Self-Efficacy Buffers the Relationship between Educational Disadvantage and Executive Functioning
Open accessAbstract
Previous studies showed that control beliefs are more strongly related to global cognition and mortality among adults with low education, providing preliminary evidence that self-efficacy buffers against the negative impact of educational disadvantage on physical and cognitive health. The current study extends these findings to a nationally representative sample of men and women aged 30 to 85 and explores which cognitive domains are most strongly associated with self-efficacy, educational attainment, and their interaction. Data were obtained from 1032 adult (30–85) participants in the United States norming study for the NIH Toolbox. Self-efficacy, executive functioning, working memory, processing speed, episodic memory, and vocabulary were assessed with the NIH Toolbox. Multivariate analysis of covariance and follow-up regressions tested the hypothesis that self-efficacy would be more strongly related to cognitive performance among individuals with lower education, controlling for age, sex, race, ethnicity, education, reading level, testing language, and depressive symptoms. Higher education was associated with higher self-efficacy and better performance on all cognitive tests. Higher self-efficacy was associated with better set-switching and attention/inhibition. Significant self-efficacy by education interactions indicated that associations between self-efficacy and executive abilities were stronger for individuals with lower education. Specifically, individuals with low education but high self-efficacy performed similarly to individuals with high education. This study provides evidence that self-efficacy beliefs buffer against the negative effects of low educational attainment on executive functioning. These results have implications for future policy and/or intervention work aimed at reducing the deleterious effects of educational disadvantage on later cognitive health. (JINS, 2015, 21, 297–304)
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In moments when action is planned and executed, higher performance expectancies may serve as a buffer or protection against responses that would detract from optimal performance, such as nonbeneficial alternate responses, off-task activity, or self-referential thinking.
“In the moments when action is planned and executed, higher performance expectancies may also serve as a buffer or protection against responses that would detract from optimal performance, such as nonbeneficial alternate responses, including off-task activity (Jiao et al., 2015;Zahodne, Nowinski, Gershon, & Manly, 2015) or self-referential thinking.”
From Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning (2016) · cites this paper as Zahodne et al., 2015
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Cites
Self-efficacy: Toward a unifying theory of behavioral change
Bandura, A. (1977) · Psychological Review · doi:10.1037/0033-295x.84.2.191 · Cited by 43,925 · see citing works
Perceived self-efficacy in cognitive development and functioning
Bandura, A. (1993) · Educational Psychologist · doi:10.1207/s15326985ep2802_3 · Cited by 7,655 · see citing works
Handbook of the Psychology of Aging
Schaie, K. W., Willis, S. L., Knight, B. G., & Park, D. C. (2016) · Elsevier eBooks · doi:10.1016/c2012-0-07221-3 · Cited by 3,436 · see citing works
Kanfer, R., & Ackerman, P. (1989) · Journal of Applied Psychology · doi:10.1037/0021-9010.74.4.657 · Cited by 2,177 · see citing works
Self-efficacy: Toward a unifying theory of behavioural change?
Teasdale, J. D. (1978) · Advances in Behaviour Research and Therapy · doi:10.1016/0146-6402(78)90009-7 · Cited by 2,038 · see citing works
Catalano, R. F., Berglund, M. L., Ryan, J. A. M., Lonczak, H. S., & Hawkins, J. D. (2004) · The Annals of the American Academy of Political and Social Science · doi:10.1177/0002716203260102 · Cited by 1,948 · see citing works
Regulation of cognitive processes through perceived self-efficacy.
Bandura, A. (1989) · Developmental Psychology · doi:10.1037/0012-1649.25.5.729 · Cited by 1,900 · cited 6× · see citing works
“It should be noted that domain-specific measures of self-efficacy may be more strongly associated with functioning than domaingeneral measures such as the NIH Toolbox Self Efficacy Survey used in the present study (Bandura, 1989).”
InfluentialThe sense of control as a moderator of social class differences in health and well-being.
