Literature Review on Attention
One of the most common of these used when researching change detection is the flicker paradigm. I shall be looking at several different research reviews highlighting the way in which the change blindness can be measured through change detection using the flicker paradigm, and how this can be associated with attention. Change blindness is one of the most researched paradigms of visual attention. Although it has only been within the last decade that psychologists have become increasingly more interested in this phenomenon, the first mentioning of change blindness can be traced as far back as the 1890’s.
Although people were aware, most research or true understanding of its relevance to visual attention in psychology did not really begin until the 1980’s. Despite the lack of knowledge of its technical term, many of us are more aware of the ways we can detect change blindness than we think. While testing using the flicker test is a little different to the other more common ways it is presented to us, a similar idea is used even amongst children. I’m sure we can all recall the spot-the-difference puzzles, which usually compare two pictures, and a number of small things changed.
When searching for the differences we are in fact using the same methods used in the flicker test for change blindness. In our everyday lives it is quite common to encounter this phenomenon. Caplovitz, Fendrich & Hughes give an ordinary example of when a person is rushing to work and cannot find their keys. (2008). Often they appear right in front of the person in an obvious place, yet due to the lack of attention on looking for them and being distracted by being late, they completely miss them.
Psychologists believe there are a few reasons that this can occur. When changing the position a person views the object from, angles and focus can alter the way in which we perceive our surroundings. Another cause that is studied by psychologists is the eye movements demonstrating the visual processing taking place. When in a hurry, we may not be processing our view as we usually would when given the time. A similar cause would be a visual obstruction. Here the view may appear to be altered by something in the way even if only for a brief amount of time.
However, in the case of this research, we can focus on how the lack of visual attention can cause us to overlook or simply not see what is right in front of us. Researchers can test for change blindness through a variety of different detection paradigms. The most common of these is the flicker paradigm. Rensink et al. developed a change detection experiment using this particular paradigm and explain it as “an original image A repeatedly alternates with a modified image A’, with brief blank fields placed between successive images. (1997). When a change has been perceived by the viewer, they are asked to hit a key and name the change that has taken place in order to rule out any cheating. (Rensink et al. 1997). This is the same method used in many other change blindness researches. Change detection has also been used to investigate the ways in which people with atypical development such as autism have any particular attentional preferences. (Watson et al. 2012). Usually the images shown to the viewer are a real life scene or location where a change occurs.
These changes are made so that they are neither too subtle nor too obvious to the participant. Changes in the images presented can include colour, location or the presence or absence of a particular object. (Watson et al. 2012). It is predicted that the participants would be able to pick up on the change that is taking place as visual transients generally capture attention. (Cavanaugh & Wurtz, 2004). It is largely thought that when viewing a display, focussed attention on a specific object is required in order to detect a change. Rensink et al. 1997). O’Regan, Deubel, Clark & Rensink highlight that internal representation of the visual field only contains the particular aspects that have been attended to in a scene. (2000). We can relate this back to the example used previously by Caplovitz, Fendrich & Hughes where we can only be reassured that our keys are not in one place by focussing our attention on that spot. Until then we are unsure of where exactly our keys might be and cannot rule out the possibility that we left them on the sofa.
This is due to the fact that when visually processing a particular scene, we make comparisons between what is visually available at the scene front of us, to information stored in our visual short term memory. (Caplovitz, Fendrich & Hughes, 2008). When we fail to allocate visual attention to a particular area we are preventing storage of the changing aspect of the scene in our visual short-term memory and therefore are unable to make any comparison. (Caplovitz, Fendrich & Hughes, 2008). This is how things can go unnoticed and to some extent, how change blindness can occur.
We can see that from this in order to make claims about change blindness where focussed attention is lacking, we must understand that the two are largely interrelated. Although extensive research has taken place surrounding change blindness in the last ten years, there still remain several unanswered questions that psychologists aim to explain and understand. Studies conducted by Utochkin try to distinguish if there are in fact any differences between near and far locations of specific features in relation to spatial attention and if speed or accuracy is altered by these locations. 2011). It is hard to say if either of these have an effect as the results of his findings do not give any unambiguous answers. Other questions remain in relation to change blindness. It is still unknown to what extent its effects have on everyday behaviour or whether it greatly impairs performance on some tasks. However, it has been proven that it can impair performance when it comes to driving ability or on a more moral level, eyewitness accounts, which is now heavily relied on in court.
This can be very influential on a criminal case and therefore may have serious consequences should change blindness come into play. So just what is it that makes people unable to make simple observations about the things around us? Even when they are right in front of us, we still struggle to acknowledge that they are there. How many times have you heard recounts of a car accident where the person at fault says, “I did not see them coming”. How many times can you recall leaving your phone somewhere and not being able to see it when its staring you in the face?
How many times have you kicked yourself for something like this occurring when at the time it seemed like they were no where to be seen? It is simple, psychological research tells us that despite continuing image shifts, attention to specific features in a visual scene can be critical in ensuring stable perception. (Cavanaugh & Wurtz, 2004). We can overcome this phenomenon however, if the right amount of spatial attention is allocated to the changing features. The flicker paradigm has become a useful psychological tool in change detection.
It allows us to rule out influences from other known causes to change blindness such as eye movements, visual saccades, or a change in location. It has been designed so that any changes detected can be directly associated with attention. By manipulating perceived images in participants, we are able to study the role of attention in relation to change blindness. Research has concluded that without due visual attention, observers are blind to change. (Rensink et al. 1997). Therefore we can infer that change blindness is a result of the absence of our focussed attention.