SAMPLE SIZE & SAMPLE DEMOGRAPHICS We will collect data from a minimum of 200 participants, with at least 100 in the Near unexpected object condition and 100 in the Far unexpected object condition. We hope to obtain a sample of exactly 100 participants, but it is possible we will sample slightly more than that due to scheduling (e.g., if we schedule additional slots to make sure we have at least 200, we will include the extra participants in the analyses). A large sample is necessary because Inattentional Blindness tasks have just one critical trial per participant. MATERIALS Detailed information about the materials can be found under the “Methods and Measures” node. PROCEDURE Participants will sign a declaration of consent. Then the chin rest will be adjusted to a comfortable height. The chin rest is only used for the following tests: Breadth of Attention Test, UFOV, IB Motion, IB Cross. First IB Motion is conducted, follwed by the general questionnaire (to directly reject participants knowing the exact IB task and having anticipated the unexpected object). The 7 individual differences tasks (Navon & Navon-Switchspeed are presented as one test in direct succession and with build-on-each-other instructions) are then performed in a randomized order. After 3 of the 7 interindividual differences tests the CFQ is filled out by the participants. As a last test the second IB task (IB Cross) is conducted by the participants. At the end, participants have to answer a last question: "Did you anticipate that an unexpected object will appear during the last test that you will be questionned about?" and then are debriefed. **Summary of procedure:** - Declaration of consent - Adjusting of chin rest - IB Motion - General Questionnaire - 7 individual differences tasks (in randomized order) - CFQ after 3 of the 7 tasks - IB Cross - Question: unexpected object anticipated in IB Cross? - Debriefing TESTING LOCATION The study will be conducted at the German Sports University. Participants will be tested alone or in groups of two people. When participants are tested in groups of two, they will not see the other participant because room dividers separate the two work spaces. Also, participants are routinely instructed to work quietly. EXPERIMENTERS The data collection is led by Carina Kreitz (M.Sc. Psych). She will thoroughly instruct a student assistant and two interns (all psychology students). DATA COLLECTION Participants will be recruited by flyers placed around the German Sports University Cologne and the University of Cologne. Additionally, students can register for the study in lists passed around in courses. The registration call will not contain any information about the study other than that it is a study about cognitive abilities, that it will last 2 - 2 1/4 hours, and that subjects will be paid 13 Euro and a chocolate bar. Participants are assigned to the two experimental conditions (near/far) in a balanced fashion (see attached file). When two participants take part at the same time, one will be assigned to one condition (e.g. near) and the other to the other condition (e.g. far). Each participant will be assigned to the same condition in IB Cross as in IB Motion. For each participant the individual difference tests are presented in a randomized order (see attached file). But if two participants take part at the same time they will complete the tasks in the same order in order to minimize interruptions and distraction. Participants are instructed at the beginning to just sit quietly and wait when they finish a test. When both participants have finished a test, the experimenter will start the next test for both participants simultaneously. To equate the effects of ordering across groups, we will randomly generate 100 orders of the 7 tasks and then duplicate that same set of 100 orders for the second condition. Participants are always grouped in pairs of two (see boxes with bold lines in the attached file). Hence, if two participants are tested simultaneously one box will be filled. If only one participant takes part then the second row of the box will remain empty until the next single participant will be tested. The randomization of the individual differences test is done in excel with random numbers. Each test is assigned a random number between 0 and 1 and then the numbers are sorted in ascending order leaving the 7 tests in a random sequence. This is done 100 times and the sequences are transferred to our sequence list. The experimental instructions will be delivered to the participants on the screen before each test. Participants are additionally encouraged to ask questions if not clear about the instructions. All tests will be shown on a computer display. Only the two questionnaires (CFQ and general) will be filled out on paper. Participants will be unaware that they are participating in an inattentional blindness study. To prevent task knowledge spilling over from tested participants to still-to-be-tested participants, the debriefing text will ask participants to avoid sharing information about the experimental procedure with their fellow students. DATA EXCLUSION The experimenters will keep a lab log. On the basis of the lab log data may be excluded prior to examining the data. Data will be excluded if there are technical failures, procedural errors by the experimenter, failures to follow instructions, or knowledge that an unexpected object would appear (i.e., they were familiar with inattentional blindness and realized that was what we were testing in the inattentional blindness task). Any excluded data and the reason for exclusion will be noted in the data file and lab log. Excluded participants will not be replaced by new participants.