experimental psych exam 2

describe the tension between internal & external validity

internal validity is important, but experimental design/controls may be so artificial that the results are also artificial (no longer pertain to real people)

describe ecological validity

a sub-type of external validity that refers to how much a study’s tasks & manipulations are similar to the kinds of situations people might encounter in their everyday lives

describe “setting the stage”

refers to the background information or rationale that is provided to particcipants for why the study is being conducted

describe staged manipulations

to create key state (mood, stress) or situation (social interaction) or to stimulate real world (mock jury)

(experience you want participants to have)

describe some disadvantages to staged manipulations

may be harder to replicate, may be harder to interpret (which part of the staged event was responsible for the observed effects?)

describe strength of manpulations

make manipulation strong to maximize your chance of observing an affect

what does the strength of manipulation depend on

what previous research has shown

how can a manipulation be too strong or too weak

if it represents a significant departure from levels encountered in the real world

what can also affect decisions about manioulation strength?

by ethical considerations (how much alcohol or caffeine, how intense the pain of dehydration)

describe what entail cost of the manipulation

cost of material/equipment, salaries of confederates or others, payments to participants, number of participants, lab space

what is the goal of manipulation

a balance between strength vs cost of manipulation

describe self-report measures

memory (recall/recognition), surveys (personality inventories, mental health assessments), judgements (crime severity), decisions (Moral dilemma), attributions

describe behavioral measures

describe __ measures

why it is good to have multiple dependent measures?

if the independent variable has the same effect on several measures on the same dependent variable, confidence is increased for results

describe order effects

changes in DV that are due to the timing or order in which data are collected including practice effects, fatigue effects, contrast effects

how can we avoid order effects

describe ceiling effect

a task/test that’s so “easy” everyone scores close to 100%

describe floor effect

a task/test that’s so “difficult,” everyone scores close to 0

why are floor and ceiling effects problematic?

because they obscure the effect of the IV

describe placebo effect

“improvement” due to expectation, rather than treatment

describe placebo group

received identical treatment but without the active agent/ingredient

observer (expectancy) effects

knowledge of condition can produce expectations that influence how experimenter interacts with participants

describe experimenter bias

knowledge of condition can produce “bias” in how measures/scores are recorded/interpreted

what are solutions to observer effects and experimenter bias?

single-blind experiment

double-blind experiment

single-blind experiment

participants don’t know which condition they’re in

double-blind experiment

neither participants nor experimenter know which condition participants are in