Article

Black Doctoral Students’ Mental Health: Unmasking Student Experiences

Authors: Carmen Michele McCallum (Eastern Michigan University) , Allison Boone (Eastern Michigan University) , Susanna Long (Eastern Michigan University) , Kellyn Mackerl-Cooper (Eastern Michigan University) , Elijah Vasquez (Eastern Michigan University) , Gloryvee Fonseca-Borlin (University of Michigan)

  • Black Doctoral Students’ Mental Health:  Unmasking Student Experiences

    Article

    Black Doctoral Students’ Mental Health: Unmasking Student Experiences

    Authors: , , , , ,

Keywords: graduate student mental health, wellness, graduate studies, mental health

How to Cite:

McCallum, C. M., Boone, A., Long, S., Mackerl-Cooper, K., Vasquez, E. & Fonseca-Borlin, G., (2022) “Black Doctoral Students’ Mental Health: Unmasking Student Experiences”, Currents: Journal of Diversity Scholarship for Social Change 2(1). doi: https://doi.org/10.3998/ncidcurrents.1778

1838 Views

217 Downloads

Published on
18 Feb 2022
Peer Reviewed

The research on graduate student mental health is extremely limited (Evans et al., 2018; Liu et al., 2019). Researchers who focus on mental health in college settings tend to focus on undergraduate students (Benton, et al., 2003). However, more recently, scholars have acknowledged that there is a mental health crisis in graduate education (Evans et al., 2018; Hyun et al., 2007). Several studies that focused on graduate student mental health have found that over 40% of participants identified as having a mental health condition (Pain, 2018; Graduate Assembly, 2014). This alarming rate is over six times the amount of the general public (Pain, 2018). Clinical depression, anxiety, and stress are the most common mental health concerns reported. These facts become even more disturbing when we recognize that graduate school often exacerbates mental health conditions (Hyun et al., 2007; Kausar, 2010; Peluso, et al., 2011). Yet, despite these statistics, scholars rarely focus on the lived experiences of graduate students who suffer from mental health conditions. The true impact of mental health on graduate students’ academic performance, retention, and graduation rates remains unknown (Turner & Berry, 2000). This uncertainty magnifies when we focus on students of color, especially Black students.

Research indicates the impact of poor mental health does not fall equally across all categories of students. Black students in particular have to deal with the cultural ramifications of having a mental health condition. Research on communities of color show that mental illness is taboo among Black students (Nittle, 2020; Primm, 2018) and seeking help for a mental health concern is often viewed as a sign of weakness (Armstrong, 2019). In a recent study conducted by the National Alliance on Mental Illness (2020), 63% of African Americans associated having a mental health condition as a sign of weakness. This suggests Black graduate students are less likely to reveal that they have mental health concerns or seek help when challenges occur. Additionally, Black students have to deal with the burden of living within a society of systematic racism and attending institutions that have been historically discriminatory (Mitchell et al., 2010). They experience racial microaggressions, which include, but are not limited to, racial slights, irritations, unfair treatment, stigmatization, personal threats, or attacks (Sue et al. 2007; Smith, Allen, & Danley, 2007) based on presumptions about their race. These racialized experiences can lead to race-based trauma, which can impact students’ psychological well-being, time to degree, and degree completion (Burt et al., 2018; Bryant-Davis, 2007; Bryant-Davis & Ocampo, 2005). The pressure to succeed within academic structures that disenfranchise Black individuals invariably causes stress, often leading to mental health challenges and illness (McGee & Stovall, 2015). These mental health concerns warrant exploring the unique lived experience of Black graduate students.

The Study

The purpose of this study was to explore the lived experiences of Black graduate students who identify as having mental health challenges. It is important to note that data collection for this study occurred during summer 2020. During this summer, the world was experiencing two pandemics: one associated with COVID-19 and the other associated with the killing of unarmed Black men and women in the United States. It is important to provide this context, as these two pandemics greatly influenced students’ lived experiences. Chirikov and colleagues’ (2020) study of roughly 40,000 PhD students surveyed between May 2019 and July 2020 found that mental health conditions jumped 13 to 19 percentage points in comparison to 2019 COVID-19 forced most higher-education institutions to move all in-person classes online and prevented students, faculty, and staff from being on college campuses. The murders of George Floyd, Breonna Taylor, and countless others caused society to pause and acknowledge the Black Lives Matter movement, the existence of white supremacy, and the recognition that anti-Blackness is woven into the fabric of higher education and society. Protests for injustices inflicted on Black Americans by the police occurred across the country and around the world. It is within this context that we began our interviews with Black graduate students.

