A researcher wants to study how facial feature influence people's judgment of trustworthiness. He plans to have participants rate two different sets of computer-generated faces (labeled A and B) for their " trustworthiness". Each set has ten faces. The two sets of faces differ in the color of the iris (the color part of the eye). The ten faces in set A have brown iris; the ten faces in set B have blue iris. The psychologist hypothesizes that color will influence participants' ratings of trustworthiness. Each participant will rate all twenty faces.

Answer the following questions.

1) Describe the independent variable in this study, including the independent variable and all its conditions?

2) Describe the dependent variable(s) in this study, including the dependent variable, and how it is measured? (2 points)

3) What type of experimental design did this researcher use? Please be as specific as possible

4) If the psychologist would like to have 30 ratings for each face, how many participants will the psychologist need to recruit for the experiment(note: Multiple ratings for one picture from one participant would average into a single one rating, meaning that if one participant rates the same picture multiple times it will be only counted as one rating)? (2 points)