Published papers

The purpose of this study is to show the characteristics of person misidentifications, that is, experiences in which persons are misidentified as known persons. A total of 121 participants were asked how many times they misidentified persons in the last year and details of a recent person misidentification were recorded through a traditional questionnaire. Additionally, they answered questions in a diary method questionnaire, about the details of person misidentification each time they experienced it, during the two-week survey period. The questionnaires revealed that the participants misidentified both known and unknown persons as familiar persons approximately six (traditional questionnaire) or 19 (diary method) times a year on average, regardless of whether they expected the persons to be there. They were more likely to misidentify a person as a familiar than as a less familiar person. It was also shown that the similarity of the faces of the person actually seen and the person they were mistaken for was not as high as the similarities of build and clothing. This study is expected to provide suggestions for models of person identification and enhance the research on errors.

Mistaking a person for another sometimes occurs; however, few studies have examined it experimentally. Therefore, the reasons behind this kind of person misidentification and its occurrence rate remain unclear, and thus we aimed to demonstrate person misidentification occurs with a certain probability through a field experiment. We also sought to examine whether the similarity between two people affects the occurrence of person misidentification. When 66 undergraduate participants made a rendezvous with an acquaintance, another person who wore similar clothes to the acquaintance or had a similar face appeared. The results showed that in both the conditions, approximately half of the participants made the person misidentification error, and one-fourth even spoke to the person mistakenly. Moreover, the results indicated that clothing contributed to person misidentification just as much as the face at first sight but became less important over time. This suggests a dynamic shift in person identification depending on time.

Performing a cognitive task prior to making a recognition judgment increases the probability of old responses, which is known as the revelation effect. The criterion shift account (Niewiadomski & Hockley, 2001) proposes that occupation of working memory causes the revelation effect. However, we proposed that working memory does not cause it. Two experiments were conducted to disconfirm the relationship between working memory and the revelation effect and to consider an alternative explanation that metacognition causes the effect. In Experiment 1, the revelation effect was caused by a finger movement task, which puts little or no load on working memory. In Experiment 2, a metacognitive instruction that a cognitive task would make subsequent recognition easier induced a conservative criterion shift. The finding that a simple motor task caused the revelation effect in Experiment 1 disconfirms the relationship between working memory and the revelation effect and extends the boundaries of the occurrence of the effect. The findings in Experiment 2 suggest that metacognition may be related to the occurrence of the revelation effect. This study implies a paradoxical aspect of human cognition in that metacognition, which usually makes cognition more effective and rational, may also cause an irrational phenomenon, the revelation effect.

Previous studies on false memory of non-semantic stimuli reported that false memories were produced for items that were unstudied but that were similar to the studied items. However, it remains unclear what representations of false memory are constructed by studied items and how the representations of studied items contribute to the occurrence of false memory. Therefore, we examined whether false memory is produced in the Deese-Roediger-McDermott (DRM) paradigm for non-semantic stimuli (i.e., facial lists), which was divided according to the morphological characteristics quantified by principal component analysis, and whether the false memory rate could be quantitatively predicted by the morphological characteristics of the studied items with a regression analysis. Thirty-five participants memorized five faces and performed a recognition memory test, including an unstudied lure item whose morphological characteristics were approximately the average of the studied items. The results showed that the lure items were more likely to be falsely remembered than other unstudied items whose morphological characteristics were not the average of the studied items, indicating that false memory of non-semantic stimuli was produced in the DRM paradigm owing to the morphological characteristics of the studied items. In contrast, the false memory rate could not be quantitatively explained by each kind of morphological characteristic. This indicates that false memory was not caused by the particular morphological characteristic of the studied items. Moreover, these results implicate that false memory of non-semantic stimuli in the DRM paradigm was provoked by gist representation of the studied items.

People sometimes mistakenly identify an unknown person they encounter as a known person. Previous studies have elucidated this phenomenon and revealed that it is a common experience. However, no experimental study has identified factors associated with its occurrence. We termed this relatively under-examined phenomenon as “person misidentification” and examined its factors. Specifically, we focused on (1) establishing experimental procedures to detect person misidentification in a laboratory context and (2) investigating the mechanism by which visual familiarity with the encountered unknown faces contributes to person misidentification. The results indicated that the developed procedure measured 247 misidentifications in 72 of 106 participants in all experiments. Although the effect of familiarity on person misidentification was not observed in Experiment 1, this effect was detected in Experiment 2, where the manipulation of familiarity was enhanced and confirmed. Concretely, unknown faces with familiarity enhanced by subliminal exposure were more frequently misidentified as another known person. This indicates that familiarity with an encountered face contributes to and induces person misidentification. In addition, the results demonstrated that similarities, especially in terms of hairstyle, between the encountered face and the misidentified known person might be related to its occurrence. These results have rich implications and expand the literature on face processing.

Research has shown that emotional testimony given by victims or their family can affect jurors’ or lay judges’ decision-making processes, but little attention has been paid to cross-cultural and individual variations. The present study examined whether cultural and individual differences were associated with how victim impact statement (VIS) affected mock lay judges’ decision making in East Asian contexts. Participants from Japan (n = 74) and Taiwan (n = 64) reviewed a transcript of a lay participation (or Saiban-In) trial with or without an emotional VIS by the bereaved family and then made verdict and sentencing decisions individually. The results showed no main and interaction effects of VIS and culture on verdict decision, perceived strength of evidence, and sentence decision. Regression analyses showed that Need for Affect predicted higher perceived strength of evidence against the defendant and more guilty verdicts, and the effects were stronger in the VIS condition. We concluded that emotional VIS in a written format may not be biasing by nature in East Asian contexts; however, including a VIS could risk the possibility of bias in the fact-finding process of lay judges with a higher tendency to approach emotional information.

© 2018, © 2018 Taylor & Francis Group, LLC. Our memories are quite fragile. We sometimes recognize something unseen as something seen before. This error often causes serious problems, such as the misidentification of composite faces in a criminal investigation. In such a scene, people occasionally claim to have seen a face that is actually a composite face consisting of facial parts separately seen before; this error is called the memory conjunction error. Although the likelihood of the memory conjunction error increases over time, previous studies suggest that it could be suppressed by the number of response options, which are expected to affect the criterion for the “Old” response. Our results show that the presence of three response options reduced the memory conjunction error. Additionally, providing information about the existence of composite faces affected the sensitivity for detecting old faces, whereas three response options affected the criterion. This study might contribute to the improvement of procedures for eyewitness testimony.

© 2018 Hine, Itoh. Society is aging worldwide. To promote the health and quality of life in elderly people, we must find a way to enhance and improve cognitive function, especially inhibitory function that suppresses inappropriate behaviors. Previous studies have indicated that warm-up cognitive activities enhanced the activation of appropriate behavior. As with the activation of appropriate behavior, inhibitory function is expected to be enhanced by a warm-up activity, although this theory has not yet been directly tested. Here, we investigated whether inhibitory function in a task was enhanced by a warm-up activity. We used a Navon task as a warm-up activity, in which reading small letters (local Navon task) required inhibitory function more than reading a large letter (global Navon task). The Stroop task was used as the subsequent task. Our results showed that the accuracy of the Stroop task after the local Navon task was higher than after the global Navon task. This outcome suggests that inhibitory function in the Stroop task was enhanced by the local Navon task, which was an inhibitory warm-up cognitive activity. Moreover, this study contributes to the development of new techniques of cognitive training to prevent the decline in inhibitory function during aging or other clinical scenarios, such as attention-deficit/hyperactivity disorder (ADHD).