Research Question

What are the lived experiences of Black graduate students with mental health challenges?

Methods

Procedure

This study is part of a larger study that focuses on graduate student mental health. A solicitation was listed on various listservs and social media sites inviting graduate students who identified as having mental health challenges to participate in the study. One hundred and forty-six students responded and took a survey containing demographic questions, adapted scales from the Counseling Center Assessment of Psychological Symptoms (CCAPS) used to measure depression, anxiety, and academic distress (Locke et. al, 2012), and general questions about their graduate school experiences. Of the 146 respondents, one person identified as Black and one as multiracial. In order to diversify the pool, we created another call specifically requesting student of color participants. Ninety-five students of color responded, 46 of whom identified as Black or Black and multiracial. For the purpose of this study, we focused on respondents who solely identified as Black, as conversations in higher education about anti-Blackness and the need to understand Black students’ experiences continue to increase exponentially.

We restricted our analysis to the 20 students who identified as being in a doctoral program, since master’s and doctoral students have distinctly different educational experiences. All 20 students were emailed an interview request and 16 responded. Six indicated Black was not their most salient identity and were removed from the pool. The remaining 10 students were interviewed. One person was disqualified, as they were in a joint masters/PhD program and were currently taking master’s courses. All nine remaining participants self-identified as having mental health concerns (e.g., depression, stress, anxiety) (see Table 1).

The semi-structured interviews lasted approximately 30 to 60 minutes and explored students’ background information, mental health challenges, graduate school experiences before and after the onset of COVID-19, and the racial pandemic of 2020. For example, participants were asked, (1) How have the protests and national conversations on Black Lives Matter impacted you as a graduate student?, (2) In what ways have your mental health challenges impacted your graduate school experiences? and (3) Can you describe the resources available to you by your program or university designed to help you manage mental health challenges that directly impact your graduate school experience?

Data Analysis

We followed Giorgi’s (1975, 1997, 2009) procedures for phenomenological data analysis. First, we engaged in open reading of each transcript to gain an understanding of students’ experiences. We attempted to follow each students’ story as told by them without any preconceived ideas. Next, we reread each transcript and coded information relevant to our research question into meaningful units. Each meaning unit was then reread to decipher meaning as it pertains to our phenomenon. This psychological reflection allowed us to combine and retract units and begin to understand the general knowledge of students’ experience. Finally, we engaged in structural understanding and description making. We solidified general insights and created themes that represented students’ experiences.

Trustworthiness and Positionality

Multiple techniques were used throughout this study to increase trustworthiness. Peer debriefing (Merriam, 2009) took place at all stages of the study. At least two authors met after each interview to discuss the data-collection process. During data analysis, all five authors read each transcript and coded for themes. Any discrepancies were discussed among the group, and a theme was only established once consensus was reached. Second, negative-case analysis was conducted (Carspecken, 1996). Data that did not fit the primary themes was examined and then reexamined to uncover areas of contrasts within the emerging themes. Finally, we triangulated the interview data with the Likert scale and open-ended survey questions collected prior to interviewing (Merriam, 2009).

Three of the six-member research team conducted interviews. McCallum identifies as a Black, cisgender, middle-class woman in good mental health who has earned her master’s in social work and PhD in higher-education administration. She has experience conducting one-on-one counseling and is an associate professor in a higher-education leadership program that prepares master’s and PhD students for educational leadership positions. Long identifies as a white, cisgender, queer woman. At the time of the study, Long was completing a master’s in counseling with a focus in college populations. Additionally, she personally sought campus-based assistance for mental health challenges throughout her graduate education. Boone Green identifies as a white, cisgender, middle-class woman. She is earning her PhD in educational leadership with a background in higher education and student affairs.

