This study aimed to reveal the risk factors for a person to perpetrate stalking-like behaviors following the end of a romantic relationship based on personality traits (attachment anxiety and narcissism), the characteristics of a romantic relationship before a breakup, and the emotions and thoughts of a person after a breakup. To develop two scales measuring the characteristics of a romantic relationship before a breakup and the emotions and thoughts of a person after a breakup, a web-based survey of 189 females and 165 males was conducted in Study 1. In Study 2, a national survey was conducted using two-stage stratified sampling; 106 females and 110 males who experienced the end of a romantic relationship during the past five years and did not initiate their most recent breakup were analyzed. The results of a multiple-group analysis revealed that both attachment anxiety and feelings that a partner was his/her “one and only” increased egoistic preoccupations after a breakup, and the egoistic preoccupations predicted the perpetration of stalking-like behaviors in both males and females.

Grapheme-color synesthesia is a condition in which visual letters or characters induce a specific color sensation. It has been suggested that a range of linguistic properties influence synesthetic grapheme-color correspondence, but the influence of graphemic (orthographic) information is not well understood. In this experiment, synesthetes chose up to two synesthetic colors for each Japanese Kanji character. The results showed that characters that could be divided into right and left subcomponents (radicals) were associated with a higher number of synesthetic colors than characters that could not be divided. This tendency was stronger for projectors, who perceive colors visually in external space, than for associators, who perceive colors in their ‘minds eye’. The results of this study suggest that the graphemic information of Kanji characters affects the number of synesthetic colors, especially for projectors.