A Research Proposal:

Inattentional Blindness: Canauditory distractor make a difference?

Stephen F. Austin StateUniversity

So many people go about in this worldfocusing on the big changes and not noticing the little changes thatare occurring right before their eyes. Is it that humans decide toignore the little things in front of them or is it a lack ofattention? For example, an individual may be driving down the roadpaying attention only to what is in front, yet never noticing thetype of the car that just passed. This is what is known asinattentional blindness-a situation in which a stimulus not attendedto is not perceived, even though a person is looking directly at it(Goldstein, 2002). Inattentional blindness can be affected in manyways and today's research is focusing on the type of external noisecan that distract an individual from paying attention. Thedescription of external noise that distracts an individual can bebroken into many characteristics: the type, the space, and thesize.

The type of distractor used in inattentionalblindness experiments can influence the results in many ways. Forexample, Lu and Dosher (1997) focused on attention and the effectsthat it had on an individual's performance on perceptual tasks. Theydefined their distractor as random drawings on paper. They found thata distractor actually enhanced the level of performance. Somethingout of the ordinary like the random drawings are more likely to drawattention to the human eye.

However, Mack and Rock (1999) were moredrawn to the idea of similarity of the stimulus versus the distractorand used the "own name effect" to determine the rates ofinattentional blindness. The "own name effect" was defined as havingone screen with the individual's own name, and then the next screenshowed the same name but the first vowel of the name had beenchanged. For example, in their experiment they first used Jack andlater changed to Jeck. The results of this part of their studyindicated that individuals did consciously perceive this change. Atthis point in Mack and Rock's (1999) study it was beginning to bequestioned whether or not familiarity could play a role ininattentional blindness, yet they concluded that no evidencesupported familiarity playing a role.

Most, Simons, Scholl, and Chabris (2000)also focused on the role of featural similarity of the object versusthe stimulus. Their experiment consisted of attending to basketballteams either in a black shirt or a white shirt passing the ball.Randomly there was a woman walking through the court with anumbrella, and a majority of these participants did not notice this.But when a gorilla walked through the screen those paying attentionto the white shirts did not notice it compared to those payingattention to the black shirts. It was decided that because of theirprevious experience to attending to all black shirts, participantsnoticed the black color of the gorilla and therefore were more likelyto notice. The idea of similarity can also be supported by work doneby Most, et al. (2001) showing that similarity of an unexpectedobject greatly influenced the rate of capturing attention. This rate,in return, showed an increase of identifying the unexpectedobject.

Another characteristic of the distractor canbe the spatial location. Most, Simons, Scholl and Chabris (2000)expanded from a previous Newby and Rock study (1998)and questionedthe distance of an unexpected object from the focus of attention froma previous Newby and Rock study (1998). Mos, Simons, Scholl andChabris (2000) found that spatial location did affect the detectionof unexpected objects. They defined a "zone of attention" as thelength of the cross's arms, and hypothesized that participants wouldsee the object in this area. Results of their experiments showed thatonly 80% of observers saw the unxpected object in the zone ofattention. These results supported their hypothesis that an objectbeing placed in the zone of attention would decrease theinattentional blindness (level of inattentional blindness being 20%).Most, Simons, Scholl, and Chabris (2000) also found that when engagedin an attentionally demanding task, participants were less likely tonotice the unexpected object than when engaged in a non-attentionallydemanding task. While Newby and Rock (1998) also focused on the ideaof spatial location, they found that the distance to the focus ofattention is a critical variable. Lu and Dosher (1997) expanded onthe spatial location by focusing on the placement and movement of theunexpected object. Results showed that observers were to react fasterto the objects falling closer to and in the attended region ratherthan objects in the unattended region. Results from previousexperiments, seem to honor the idea that our eyes can randomly drift,yet when we become attentively focused on one point then it seems asthough everything around us becomes unimportant andunattended.

