Vygotsky's theory stresses the __________ of cognitive development

Both research participant bias and research bias can be controlled by

a. randomly selecting one's participants. b. using a single-blind experiment. c. using a double-blind experiment. d. randomly assigning participants to the experimental and control groups.

When people are asked to rate their happiness,

a. the vast majority indicate that they are unhappy. b. about half the respondents indicate that they are happy. c. a small minority place themselves below the neutral point on the scale. d. only those who are relatively healthy consider themselves happy.