Lachman, M. E., & Weaver, S. L. (1998) · Journal of Personality and Social Psychology · doi:10.1037//0022-3514.74.3.763 · Cited by 1,674 · see citing works
Kanfer, R., & Ackerman, P. L. (1989) · Journal of Applied Psychology · doi:10.1037//0021-9010.74.4.657 · Cited by 1,408 · see citing works
Marmot, M., Bosma, H., Hemingway, H., Brunner, E., & Stansfeld, S. (1997) · The Lancet · doi:10.1016/s0140-6736(97)04244-x · Cited by 1,291 · see citing works
Cognition assessment using the NIH Toolbox
Weintraub, S., Dikmen, S. S., Heaton, R. K., Tulsky, D. S., Zelazo, P. D., Bauer, P. J., Carlozzi, N. E., Slotkin, J., Blitz, D., Wallner-Allen, K., et al. (2013) · Neurology · doi:10.1212/wnl.0b013e3182872ded · Cited by 1,287 · cited 9× · see citing works
“Convergent validity for each task was demonstrated through significant, moderately sized correlations with gold-standard measures, ranging from 0.48 (Flanker Inhibitory Control & Attention) to 0.69 (Picture Sequence Memory) (Weintraub et al., 2013).”
InfluentialSelf-citationVision assessment using the NIH Toolbox
Varma, R., McKean‐Cowdin, R., Vitale, S., Slotkin, J., & Hays, R. D. (2013) · Neurology · doi:10.1212/wnl.0b013e3182876e0a · Cited by 1,197 · see citing works
Bandura, A., & Wood, R. E. (1989) · Journal of Personality and Social Psychology · doi:10.1037//0022-3514.56.5.805 · Cited by 1,076 · see citing works
NIH Toolbox for Assessment of Neurological and Behavioral Function
Gershon, R. C., Wagster, M. V., Hendrie, H. C., Fox, N. A., Cook, K. F., & Nowinski, C. J. (2013) · Neurology · doi:10.1212/wnl.0b013e3182872e5f · Cited by 895 · see citing works
Self-citationSeeman, T. E., Lusignolo, T. M., Albert, M., & Berkman, L. (2001) · Health Psychology · doi:10.1037/0278-6133.20.4.243 · Cited by 855 · see citing works
Improving memory in old age through implicit self-stereotyping.
Levy, B. R. (1996) · Journal of Personality and Social Psychology · doi:10.1037//0022-3514.71.6.1092 · Cited by 840 · see citing works
Bandura, A., & Wood, R. E. (1989) · Journal of Personality and Social Psychology · doi:10.1037/0022-3514.56.5.805 · Cited by 746 · see citing works
Improving memory in old age through implicit self-stereotyping.