Findings

Findings reveal that students’ mental health concerns differed before and during the two pandemics that occurred in summer 2020. Therefore, we present the findings in two categories with subthemes: During the Global Pandemics and Before the Global Pandemics. We made the decision to discuss these moments in time separately to increase coherence and understanding among readers. Yet, in reality, we know that lived experiences never operate in isolation, and the two moments in time are overlapping and intertwined in how students perceive their graduate school experience. Nonetheless, we believe separating the moments provides a distinct picture that illuminates important differences regarding Black graduate students’ experiences before and after the onset of two global pandemics. During the Global Pandemics subthemes are: (1) Lack of Productivity, (2) Increased Focus on Mental Health, and (3) Mental Health Cost Due to Racialized Trauma. Before the Global Pandemics subthemes are: (1) To Tell or Not Tell Faculty and (2) Unsuitable Mental Health Services.

During the Global Pandemics

Lack of Productivity

All students acknowledged that COVID-19 was a major disruption to their lives. They were no longer able to attend in-person classes, work in their preferred environments, or collaborate with peers in person. This disruption caused students to experience an increase in stress and anxiety and a decrease in productivity and feelings of control and balance. While discussing how she was coping during the pandemic Jennifer shared:

COVID-19 has had a big impact on me. . . . I need to see and work with my peers. . . . I also am someone who works better in groups. So, I used to go write at coffee shops with my classmates, and Panera Bread and Corner Bakery, and that was honestly how I got my work done . . . since COVID happened. . . . I have barely been able to write on my dissertation in the last four, five months. . . . the lack of productivity [causes] anxiety.

Jennifer and several students spoke about the isolation they were experiencing professionally and personally during the pandemic that impacted their mental health and productivity toward completion of their degree. Similar to Jennifer, Alex struggled with having to use her apartment for all of her professional and personal needs. The inability to connect with others took a toll on her mental health and ability to complete work in her program. Alex explained:

There has definitely been an adjustment period of not really having the privilege or luxury to have different spaces that I can really get my work done. And having to make our small apartment work for all of my needs; my relaxing needs, my spiritual wellness overall, getting my work done, and getting my assistantship work done. It was rough. A lot of my motivation, it took a toll [on my mental health]. And my ability to really be productive, it was hard. Just having that discipline that I usually have to get stuff done wasn’t there.

The pandemic upended the ways that students had grown accustomed to ensuring their productivity, causing stress and anxiety. This disruption caused students to experience an increase in stress and anxiety and a decrease in productivity and feelings of control and balance.

Increased Focus on Mental Health

During a typical school year, students indicated they would often neglect their mental health. The demands of being in a PhD program coupled with personal and work responsibilities often left little time for students to focus and attend to their mental health. However, during the summer of 2020, the world seemed to pause, creating an opportunity for students to become more attuned with themselves and the impact their mental health challenges were having on their graduate school experiences. Some reached out to therapists, which led them to engage in counseling sessions that were therapeutic and rewarding. During the transition to telehealth by many mental health professionals, Jennifer found a new opportunity. She explained:

I have been struggling with anxiety for about ten years and trying to figure out how to have it under control. . . . And being in the doctoral program has definitely increased it and brought a lot of other things up. . . . During COVID, I mean the one positive about COVID is that all the doctors were doing Zoom that weren’t before. So I was actually able to get a psychiatrist, because I wanted a Black woman.

Others reconnected with their therapist and committed to refocusing on positive mental health. Marie shared the following:

[The pause] has caused me to take better care of myself. . . . I am making sure I’m taking my medicine every day. I’m making sure that I’m in touch with my therapist . . . for me I’m like, okay, I’m already in the house in an uncertain state. . . . What I can control is, if I take my medicine; if I feel like I can reach out to my therapist and keep my regular therapy appointment. . . . And so, for me, what it has caused me to do is hold onto things that I can control, because everything else is so out of control right now.

While it was anticipated that students would express challenges regarding the COVID-19 pandemic and the resultant shift to fully online learning and campus closures, it was unexpected that many students also expressed the ways in which they were able to focus more on their mental health. The disruption to students’ typical schedules and behaviors provided the opportunity or the motivation to reprioritize their well-being.

Mental Health Cost Due to Racialized Trauma

All students were deeply disturbed by the killing of George Floyd and the subsequent protests that followed. However, all students acknowledged that the angst they were experiencing was not new. Alex explained it this way:

Every time I hear someone getting murdered, a Black person or in my area a lot of brown people are getting murdered too, it’s just like another weight on my chest. It’s something that’s never going to go away. It’s something that gets worse. It never goes away. . . . I look at memories on Facebook of things I was posting about four or five years ago. It’s all the same. . . . [it’s] happening again. Not a lot has changed. But being back in school, it really has challenged my mental health because it makes me question everything. It makes me just try to figure out what my part is going to be in this.

