2. The Beginnings

12. Observing Changes over Time

16. Patterns of Developmental Growth

41. Observation Scientific observation is a method of testing a hypothesis by unobtrusively watching and recording participants’ behavior in a systematic objective manner, in a natural setting, in a laboratory or in a searches of archival data.

42. The Experiment Experiment : a research method in which the researcher tries to determine the cause-and-effect relationships between two variables by manipulating one (called the independent variable ) and then observing and recording the resulting changes in the other (called the dependent variable ).

43. The Experiment independent variable: the variable that is introduced to see what effect it has on the dependent variable (Also called experimental variable ) dependent variable: the variable in an experiment that may change as a result of whatever new condition or situation the experimenter ads. In other words, the dependent variable depends on the independent variable.

44. The Experiment experimental group: is a group of participants in a research study who experience some special treatment or condition (the independent variable). control group: a group of participants in a research study who are similar to the experimental group in all relevant ways but they do not experience the experimental condition (the independent variable).

45. Applying the Scientific Method

47. Cross-Sectional Research Cross-sectional research is a research design that compares groups of people who differ in age but are similar in other important characteristics.

48. Longitudinal Research Longitudinal research is a research design in which the same individuals are followed over time and their development is repeatedly assessed. 1 2 3

49. Some Findings from Longitudinal Research

51. Applying the Scientific Method