Abstract
Teaming scenarios are beneficial for many complex tasks but can also encounter many challenges such as appropriate communication, coordinating with teammates, or fatigue. Cognitive fatigue has many negative effects on individuals such as impaired decision-making, reduced attention, and slower reaction times. This systematic literature review reports findings from 17 total articles on the effect of cognitive fatigue in teams. The review searched articles published from January 2016 to November 2023. The key findings suggest that cognitive fatigue significantly increases reaction time, increases the number of errors, and decreases the number of positive outcomes. To conclude, this study discusses potential implications of these findings to relevant domains, how they could relate to human-autonomy teams, and directions for future research.
Introduction
Teams are key components in various industries, especially in safety-critical domains where collaborative efforts are necessary to accomplish challenging goals (Bennett et al., 2022; Sawant et al., 2022). A team is a group of individuals collaborating toward a common goal, leveraging their diverse skills and expertise to effectively address complex challenges (Bennett et al., 2022; Park & Park, 2019; Salas et al., 1992). Such teams exist in many different sectors. In healthcare, surgical teams collaborate to carry out procedures, with each member playing a crucial role in patient care. Surgeons perform the procedures, anesthesiologists manage patient sedation, nurses assist with patient care, and surgical technologists prepare and manage surgical instruments (Halverson et al., 2011; Undre et al., 2006). In aviation, co-pilots, pilots, and cabin crew members work together to manage flight operations to ensure safe and effective travel (Salas et al., 2006). Similar to this, tactical units in the military work together to complete missions under pressure, and the success of their operations frequently depends on effective teamwork (Salas et al., 1992). In these high-stakes situations, the fundamentals of effective teamwork such as clear communication, trust, and coordinated effort are essential (Burke et al., 2006; Salas et al., 2008). These principles ensure that teams can work well together and adjust to dynamic and often unpredictable situations.
Despite the critical nature of teamwork in these domains, teams face numerous challenges that can hinder their progress. Misaligned goals, communication breakdowns, fatigue and conflicting priorities can lead to inefficiencies and errors (Manser, 2009; Power; 2018). These challenges can jeopardize safety and mission success in high-stake environments. One significant challenge that teams encounter is cognitive fatigue, which can adversely affect team dynamics and performance. Cognitive fatigue refers to a state of mental exhaustion resulting from prolonged periods of cognitive activity, which can affect cognitive performance (Boksem et al., 2008; Kluger et al., 2013; Lorist et al., 2000). Studies have shown that cognitive fatigue can impair decision-making, reduce attention, and increase the likelihood of errors, all of which are detrimental to team performance (Boksem et al., 2008; Faber et al., 2012; Lorist et al., 2000). Common effects of cognitive fatigue also include decreased vigilance, slower reaction times, and impaired memory and judgment (Smith et al., 2016; Van Cutsem et al., 2017). Factors contributing to cognitive fatigue include extended work hours, high workload, monotonous tasks and inadequate rest (Leso et al., 2021; Lim et al., 2010). The effect of cognitive fatigue is more severe in situations where safety risk is high because mental acuity is essential for task completion (Fan & Smith, 2020; Owens, 2007; Weeks et al., 2010). Studies of teams in sports have generated similar findings; for instance, in a soccer game, the decision-making ability of individuals when mentally fatigued is shown to be impaired through increased response time and decreased accuracy during decision-making events (Smith et al., 2016). Thus, addressing cognitive fatigue in teams is essential to maintaining high performance and safety standards, especially in industries where the stakes are incredibly high.
As technology is rapidly introduced into modern work systems, it is important to understand how previously identified human-only team characteristics can translate to human-artificial intelligence (AI) teams. Much like the shift from individual work to teamwork (Salas et al., 2000), the transition between human-only and human-AI teaming does not merely consist of adding technological agents without any type of adaptation to the task or the team organization (Mallick et al., 2023). The application of these novel teaming scenarios has the potential to induce additional mental fatigue due to the lack of pre-defined mental models on working with AI teammates. Therefore, the findings from this review aim to better understand the state of mental fatigue in teaming environments and adapt this understanding to the field of human-AI teaming.
