Instructing beginning teachers in reinforcement procedures which improve classroom control

Systematic reinforcement procedures were used to increase study behavior in the classrooms of three beginning teachers experiencing problems of classroom control. Classroom study rates were recorded during a baseline period. During subsequent experimental periods, the teachers changed one or more reinforcement contingencies (teacher attention, length of between-period break, a classroom game) to bring about increased study rates and concomitant reductions in disruptive behaviors. A brief reversal period, in which these contingencies were discontinued, again produced low rates of study. Reinstatement of the contingencies resulted once again in marked increases in study behaviors.     

Luminance thresholds for the Bezold-Brücke hue shift

This study presents data on the luminance difference at which a hue difference is first perceived between two identical spectral lights. Thresholds were obtained for both luminance increments and decrements from a 2.00 log troland standard for wavelengths between 470 nm and 690 nm. A predicted luminance threshold for each wavelength was calculated based on wavelength discrimination data and the Purdy constant hue contours; i.e. that luminance at which the constant hue contour intersects the wavelength discrimination bound for a given wavelength. A generally good agreement was obtained between observed and predicted values.