Attention

1. Attention • Limited amount of mental resources • Mental “resources” = general term could refer mental processes, mental representations, or mental structures • Or, one way to think about it: you can only pay attention to so many things at a time

2. Doing 2 things at once • E.g., choice RT task • Seems very simple: you are fast (less than 1 sec) and rarely make mistakes • E.g., are two letters the same or different? • Can people do 2 choice RT tasks at the same time?

3. Specific details • Task 1: see on the computer screen, either an “A” or a “B”; your job is to press the “A” or the “B” as fast you can (should take less than a second, and no errors) • Task 2: hear either a low-pitched tone or a high-pitched tone; your job is to say out loud either “low” or “high” as fast as you can (very easy, fast, and accurate)

4. One more detail • Sometimes, people hear a tone and respond • Sometimes, people see a letter and respond • Other times, people do both

5. Stimulus onset asynchrony (SOA) • Time between the letter appearing on the screen and the tone being played • E.g., if 2 seconds goes by between letter and tone, then basically doing them at separate times (long SOA) • If short SOA, then very little time between letter and tone, so do two things at once (e.g., shortest possible = 0)

6. measures • Look at RT, accuracy • Generally, accuracy is not affected (almost 100% accurate on both tasks) • SOA Letter RT Tone RT • 0 400 ms 800 ms • 50 ms 400 ms 750 ms • 100 ms 400 ms 700 • 200 ms 400 ms 600 • 300 ms 400 ms 500 • 400 ms 400 ms 400 • 500 ms 400 400

7. interpretation • As SOA gets shorter, RT to Tone task gets longer, showing that the two tasks interfere with each other • i.e., cannot pay attention to both at the same time

8. Tone RT

9. Dual-task experiments • Testing to see if someone can do two tasks at once • Measure performance on one task by itself (driving) • Measure performance on the other task by itself (using the cell phone) • Measure performance when both tasks done together (driving + using cell phone)

10. Measuring task performance • Measuring driving task (use RT, accuracy) • RT is from beginning of task until the end (e.g., driving around the block) • Measure accuracy by looking at driving errors (e.g., too fast, not using signal) • Measuring cell phone task (use RT, accuracy)

11. “conditions” of study • “Single-task” conditions: when you do tasks by themselves • Single-task driving • Single-task cell phone • Dual-task condition: put two tasks together, people do tasks at same time (“concurrently”)

12. Driving Task Single-task Dual-task Normal pace, no errors Cell phone task Can do them together: No errors on either task Normal pace on both tasks Either RTs will increase And/or make mistakes On tasks (one or either) Quickly, no errors Single-task Can’t do 2 things together:

13. Selective attention • Ignore one thing and do another thing • “direct” your attention to one thing and ignore other things

14. What is the color of the ink? Do it as fast as you can. RED GREEN YELLOW BLACK

15. Stroop effect • People have difficulty naming the color of the ink • Measure RTs: people are really slow when the color of the ink is different than the word (e.g., “RED” in blue letters) • To do task: focus on color of ink, and ignore the word (therefore, selective attention)

16. Paper-and-pencil • Whole page of stimuli (colored words); have someone speak out loud their responses and go as fast as they can • Measure how long it takes for the whole page of stimuli • Total RT divide by number of stimuli = RT per stimulus