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.     

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.     

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.     

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.     

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.