There are two different tasks possible in this experiment. The first task is to estimate the number of dots in the display. After viewing the brief display, move the slider to the position that corresponds to your estimate of the number of dots. Set the slider, then press the space bar or enter key or click on the enter button. The second task is to estimate the ratio of dots shown in two successive brief displays. Estimate the number of dots in the first display (the standard) and the number of dots in the second display and then mentally divide the second number by the first. You should do this division by estimating the ratio, rather than by actually performing the long division in you head. Enter the resulting fraction or ratio in decimal form, i.e., 0.4, 1.2, etc., and then press the enter key or click on the enter button. During each block of trials, the number of dots in the standard (the first display) is constant .
When using the logarithmic and linear slider input methods, the value of the scale is given by the position of the left side of the slider. For the most accurate response, align the left side of the slider with the first digit of the label. For example, to input the value 400, the observer should align the left side of the slider with the left side of the digit '4.'
To start a new block of trials, click on the Start block button or press the ENTER key or SPACE bar. To examine your performance, click on the peek/reset block key. (NOTE: Clicking on the peek/reset key resets the trial counter to the next block of trials.)