Inattentional Blindness: Can auditory distractor make a difference?
So many people go about in this world focusing on the big changes and not noticing the little changes that are occurring right before their eyes. Is it that humans decide to ignore the little things in front of them or is it a lack of attention? For example, an individual may be driving down the road paying attention only to what is in front, yet never noticing the type of the car that just passed. This is what is known as inattentional blindness-a situation in which a stimulus not attended to is not perceived, even though a person is looking directly at it (Goldstein, 2002). Inattentional blindness can be affected in many ways and today's research is focusing on the type of external noise can that distract an individual from paying attention. The description of external noise that distracts an individual can be broken into many characteristics: the type, the space, and the size.
The type of distractor used in inattentional blindness experiments can influence the results in many ways. For example, Lu and Dosher (1997) focused on attention and the effects that it had on an individual's performance on perceptual tasks. They defined their distractor as random drawings on paper. They found that a distractor actually enhanced the level of performance. Something out of the ordinary like the random drawings are more likely to draw attention to the human eye.
However, Mack and Rock (1999) were more drawn to the idea of similarity of the stimulus versus the distractor and used the "own name effect" to determine the rates of inattentional blindness. The "own name effect" was defined as having one screen with the individual's own name, and then the next screen showed the same name but the first vowel of the name had been changed. For example, in their experiment they first used Jack and later changed to Jeck. The results of this part of their study indicated that individuals did consciously perceive this change. At this point in Mack and Rock's (1999) study it was beginning to be questioned whether or not familiarity could play a role in inattentional blindness, yet they concluded that no evidence supported familiarity playing a role.
Most, Simons, Scholl, and Chabris (2000) also focused on the role of featural similarity of the object versus the stimulus. Their experiment consisted of attending to basketball teams either in a black shirt or a white shirt passing the ball. Randomly there was a woman walking through the court with an umbrella, and a majority of these participants did not notice this. But when a gorilla walked through the screen those paying attention to the white shirts did not notice it compared to those paying attention to the black shirts. It was decided that because of their previous experience to attending to all black shirts, participants noticed the black color of the gorilla and therefore were more likely to notice. The idea of similarity can also be supported by work done by Most, et al. (2001) showing that similarity of an unexpected object greatly influenced the rate of capturing attention. This rate, in return, showed an increase of identifying the unexpected object.
Another characteristic of the distractor can be the spatial location. Most, Simons, Scholl and Chabris (2000) expanded from a previous Newby and Rock study (1998)and questioned the distance of an unexpected object from the focus of attention from a previous Newby and Rock study (1998). Mos, Simons, Scholl and Chabris (2000) found that spatial location did affect the detection of unexpected objects. They defined a "zone of attention" as the length of the cross's arms, and hypothesized that participants would see the object in this area. Results of their experiments showed that only 80% of observers saw the unxpected object in the zone of attention. These results supported their hypothesis that an object being placed in the zone of attention would decrease the inattentional blindness (level of inattentional blindness being 20%). Most, Simons, Scholl, and Chabris (2000) also found that when engaged in an attentionally demanding task, participants were less likely to notice the unexpected object than when engaged in a non-attentionally demanding task. While Newby and Rock (1998) also focused on the idea of spatial location, they found that the distance to the focus of attention is a critical variable. Lu and Dosher (1997) expanded on the spatial location by focusing on the placement and movement of the unexpected object. Results showed that observers were to react faster to the objects falling closer to and in the attended region rather than objects in the unattended region. Results from previous experiments, seem to honor the idea that our eyes can randomly drift, yet when we become attentively focused on one point then it seems as though everything around us becomes unimportant and unattended.
Finally the size of the distractor can influence inattentional blindness. The Mack and Rock (1999) experiment consisted of a black disc and they found that anything larger than 1 degree could be seen, even at a point of fixation. Final point of thought was that the larger the object, the more likely to capture the attention.
However, what happens when an auditory distractor is added to the type of distractors, rather than visual only? In 2000, Vroomen and Gelder ran an experiment consisting of two tones, either high or low, to see the amount of influence they had on inattentional blindness. According to Vroomen and Gelder, the results showed that sound could enhance visual perception. In other words, participants were more likely to see an unexpected object when there was a auditory distractor. Previous experiment by Stein, London, Wilkinson, and Price (1996) also provided support for the idea of sound enhancing visual perception. Sound in some way is not becoming a distractor, rather it is influencing participants ability to notice an unexpected object.
Although Vroomen and Gelder (2000) noticed that types of tones do affect the amount of inattentional blindness, what happens if some type of rhythm (i.e. music) exists? Are participants more likely to notice the unexpected object with music that has a an unpredictable flow, i.e. classical music, or music with a repetitive flow, i.e. techno music more likely to effect the amount of inattentional blindness? While research has not focused on different types of music being the auditory distractor the goal of this experiment is to examine this idea.
It is hypothesized that gender, spatial location, and type of music will influence the detection of the unexpected object. Female participants and senior participants will be more likely to detect the unexpected object under techno music, while male participants will be more likely to detect the object under classical music. Why? Most likely because techno has a predictable and repetitive flow, and this seems to be more interesting to males versus classical music which requires more attention because of dynamic and unpredictable changes, which females may present more patience.
