努力：成本还是奖赏?

doi:10.3724/SP.J.1042.2019.01439

摘要/Abstract

摘要：

努力(Effort)与奖赏系统关系密切。当前关于努力在奖赏加工中的作用存在两个截然相反的观点：努力是一种成本还是一种奖赏?理论模型包括：其一, 努力是一种成本, 会降低奖赏的价值, 相应的理论解释包括内部成本模型、机会成本模型及信号模型等; 其二, 努力能够提升奖赏的价值, 相应的理论解释包括认知失调和努力的合理化模型、习得性勤奋理论及认知需求理论等。这两种观点均得到了来自于动物学、行为学、电生理学以及神经影像学等证据的支持。未来研究需要对努力准确定义, 从时间进程角度对努力的理论进行整合, 进一步考察努力的相关影响因素。

关键词: 努力, 成本, 奖赏

Abstract:

Effort plays a critical role in reward processing, which has been couched within two contradictory theories regarding effort as either a cost or a reward. On the one hand, effort is regarded as a cost whereby it reduces reward value, which has been articulated in the intrinsic cost model, the opportunity cost model, and the signal model. On the other hand, effort can boost the value of reward, which has been explained by the cognitive dissonance model, the learned industriousness model, and the need for cognition model. Both theories have been supported by converging evidence from animal studies, human behavioral studies, electrophysiological studies, and neuroimaging studies. Future research is needed to specify the definition of effort, integrate the competing theories in terms of the time course of effort expenditure, and explore potential factors that impact on effort.

Key words: effort, cost, reward

中图分类号:

B848

易伟, 梅淑婷, 郑亚. (2019). 努力：成本还是奖赏?. 心理科学进展 , 27(8), 1439-1450.

YI Wei, MEI Shuting, ZHENG Ya. (2019). Effort: Cost or reward?. Advances in Psychological Science, 27(8), 1439-1450.