The goal of this article is to systematically analyze and consolidate the current literature on the state of mental fatigue in current teaming environments and better understand how to adapt future work to account for the shift in teaming dynamics. To guide this review, the following research questions (RQ) were of interest:
Method
Search Strategy
A systematic literature review was conducted following the 2020 PRISMA guidelines (Page et al., 2021) as shown in Figure 1. The following keywords along with the appropriate boolean operators (AND/OR) were used to search the selected databases: “cognitive fatigue” OR “mental fatigue” in conjunction with (AND) “human-AI teaming,” “HAT,” “human-machine teaming,” “human-human teaming,” “human-automation teaming,” “human-autonomy teaming,” “human-agent teaming.” The search dated from January 1, 2016 through November 15, 2023. The following databases generated the corresponding number of results, 117 articles from PubMed, 315 from Web of Science, 2 from IEEE Xplore, 2 from PsycInfo, 82 from ProQuest, and 33 from Scopus, resulting in 551 total articles.
PRISMA data collection process.
Data Collection
The articles were uploaded into the Rayyan review software (Ouzzani et al., 2016) for the remainder of the review. Before the selection process, 59 duplicates were removed from the collection of articles. The remaining articles were screened using the following inclusion/exclusion criteria to determine the relevance of the articles: (a) articles must be published in a peer reviewed journal; (b) articles must manipulate or measure cognitive fatigue in a teaming environment; (c) articles must be empirical; (d) literature reviews, posters, extended abstracts, conference proceedings were excluded. The first author completed the title and abstract screening resulting in 93 articles for full-text review. Two reviewers analyzed the full text of the remaining articles. Cohen’s kappa was calculated to measure the agreement of selected articles (k = 0.72). A consensus meeting was performed by the reviewers resulting in a final 17 articles for this review.
Results
Research Tasks
RQ1 focusing on the type of task used to examine cognitive fatigue in teams is an important consideration to verify the generalizability across various domains. The majority of studies included in this review utilized a sports task to examine the effects of cognitive fatigue on teams. Ten studies employed soccer tasks and three studies employed basketball tasks. Tasks with one study each included rugby, netball, surgery, and a visual classification task.
Variables Studied
Each article included in this review analyzed cognitive fatigue as an independent variable or a dependent variable (RQ2). Cognitive fatigue was an independent variable in seven of the articles and a dependent variable in ten of the articles. Four of the studies with cognitive fatigue as an independent variable used the Stroop task for 30 min as the method of induction. Other independent variables used throughout the studies included: spatial orientation, team size, competition and training settings, tactical rules, and more. The main dependent variables with cognitive fatigue included: rate of perceived exertion, decision making accuracy and response time, physical activity, technical performance, and more.
Key Findings
The main findings from this review suggest that cognitive fatigue significantly impacts teams through various metrics such as decision-making, technical performance, and perceived exertion (RQ3). More importantly, the decision-making ability for team members is often impaired in terms of response time while maintaining appropriate decision-making accuracy during a congested soccer match schedule (de Sousa Fortes et al., 2023). Moreover, without proper recovery, cognitive fatigue can remain increased for at least 24 hr following a demanding task (Díaz-García et al., 2023), leading to a greater increase in decision-making response time over consecutive days. Additionally, the overall technical performance recorded by team members was shown to decrease when cognitively fatigued. The number of involvements by team members during rugby or soccer tasks didn’t necessarily equate to negative outcomes but, the quantity of positive outcomes decreased (Badin et al., 2016; Mariano et al., 2023). Furthermore, Kunrath et al. (2020) observed an increase in the number of errors with the induction of cognitive fatigue in small-sided soccer games.
Given the previous objective findings, subjective measures such as rate of perceived exertion are equally important when considering the effects of cognitive fatigue. Most studies that measured rate of perceived exertion observed team members feeling they exerted more physical effort to complete the given task. However, two studies found no significant difference in the perceived exertion of team members when cognitively fatigued (Fortes et al., 2020; Moreira et al., 2018). The differences could be attributed to factors such as youth participants unaware of their perceptions or the type of task being performed.
Discussion
Team settings offer a dynamic space for team members to effectively collaborate on problems that exceed an individual’s capabilities. Consequently, working in a team on a shared problem can inherently be demanding and lead to challenges such as cognitive fatigue. The following section aims to consolidate the implications of the articles included in this review and provide insight into how these effects can be generalized.
