Whether you are an air traffic controller, a transportation security officer, a gamer, a student studying for finals, a writer trying to meet a deadline, or a parent, the ability to maintain attention for extended periods without getting distracted can be crucial. However, as many humans have experienced, sustaining attention to a task, especially one that is mundane, can be challenging at times. Endogenous distractions, such as fatigue, anxiety, anticipation, or exogenous distractions, such as dinner time, the end of a shift, cute cats, or disturbing pictures, can easily disrupt tasks that require high levels of vigilance.

Unfortunately, humans do not have the same abilities as animals that evolved unihemispheric sleep to cope with survival issues requiring long periods of wakefulness and attention. Migrating birds, such as albatrosses, Arctic terns, blackcaps (Sylvia atricapilla) or white-crowned sparrows (Zonotrichia leucophrys), and marine mammals, such as dolphins (Tursiops spp) and fur seals (Callorhinus spp) or sea lions (Zalophus californianus), are able to travel significant distances, respond to stimuli continuously, and care for offspring with minimal disruption due to this evolutionary superpower (one that I often wish since Hermione’s time-turner is not real!).

Despite our best efforts to uncover the mechanism behind unihemispheric sleep and implement it into humans to facilitate continuous vigilance without degradation or a reliance on various stimulants, scientists still have much to learn about the ins and outs of sustained attention. Researchers from several universities and health-care facilities conducted two studies to test a variation of a previously validated sustained attention task and evaluate the role of emotion during this task.

Esterman and colleagues modified the gradual onset continuous performance task (gradCPT) in which participants experience a rapidly paced go (e.g., select any digit that is not 3) / no-go (e.g., ignore 3) continuous performance task to assess different factors that may disrupt performance. In the current study, the researchers manipulated background images not relevant to the task of identifying specific numbers. These background images were intended to act as implicit emotional distractors and consisted of positive, negative, or neutral valence images as shown in the figure below.

Since this task was a variation of their original validated task, this study served two purposes: (1) to establish the influence of emotional distractors on a sustained attention task and (2) to validate the novel task. In addition to typical measures in sustained attention tasks (e.g., reaction time, accuracy), the researchers gave the participants a pop quiz memory test for the background images, followed by two rating tasks on the arousal level and the valence level for each image. These additional tasks were used to validate the effectiveness of the images selected as emotional distractors.

The results from the first experiment, which involved 64 adults recruited from the community, supported the hypothesized relationships. Participants rated negative images more negatively and as more arousing than neutral or positive images, as seen in the image below.

In the next figure below, participants showed more accuracy and faster reaction times when positive valence backgrounds were present, but were significantly less accurate and slower when negative valence images were presented.

Finally, several measures indicated that the results were both reliable and valid as participants subjectively rated that they were more distracted and negatively affected by the negative images as shown in the figure below.

As shown in the violin plots below, subjective measures (e.g., ratings of affect and distraction) were correlated with objective measures (e.g., accuracy and reaction time), further supporting the validity of the task. Participants were less accurate when distracted or experiencing more negative emotion (see the violin plots on the left side of the figure below). These same subjective experiences were also associated with slower reaction times (see the violin plots on the right side of the figure below). Recall of a subset of the images was more accurate for negative images than for either neutral or positive images, supporting previous research indicating humans process negative stimuli more quickly and thoroughly.

The second study extended the first study with a slightly more diverse sample, a comprehensive recognition task of all images used, a variation of the digit task (“go” on evens, “no go” on odds), and a control condition in which neutral stimuli were replaced with blank, white backgrounds. Once again, the results were the same as the first experiment, as seen in the image below. Participants were significantly less accurate and slower with negatively valenced background images. White background images may have created less interference with the sustained attention task, as shown by the significantly lower reaction times.

To top off the study, some participants returned to re-test on the task while in an fMRI, which produced the same results as the first two experiments. These studies established the validity of this sustained attention task while also providing support for the role of an unconscious influence of emotional affect during this cognitive task.

According to the authors,

“Upsetting thoughts (e.g., a bad memory) and experiences (e.g., seeing a roadkill) can disrupt our ability to maintain our attentional focus (e.g., when driving), yet translating this phenomenon to the laboratory has remained elusive. In the current study we developed a paradigm to quantify the effects of negative distractions on sustained attention. We found that indeed negative distractions disrupted ongoing task performance as well as self-report measures of distraction. Negative distractors were more likely to be remembered later, and impacted participants’ mood. We hope this new task can help have both basic (neuroimaging) and clinical (e.g., in anxiety and PTSD) applications.”

While the results of this study are intriguing, perhaps the more exciting possibility is its application to clinical settings. The researchers suggest that individuals experiencing significant distractions due to different clinical conditions (e.g., PTSD or anxiety) may show even stronger results on this task. Further insights may also be gained when paired with brain imaging scans as participants complete the tasks, as demonstrated by the follow-up study conducted by Esterman and colleagues.

Featured Psychonomic Society article

Esterman, M., Agnoli, S., Evans, T. C., Jagger-Rickels, A., Rothlein, D., Guida, C., … & DeGutis, J. (2025). Characterizing the effects of emotional distraction on sustained attention and subsequent memory: A novel emotional gradual onset continuous performance task. Behavior Research Methods, 57(5), 141. https://doi.org/10.3758/s13428-025-02641-2