Behavior and pre-object frontal theta. A, Percent correct was significantly higher on low versus high load trials. B, RTs were significantly shorter on low versus high load trials. C, Frontal theta amplitude measured before the onset of the object was significantly greater for high versus low load (p < 0.05). Together, these results demonstrate that the WM manipulation was effective. Error bars indicate SEM. ***p < 0.001. n.s., Not significant.