Levy, B. R. (1996) · Journal of Personality and Social Psychology · doi:10.1037/0022-3514.71.6.1092 · Cited by 618 · see citing works
Manly, J. J., Jacobs, D. M., Touradji, P., Small, S. A., & Stern, Y. (2002) · Journal of the International Neuropsychological Society · doi:10.1017/s1355617702813157 · Cited by 611 · see citing works
Self-citationHandbook of the psychology of aging
Bergmann, K. (1980) · Journal of Psychosomatic Research · doi:10.1016/0022-3999(80)90086-0 · Cited by 594 · see citing works
Basal cortisol levels and cognitive deficits in human aging
Lupien, S., Lecours, A., Lussier, I., Schwartz, G., Nair, N., & Meaney, M. (1994) · The Journal of Neuroscience · doi:10.1523/jneurosci.14-05-02893.1994 · Cited by 566 · see citing works
Bouffard‐Bouchard, T., Parent, S., & Larivée, S. J. (1991) · International Journal of Behavioral Development · doi:10.1177/016502549101400203 · Cited by 396 · see citing works
Biobehavioral bases of coronary heart disease
Dembroski, T. M., Schmidt, T., & Blümchen, G. (1983) · KARGER eBooks · Cited by 346 · see citing works
Zahodne, L. B., Glymour, M. M., Sparks, C., Bontempo, D., Dixon, R. A., MacDonald, S. W. S., & Manly, J. J. (2011) · Journal of the International Neuropsychological Society · doi:10.1017/s1355617711001044 · Cited by 339 · see citing works
Self-citationEarly Adult to Midlife Cardiovascular Risk Factors and Cognitive Function
Yaffe, K., Vittinghoff, E., Pletcher, M. J., Hoang, T. D., Launer, L. J., Whitmer, R. A., Coker, L. H., & Sidney, S. (2014) · Circulation · doi:10.1161/circulationaha.113.004798 · Cited by 308 · see citing works
Emotion assessment using the NIH Toolbox
Salsman, J. M., Butt, Z. A., Pilkonis, P. A., Cyranowski, J. M., Zill, N., Hendrie, H. C., Kupst, M. J., Kelly, M. A. R., Bode, R. K., Choi, S. W., et al. (2013) · Neurology · doi:10.1212/wnl.0b013e3182872e11 · Cited by 274 · see citing works
Acculturation, reading level, and neuropsychological test performance among African American elders
Manly, J. J., Byrd, D. A., Touradji, P., & Stern, Y. (2004) · Applied Neuropsychology · doi:10.1207/s15324826an1101_5 · Cited by 254 · see citing works
Self-citationRelationships between Metacognition, Self-efficacy and Self-regulation in Learning
Cera, R., Mancini, M., & Antonietti, A. (2013) · Journal of Educational Cultural and Psychological Studies (ECPS Journal) · doi:10.7358/ecps-2013-007-cera · Cited by 145 · see citing works
The Adaptive Value of Feeling in Control during Midlife.
Lachman, M. E., & Firth, K. (2004) · Cited by 133 · see citing works
Self-efficacy beliefs and change in cognitive performance: MacArthur studies on Successful Aging.
Seeman, T., McAvay, G., Merrill, S., Albert, M., & Rodin, J. (1996) · Psychology and Aging · doi:10.1037//0882-7974.11.3.538 · Cited by 126 · see citing works
Perceived control reduces mortality risk at low, not high, education levels.
Turiano, N. A., Chapman, B. P., Agrigoroaei, S., Infurna, F. J., & Lachman, M. E. (2014) · Health Psychology · doi:10.1037/hea0000022 · Cited by 114 · see citing works
Leganger, A., & Kraft, P. (2003) · Journal of Health Psychology · doi:10.1177/13591053030083006 · Cited by 113 · see citing works
Norming plans for the NIH Toolbox
Beaumont, J. L., Havlik, R., Cook, K. F., Hays, R. D., Wallner-Allen, K., Korper, S. P., Lai, J.-S., Nord, C., Zill, N., Choi, S., et al. (2013) · Neurology · doi:10.1212/wnl.0b013e3182872e70 · Cited by 106 · see citing works
Self-citationSelf-efficacy beliefs and change in cognitive performance: MacArthur studies on Successful Aging.
Seeman, T. E., MCAVAY, G. J., Merrill, S., et al. (1996) · Psychology and Aging · doi:10.1037/0882-7974.11.3.538 · Cited by 97 · see citing works
Manly, J. J., Smith, C. A., Crystal, H., Richardson, J. L., Golub, E. T., Greenblatt, R. M., Robison, E., Martin, E. M., & Young, M. (2011) · Journal of Clinical and Experimental Neuropsychology · doi:10.1080/13803395.2010.547662 · Cited by 83 · see citing works
Self-citationWhich Psychosocial Factors Best Predict Cognitive Performance in Older Adults?
