se, but instead the expectation for the presentation of a visual item. Studies investigating the effect of expectation on episodes of inattentional blindness have shown that once observers are made aware of the importance of the stimuli to be presented, for example stating that one will later be tested on it, the phenomenon essentially disappears. While admitting to possible ambiguities in methodology, Mack, one of the foremost researchers in the field, holds strongly that inattentional blindness stems predominantly from a failure of attentional capture. She points out that if expectation does not mediate instances of very closely linked phenomena such as attentional blink and change blindness (whereby participants have difficulty identifying the changing object even when they are explicitly told to look for it), it is unlikely that inattentional blindness can be explained solely by a lack of expectation for stimulus presentation. Perceptual cycle The perceptual cycle framework has been used as another theoretical basis for inattentional blindness. The perceptual cycle framework describes attention capture and awareness capture as occurring at two different stages of processing. Attention capture occurs when there is a shift in attention due to the salience of a stimuli, and awareness capture refers to the conscious acknowledgement of stimuli. Attentional sets are important because it is composed of characteristics of stimuli an individual is processing. Inattentional blindness occurs when there is an interaction between an individual's attentional set and the salience of the unexpected stimulus. Recognizing the unexpected stimulus can occur when the characteristics of the unexpected stimulus resembles the characteristics of the perceived stimuli. The attentional set theory of inattentional blindness has implications for false memories and eyewitness testimony. The perceptual cycle framework offers four major implications about inattentional blindness 1) environmental cues aid in the detection of stimuli by providing orienting cues but is not enough to produce awareness, 2) perception requires effortful sustained attention, interpretation, and reinterpretation, 3) implicit memory may precede conscious perception, and 4) visual stimuli that is not expected, explored, or interpreted may not be perceived. Other bases for attentional blindness include top down and bottom up processing. Experiments To test for inattentional blindness, researchers ask participants to complete a primary task while an unexpected stimulus is presented. Afterwards, researchers ask participants if they saw anything unusual during the primary task. Arien Mack and Irvin Rock describe a series of experiments that demonstrated inattentional blindness in their 1998 book, Inattentional