UCLA%20scientist%20Naomi%20Eisenberger%2C%20who%20studies%20brain%20activity%20during%20acts%20of%20kindness%2C%20found%20that%20even%20during%20the%20height%20of%20COVID%2C%20two%20or%20three%20acts%20of%20kindness%20a%20week%20significantly%20reduced%20levels%20of%20depression%20and%20anxiety.