Finally the size of the distractor caninfluence inattentional blindness. The Mack and Rock (1999)experiment consisted of a black disc and they found that anythinglarger than 1 degree could be seen, even at a point of fixation.Final point of thought was that the larger the object, the morelikely to capture the attention.

However, what happens when an auditorydistractor is added to the type of distractors, rather than visualonly? In 2000, Vroomen and Gelder ran an experiment consisting of twotones, either high or low, to see the amount of influence they had oninattentional blindness. According to Vroomen and Gelder, the resultsshowed that sound could enhance visual perception. In other words,participants were more likely to see an unexpected object when therewas a auditory distractor. Previous experiment by Stein, London,Wilkinson, and Price (1996) also provided support for the idea ofsound enhancing visual perception. Sound in some way is not becominga distractor, rather it is influencing participants ability to noticean unexpected object.

Although Vroomen and Gelder (2000) noticedthat types of tones do affect the amount of inattentional blindness,what happens if some type of rhythm (i.e. music) exists? Areparticipants more likely to notice the unexpected object with musicthat has a an unpredictable flow, i.e. classical music, or music witha repetitive flow, i.e. techno music more likely to effect the amountof inattentional blindness? While research has not focused ondifferent types of music being the auditory distractor the goal ofthis experiment is to examine this idea.

It is hypothesized that gender, spatiallocation, and type of music will influence the detection of theunexpected object. Female participants and senior participants willbe more likely to detect the unexpected object under techno music,while male participants will be more likely to detect the objectunder classical music. Why? Most likely because techno has apredictable and repetitive flow, and this seems to be moreinteresting to males versus classical music which requires moreattention because of dynamic and unpredictable changes, which femalesmay present more patience.



The goal of the experiment is to obtain atleast forty males and forty females to see if there is a differencein the attention span of gender. Are males more likely to have anincreased inattentional blindness span versus females? Also, thecollege student participants will be asked to verify theirclassification. The question behind this is the higher theclassification the more likely they are to have a decrease inattentional blindness. A sign up sheet will be posted on thepsychology department experimental sign up board, and payment will bemade in a blue card for extra credit.


A computer-based program will be set up in acomputer room. This program will display a black cross and every 200milliseconds (Most, Simons, Scholl, & Chabris, 2000) the screenwill change and an unexpected object (i.e. black triangle on onetrial with a red triangle outlined in black on another trial) willappear randomly in a different quadrant on each trial. The size ofthe triangle will vary on each trial, ranging from small tolarge.

The students will be provided withheadphones, and each computer will either play techno or classicalmusic.


Participants will be instructed to quietlysit at a computer in the room, where the screens of the computerswill be in black. Only 10 participants will be allowed to run at atime to prevent each participant from sitting next to each other.Participants will be asked to read and sign a consent form, and willbe informed that participation is completely anonymous.

Participants will be informed to turn on thecomputer screen by hitting the right button on the mouse. Furtherinstructions are written on the computer and to follow themcompletely. Participants are asked to place the headphones on theirhead and told that volume can be adjusted as needed. The reason forfreely choosing the volume is that some participants may be hard ofhearing than others. Music will remain constant for the experimentalgroup, whereas the control group will not hear the music.Participants will then begin the experiment by using the mouse toclick start. When the participants were aware of the unexpectedobject, instructions were to press the space bar. The length of theexperiment will last about 30 minutes.


The design of the experiment will be abetween subject, measured by an ANOVA. The independent variable isthe auditory distractor, gender and the placement of the unexpectedobject. The dependent variable is how much does the auditorydistractor affect the inattentional blindness. The measuring scalewill be designed based on the calculation of the number of times thespace bar is pressed during the experiment.


The results will show a main effect for typeof music, with 75% of the participants that hear the techno musicwill have a decrease in the attentional blindness, without looking atgender. Classification of the participant will not influence theamount of inattentional blindness. With the addition of a certainrhythm (i.e. the techno music), male participant's inattentionalblindness will see an increase versus the femaleparticipants.