Students indicated that they have consistently experienced an increase in stress, anxiety, and depression every time another Black person has been murdered by police. What was new was the recognition from other cultures and races that the murdering of Black folks by police is not a Black folks problem—rather, it is everyone’s problem. Jackson expressed his frustration and stated, “It’s just like we’ve been saying for all this time, for however many years, and now you finally get it.” This shift made students question their role in solving the problem and how graduate school fit into that equation. Alex wondered aloud, “Why does this stuff even matter? Why does me getting my PhD matter? Why does me doing schoolwork matter if my people are dying?” For Black graduate students in particular, the weight of two pandemics, a global health- and a social-injustice pandemic, was especially felt.

Before the Global Pandemics

To Tell or Not Tell Faculty

Thinking back to their experiences prior to the pandemics, students explained the struggle they felt deciding whether or not to disclose to a faculty member that they had mental health challenges, due to fear that they would be treated differently. One particular student, David, stated he chose to keep the fact that he had a mental health concern private because the school and faculty members made it seem as if being stressed and depressed was an indication that you were a committed graduate student. If you did not have these symptoms, you were not trying hard enough. Being that this was his perception of the faculty’s mentality, he was certain the faculty would not be empathetic toward his concerns. David explained that:

One of my professors always jokes about how if you’re not crying or having anxiety, you might not be doing enough. They often say that you’re supposed to be stressed out; that you’re supposed to cry. Is that really what they want? We had a professor tell us she had two heart attacks on her way to tenure . . . and then said I should have published more . . . they just do not seem to care.

Contrastingly, some students felt it was important to share their mental health concerns with faculty. Doctoral students and faculty tend to work closely together due to the nature of their program. Although a risk, confiding in a faculty member about mental health concerns and their possible impact on graduate school work may benefit the faculty-student relationship. Jordan stated why she felt it was important to disclose to her faculty advisor:

I was starting to feel more comfortable discussing more openly about my mental health situation. I never really disclosed a whole, whole lot about it . . . but once I started to talk about it, it came to the point where I realized [faculty member] needs to know this about me because we’re going to be working together for the next four years! He needs to understand that this is how my brain functions and this is how I work. It’s important. . . . I think me just growing more as a person and breaking away more from that stigma of mental health that is always floating around in the back of my brain.

Deciding whether or not to disclose to a faculty member appeared to be a personal decision. Some who decided to confide in a faculty member found that their relationship was strengthened by a mutual understanding of what may occur due to mental health concerns. Others stated they confided in a faculty member and did not get any support. The majority reported that they decided not to confide due to a lack of trust in the relationship.

Unsuitable Mental Health Services

There are typically two offices at a university that provide mental health services to students: the Office of Students with Disabilities and the university’s counseling office. The majority of students in this study were unaware that these offices provided service to graduate students, were hesitant to access these services due to the fear of repercussions from faculty, or they attempted to access services only to find they did not provide accommodations that were relevant to graduate students’ work. Jennifer explained why she believed the disability services office did not take into account graduate students’ work or their schedules:

They’re [disability services] open during the day and our program was at night, and I don’t live there. You needed to go in person. And also, there was nothing they were going to be able to give me. Because it’s not like with a dissertation you get extra time or note-takers . . . they’re not the type of accommodations that a doctoral student can utilize and would be beneficial.

Jordan agreed with Jennifer. Although she was aware of services the university provided, she was hesitant to utilize those services due to fear that faculty and others may view her as less capable of doing her job or they may become hesitant to consider her for a future position. Jordan explained:

I think for me as a graduate student with mental health challenges, even though I think we’ve really tried to break the walls of the stigma down, there’s still a part of me that would not go to the counseling center [on campus]. Because, even though I’m a graduate student, I also am a graduate teaching assistant. And I also potentially may want to work at the university one day. And so, the people with whom I would speak to would potentially be my colleagues.

In general, students felt the mental health services offered by their universities did not take into account graduate students’ unique schedules and need for confidentiality. These sentiments were expressed by the majority of students in the study and were offered as justification for what they choose not to utilize services on campus.

