In a field study by shultz and his colleagues (2007),several households in a neighborhood received weeklyfeedback about their level of energy consumption relativeto their neighbors. feedback about how much energy theyused relative to their neighbors provided participants norms.

The given blank can be filled with descriptive.

Explanation:

There are two kinds of norms that are relevant to a social norms approach. These are injunctive norms and descriptive norms. The injunctive norms comprise perceptions of which behaviors are generally disapproved or approved. They help a person in predicting what unacceptable and acceptable social behavior is.  

On the other hand, descriptive norms comprise perceptions of which behaviors are performed generally. They generally signify towards the perception of others' behavior, these norms are dependent upon the observations of those surrounding an individual. Thus, the given case is an illustration of descriptive norms.  

b exhibiting favoritism toward the kikuyu people.