Method
Participants
The goal of the experiment is to obtain at least forty males and forty females to see if there is a difference in the attention span of gender. Are males more likely to have an increased inattentional blindness span versus females? Also, the college student participants will be asked to verify their classification. The question behind this is the higher the classification the more likely they are to have a decrease in attentional blindness. A sign up sheet will be posted on the psychology department experimental sign up board, and payment will be made in a blue card for extra credit.
Materials
A computer-based program will be set up in a computer room. This program will display a black cross and every 200 milliseconds (Most, Simons, Scholl, & Chabris, 2000) the screen will change and an unexpected object (i.e. black triangle on one trial with a red triangle outlined in black on another trial) will appear randomly in a different quadrant on each trial. The size of the triangle will vary on each trial, ranging from small to large.
The students will be provided with headphones, and each computer will either play techno or classical music.
Procedures
Participants will be instructed to quietly sit at a computer in the room, where the screens of the computers will be in black. Only 10 participants will be allowed to run at a time to prevent each participant from sitting next to each other. Participants will be asked to read and sign a consent form, and will be informed that participation is completely anonymous.
Participants will be informed to turn on the computer screen by hitting the right button on the mouse. Further instructions are written on the computer and to follow them completely. Participants are asked to place the headphones on their head and told that volume can be adjusted as needed. The reason for freely choosing the volume is that some participants may be hard of hearing than others. Music will remain constant for the experimental group, whereas the control group will not hear the music. Participants will then begin the experiment by using the mouse to click start. When the participants were aware of the unexpected object, instructions were to press the space bar. The length of the experiment will last about 30 minutes.
Design
The design of the experiment will be a between subject, measured by an ANOVA. The independent variable is the auditory distractor, gender and the placement of the unexpected object. The dependent variable is how much does the auditory distractor affect the inattentional blindness. The measuring scale will be designed based on the calculation of the number of times the space bar is pressed during the experiment.
Results
The results will show a main effect for type of music, with 75% of the participants that hear the techno music will have a decrease in the attentional blindness, without looking at gender. Classification of the participant will not influence the amount of inattentional blindness. With the addition of a certain rhythm (i.e. the techno music), male participant's inattentional blindness will see an increase versus the female participants.
These trends will support those of Mack and Rock's (1999), whose data focused on the percentage of the observers noticing the unexpected object from the distance from the line. According to Mack and Rock's (1999) data, the farther the unexpected object is the more likely the increase in attentional blindness. Most, Simons, Scholl, and Chabris (2000) data agreed with Mack and Rock (1999) study. Location near the arm of the cross lead to a decrease in the amount of inattentional blindness.
Discussion
Different people can be tuned to attend to many different objects. While some individuals are not aware of their surroundings, others can sometimes be too aware. As a children age, parents teach their children to be aware of surroundings and to always pay attention to what is directly in front of them. One major idea that parents promote when the child turns sixteen and begins driving is to be aware of your blind spot, pay attention and really pay attention. The idea of inattentional blindness can be attributed to many different ideas, maybe the space of the focus of attention was too far from the unattended object and therefore it was not noticeable. According to Mack and Rock (1999) and Lu and Dosher (1997) this did have an influence on the experiment's results. Mack and Rock (1999) point out that subjects learn to inhibit attention from a farther spatial location, and this leads to a significant increase in the inattentional blindness. Or Mack and Rock attributed the increase of inattentional blindness to the size of the object not being largeenough to capture the attending eye.
Yet, what type of problems will be faced in running an experiment such as this? Mack and Rock (1998) experienced the role of expectation by the participants. For each participant, the difficulty level of the experiment will vary. For someone who already suffers from an attentional disorder, this experiment could be tougher to handle. This may impact the results in a negative way, may need a process of elimination when getting participants.
The goal of the experimenter will be to let participants know little information regarding the hypotheses of the experiment. By controlling the amount of information given in the consent form and instructions, unwanted behavior can be controlled.
Another problem faced by the experimenter is the "practice effect." Overtime participants may become used to the idea of finding the object and have figured out the hypotheses, going back to the idea of the unwanted behavior. Also, the length of the experiment could affect the participants behavior. For example, the participants may become bored with the idea of pressing a space bar over and over. There may be a greater chance of participants becoming bored with the techno music because of the repetitive behavior.
Finally, playing the music before the directions are read completely could influence what information was actually taken in and how well participants understand the instructions. The different type of music could also affect how quickly the decision is made; for example, with the techno music participants may begin to press the space bar along with the beat of the music rather than paying attention to the previous instructions given.
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Mack, A. & Rock, I. (1999). Inattentional Blindness. Psyche, Cambridge, MA:MIT.
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(B)Most, S.B., Simons, D.J., Scholl, B.J., Jimenez, R., Clifford, E., & Chabris, C.F. (2001). How not to be seen: The contribution of similarity and selective ignoring to sustained inattentional blindness. Psychological Science, 12(1), 9.
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Vroomen, J. & Gelder, B. (2000). Sound enhances visual perception: Cross-modal effects