Effect Of Repeatedly Exposed Emotional Faces On Attentional Bias Of University Students With High Depression Ratings

Depression is one of the most important and commonly occurred mental disorders. WTO predicted that depression would become the second pathogeny of death and deformity by 2020. The prevalence rates in our country were 16.7% in males and 19.5% in females. The average prevalence age of depression was 25 years old, and it most occurred at 15-19 years old and 25-29 years old, among which, about 10%-15% had suicidal risk. Some researchers reported that university students had higher depression ratings, for example, 42.1% had low depressive emotion and 50.3% had depressive disorder.Many studies showed that the factors inducing depression are miscellaneous and cognition especially cognitive bias (processing bias for negative stimulus) is one of the important reasons for the production, persistence, and development of depressive disorder. Attention is the first step of cognitive process, therefore, the role of attention in cognitive bias has attracted the interests of many scholars. Some studies found that because of the existence of attentional bias, negative stimuli are processed firstly and magnified by depressed individuals, which would cause the maintenance and development of depression. Simultaneously, some studies found that attentional bias can even modulate the emotional response (happy or sad) during the process of individuals coping with pressure. That is to say, difference in attentional bias of individuals will induce their difference in sensitivity to depression. Some depression-related words or sad faces can induce negative attentional bias easily. Compared with emotional words, emotional faces are taken as stimulus more often because pictures contain more potential information and have more macroscopic effects.Stimulus was exposed only once in previous studies, but some researchers found that the attentional bias to negative emotional stimuli disappeared when threatening pictures were presented for the fourth time to the individuals with high trait anxiety with dot-probe task. It showed that when the emotional stimulus was presented repeatedly, the threatening efficacy of the emotional stimulus was reduced, which induced the sensitivity of the anxious individuals to negative stimulus to decrease and therefore the attentional bias disappeared. If repetitive stimulation can induce the change of attentional bias of depressive individuals, it can further prove that depressive emotion is not a traitlike characteristic but a state marker of depression and can provide theoretical bases for the application of exposure therapy and systematic desensitization therapy for depressive individuals.In this study, the effects of repeatedly exposed emotional faces on attentional bias of university students with high depression ratings were studied with cognitive behavior experiment (dot-probe task) to further explain the attentional bias. The emotional faces were presented for four times totally and the reaction time and accuracy were recorded for each presentation. The results were described as follows:1.In dot-probe task, when repeatedly presenting neutral and negative emotional faces for 1000 ms, the following results were obtained:(1) The accuracies of all the individuals had no difference; (2) For the individuals with high depression ratings, the reaction time of the fourth expose was significantly shorter than that of the first three exposures (F=4.683,P <0.01), and no significant difference was found in other groups and exposures; (3) Compared with the controls, the individuals with high depression ratings had higher average attentional bias to sad faces and showed obvious main effect (F=9.227, P<0.05). The exposures of the emotional faces also showed obvious main effect (F=38.063, P< 0.05). There existed obvious interaction in picture type X exposure X group (F=22.849, P< 0.05).2.In dot-probe task, when repeatedly presenting negative emotional faces for 1000 ms and 14 ms, the following results were obtained:(1) The accuracies of all the individuals had no difference; (2) For the individuals with high depression ratings, the reaction time of the fourth expose was significantly shorter than that of the first three exposures (F=1.838, P <0.01), and no significant difference was found in other groups and exposures; (3) Compared with the controls, the individuals with high depression ratings had higher average attentional bias to sad faces exposed for 1000 ms and showed obvious main effect (F=12.032, P<0.05). The exposures of the emotional faces also showed obvious main effect (F=91.637, P<0.05). There existed obvious interaction in exposed time×exposure×group (F=16.766, P<0.05).3.In dot-probe task, when repeatedly presenting negative emotional faces for 1000 ms but with different SOAs (700 ms and 100 ms), the following results were obtained:(1) The accuracies of all the individuals had no difference; (2) For the individuals with high depression ratings, the reaction time of the fourth expose was significantly shorter than that of the first three exposures (F=0.355, P<0.01), and no significant difference was found in other groups and exposures; (3) Compared with the normal controls, the individuals with high depression ratings had higher average attentional bias to sad faces with SOA of 100 ms and showed obvious main effect (F=47.640, P<0.05). The exposures of the emotional faces also showed obvious main effect (F=111.937, P<0.05). There existed obvious interaction in SOA value×exposure×group (F=10.295, P<0.05).The present study observed the attentional bias of depressed individuals systematically from the angle of the maintenance and disengagement of attention with dot-probe task and repeatedly presenting emotional faces, inhibition aspect of attention, and the evaluation characteristics of depressed individuals for emotional stimuli. Therefore, on the one hand, the present study has deepen the theory research of cognitive bias in depression, which will be beneficial to understanding the development of depression and attentional bias of depressed individuals; on the other hand, it would offer theoretical basis for cognition therapy of depressed individuals, that is to say, depressed individuals can be cured through repeatedly presenting negative stimuli.