Psychologists' personal values and goals

A) are carefully tested by means of observation and experimentation.
B) lead them to avoid experiments involving human participants.
C) can bias their observations and interpretations.
D) have very little influence on the process of scientific observation.

Psychologists' personal values and goals can bias their observations and interpretations, as they may have a subjective perspective that influences their interpretations of study results. However, this does not necessarily mean that they avoid experiments involving human participants, and their personal values and goals may still be tested through observation and experimentation. Therefore, option C is the best choice. Option A is incorrect because personal values and goals are not normally subjected to experimentation. Option B is incorrect because psychologists frequently study human participants in a range of different experimental contexts. Option D is incorrect because personal values and goals can influence the scientific observation process.