Discrimination of time intervals marked by brief acoustic pulses of various intensities and spectra

Experienced observers were asked to identify, in a four-level 2AFC situation, the longer of two unfilled time intervals, each of which was marked by a pair of 20-msec acoustic pulses. When all the markers were identical, high-level (186-dB SPL) bursts of coherently gated sinusoids or bursts of band-limited Gaussian noise, a change in the spectrum of the markers generally did not affect performance. On the other hand, for 1-kHz tone-burst markers, intensity decreases below 25 dB SL were accompanied by sizable deterioration of the discrimination performance, especially at short (25-msec) base intervals. Similarly large changes in performance were observed also when the two tonal markers of each interval were made very dissimilar from each other, either in frequency (frequency difference larger than 1 octave) or in intensity (level of the first marker at least 45 dB below the level of the second marker). Time-difference thresholds in these two latter cases were found to be nonmonotonically related to the base interval, the minima occurring between 40- and 80-msec onset separations.     

Peripheral information extraction: A developmental examination of reading processes

Three experiments examining the information extraction processes are presented. In Experiments I and II, adults and children were presented paragraphs to read and search for specified targets, respectively. Two types of typographical (spatial) manipulations were used: case of the letters within the paragraphs was as normally experienced, or in alternating upper and lower case letters. Spacing between words was either as normal, filled with a neutral symbol, or absent. The response measures were reading and search speed in words per minute. Sensitivity to case (word shape) and space (word boundary) increased as a function of experience and was different for reading compared with search. In Experiment III subjects were asked to judge whether briefly presented pairs of letters were the same or different. Retinal (spatial) location was varied from trial to trial; dependent measure was reaction time. Results showed a developmental progression in response time with complex interactions. Theoretical interpretations of these data are discussed in support of the initial stage of Hochberg's peripheral to cognitive search guidance model.     

A comparison of frequency, interval, and time-sampling methods of data collection

Data representing high, medium, and low response rates in constant and nonconstant patterns were generated by electromechanical equipment to determine whether the same data collected by time-sampling, interval recording, and frequency recording would be represented similarly by each method. Results indicated: (1) that time-sampling provided an extremely inaccurate estimate of responding, and (2) that interval recording accurately represented responding of low and medium rates, but grossly underestimated high-rate responding.     

Facilitating paper recycling: effects of prompts, raffles, and contests

The effects of prompts and reinforcement to promote paper recycling were compared in six university dormitories. For a Prompt condition, residents were urged to recycle paper for ecological reasons via flyers distributed to each room. For a Raffle contingency, residents were given one raffle ticket for every pound of paper brought to a collection center. For a Contest contingency, two dorms were paired and the dorm whose residents delivered the most paper won $15 for its treasury. Contingency awareness was strengthened via a flyer placed under the door of each resident's room. Flyers alone had little effect in increasing paper-recycling behaviors, but the raffle (substantially) and the contest (somewhat) increased the amount of paper brought to a dorm's recycling center. Students whose rooms were closest to the collection center showed the greatest participation. Removal of the reinforcement contingencies resulted in a return to baseline levels.     

SELF-RECORDING IN TRAINING GIRLS TO INCREASE WORK AND EVOKE STAFF PRAISE IN AN INSTITUTION FOR OFFENDERS1

Self-recording procedures were used by four adolescent girls to increase work and comments (cues) that evoked staff praise during vocational training sessions in a maximum-security institution for offenders. The girls were selected on the basis of their not responding to a staff-directed token program. The self-recording procedures were directed by a therapist who saw the girls outside the vocational training sessions. According to a multiple-baseline design, self-recording of work was introduced sequentially to each of the two or three settings the girls attended each day. A few days after work had increased, self-recording of cues was introduced. Tokens were delivered by the therapist for work and cues recorded by the girls. Work and cues increased following self-recording for three of the girls and increased cues evoked higher rates of staff praise. Girl and staff behaviors were maintained during short follow-up periods when tokens were not given for the girls' records. The procedures failed to effect desirable changes with a fourth girl's work, and self-recording of work was terminated without introducing cueing.     

Intersubject variability in perceived oscillation as a function of threshold for binocular disparity.

Four groups of 15 female subjects each were classified along a quantitative dimension for proportion of perceived oscillation and threshold for binocular disparity. Analyses of variance showed that significant differences in proportion of perceived oscillation were accompanied by significant differences in threshold for binocular disparity for perceivers of "high" and "low" oscillation (p less than .05). For perceivers of "intermediate" oscillation significant differences in proportion of perceived oscillation but not threshold for binocular disparity were found. It was suggested that: (1) intersubject variability in perceived oscillation may be governed by the threshold for binocular disparity, (2) "low" perceivers may be especially sensitive to the magnitude of the cue, (3) "intermediate" perceivers' subjective reports may be primarily dependent on response criteria and the multiplicity of subjective factors which constitute it, (4) "high" perceivers apparently have least response sensitivity and they cannot maintain a consistent response criterion.