Zahodne, L. B., Nowinski, C. J., Gershon, R. C., & Manly, J. J. (2014) · Journal of the International Neuropsychological Society · doi:10.1017/s1355617714000186 · Cited by 69 · see citing works
Self-citationAlfassi, M. (2003) · Journal of instructional psychology · Cited by 61 · see citing works
Windsor, T. D., & Anstey, K. J. (2008) · Aging Neuropsychology and Cognition · doi:10.1080/13825580802348570 · Cited by 56 · see citing works
Late life cognition among men: A life course perspective on psychosocial experience
Wight, R. G., Aneshensel, C. S., Seeman, M. S., & Seeman, T. E. (2003) · Archives of Gerontology and Geriatrics · doi:10.1016/s0167-4943(03)00046-3 · Cited by 18 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Wulf, G., & Lewthwaite, R. (2016) · Psychonomic Bulletin & Review · doi:10.3758/s13423-015-0999-9 · Cited by 1,238 · see citing works
Jia, X.-H., & Tu, J.-C. (2024) · Systems · doi:10.3390/systems12030074 · Cited by 218 · see citing works
Factors associated with the utilization of institutional delivery services in Bangladesh
Yaya, S., Bishwajit, G., & Ekholuenetale, M. (2017) · PLoS ONE · doi:10.1371/journal.pone.0171573 · Cited by 128 · see citing works
Wulf, G., Lewthwaite, R., Cardozo, P. L., & Chiviacowsky, S. (2017) · Quarterly Journal of Experimental Psychology · doi:10.1080/17470218.2016.1276204 · Cited by 109 · see citing works
Self-motivated and directed learning across the lifespan
Cronin-Golomb, L. M., & Bauer, P. J. (2022) · Acta Psychologica · doi:10.1016/j.actpsy.2022.103816 · Cited by 83 · see citing works
A cross-cultural study: Teachers’ self-efficacy beliefs for teaching thinking skills
Dilekli, Y., & Tezci, E. (2019) · Thinking Skills and Creativity · doi:10.1016/j.tsc.2019.100624 · Cited by 40 · see citing works
Wu, L., Zhang, X., Wang, J., Sun, J., Mao, F., Han, J., & Cao, F. (2021) · Journal of Affective Disorders · doi:10.1016/j.jad.2021.01.031 · Cited by 36 · see citing works
Psychosocial Protective Factors in Cognitive Aging: A Targeted Review
Zahodne, L. B. (2021) · Archives of Clinical Neuropsychology · doi:10.1093/arclin/acab051 · Cited by 31 · see citing works
Self-citationOlsson, C., Ekelund, J., Degerstedt, Å., & Thorstensson, C. A. (2019) · Disability and Rehabilitation · doi:10.1080/09638288.2018.1555616 · Cited by 25 · see citing works
Xia, B.-Y., Yu, J., & Wu, X. (2022) · Annals of Palliative Medicine · doi:10.21037/apm-22-528 · Cited by 22 · see citing works
Limbu, Y. B., Giovannetti, M., & Cardinali, S. (2020) · British Food Journal · doi:10.1108/bfj-12-2019-0906 · Cited by 16 · see citing works
Shiraly, R., Shayan, Z., Keshtkar, V., & Hamed, M. (2017) · International Journal of Preventive Medicine · doi:10.4103/ijpvm.ijpvm_340_16 · Cited by 10 · see citing works
Moncrief, G. G., Aita, S. L., Tyson, B. T., Abecassis, M., Roth, R. M., Caller, T. A., Schmidt, S. S., & Jobst, B. C. (2021) · Epilepsy & Behavior · doi:10.1016/j.yebeh.2021.108042 · Cited by 15 · see citing works
Lee, J.-E., Cho, E., Kim, H., Lee, K. H., Kim, E., & Ye, B. S. (2023) · Applied Nursing Research · doi:10.1016/j.apnr.2023.151726 · Cited by 15 · see citing works
Islam, M. M., & Shahjahan, M. (2021) · Journal of Health Research · doi:10.1108/jhr-07-2020-0284 · Cited by 15 · see citing works
