Final answer:
Internal validity is the extent to which an experiment accurately measures the causal relationship between variables.
Experiments are considered to be high in internal validity because they involve control over variables and manipulation of the independent variable.
Step-by-step explanation:
Internal validity refers to the extent to which an experiment accurately measures the causal relationship between the independent and dependent variables, without any confounding variables affecting the results.
Experiments are considered to be high in internal validity because they involve significant control over extraneous variables and manipulation of the independent variable.
By carefully controlling these factors, researchers can make causal statements about the relationship between variables.