Figure 6.

GAMM showing change in s.d. visual width (a) and visual depth (b) as a function of object numbers and time, accounting for bower identity. Visual angle s.d. width increased (i.e. quality decreased) and then became stable as time passed, whereas this measure decreased rapidly at first as object number increased (i.e. quality increased), and then remained stable. Visual angle s.d. depth increased over time. As object numbers increased the depth s.d. initially increased, then decreased and remained stable.