参考文献 123

[1]	Alessandri J., Darcheville J-C., Delevoye-Turrell Y., & Zentall T. R . (2008). Preference for rewards that follow greater effort and greater delay. Learning & Behavior,36(4), 352-358.
[2]	Anzak A., Tan H., Pogosyan A., Foltynie T., Limousin P., Zrinzo L., .. Brown P . (2012). Subthalamic nucleus activity optimizes maximal effort motor responses in Parkinson's disease. Brain,135(9), 2766-2778.
[3]	Arkes H. R., Joyner C. A., Pezzo M. V., Nash J. G., Siegel-Jacobs K., & Stone E . (1994). The psychology of windfall gains. Organizational Behavior and Human Decision Processes,59(3), 331-347.
[4]	Armus H . (1999). Effect of response effort on secondary reward value. Psychological Reports,84(1), 323-328.
[5]	Aronson E. &Mills J., (1959). The effect of severity of initiation on liking for a group. The Journal of Abnormal and Social Psychology,59(2), 177-181.
[6]	Barch D. M., Treadway M. T., & Schoen N . (2014). Effort, anhedonia, and function in schizophrenia: Reduced effort allocation predicts amotivation and functional impairment. Journal of Abnormal Psychology,123(2), 387-397. doi: 10.1037/a0036299
[7]	Benozio A. &Diesendruck G., (2015). From effort to value: Preschool children's alternative to effort justification. Psychological Science,26(9), 1423-1429.
[8]	Benzion U., Rapoport A., & Yagil J . (1989). Discount rates inferred from decisions: An experimental study. Management Science,35(3), 270-284.
[9]	Bonnelle V., Veromann K-R., Burnett Heyes S., Lo Sterzo E., Manohar S., & Husain M . (2015). Characterization of reward and effort mechanisms in apathy. Journal of Physiology-Paris,109(1-3), 16-26.
[10]	Botvinick M. M., Huffstetler S., & McGuire J. T . (2009). Effort discounting in human nucleus accumbens. Cognitive,Affective, & Behavioral Neuroscience,9(1), 16-27.
[11]	Brehm J.., &Self E.A . (1989). The intensity of motivation. Annual Review of Psychology,40 109-131.
[12]	Bustamante E. E., Davis C. L., & Marquez D. X . (2014). A test of learned industriousness in the physical activity domain. International Journal of Psychological Studies,6(4), 12-25.
[13]	Cacioppo J. T., Petty R. E., Feinstein J. A., &Jarvis W. B. G., ., (1996). Dispositional differences in cognitive motivation: The life and times of individuals varying in need for cognition. Psychological Bulletin, 119( 2), 197-253.
[14]	Cacioppo J. T., Petty R. E., & Kao C. F . (1984). The efficient assessment of need for cognition. Journal of Personality Assessment,48(3), 306-307.
[15]	Carter E. C., Kofler L. M., Forster D. E., & McCullough M. E . (2015). A series of meta-analytic tests of the depletion effect: Self-control does not seem to rely on a limited resource. Journal of Experimental Psychology: General,144(4), 796-815.
[16]	Chong T. T-J., Apps M., Giehl K., Sillence A., Grima L. L., & Husain M . (2017). Neurocomputational mechanisms underlying subjective valuation of effort costs. PLoS Biology,15(2), e1002598.
[17]	Chong T. T-J., Bonnelle V., Manohar S., Veromann K-R., Muhammed K., Tofaris G. K., .. Husain M . (2015). Dopamine enhances willingness to exert effort for reward in Parkinson's disease. Cortex,69 40-46.
[18]	Christie S.., &Schrater P., (2015). Cognitive cost as dynamic allocation of energetic resources. Frontiers in Neuroscience,9 289.
[19]	Clement T. S., Feltus J. R., Kaiser D. H., & Zentall T. R . (2000). “Work ethic” in pigeons: Reward value is directly related to the effort or time required to obtain the reward. Psychonomic Bulletin & Review,7(1), 100-106.
[20]	Cocker P. J., Hosking J. G., Benoit J., & Winstanley C. A . (2012). Sensitivity to cognitive effort mediates psychostimulant effects on a novel rodent cost/benefit decision-making task. Neuropsychopharmacology,37(8), 1825-1837. doi: 10.1038/npp.2012.30
[21]	Cowan N., Rouder J. N., Blume C. L., & Saults J. S . (2012). Models of verbal working memory capacity: What does it take to make them work? Psychological Review,119(3), 480-499.
[22]	Croxson P. L., Walton M. E., O'Reilly J. X., Behrens T. E., & Rushworth M. F . (2009). Effort-based cost-benefit valuation and the human brain. Journal of Neuroscience,29(14), 4531-4541.
[23]	Culbreth A. J., Moran E. K., & Barch D. M . (2018). Effort-cost decision-making in psychosis and depression: Could a similar behavioral deficit arise from disparate psychological and neural mechanisms? Psychological Medicine,48(6), 889-904.
[24]	Czaczkes T. J., Brandstetter B., di Stefano I., & Heinze J . (2018). Greater effort increases perceived value in an invertebrate. Journal of Comparative Psychology,132(2), 200-209.
