This book focuses on the latest developments in psychology research. The chapters included in this book examine the relationship between identity, ideology, victimization and ideological segregation and diverse emotional variables; personality traits of spitefulness in humans and non-humans; the theoretical panorama on the experience of guilt; the interpretation of guilt in adolescents from the perspective of guilt-eliciting situations, trait guilt, self-disgust, and feelings of inferiority; individual differences in attitudes toward gay males; research findings on the relationship between tobacco consumption, negative affect, negative reinforcement, and relapse; the possible influence of parental Problematic Internet Use (PIU) on the mental health of their children; the epidemiology of suicidality, mortality and overdose associated with Z-drugs; social influences on meat consumption; and "engineer’s intuition" in the construction industry in Japan.