Speed/accuracy tradeoff

• Negative relationship between RT and accuracy

• the faster you go (RT), the worse your performance (accuracy)

• when you go really fast, performance at worst

• worst performance = guessing or chance

Guessing or chance performance

• Just by chance, you get the right answer sometimes

• on a multiple-choice test, with four alternatives per question, one-quarter chance of getting answer right

• e.g., with 60 m-c questions, guessing gets you 15 correct (1/4)

Slowing down on a task

• Slower you go, the more accurate you get

• maximum = “ceiling” or asymptote (flattens out)

Interpreting SAT

• Individuals with fast RTs, accuracy may decline due to SAT

• individuals with slow RTs, accuracy may increase due to SAT

Speed/Accuracy Tradeoff

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Asymptote

Verbal report

• Listening to what people are saying goes on in their heads when doing a task

• done while a person is doing a task

• verbal report = what is said (the words)

• assumption = people already, normally, have thoughts going on while doing a task

Verbal reports (cont.)

• Called “protocol” = transcript of what a person said out loud while doing a task

• also known as “think aloud” technique

• a “window” into mental structures, processes, and representations

• thoughts in the protocol represent the mental processes during the task

• Thought is the outcome or end-result of a mental process

• e.g., reading an overhead, think-aloud might produce “click” as your verbal report, which represents the output of having perceived and read the word “click”

Measuring RT

• Typical device is the computer

• e.g., how long to press a key

• or how long to speak (vocal response)

• or how long to make any physical response (manual [hand] responses or foot responses)

Measuring RT (cont.)

• Use a stopwatch (seconds or minutes)

• compare to computer (milliseconds)

• or, give a fixed period of time and see how far they get --> see how much is done in that period of time (response-deadline method)

Measuring accuracy

• Typically, done on a computer

• or keep a record, then go back and compute accuracy

• easy approach = count number of correct responses (paper-and-pencil)

Measuring verbal reports

• Typically use cassette recorder and microphone to record the verbal report

• then, transcribe (to paper) and analyze the transcripts