• Longitudinal Design: a developmental design where a single sample of participants is followed over time and tested at different ages o Within subjects variables
    • Tested at age 5, age 10, age 15, and age 20
  • Cross sectional design: design where multiple samples of participants of different ages are tested ONCE o Between subjects variables
    • Different samples are tested at different ages
      • Sample 1: Age 5
      • Sample 2: Age 7
      • Sample 3: Age 9
    • Generation/Cohort Effects: a confound that can occur in cross­sectional designs due to different experiences that different generations have o These effects occur when the experience of one generation (growing up with or without computers) are very different from those of another generation and affect the way the participants complete the task or measure in the study

 If younger and older participants are tested with a survey presented on a computer, it is possible that the older adults may have more difficulty competing the survey because some may lack experience with computers

  • Cohort­Sequential Design: where multiple samples of participants of different ages are followed over time and tested at different ages o Age is treated as both between subjects and within subjects variable o Age groups are tested multiple times as they develop o Must wait for the participants to age
  • Small­n Design: an experiment with one of few participants to better understand the behavior of those individuals o A measure of a students disruptive behavior to determine the rate it currently exists

 This is called a baseline measurement o Treatment is then implemented and the behavior is measured again

  • To be certain that it was the treatment that caused the behavior to change, the treatment is then ended and disruptive behavior is measured again to take another baseline measurement
  • Baseline measurement: measurement of behavior without treatment used as a comparison
  • Discrete Trials Design: small­n design that involves a large number of trials completed by one or few individuals and conducted to describe basic behaviors o Helps researchers describe basic behavioral processes, such as the way that information is forgotten in memory
  • Baseline design: a small­n design that involves baseline measurements of behavior as compared with measures of behavior during the implementation of a treatment o Goal is to determine if a treatment creates a desired change in the behavior of interest
  • Carryover Effects: when participants’ experience in one condition affects their behavior in another condition of the study
  • A­B­A/Reversal Design: small­n baseline design where the baseline behavior is measured, followed by implementation of a treatment, followed by another baseline measure after the treatment has ended
  1. Chapter Summary:
  • Developmental psychologists use specialized designs to allow them to examine different types of age effects in a study. Because age cannot be manipulated as a true IV, many of these designs are quasi­experiments that compare age across participant groups or within participant groups longitudinally
  • The primary difference between longitudinal, cross­sectional, and cohort­sequential designs is in how age is treated as a variable
  • Small­n designs allow psychologists to test laws of behavior and to test treatments that might be effective for a single participant or a small groups