Green, K. H., Becht, A., van de Groep, S., van der Cruijsen, R., Sweijen, S., & Crone, E. A. (2023) · Social Development · doi:10.1111/sode.12674 · Cited by 17 · see citing works
Executive Functions and Information Systems Learning
Sullivan, Y. W., Davis, F. D., & Koh, C. E. (2022) · MIS Quarterly · doi:10.25300/misq/2022/15979 · Cited by 13 · see citing works
Zahodne, L. B., Schupf, N., & Brickman, A. M. (2017) · Brain Imaging and Behavior · doi:10.1007/s11682-017-9776-x · Cited by 12 · see citing works
Self-citationQuantifying the Relationship Between Self-Efficacy and Mathematical Creativity: A Meta-Analysis
HERIANTO, H., Sofroniou, A., Fitrah, M., Rosana, D., Setiawan, C., Rosnawati, R., Widihastuti, W., Jusmiana, A., & Marinding, Y. (2024) · Education Sciences · doi:10.3390/educsci14111251 · Cited by 10 · see citing works
Rahman, M. A., Kundu, S., Rashid, H. O., Shanto, H. H., Rahman, M. M., Khan, B., Howlader, M. H., & Islam, M. A. (2022) · PLoS ONE · doi:10.1371/journal.pone.0278093 · Cited by 10 · see citing works
Effects of self-efficacy on frontal midline theta power and golf putting performance
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Jolly, S. P., Chowdhury, T. R., Rahman, M., Alam, A., & Afsana, K. (2020) · PLoS ONE · doi:10.1371/journal.pone.0235340 · Cited by 8 · see citing works
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Navayuth, T., & Yurayat, P. (2022) · Journal of Education and Learning · doi:10.5539/jel.v11n4p131 · Cited by 4 · see citing works
Yeung, M. K.-C., Li, C. T. Y., Chung, H. C. W., Au, T.-H., Lee, S.-Y., & Bai, J. (2025) · Molecular Autism · doi:10.1186/s13229-025-00680-2 · Cited by 4 · see citing works
Ma, C., Wang, Y., Fu, J., & Zhao, X. (2025) · Contemporary Educational Psychology · doi:10.1016/j.cedpsych.2025.102424 · Cited by 3 · see citing works
Predictors of Institutional Delivery in Nepal: Analyzing Nepal Demographic and Health Survey 2016
Parajuli, A., Janak, K. C., Magar, E. B., Chaudhary, R., Gupta, M., & Marahatta, D. (2023) · Journal of Multidisciplinary Research Advancements · doi:10.3126/jomra.v1i2.61193 · Cited by 3 · see citing works
Øie, M. B., Haugen, I., Stubberud, J., & Øie, M. G. (2024) · Frontiers in Psychology · doi:10.3389/fpsyg.2024.1320986 · Cited by 3 · see citing works
Umairi, K. S. A. (2024) · Eurasia Journal of Mathematics Science and Technology Education · doi:10.29333/ejmste/14990 · Cited by 2 · see citing works
Wang, Y., Chong, Y., Men, R., Li, F., Pan, H., & Xu, X. (2026) · Frontiers in Psychiatry · doi:10.3389/fpsyt.2025.1653871 · Cited by 2 · see citing works
Memory self-efficacy and working memory
Mashinchi, G. M., Hall, S., & Cotter, K. A. (2023) · Aging Neuropsychology and Cognition · doi:10.1080/13825585.2023.2259023 · Cited by 3 · see citing works
Executive Functioning of Individuals With Substance Use Disorder
Valdes, K. A., & Lunsford, D. (2021) · Annals of International Occupational Therapy · doi:10.3928/24761222-20210921-01 · Cited by 2 · see citing works
Desenvolvimento de carreira de mulheres em STEM: o papel dos autoconceitos
Martins, B. (2022) · doi:10.14393/ufu.di.2022.295 · Cited by 2 · see citing works