Discussion

Our findings illuminate the importance of context. Students are not just graduate students attending a particular university. They bring with them elements of their race, identity, and culture, as well as what they experience in the world outside of their program, as evidenced by the influence of racial trauma that impacts their graduate school experiences. An acknowledgement of this fact will help researchers better understand the lived experiences of Black graduate students. It is also important to note the role of graduate school in relation to Black graduate students’ mental health. How a faculty member responds to students and the kinds of services offered could make a difference in a student’s overall experience. Finally, our findings suggest an important need for more research on Black graduate students with mental health challenges. There are aspects of the Black student experience that are directly related to their race and culture; however, if addressed, all graduate students with mental health challenges could benefit from services provided.

Implications for Practice

Higher education institutions must do more than recognize that there is a mental health crisis in graduate education. They must begin to look at their role in perpetuating the ideology that graduate school is supposed to have a negative impact on students’ mental health and create supportive spaces and accommodations that will help graduate students be successful in their pursuit of a graduate degree. We offer the following recommendations:

Institutions

  1. Ensure resources and mental health support services are accessible to graduate students. Especially those who may be unable to participate during regular business hours. Regularly promote these services to graduate students.

  2. Provide safe spaces to have open dialogue about the toll that the ongoing COVID-19 pandemic and racial injustices are having on students’ mental health and well-being. This responsibility should not fall on faculty alone, as students are less willing to disclose struggles to those who are responsible for their evaluation and promotion within their programs.

Faculty

  1. Discuss mental health and well-being at program orientations; share and promote support services offered by the institution and encourage students to utilize them.

  2. Create a culture where mental health and well-being are as prioritized and promoted by faculty as other metrics of student success such as degree progress, academic presentations, and research.

Students

  1. Recognize that you are not alone; many graduate students struggle with mental health. Pay attention to your own levels of stress, exhaustion, or feelings of being overwhelmed. Seek out mental health services such as counseling and therapy early on, before challenges worsen.

  2. Connect with peers for support. Consider starting peer support groups, which are shown to reduce feelings of isolation and increase health, social, and academic benefits for students.

Biographies

Carmen M. McCallum’s interests include access and retention within graduate education, Black students and faculty, programmatic assessment and evaluation, and graduate students’ mentoring experiences. She is particularly interested in understanding how race, ethnicity, gender, and socioeconomic status influence students’ graduate school experiences. Carmen can be reached at cmccall5@emich.edu.

Allison Boone Green’s research interests include women in leadership, leadership identity development, transformational learning, and the impact of experiential education on student learning and development. Allison can be reached at aboone2@emich.edu.

Susanna Long’s research interests include mental-health support on college campuses, resiliency building, first-generation student experiences, and LGBTQ+ identity development. Susanna can be reached at slong24@emich.edu.

Kellyn Mackerl-Cooper’s research interests include Black women and the impacts that colorism has on their perception of success in their careers and Black men seeking mental-health services, recognizing the effects on pride, manhood, and ego. Kellyn can be reached at kmackerl@emich.edu.

Elijah Vasquez As a scholar-practitioner in student affairs, he hopes to work with first-generation students of color. His research interests focus on first-generation student experiences, holistic student learning and development, and student transition and accessibility, as well as inclusion and diversity in higher education. Elijah can be reached at evasque3@emich.edu.

Gloryvee Fonseca-Bolorin’s research interests include strength-based approaches to student support programs and social science research on campus climate, sense of belonging, racial-ethnic identity, and persistence in higher education. She can be reached at gfonseca@umich.edu.

Notes

  1. McCallum, C. M., Green, B. A., Long, S., Mackerel-Cooper, K., & Fonseca-Borlin, G. Black doctoral students’ mental health: Unmasking student experiences. Currents, (2)1.

References

Benton, S. A., Robertson, J. M., Tseng, W.-C., Newton, F. B., & Benton, S. L. (2003). Changes in counseling center client problems across 13 years. Professional Psychology: Research and Practice, 34(1), 66–72.

