Change Detection

Introduction Most people are unaware of the changes in their visual environments until attention is drawn directly to those minor changes. Individuals do not often detect changes because of the lack of attention or insignificance of the change. In order for an individual to notice a change like color, location and identity of an object, attention must somehow be drawn to that object. A general conclusion from this body of work is that attention is necessary for detecting change (Rensink et al. , 1997). Being unable to detect a change in an object is called change blindness. Researchers seem to think that change blindness is the cause of many car accidents. Looking away from a road then looking back is a change that is very difficult to perceive which results in quite a few car accidents. Method In this experiment two pictures were represented in modification for each trial. On half of the trials the two pictures were alike but in the other half the pictures changed in some way. For each pair either the pictures appeared instantly after each other or they flickered. The participants in this study consist of a psychology class in the College of Staten Island. In order to start this experiment, students were asked to sign in to their CogLab accounts. To start the first trial of the change detection experiment, participants were required to press the space bar. One picture will appear after the other. The task in this experiment is to detect whether or not there is a change in the two pictures. If the image changes students press the â€Å"c† key but if the image doesn’t change students press the â€Å"n† key. This test measures our reaction time as well as our ability to detect changes in the pictures. The independent variable in this experiment is was the flicker and no flicker conditions. Two dependent variables were measured which were reaction time and proportion of correct judgments. Reaction time was the time between the appearance of the stimuli and the time that it took participants to make a response. Results It has been predicted that the percentage correct is smaller and the reaction time is slower for the flicker condition the no flicker condition. In the no flicker condition it is easier to identify the change in the picture because the change is almost immediately distinguished. On the other hand, the pictures with the flicker condition, the blank gray leads to changes throughout the picture which results in participants having to look at the picture item by item until the change is noticed. My results show that these predictions are somewhat true. In the flicker condition my reaction time was 11281. 6 ms and the proportion correct of change detected was 0. 625. In the no flicker condition my reaction time was 7667. 143, which is apparently significantly longer than predicted to be, but my proportion correct was . 875 which is slightly greater. Discussion The basic idea of this experiment is that people cannot store many details of a scene in memory. The vital aspect seems to be attention. In order to identify a change in an object, it is necessary to pay attention to that certain object; otherwise no change will be detected. The brain is unable to see a change happening to an element it has not yet stored. Selective attention is a key part in detecting a change in an object, scene or picture. My results for this experiment confirm that divided attention and change detection come hand in hand.