Abstract
The concept of ‘change blindness’ has been well-established for decades now. It has been proved that attention is crucial in change detection, but the role of other factors has also been postulated. The authors of following the study intended to test the existence of the ‘change blindness’ phenomenon in a real-world situation, overcoming the limitation of passive viewing of 2-D displays present in previous studies via two experiments.
In the first experiment, a pedestrian initiated a conversation with a subject, and during the interaction, he was replaced by a counterpart. Only 46.6% of the subjects detected this change. Furthermore, subjects from the same social group as the pedestrians detected the change but those from a different social group did not.
The second experiment was thus performed to analyze the effect of social groups on the study findings and to eliminate this bias. This study concludes that even amongst real-world settings, humans may ignore spontaneous and transitory changes in the environment and in objects, despite that object being the central focus of attention, and provides a basis and guidelines for future research in this unexplored arena.
Failure to Detect Changes to People During a Real-World Interaction
The article being discussed in the following paper is ‘Failure to Detect Changes to People during a real-world interaction’ by Daniel J. Simons and Daniel T. Levin, published in the Psychonomic Bulletin & Review, 1998.
The concept of ‘change blindness’ is not newfound. It has been well established for decades now that if retinal information signaling is masked in some way, humans are unable to detect changes in details in the surroundings when the view switches from one to another (Blackmore, 1995, Henderson, 1997, Simons, 1996).
Recent studies have also shown that while viewing an object and retaining its particular details, attention has a major role to play. People tend to focus their attention on details of objects which are central in the visual field, while peripherally located objects are relatively less keenly observed (Treisman, 1993). Hence the “center of interest” theory, which implicates that attention is crucial in change detection, with changes being noticed more readily if the attention is focused by specifying the location or type of change (O’Regan, 1996).
This theory, however, is also subject to certain criticisms, with the main argument being that factors other than attention also contribute towards the ability to detect change. This has been proven by studies involving motion pictures which showed that despite the attention being focused directly on the object undergoing change, approximately 66% of the study participants failed to detect the change (Levin, 1997).
Although motion picture studies and studies involving photographs implicate a role of factors other than attention being involved in change detection, these studies have the limitation of being not generalizable to the real world images as they differ from motion pictures in various aspects (Levin, 1997). Hence, with this background, the authors of following the study intended to test whether the phenomenon of ‘change blindness’ does exist in a real-world situation overcoming passive viewing of 2-D displays as a confounding factor, which was present in previously conducted studies and was thought to contribute towards their results.
Methodology
The research hypothesis was tested by means of two experiments. In the first experiment, study participants were approached by a pedestrian who asked them for directions (a real-world interaction), and in the midst of this interaction, the pedestrian was substituted by a counterpart, during an interruption created by carrying a door between the subject and the pedestrian (lasting for approx. 1 sec).
A total of 15 subjects were approached with ages ranging from 20 to 65. At the end of this interaction, the subjects were told that they were part of a study being conducted by the psychology department and were asked whether they had noticed anything unusual about the interaction or whether they had noticed the change/switch in the pedestrian asking for directions.
The second experiment was carried out in the same way as the first experiment, with only two major differences: in this interaction, both the pedestrians were dressed as construction workers, however, their clothing differed and secondly, all the subjects belonged to the younger age group (Cornell graduate or undergraduate students). A total of twelve subjects were recruited for this experiment.
The independent variables in both studies were demographic features of the subjects including age, sex, etc. while the dependent variable was the ‘change blindness’ phenomenon, which was treated as a categorical variable i.e. change blindness was either present or absent.
Results
In Experiment 1, only 46.6% of the subjects noticed the change while the rest continued the conversation, oblivious to the change. Most subjects noticing the change belonged to the 20-30-year-old age group while those being unable to do so belonged to an older age group (35-65 yrs).
A plausible explanation for these findings is the role of social group membership. It has been proposed that people differ in their encounters with members of one’s own social group (“in-group”) as compared to those belonging to a socially distinct group (“out-group”).
