WHAT AND THE WHERE OF THE PIGEONS PROCESSING OF COMPLEX VISUAL-STIMULI

Eight pigeons were trained on a go-no go visual discrimination involvi ng 1 S+ and 15 S(-)s. The 16 discriminative stimuli were black-and-whi te line drawings created by the factorial combination of 4 different g eometric shapes (wedge, cylinder, cone, handle) in 4 different spatial locations (right, left, above, below) in relation to a common shape ( cube). All of the pigeons readily learned this complex visual discrimi nation. Each bird's pecking behavior was controlled by both attributes of the line drawings, but somewhat stronger stimulus control was exer ted by the location of the added component than by its shape. Across a ll 8 pigeons, there was an inverse relation between stimulus control b y component shape and component location. These results document pigeo ns' joint processing of ''what'' and ''where'' information in visual d iscrimination learning.