FIGURE 3.

Scatter plot of adjusted threshold versus centered subjective arousal for Experiment 1. To be able to visualize the threshold as a function of arousal while controlling for baseline threshold, threshold scores were adjusted as follows: The threshold scores were fitted to a regression model Y ′ = B₀ + B₁X₁ + B₂X₂ + B₃${\mathrm{X}}_{\mathrm{2}}^{\mathrm{2}}$, where Y′ is predicted test threshold, X₁ is baseline threshold, and X₂ is centered subjective arousal [regression coefficients (B) are presented in Step 3 in Table 3]. Next, the threshold scores (Y) were adjusted so that Y _adjusted = Y-B₁X₁. The solid curve shows the quadratic polynomial regression line of adjusted threshold on centered arousal scores, thus representing Y_adjusted′ = B₀ +B₂X₂ +B₃X₂².