When amidst those from the out-group, people tend to focus more on the general attributes and features of the social group the person belongs to rather than on the distinguishing details of individuals. The opposite happens in the company of those from the in-group in which more attention is paid to individuals’ differentiating characteristics (Rothbart, 1985). This tendency to stereotype people of a particular group and overlook their individual features can contribute towards the findings in Experiment 1, where younger subjects considered themselves as being a part of the same social group as the pedestrians asking for directions and hence focused more on their individuating features.
The second experiment was thus designed and conducted to overcome this bias and the results yielded that only 33.3% of the subjects from the same age group who had successfully identified the change previously, noticed the change this time. This proved the hypothesis that younger subjects in experiment 1 were more successful in detecting the change since they perceived the pedestrians to be belonging to their own social group.
Conclusions
This study concludes that even amongst real-world settings, humans may ignore spontaneous and transitory changes in the environment and in objects, even if that object happens to be the central focus of the person’s attention at that point in time. Therefore, it can be concluded that attention alone is not the prerequisite for change detection but several other factors, including a focus on the distinguishing and identifying properties of the object, interplay in producing noticeable changes.
Change Blindness in Real-Life Situations
The above-mentioned study proves that the phenomenon of change blindness is applicable not only to the viewing of motion pictures and photographs but also to real-life situations. If we look at our everyday lives, we will realize that we encounter this phenomenon very often, though we do not often realize that this phenomenon did occur.
For instance, while talking to a group of people, all of whom are unfamiliar, if there is a switch in the person making the conversation, one tends to ignore the switch. This may partly be because our main focus is on the conversation and not the person making the conversation, but also because of other factors, including the role of ‘change blindness’. We may later at some point realize that such a switch did occur or at times we may never realize it at all.
A similar example took place a couple of weeks ago. My friend and I were watching our favorite sitcom when we came across a commercial advertising a particular brand of energy drink. This commercial was based on two females in different settings, one at home and the other at work. Both of them, when exhausted from the day’s labor, came across this energy drink and after having it, felt totally refreshed.
Throughout the commercial, the scenes switch between both females, each one of them being the focus of the commercial alternately. Both these females, although from approximately the same age group, were dressed differently, and were even different physically. One of the females had a particular shade of hair color which I happened to admire and I pointed this out to my friend.
My friend refused to acknowledge that there were two different females in that commercial. According to her, the commercial comprised of a single female being portrayed in different settings i.e. at home and at work. She had completely overlooked the fact that the commercial was based on two different females and was unwilling to accept this even when I pointed this out to her. We then waited for a rerun of the same commercial in the next commercial break, and this time, my friend did notice the stark difference in the two females being portrayed in the commercial and was amazed at not noticing such an obvious difference previously. Such happenings are not unusual.
Studies of ‘change blindness’ have shown that when questioned, naive subjects do predict successful change detection for example, when individuals unfamiliar with the study were questioned whether they, if subjected to a similar situation, would be able to detect the change in the pedestrians, most of them replied in affirmative. However, when faced with the same situation, most individuals fall prey to this phenomenon of ‘change blindness’.
Thus, although it may seem unreal and unacceptable, we do encounter the phenomenon of ‘change blindness’ in our everyday lives though we tend to be oblivious to it. The role of attention, albeit of prime importance in determining our capability to detect the change, is not the sole factor contributing towards it and the role of other factors has also been postulated.
References
- Blackmore, S. J. (1995). Is the richness of our visual world an illusion? Transsaccadic memory for complex scenes. Perception, 1075-1081.
- Henderson, J. M. (1997). Transsaccadic memory and integration during real-world object perception. Psychological Science, 51-55.
- Levin, D. T. (1997). Failure to detect changes to attended objects in motion pictures. Psychonomic Bulletin & Review, 501-506.
- O’Regan, J. K. (1996). “Mud splashes” render picture changes invisible. Investigative Ophthalmology & Visual Science, 213.
- Rothbart, M., & John, O. P. (1985). Social categorization and behavioral episodes: A cognitive analysis of the effects of intergroup contact. Journal of Social Issues, 41, 81-104.
- Simons, D. J. (1996). Insight, out of mind: When object representations fail. Psychological Science, 301-305.
- Treisman, A. (1993). The perception of features and objects. In A. B. Weiskrantz, Attention: Selection, awareness, and control: A tribute to Donald Broadbent (pp. 5-35). Oxford: Oxford University Press.