Depression is a relatively prevalent mental health condition. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) [1], depression is classified as a disorder marked by a blend of emotional, cognitive, and neurotrophic shifts. Its primary symptoms include feelings of sadness, emptiness, or irritability, accompanied by bodily and cognitive changes that significantly impact an individual's neurological function. This condition extends beyond the patient's personal experiences, influencing their interactions with family and friends. In severe instances, it can even disrupt the patient’s social capabilities. Annually, more than 700,000 individuals with depression succumb to suicide. According to projections, by 2030, depression will surpass cardiovascular disease as the leading cause of disability[2]. A study on disease burden published in The Lancet highlighted that individuals aged 15 to 24 are most susceptible to depression[3].
Individuals with depressive disorders often experience a diminished quality of life, compromised cognitive functioning, and social and interpersonal challenges, which significantly contribute to the progression of their condition[4]. Research on social cognition and depression has focused on facial emotion recognition, which is inversely related to the severity of depressive psychopathology[5]. Studies have revealed that people with depression tend to perceive neutral or ambiguous faces as sad[6–9] and are more adept at identifying sadness than nondepressed individuals[10]. A comprehensive meta-analysis indicated that depressed individuals also struggle with recognizing a broader spectrum of facial emotions[11].
Much of the existing research is cross-sectional, providing limited insights into the causal relationship between emotion recognition and depression. Cognitive neuropsychological models suggest that alterations in automatic emotion processing may precede and predict the onset of depressive symptoms [12–14]. A study by Tranter et al. [15] revealed that early in antidepressant treatment, before symptom improvement, the ability to recognize happy faces predicted a reduction in depressive symptoms in six weeks. Conversely, the recognition of sad emotions correlated with the persistence of depression after six months[6, 16]. Milders et al.[10] observed that despite a decrease in depressive symptom severity in six months, patients’ responses to sad facial expressions remained consistent. Over an extended period (2.5 years), a negative bias in facial expression recognition persisted in patients with major depressive disorder, irrespective of their relapse status [17].
Beck’s theory of cognitive impairment emphasizes that depression is accompanied by a negative attentional bias toward information processing and that this bias hypothesis has strong explanatory power in the onset and maintenance of depression, which is manifested primarily in reduced attention given to positive information and a preference for negative information[18]. Attentional bias can manifest as a sharper response to a stimulus, prolonged exposure to a stimulus from which the individual is unable to extricate himself or herself, or a combination of both of the above, but either of the above can impair the individual’s perception and processing of other stimuli, resulting in a narrowing of attention, interfering with goal-directed behaviors, and even seriously impairing the individual’s ability to make judgments and decisions[19]. However, many studies have shown that the attention span of individuals is limited. Although a number of studies have found a negative attentional bias in some of the assignments used to detect cognitive responses in depressed individuals, the occurrence of this attentional bias has been found to be a significant factor in the development of a negative attentional bias. However, the mechanism by which this attentional bias occurs is complex, and no obvious conclusions have been reached yet. Regarding how attention is affected by emotion, some psychologists have suggested that this effect is due to competition between multiple “biases” [20]. According to the components of attention theory, the three components of attention are attentional orienting, attentional disengagement, and attentional shifting [21]. The majority of scholars have focused on attention orienting and attention disengagement [22]. Previous studies have shown that, compared with nondepressed individuals, depressed individuals lack a “protective bias”, which is characterized by a tendency to avoid negative information; this lack of protective emotion makes it more difficult for depressed individuals to deregulate their attention from negative emotional information[23]. The lack of this protective emotion makes it more difficult for depressed individuals to disengage from negative emotional information[23]. According to the protective bias hypothesis, depressed patients do not develop an attentional bias during the attentional phase of negative information but rather have difficulties in attentional disengagement after the information has become the focus of attention, and such disengagement difficulties are associated with ineffective use of emotion management and persistent negative affection.
Adolescents’ self-awareness is rapidly developing, and self-awareness refers to the sum of an individual’s ideas about his or her own physical and mental state and his or her position in society [24]. Self-centered thinking is highlighted by the construction of an “imaginary audience” and “personal myth”; according to Erikson’s theory of mental development, adolescents experience a crisis of self-identity during this period[25]. Negative self-consciousness interferes with cognitive functioning and social interaction. Maintaining a negative sense of self for a long period of time can lead to disorganization of adolescents’ self-reference system and the creation of negative cognitive biases. Such cognitive biases at the developmental stage may lead to depressive episodes in adolescents[26].
To verify the above questions, the present study was designed to detect cognitive differences between depressed and normal adolescents using the attentional blink effect of facial emotion recognition in a “two-target paradigm (T1-T2 paradigm)” experimental design [27]. The two-target paradigm requires adolescents to make judgments about two emotional faces at very brief intervals. Adolescents’ recognition of the emotion of the first face interferes with their recognition of the emotion of the second face, an effect known as “attentional blink (AB)”.
Broadbent discovered the phenomenon in 1987, and Raymond et al. first named this phenomenon in 1992. The term “attentional blink” refers to the phenomenon in which participants are presented with two target stimuli in rapid succession, separated by a short period of time, and their recognition of the second target stimulus decreases. Typically, this results in a decrease in recognition or detection performance for the second target after the observer has recognized the first target. Several studies have suggested that AB is caused by limitations in ability inherent in the two simple behaviors of perceiving and reporting visual stimuli (e.g., consolidation of relevant information in working memory) [28]. Greater attentional blinks are induced when emotional stimuli act as T1, i.e., emotional attentional blinks[29]. When the emotional stimulus is the second stimulus in the target stimulus (T2), it reduces the attentional blink, i.e., the emotional antagonistic attentional blink[30]. The inclusion of emotional stimuli in the attentional blink task provides a window of observation and a research tool for us to better understand and study the preferential conscious processing of emotional stimuli in humans.
Most of those previous studies used the rapid serial visual presentation (RSVP) technique. The RSVP method, which involves the presentation of a rapid sequence of stimuli, has been pivotal in understanding the AB effect, where the detection of a second target is hindered when it appears shortly after the first. Indeed, the process involves not only discriminating targets but also filtering out irrelevant stimuli. The uncertainty about the timing of the first target (T1) onset adds another layer of complexity to this task. The models proposing limitations in perceiving and reporting visual stimuli as the cause of AB align with the idea that AB might stem from the constraints of working memory and how information is consolidated[31]. If this holds true, it challenges the necessity of presenting irrelevant objects in the RSVP or introducing temporal uncertainty at T1 onset. This line of thinking suggests that the core issue lies within how information is processed and consolidated rather than in the complex setup of RSVP, which involves multiple distractors and temporal uncertainties. By recording and calculating the nature and extent of the AB effect in adolescents with depression under different emotional stimulus conditions, we can understand the characteristics of adolescents’ prioritized conscious processing of emotional stimuli in an emotion recognition task and thus explore the possible factors influencing the onset of depression in adolescents. According to the general conclusion of the AB effect, when T1 and T2 are emotional materials of the same nature, interference from T1 to T2 occurs but not when the conscious resources required for T1 processing are not enough to consume all the cognitive resources of the individual. If depressed adolescents have a deficit in “protective tendency” in the face of negative stimuli, they will invest more in processing the negative stimuli, have difficulties in attentional disengagement, and produce a priming effect on T2 recognition.
Therefore, when T1 was a neutral emotional face and T2 was a negative emotional face, depressed adolescents’ accuracy on the T2 task was significantly greater than that of the controls, and an emotionally antagonistic AB effect occurred; when both T1 and T2 were negative stimuli, no emotional AB effect occurred in the depressed group relative to the controls.