Bryant-Davis, T. (2007). Healing requires recognition: The case for race-based traumatic stress. Counseling Psychologist, 35(1), 135–143. https://doi.org/10.1177/0011000006295152https://doi.org/10.1177/0011000006295152

Bryant-Davis, T., & Ocampo, C. (2005). The trauma of racism: Implications for counseling, research, and education. The Counseling Psychologist, 33(4), 574–578. https://doi.org/10.1177/001100000527658https://doi.org/10.1177/001100000527658

Burt, B. A., Williams, K.L., & Smith, W. A. (2018). Into the storm: Ecological and sociological impediments to black males’ persistence in engineering graduate programs. American Educational Research Journal. https://doi:org.10.3102/0002831218763587https://doi:org.10.3102/0002831218763587

Chirikov, I., Soria, K. M., Horgos, B., & Jones-White, D. (2020). Undergraduate and graduate students’ mental health during the covid-19 pandemic. UC Berkeley Center for Studies in Higher Education. Retrieved from https://escholarship.org/uc/item/80k5d5hwhttps://escholarship.org/uc/item/80k5d5hw

Evans, T. M., Bira, L., Gastelum, J. B., Weiss, L. T., & Vanderford, N. L. (2018). Evidence for a mental health crisis in graduate education. Nature Biotechnology, 36(3), 282.

Graduate Assembly. (2014). Graduate Student Happiness & Well-Being Report. http://ga.berkeley.edu/wellbeingreport/http://ga.berkeley.edu/wellbeingreport/

Hyun, J., Quinn, B., Madon, T., & Lustig, S. (2007). Mental health need, awareness, and use of counseling services among international graduate students. Journal of American College Health, 56(2), 109–118.

Kausar, R. (2010). Perceived Stress, Academic Workloads and Use of Coping Strategies by University Students. Journal of Behavioral Sciences, 20(1), 31–46.

Liu, C., Wang, L., Qi, R., Wang, W., Jia, S., Shang, D., Shao, Y., Yu, M., Zhu, X., Yan, S., Chang, Q., & Zhao, Y. (2019). Prevalence and associated factors of depression and anxiety among doctoral students: the mediating effect of mentoring relationships on the association between research self-efficacy and depression/anxiety. Psychology Research and Behavior Management, 12, 195–208. https://doi.org/10.2147/PRBM.S195131https://doi.org/10.2147/PRBM.S195131

McGee, E. O., & Stovall, D. (2015). Reimagining critical race theory in education: Mental health, healing, and the pathway to liberatory praxis. Educational Theory, 65(5), 491–511.

Mitchell, R. W., Wood, G. K., & Witherspoon, N. (2010). Considering race and space: Mapping developmental approaches for providing culturally responsive advising. Equity & Excellence in Education, 43(3), 294–309.

National Alliance on Mental Illness. (2020). Black/American. Retrieved from https://www.nami.org/your-journey/identity-and-cultural-dimensions/black-african-americanhttps://www.nami.org/your-journey/identity-and-cultural-dimensions/black-african-american

Nittle, N. (Ed.). (2019). America’s Mental Health Crisis. Greenhaven Publishing.

Pain, E. (2018). Graduate students need more mental health support, new study highlights. Retrieved from http://www.sciencemag.org/careers/2018/03/graduate-students-need-more-mental-health-support-new-study-highlightshttp://www.sciencemag.org/careers/2018/03/graduate-students-need-more-mental-health-support-new-study-highlights

Peluso, D. L., Carleton, R. N., Girdon, J. & Asmundson, G. (2011). Depression symptoms in canadian psychology graduate students: Do research productivity, funding, and academic advisory relationship play a role? Canadian Journal of Behavioral Science, 43(2), 119–127.

Primm, A. B. (2018). College students of color: Confronting the complexities of diversity, culture, and mental health. Higher Education Today, 1–11.

Smith, W. A., Allen, W. R., & Danley, L. L. (2007). “Assume the position . . . you fit the description”: Psychosocial experiences and racial battle fatigue among African American male college students. American Behavioral Scientist, 51(4), 551–578. https://doi.org/10.1177/0002764207307742https://doi.org/10.1177/0002764207307742

Sue, D. W., Capodilupo, C. M., Torino, G. C., Bucceri, J. M., Holder, A., Nadal, K. L., & Esquilin, M. (2007). Racial microaggressions in everyday life: Implications for clinical practice. American psychologist, 62(4), 271.

Turner, A. L., & Berry, T. L. (2000). Counseling center contributions to student retention and graduation: a longitudinal assessment. Journal of College Student Development, 41(6), 627–636.