We will use two Inattentional Blindness Tasks (static cross task (Newby & Rock, 1998) and sustained-IB task with moving stimuli (Most, Simons, Scholl & Chabris, 2000)) and a multitude of other tasks measuring individual differences in working memory capacity, breadth of attention, active inhibition, and the speed at which attentional focus can be switched between local and global elements of a display. We will also include questions to measure demographic information and self-rated abilities. Finally, we will include the cognitive failures questionnaire (CFQ). Below we describe all of the measures. The experiment includes two between-subjects conditions, one with an unexpected object near the focus of attention and one with a far unexpected object. **IB Motion** (Code enclosed) - Task adapted from Most et al. (2000), sustained IB task with moving stimuli - 6 practice trials (3 slow, 3 quick), no feedback, just get to know the task - 4 T’s and 4 L’s, half red and half blue, move around a white window and bounce from the edges in randomly chosen angles between 25° and 155° - Trial: 600 ms frozen start-screen (for orientation), 8000 ms moving stimuli, 300 ms frozen end-screen (for the cases in which target ends near the line) - The speed is adapted using a 3-1 threshold procedure (79% threshold; Levitt, 1971) - Task: “How often did the red letters cross or touch the middle line?” - Answer can be 10% off to account for unpredictable variation in trial difficulty - When the threshold is determined, the no-attention trial is presented without interruption - the unexpected object moves from right to left, starting 2.9 seconds after letters started moving - the unexpected object is a grey cross ( 0.9°) - 2 conditions: NEAR (unexpected object appears 1.5° from middle) vs. FAR (unexpected object appears 5° from middle) - Same condition for each participant in all 3 unexpected-object trials - unexpected object moves at a fixed speed (average of thresholds of 12 test participants = 270 pixel/sec --> unexpected object visible for 2.2s) - Whether the unexpected object is above or below middle line is randomly chosen for each unexpected-object trial - Questions: Did you see anything else than the 8 letters that wasn’t there before? (yes/no); In which part of the screen did you see the additional object? (above/below middle line), guess if you do not know; Color (grey, blue, red, green, yellow), guess if you do not know; Shape (rectangle, square, triangle, diamond, cross, x), guess if you do not know - 3 tracking trials - Divided attention trial - Full attention trial **IB Cross** (Code enclosed) - Adapted from Newby & Rock (1998), static cross task - 10 practice trials - Task: Which arm of the cross is longer? - One arm has a standard length of 6° (randomly chosen horizontal or vertical) and the length of the other arm is adapted using a 3-1 threshold procedure (79% threshold; Levitt, 1971) - Trials: 1000 ms fixation cross in the middle of the screen; 200 ms cross, 500 ms black-and-white masker, answer screen reminding the participant which key to press for which answer - When the threshold is determined, the no-attention trial is presented without interruption - the unexpected object is a grey square ( 0.9°) - 2 conditions: NEAR (unexpected object appears 2° from middle) vs. FAR (unexpected object appears 7° from middle) - Same condition for each participant in all 3 unexpected-object trials - In which quadrant of the screen the unexpected object is presented is randomly chosen for each unexpected-object trial - Questions: Did you see anything else than the cross in the last trial that wasn’t there before? (yes/no); How sure are you about your answer? (very sure, somewhat sure, not sure at all); In which quadrant of the screen did you see the additional object? (top right, bottom right, bottom left, top left), guess if you do not know; Shape (rectangle, square, triangle, diamond, cross, x), guess if you do not know - 3 cross-task trials - Divided attention trial - Full attention trial **2-Back-Identity** (Code enclosed) - Letters are preseneted centrally on the screen (500 ms + 2000 ms Interstimulus Interval) - 100 trials (25% targets) - Task: Press target button if letter matches the one 2 stimuli earlier. - Controlled for 1-Backs und 3-Backs between subjects (difficulty) **2-Back-Spatial** (Code enclosed) - Same as 2-Back-Identity, but not different letters presented centrally on the screen but circles presented at one of 8 positions (aranged on an imagenary circle with a 15° diameter) **OSPAN** - Automated Operation Span - Exactly as in Unsworth, Heitz, Schrock & Engle (2005) **Flanker** (Code enclosed) - Eriksen Flanker Task (intentional filtering) - In this task participants view a string of 5 letters composed of S and H characters and respond to the central letter via a corresponding key press. The letter strings can be either compatible or incompatible. An example of a compatible string is SSSSS, and an incompatible string is SSHSS or HHSHH. Half of the trials are compatible, and half are incompatible (50/50). **UFOV** (Code enclosed) - Useful Field of View - Simultaneous presentation of an arrow (< or > in the middle of the screen) and 8 stimuli arranged on an imaginary circle (7 distractors --> black squares, 1 target --> black circle) for 150 ms - Then participants have to first indicate by button press the direction of the arrow and then the position of the target circle - 3 different distances of the circle/squares-task: approx. 6.3, 9.5 and 12.7° from fixation **Breadth of Attention Test** (Code enclosed) - Adapted from Hüttermann, Memmert, Simons & Bock (2013) - Adaptive staircasing (3-1 method leading to a 79%-threshold; Levitt, 1971) seperately for the vertical and horizontal thresholds, then averaging both thresholds - Stimuli on each side of fixation consisting of two adjacent objects (grey circle, black circle, grey square, black square) identically distant from fixation, presented for 200 ms - Task: “How many grey squares were there in total?” --> 0, 1, 2, 3 or 4 - Vertical and horizontal trials presented randomly mixed **Navon** (Code enclosed) - A big letter is composed of small letters (e.g. H composed of Ts); Big letter approx. 4.5 cm and small letters approx. 0.6 cm - There are two target letters (H and L) - Each stimulus contains exactly one target, but either as the big or the small letter - Participant is asked to react as quickly as possible and indicate if the H or the L is in the stimulus (regardless of whether it is the small or the big one) - Interstimulus interval = 1500 ms - Aim: measure people’s bias in processing (global vs. local) **Navon-Switchspeed** (Code enclosed) - Is the same as the “normal” Navon task, but the trials are speeded: the interstimulus interval is only 16 ms, thus each time the participant reacts the new stimulus is shown directly. - Aim: measure people’s capability of switching between the local and the global focus and thereby measure interindividual differences in switching speed. **CFQ** - German version of the cognitive failures questionnaire (Lumb, 1995), 32 Items - Used questionnaire under "files" **General Questionnaire** - used questionnaire under "files" - Knowledge of the study, general knowledge about IB, demographics, normal sight?, self-rated ability of selective attention / divided attention / switching between different tasks or sensations / local vs. global perception, mental fitness and tiredness at the moment of the study, motivation, sports and computer gaming