Figure 4. The individual differences model assumed a bell-shaped distribution of the 96 trauma patients with respect to hypnotic state. Hypnotic state is an unmeasured, memory performance as a function of hypnotic state. Hypnotic state is an unmeasured, theoretical variable of the individual differences model. The mean and standard deviation of the distribution of hypnotic state are set to zero and one, respectively. Thus, the scale of hypnotic state is in standard deviations from the mean of the distribution of trauma patients.