ElAdl, A. M. (2024) · Al-Maǧallaẗ Al-Tarbawiyyaẗ Al-Šāmlaẗ · doi:10.21608/ejc.2024.348264 · Cited by 1 · see citing works
Dana, G. P. T., & Roy, S. K. (2020) · Springer eBooks · doi:10.1007/978-981-15-3045-6_16 · Cited by 1 · see citing works
Computerized Cognitive Intervention in Cognitively Normal Very Elderly Individuals
West, R. K. (2016) · CUNY Academic Works (City University of New York) · Cited by 1 · see citing works
Lehman, B. L. (2018) · Scholarship & Creative Works - Digital UNC a service of University Libraries (University of Northern Colorado) · Cited by 1 · see citing works
Predictors of Regular Outdoor Walking among Iranian Older Males, Shiraz, 2016
Shiraly, R., & Keshtkar, V. (2018) · Shiraz E-Medical Journal · doi:10.5812/semj.61210
(2021) · American Academy of PediatricsItasca, IL eBooks · doi:10.1542/9781610025072-ch11
(2024) · Al-Maǧallaẗ Al-Tarbawiyyaẗ Al-Šāmlaẗ · doi:10.21608/ejc.2024.348256
Tsega, Y., Endawkie, A., Kebede, S. D., Abera, K. M., Abeje, E. T., Enyew, E. B., Daba, C., Asmare, L., Bayou, F. D., Arefaynie, M., et al. (2025) · BMC Health Services Research · doi:10.1186/s12913-025-13884-2
Liu, Y., & Zhao, X. (2026) · Frontiers in Public Health · doi:10.3389/fpubh.2026.1817281
Coupled Changes in Daily Control Beliefs and Cognition: Variations by Education and Income
Hamm, J. M., Lachman, M. E., Klepacz, L. M., & amin, D. H. (2026) · International Journal of Behavioral Development · doi:10.1177/01650254261454866
- Authors
- Zahodne, L. B., Nowinski, C. J., Gershon, R. C., & Manly, J. J.
- Affiliations
- Columbia University (US)
- Northwestern University (US)
- Corresponding author
- Zahodne, Laura B.
- Venue
- Journal of the International Neuropsychological Society
- Publisher
- Cambridge University Press (CUP)
- Published
- 2015-04
- Volume
- 21
- Issue
- 4
- Pages
- 297-304
- ISSN
- 1355-6177 (ISSN-L)
- 1469-7661
- PMC
- PMC4871130
- OpenAlex
- W2314215661
- Cited by
- 45
- References
- 37
- Citations by year
- 2026: 3 · 2025: 3 · 2024: 9 · 2023: 5 · 2022: 6 · 2021: 6 · 2020: 3 · 2019: 2 · 2018: 2 · 2017: 4 · 2016: 2
- FWCI
- 4.02
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Journal of the International Neuropsychological Society (publishedVersion)
- PubMed (publishedVersion)
- PubMed Central (acceptedVersion)
- Funders
- National Institutes of Health
- U.S. Public Health Service (HHS-N-260-2006-00007-C)
- National Institute on Aging (K99AG047963)
- Topics
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Abilities and Testing
- Social Sciences › Psychology › Clinical Psychology › Historical and Modern Theater Studies
- Social Sciences › Health › Health disparities and outcomes
- Keywords
- self-efficacy, educational disadvantage, educational attainment, executive function, cognitive aging, NIH Toolbox, working memory, processing speed, episodic memory, vocabulary, set switching, cognitive health
- MeSH terms
- Adult, Aged, Aged, 80 and over, Educational Status, Female, Humans, Male, Memory, Short-Term, Middle Aged, Models, Psychological, Neuropsychological Tests, Sex Factors, United States, Vocabulary, Databases, Factual, Self Efficacy, Executive Function
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