Figure 2.

Effects of varying the effort (response requirement) for cigarette puffs, and the presence or absence of an alternative monetary reinforcer, on smoking in smokers with schizophrenia (left; reprinted from Tidey et al., 1999) and smokers without psychiatric disoders (right; data from Bickel et al., 1995). Data were collected in the 1990s in Burlington. VT. Points represent Mean +/− SEM.