Visual prior entry

It has long been claimed that attended stimuli are perceived prior to unatt ended stimuli - the doctrine of prior entry. Most, if not all, studies on w hich such claims have been based, however, are open to a nonattendational i nterpretation involving response bias, leading some researchers to assert t hat prior entry may not exist. Given this controversy, we introduce a novel methodology to minimize the effect of response bias by manipulating attent ion and response demands in orthogonal dimensions. Attention was orientated to the left or right (i.e. spatially), but instead of reporting on the bas is of location, observers reported order (first or second) of vertical vers us horizontal line segments. Although second-order response biases were dem onstrated, effects of attention in accordance with the law of prior entry w ere clearly obtained following both exogenous and endogenous attentional cu ing.