When plotting reinforcement schedules on a graph with time on the x-axis and cumulative number of responses on the y-axis, distinct visual characteristics emerge. Ratio schedules (variable and fixed) have similar, steep slopes. The variable ratio line remains straight and is marked at random points where reinforcement occurs. The fixed ratio line has consistently spaced marks for reinforcement, but exhibits a small drop after each mark before resuming its overall steep slope. Interval schedules (variable and fixed) have similar slopes at roughly a 45-degree angle. The variable interval line remains straight and is marked at random points for reinforcement. The fixed interval line has consistently spaced reinforcement marks, with a drop in the line following each reinforcement.