Poisson models for assessing rater agreement in discrete response studies

In this paper we discuss a method for assessing agreement among raters who are scoring the number of times, a specified event occurs. In such cases, it seems reasonable to define agreement in terms of raters' behaviours in correctly identifying responses which have in fact occurred, and in their falsely counting responses which have not. We exploit the discrete nature of the response variable, and examine a class of models for mean response assuming an underlying Poisson distribution. Test statistics are given for deciding on the applicability of the models, and whether there is agreement with respect to correctly detecting responses, as well as with falsely scoring responses.     

Participation,influence, and satisfaction in group decision making

The hypothesis that attitudinal effects of participation depend on individual differences in motivation was tested in a laboratory experiment with 56 three-man groups (leader and two members). Measures of the attractiveness of power and social acceptance were obtained prior to a group decision task, after which members described their perceived participation, influence, and satisfaction. Results showed that: (a) influence was more strongly related to satisfaction for members with strong, as opposed to weak, power motives; (b) for members with strong affiliation motives, participation was more strongly related to satisfaction than was influence. Relationships varied across satisfaction aspects. It was concluded that participation may be associated with favorable role attitudes through different motive-attainment mechanisms in the group decision-making process.     

Concurrent variation of response bias and sensitivity in an operant-psychophysical test

The yes-no signal detection procedure was applied to a single-response operant paradigm in which rats discriminated between a standard auditory intensity and attenuated comparison values. The payoff matrix was symmetrical (with reinforcing brain stimulation for correct detections and brief time-out for errors), but signal probability and intensity differences were varied to generate a family of isobias and isosensitivity functions. The d’ parameter remained fairly constant across a wide range of bias levels. Isobias functions deviated from a strict matching strategy as discrimination difficulty increased, although an orderly relation was maintained between signal probability value and the degree and direction of response bias.     

Auditory evoked brain responses: Intensity functions from bipolar human scalp recordings

Average evoked brain responses were computed from four simultaneous recordings during binaural tone stimulation at 10 intensity levels. Amplitudes and latencies were measured for the prominent components, and linear regression coefficients were computed. The results indicate that the sensitivity of the evoked response to stimulus intensity is dependent upon the selection of the appropriate measure. Linear amplitude functions were demonstrated. Additional research relating these responses to psychophysical measures is suggested.     

Successive luminance difference thresholds and brightness as a function of the interstimulus interval and durations of successive flashes

Monocular,successive luminance difference thresholds (ΔI) and brightness matches (PSE) were obtained by the method of constant stimuli for two flashes successively presented to the same retinal area. Variations in interstimulus interval first-flash duration,and second-flash duration were the independent variables investigated. ΔI decreased as a function of ISI,while PSE remained relatively uninfluenced. An intensity-duration reciprocity was observed with increases in either first- or second-flash duration. Equal increases in duration of both flashes led to a constant value of ΔI. A Broca-Sulzer effect was also noted. In another study, a 10-msec, variable-luminance Standard was followed after 500 msec by either a 10-msec or a 320-msec test flash that was compared to the Standard. The results indicated that the rate of change of brightness with changes in luminance of the Standard was faster for the 10-msec flash than for the 320-msec flash. The rate-of-change hypothesis would predict that the 10-msec flash should have the smaller ΔI. The results for two Ss indicated the opposite: AI was smaller for 320-msec than for 10-msec flashes. A modification of the hypothesis was suggested such that it may be the energy increment (Δlt) required for detection that is related to the rate at which brightness changes with energy.