patient comparison group. Other validation studies and research are suggested.     

Forms of social awareness and helping

People encounter situations from different forms of awareness; that is, they can attend to different focal topics (e.g., self, other person, or other person's situation) from different perspectives (e.g., the self's viewpoint, the other person's viewpoint). Two studies assessed whether brief interactions would produce different forms of social awareness, whether the form of awareness would persist to a subsequent interaction, and whether it would influence helping in that encounter. Pedestrians on a city sidewalk were induced to become self-focused (experimenter took their picture), become other-focused (they took experimenter's picture), or empathically adopt the perspective of another person (they advised experimenter where to take a picture). In Study 1, subjects were interviewed after leaving the experimenter. First- and third-person pronoun use and self-ratings suggested that subjects had different forms of awareness. In Study 2, pedestrians participated in one of the same three interaction conditions or a control noninteraction condition and subsequently encountered a confederate in need of help. Subjects in the self-focused and empathic condition helped more than subjects in the other-focused or control condition. Results suggest that forms of awareness created in a brief interaction do persist to subsequent interactions and influence helping. Other variables may influence helping by altering forms of social awareness.