Cognitive fatigue has been found to be a concern for the effectiveness of teams, specifically in the sports domain. Coutinho et al. (2018) demonstrated that cognitive fatigue can decrease the coordination between teammates by altering the tactical strategies in soccer matches. Specifically, when teammates are cognitively fatigued, the spacing between players becomes more clustered due to fixating on the opponents rather than their own teammates (Fortes et al., 2020). The lack of coordination can be problematic in the soccer domain as controlling the most space is advantageous for the team’s success (Memmert & Rein, 2018). Additionally, tactics that result in a lack of direction or specific goals can lead to higher cognitive fatigue than explicit strategies (Ponce-Bordón et al., 2021). In the sports world, it is common for strategies to change throughout a match to adapt to the opponent. These in-game adaptations often happen quickly and are determined by the captain on the field. Similar to soccer, the captains on the field during rugby matches are responsible for many tasks such as fundamental strategy changes (Devine, 2021). When cognitively fatigued, the time it takes to decide on the appropriate changes can be hindered (de Sousa Fortes et al., 2023). Petrut et al. (2020) found similar delayed reaction times in surgical teams. In a general sense, the larger responsibilities often fall in the hands of the manager, thus potentially decreasing the decision-making ability in more cognitively demanding domains.
Interestingly, higher motivation was associated with lower levels of cognitive fatigue in soccer tasks (Ponce-Bordón et al., 2021). This could be beneficial during pre-game briefings as Thompson et al. (2022) determined, through a focus group with elite female soccer players, that long team meetings contribute to increased cognitive fatigue. In addition, cognitive fatigue is higher during training and preparation sessions compared to actual competition periods due to over analysis (Russell et al., 2022). Team meetings can benefit from less repetitive content, shorter meeting periods, increased motivation, and an emphasis on the importance of specific information.
This review shows how cognitive fatigue can interrupt the team flow and decision process required for optimal task performance and efficiency. Despite these results, caution should be observed as the generalizability across domains is unknown. Due to 15 out of 17 of the studies using sports-specific domains, there is an immense lack of diversity in the tasks implemented in these studies, leaving much room for research to unveil additional complexities of cognitive fatigue across alternative domains.
Future Research
Following the direction of the studies within this review, the future of cognitive fatigue research within teaming environments is full of diverse ideas to expand the field. To emphasize the diverse perspective of future research in this field, there is a need for more control over the personal influences of cognitive fatigue while many also mention the need for understanding cognitive fatigue with more of a realistic personal influence. An interesting approach taken by two studies mentions the need for more individualized methods of inducing and measuring cognitive fatigue (de Sousa Fortes et al., 2023; Mariano et al., 2023).
Cognitive Fatigue in Human-Autonomy Teams
Although keywords were included regarding the variety of team compositions, every team included in this review was a part of human-only teams. With the reimagined way of working with advanced technology, recent work has been dedicated to designing effective teamwork strategies and developing mental models for human teammates to interact with intelligent agents. Prior work has shown cognitive demand to be higher in fatigued states when working with artificially intelligent teammates (Lopes et al., 2022). Traditionally, teams have been successful when capable of monitoring their teammate’s cognitive load, proving difficult when working alongside an autonomous agent (Endsley, 2023). These problems could be intensified as autonomous agents often operate as a black box with little to no understanding of what goes on behind the scenes (Rai, 2020).
Additionally, autonomous agents cannot become cognitively fatigued, leaving room for these teams to potentially be the most capable by designing tasks to utilize the strengths of each teammate. Accordingly, human-autonomy teams will likely benefit the most if the autonomous agent has an awareness of the cognitive fatigue state of the human teammate and can adapt accordingly. Further research should examine how cognitive fatigue affects humans when working alongside machines, specifically in a teaming environment, and compare the effects of human-only teams to human-autonomy teams.
Conclusion
This review sheds light on the detrimental effects of cognitive fatigue on team member performance such as increased decision-making response times, increased rate of perceived exertion, and decreased technical performance. Additional research is required to expand the knowledge into other domains not included in this review. Moreover, understanding how cognitive fatigue affects various team compositions such as human-autonomy teams is valuable to the field of human factors to provide a foundation for the successful development of future teams.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
