Psychology 7

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Psychology 7 Experimental Psychology
Introduction to Experiments
Testing whether fish have feelings
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• CNN.com April 6, 2005
• Study Kids who watch TV more likely to bully
• The more television 4 year old children watch,
  the more likely they are to become bullies later
  on in school, a U.S. study said on Monday.
• 1,266 4 year olds with assessments of bullying
  behavior from estimates provided by their mothers
  from ages 6 to 11
• Overall, about 13 of the children turned out to
  be bullies.

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EXPERIMENTAL RESEARCH

• In experimental research, the researcher
  manipulates at least one variable and then
  measures at least one outcome
• Example Subjects could be randomly assigned to
  either (1) drink 5 cups of coffee a day or (2)
  drink 0 cups of coffee. Then compare cholesterol
  of 2 groups after a certain length of time (6
  months, 1 year, 5 years, )
• Manipulated variables are called independent
  variables and outcome variables are called
  dependent variables
• In non-experimental research, independent
  variables are those hypothesized to be the cause
  and dependent variables are those hypothesized to
  be the effect

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EXPERIMENTAL CONTROL

• A key idea in experiments is that, as much as
  possible, only the manipulated variables differ
  between conditions
• Drink coffee vs. Drink no coffee
• Drink coffee vs. Drink de-caf.
• Variables that vary along with the independent
  variable are known as confounding variables
• Sham surgeries in animal experiments
• Random assignment should hold constant most
  extraneous variables, at least in large samples

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Random Assignment

• Say we have 100 subjects for our coffee
  experiment, 50 who exercise regularly and 50 who
  do not
• If we randomly assign (e.g., flip a coin) to the
  coffee vs. de-caf conditions, how many exercisers
  do we expect in each condition? How many no
  exercisers?
• Is exercise a lurking variable in this design?
• Say we have 6 subjects for our coffee experiment,
  3 who exercise and 3 who do not.
• Will random assignment eliminate exercise as a
  possible confounding variable?
• Sample size and extraneous variables
• Say we assign 50 students in the front of the
  class to the coffee condition and 50 in the back
  to the de-caf condition.

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• In a perfectly run experiment, any difference
  between experimental groups on the dependent
  variable must be caused by the manipulated
  variable
• Since only the manipulated variable differs
  between groups
• Experiments can, in principle, show causation
• However, still need theory to interpret the
  effects of a manipulation

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Touch Therapy for Premature Infants

• Premature infants often in incubators with less
  human contact than full-term infants
• Research with rats had shown (1) isolation from
  mother reduced pups weight gain, (2) touching
  rats improved weight gain
• Human contact/touching improve health outcomes
  for premature infants?

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Experimental Study of Touch

• 40 pre-term infants (randomly assigned to a touch condition
  (experimental group) or no treatment (control
  group)
• Experimental Condition
• 15 minute session of stimulation each hour for 3
  consecutive hours for 10 days (weekends off)
• Both tactile and kinesthetic stimulation
• Tactile for 5 min., kinesthetic for 5 min.,
  tactile again for 5 min.
• Control Condition No treatment normal nursing
  rounds

Scafidi et al. (1986)
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Operational Definitions for Independent Variable

• Tactile Stimulation the neonate was placed in
  the prone position, and the person providing the
  stimulation gently stroked with his palms for
  1-min. periods (12 strokes at approximately 5 sec
  per stroking motion) over each region in the
  following sequence (1) from the infants head
  and face to the neck (2) from the neck across
  the shoulders (3) from the upper back to the
  waist (4) from the thigh to the foot to the
  thigh on both legs and (5) from the shoulder to
  the hand to the shoulder on both arms.
• Kinesthetic the infant was then placed in a
  supine position. five, 1-min. segments of 6
  passive flexsion/extension movements lasting
  approx. 10 s apiece for each arm, then each leg
  and finally both legs together.

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Dependent Variables

• Weight gain Measured from hospital charts (not
  recorded by researchers), along with other data
  (feedings, temperature, heart rate, etc.)
• Sleep/wake time At end of 12 day period,
  observer stood over each crib and recorded all
  state changes for 45 min.
• Observer was blind to experimental condition
• Activity levels Measured by same observer as
  above

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Group Comparisons at Start of Study
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Results (Weight gain)
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Results (Waking time)
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Results (Activity level)
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Conclusions from Study

• In addition to above results, infants in touch
  group were discharged from hospital 6 days
  earlier on average than those in control group
  savings of 3,000 per infant (1985 )
• these studies suggest that tactile/kinesthetic
  stimulation may have important clinical and
  developmental benefits for small preterm
  infants.
• Alternative explanations for findings? Variables
  confounded with experimental manipulation?

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Goals of Psychological Research

• To describe behavior
• To predict behavior
• To determine the causes of behavior
• To explain behavior

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• Basic Psychology Research Attempts to answer
  fundamental questions regarding the operation of
  brain mechanisms and the generation of behavior
• Applied Psychology Research Attempts to find
  solutions to practical problems

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Automaticity Experiments

• To what extent is social behavior driven by
  influences we are unaware of and are thus outside
  of conscious control?
• Proposal that behaviors are represented in memory
  and increasing the activation of those
  representations increases the likelihood of
  performing the behavior
• If a behavioral representation is primed outside
  of conscious awareness, the behavior may be more
  likely to occur despite no conscious intention to
  perform it

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• Subjects performed a scrambled sentence task in
  order to prime specific behavioral
  representations
• Psy 7 great is
• love I really research methods really
• Interrupted person he other the
• 3 prime conditions within scrambled sentences
• Rude bold, rude, bother, disturb, intrude,
• Polite respect, honor, considerate, appreciate,
  polite,
• Neutral occasionally, normally, send,
• Dependent variable how long would subjects wait
  before interrupting an experimenter talking to a
  confederate in order to complete the study?

Bargh, Chen, Burrows (1996)
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• 2nd experiment same method, but primed an
  elderly stereotype to see whether could prime
  behaviors consistent with the stereotype
• Elderly primes Florida, old, grey, wise,
  stubborn, bingo,
• Neutral primes clean, private, thirsty,
• Predicted that subjects would walk more slowly
  after being primed with the elderly stereotype,
  even though words related to slowness were not
  included in the prime list
• Dependent variable How long it took subjects to
  walk from the lab room to the elevator on their
  way out of the study

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Psi

• Anomalous processes of information or energy
  transfer.
• Processes that are currently unexplained by known
  physical or biological mechanisms.

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• Ganzfeld Procedure (based on signal to noise
  model of psi)
• Receiver (R) and Sender (S) separated.
• R placed into Ganzfeld. Relaxation Exercises.
• 3a. R reports thoughts, feelings and images for
  30 minutes while
• 3b. S watches randomly chosen film clip (the
  target) 6 times
• 4. R shown 4 film clips--the target and 3 decoys
• Rates each for similarity to ganzfeld
  thoughts and images.
• 5. If highest rating given to target, session
  scored as a hit.
• Expected chance hit rate 25.

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Logic of Psi Experiments

• Film clip is randomly assigned in each case
• If only the sender clip differs between
  conditions for the receiver, then only the sender
  clip could cause differences in receiver imagery
• If something else co-varies with the sender clip,
  it may offer an alternative explanation for the
  results

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Evidence for Psi

• A number of studies find hit rates (imagery
  most closely matches sender video) of 32-33
• Significantly greater than chance rate of 25 if
  have very large number of trials
• Some arguments that some senders/receivers are
  better e.g., Juliard musicians
• Possible problems?
• Leakage experimenter bias
• Stopping data collection at strategic times
• Logical problems with possible mechanisms?