This question is related to Altruism. Could you help me answer these questions? Thank you,

(a) When did observability work especially well? Why? (b) Although this finding is not reported in the study, people often wonder whether individuals were more likely to sign up for the SmartAC program if, when they saw the sign-up sheet, they saw that lots of others had already signed up. Would such a finding be consistent with the explanation for prosocial behavior provided in class? How so? How might you extend the experiment to test for this result?predicts donations more than relatedness or harassment. Proc R Soc B 280: 20122573 4. Yoeli, E., Hoffman, M., Rand, D. G., & Nowak, M. A. (2013). Powering up with indirect reciprocity in a large-scale field experiment. Proceedings of the National Academy of Sciences, 110(Supplement 2), 10424-10429. 5. Hoffman. F.. Mccabe. K..Shachat K. & Smith