These trends will support those of Mack andRock's (1999), whose data focused on the percentage of the observersnoticing the unexpected object from the distance from the line.According to Mack and Rock's (1999) data, the farther the unexpectedobject is the more likely the increase in attentional blindness.Most, Simons, Scholl, and Chabris (2000) data agreed with Mack andRock (1999) study. Location near the arm of the cross lead to adecrease in the amount of inattentional blindness.



Different people can be tuned to attend tomany different objects. While some individuals are not aware of theirsurroundings, others can sometimes be too aware. As a children age,parents teach their children to be aware of surroundings and toalways pay attention to what is directly in front of them. One majoridea that parents promote when the child turns sixteen and beginsdriving is to be aware of your blind spot, pay attention and reallypay attention. The idea of inattentional blindness can be attributedto many different ideas, maybe the space of the focus of attentionwas too far from the unattended object and therefore it was notnoticeable. According to Mack and Rock (1999) and Lu and Dosher(1997) this did have an influence on the experiment's results. Mackand Rock (1999) point out that subjects learn to inhibit attentionfrom a farther spatial location, and this leads to a significantincrease in the inattentional blindness. Or Mack and Rock attributedthe increase of inattentional blindness to the size of the object notbeing largeenough to capture the attending eye.

Yet, what type of problems will be faced inrunning an experiment such as this? Mack and Rock (1998) experiencedthe role of expectation by the participants. For each participant,the difficulty level of the experiment will vary. For someone whoalready suffers from an attentional disorder, this experiment couldbe tougher to handle. This may impact the results in a negative way,may need a process of elimination when gettingparticipants.

The goal of the experimenter will be to letparticipants know little information regarding the hypotheses of theexperiment. By controlling the amount of information given in theconsent form and instructions, unwanted behavior can be controlled.

Another problem faced by the experimenter isthe "practice effect." Overtime participants may become used to theidea of finding the object and have figured out the hypotheses, goingback to the idea of the unwanted behavior. Also, the length of theexperiment could affect the participants behavior. For example, theparticipants may become bored with the idea of pressing a space barover and over. There may be a greater chance of participants becomingbored with the techno music because of the repetitivebehavior.

Finally, playing the music before thedirections are read completely could influence what information wasactually taken in and how well participants understand theinstructions. The different type of music could also affect howquickly the decision is made; for example, with the techno musicparticipants may begin to press the space bar along with the beat ofthe music rather than paying attention to the previous instructionsgiven.



Goldstein, B. E. (2002). Sensation and Perception, 6th ed.Wadsworth, U.S.

Mack, A. & Rock, I. (1999). Inattentional Blindness. Psyche,Cambridge, MA:MIT.

(A)Most, S.B., Simons, D.J., Scholl, B.J., &Chabris, C.F.(2000). Sustained inattentional blindness: The role of location inthe detection of unexpected dynamics. Psyche: An InterdisciplinaryJournal of Research on Consciousness 6(14).

(B)Most, S.B., Simons, D.J., Scholl, B.J., Jimenez, R., Clifford,E., & Chabris, C.F. (2001). How not to be seen: The contributionof similarity and selective ignoring to sustained inattentionalblindness. Psychological Science, 12(1), 9.

Newby, E. & Rock, I. (1998). Inattentional blindness as afunction of proximity to the focus of attention. Perception, 27(9),1025-1040.

Rees, G., Frith, C., & Lavie N. (2001). Processing ofirrelevant visual motion during performance of an auditory attentiontask. Neuropsychologia, 39(9), 937-949.

Shong, L.L & Dosher, B. A. (1998). External noisedistinguishes attention mechanisms. Vision Research, 38(5),1183-1198.

Vroomen, J. & Gelder, B. (2000). Sound enhances visualperception: Cross-modal effects