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

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?

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)

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

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)

measures Look at RT, accuracy Generally, accuracy is not affected (almost 100% accurate on both tasks) SOA Letter RT Tone RT ms 800 ms 50 ms 400 ms 750 ms 100 ms 400 ms ms 400 ms ms 400 ms ms 400 ms ms

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

Tone RT

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)

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)

“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”)

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

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

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

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)

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