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Experiments. September 19, 2008. Human subjects research. Observations Case studies Recordings Experiments Questionnaires Interviews Before starting . . . IRB (Institutional Review Board) http://orca.byu.edu/IRB/. Human subjects research. For each type of HSR, we will examine
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Experiments September 19, 2008
Human subjects research Observations Case studies Recordings Experiments Questionnaires Interviews Before starting . . . IRB (Institutional Review Board) http://orca.byu.edu/IRB/
Human subjects research For each type of HSR, we will examine a. What it is/when to use it (with what kind of data) b. How to use it (example studies using these methods) c. Advantages and disadvantages • observer’s paradox • data collection • data analysis • variable control
3. Recordings a. What are they/when to use them: Note: Ethical question on recordings (book says OK, but US / IRB issues) observations/case studies/interviews pronunciation: ethnic influence foreigner talk/L2 speech first language acquisition vocabulary: frequency of usage regionalisms conversation/discourse analysis
3. Recordings b. How to use them Practical considerations: Audio only or audio and video? What kind of recorder/microphone? (analog or digital?) Problems with subjects wanting/being able to record Identifying speakers Quiet place, no kids running around, traffic New technologies: Recording from Internet (e.g. BBC or regional English): Replay A/V For transcripts only, can sometimes get these on Web: e.g. CNN, NPR, movie scripts PodCasting, etc
3. Recordings c. Advantages/disadvantages Advantages Disadvantages
4. Experiments a. What they are: "Control as many variables as possible and manipulate one (or more) to find out what effect that variable has on the overall result" Have explicit hypothesis, and then attempt to prove (or disprove) that hypothesis When to use them: 1. Psycholinguistics (Speech perception, lexical access, grammatical judgments, pragmatic development) 2. Sociolinguistics 3. Language acquisition (L1 and L2) 4. Pedagogy Education (e.g. different teaching methods; 8 AM vs 9AM classes; Reading)
4. Experiments b. How to use them What is typically tested: • Responses (Accuracy) • Response times • Eye movements
4. Experiments b. How to use them: Examine just a few variables Have a control group Make sure subjects differ on only one or two variables (M/F, but men 15-25 and women 45-55) Eliminate experimenter bias (double blind study) Use large enough sample size and right equipment Run a pilot study first Make sure has internal and external validity 1. Internal validity: Is the measure reliable? (E.g. bathroom scales that read differently each time) 2. External validity: Are the results relevant to situations outside of the experiment? (E.g. test involving BYU linguistics students, who have extensive language experience abroad)
Experiment Example 1a Response times Stroop Test http://www.pbs.org/wgbh/nova/everest/exposure/strooptest.html
ball doze bash door bean deck bell dark darn bore respond big dutch bang doll bill deal bark dog dart board respond Example Experiment 1b
Example Experiment 1b POX TOME SHINE RUCK RACK GUT LICE COT SOT SHOAL TOR DENT POX BOAST SHINE SIP RACK LOOM LICE ROOK NODE GAUZE TEAL SHINE VAULT FEIGN MOAT NARK PAR BANE TOME DELL GOAT LEACH SHUN DENT CRANE MOAT LEER SOP BANE PELT PEACH BARK COT GAUZE RUCK LEER TOUT DIME NARK MAIM CRANE GRAFT RYE LUG SHALE SIFT JEST CHUMP LOOT RAND GRAFT CRANE
Example Experiment 2 Children’s perceptions of different varieties of English
Experiment 3: Reading Measuring eye movements while reading
Experiment 3: Reading Eye movement terms . . . 1. Saccade: Movements of eyes during reading 2. Regression: Saccades that move backward 3. Fixation: Time we spend looking at a certain location
The more proficient we become in reading, the less regressions and fixations we have. Fixations are 14 characters long 5-6 characters before and 7-8 after fixation
4. Experiments c. Advantages: Provide precise data for/against a given hypothesis (e.g. dichotic) With enough detail when published, can be replicated Disadvantages: Can results be generalized outside of experiment (e.g. language learning) Often, quite hard to set up experiment correctly, and to account for all variables Some people don't make good research subjects (e.g. dichotic for children)