[25]	de Morree H.M., &Marcora S.M . (2010). The face of effort: Frowning muscle activity reflects effort during a physical task. Biological Psychology,85(3), 377-382.
[26]	de Morree H.M., &Marcora S.M, (2015). Psychobiology of perceived effort during physical tasks. In: Gendolla G., Tops M., Koole S. (Eds), Handbook of biobehavioral approaches to self-regulation (pp. 255-270).New York: Springer.
[27]	Duckworth A. L., Peterson C., Matthews M. D., & Kelly D. R . (2007). Grit: Perseverance and passion for long-term goals. Journal of Personality and Social Psychology,92(6), 1087-1101.
[28]	Duncan G. J., Dowsett C. J., Claessens A., Magnuson K., Huston A. C., Klebanov P., .. Japel C . (2007). School readiness and later achievement. Developmental Psychology,43(6), 1428-1446.
[29]	Dunn T. L., Inzlicht M., & Risko E. F . (2017). Anticipating cognitive effort: Roles of perceived error-likelihood and time demands. Psychological Research, 1-24.
[30]	Eastwood J. D., Frischen A., Fenske M. J., & Smilek D . (2012). The unengaged mind: Defining boredom in terms of attention. Perspectives on Psychological Science,7(5), 482-495. doi: 10.1177/1745691612456044
[31]	Eisenberger R. (1992). Learned industriousness. Psychological Review,99(2), 248-267.
[32]	Eisenberger R. &Leonard J.M . (1980). Effects of conceptual task difficulty on generalized persistence. The American Journal of Psychology,93(2), 285-298.
[33]	Elkins-Brown N., Saunders B., & Inzlicht M . (2016). Error-related electromyographic activity over the corrugator supercilii is associated with neural performance monitoring. Psychophysiology,53(2), 159-170.
[34]	Fenichel O. (1951). On the psychology of boredom. Organization and Pathology of Thought, 349-361.
[35]	Fervaha G., Foussias G., Agid O., & Remington G . (2013). Neural substrates underlying effort computation in schizophrenia. Neuroscience & Biobehavioral Reviews,37(10 Pt 2), 2649-2665.
[36]	Festinger L. (1962). A theory of cognitive dissonance (Vol.2). Jolla, California: Stanford university press.
[37]	Fisherl C. . (1993). Boredom at work: A neglected concept. Human Relations, 46( 3), 395-417.
[38]	Floresco S. B., Tse M. T., & Ghods-Sharifi S . (2008). Dopaminergic and glutamatergic regulation of effort- and delay-based decision making. Neuropsychopharmacology,33(8), 1966-1979.
[39]	Gailliot M.., &Baumeister R.F . (2007). The physiology of willpower: Linking blood glucose to self-control. Personality and Social Psychology Review, 11( 4), 303-327.
[40]	Gailliot M. T., Baumeister R. F., DeWall C. N., Maner J. K., Plant E. A., Tice D. M., & Schmeichel B. J . (2007). Self-control relies on glucose as a limited energy source: Willpower is more than a metaphor. Journal of Personality and Social Psychology,92(2), 325-336.
[41]	Geaney J. T., Treadway M. T., & Smillie L. D . (2015). Trait anticipatory pleasure predicts effort expenditure for reward. PLoS One,10(6), e0131357.
[42]	Gheza D., de Raedt R., Baeken C., & Pourtois G . (2018). Integration of reward with cost anticipation during performance monitoring revealed by ERPs and EEG spectral perturbations. NeuroImage,173 153-164.
[43]	Giammittorio A. . (2017). Application of learned industriousness theory to brain injury rehabilitation: Examining the effect of effort training on task engagement (Unpublished doctorial dissertation). Eastern Michigan University.
[44]	Gold J. M., Kool W., Botvinick M. M., Hubzin L., August S., & Waltz J. A . (2015). Cognitive effort avoidance and detection in people with schizophrenia. Cognitive,Affective, & Behavioral Neuroscience,15(1), 145-154.
[45]	Gold J. M., Strauss G. P., Waltz J. A., Robinson B. M., Brown J. K., & Frank M. J . (2013). Negative symptoms of schizophrenia are associated with abnormal effort-cost computations. Biological Psychiatry,74(2), 130-136. doi: 10.1016/j.biopsych.2012.12.022
[46]	Griffiths T. L., Lieder F., & Goodman N. D . (2015). Rational use of cognitive resources: Levels of analysis between the computational and the algorithmic. Topics in Cognitive Science,7(2), 217-229.
[47]	Hagger M. S., Chatzisarantis N. L. D., Alberts H., Anggono C. O., Batailler C., Birt A. R., .. Zwienenberg M . (2016). A multilab preregistered replication of the ego-depletion effect. Perspectives on Psychological Science,11(4), 546-573.
[48]	Hart E. E., Gerson J. O., Zoken Y., Garcia M., & Izquierdo A . (2017). Anterior cingulate cortex supports effort allocation towards a qualitatively preferred option. European Journal of Neuroscience,46(1), 1682-1688.
[49]	Hartmann M. N., Hager O. M., Reimann A. V., Chumbley J. R., Kirschner M., Seifritz E., .. Kaiser S . (2015). Apathy but not diminished expression in schizophrenia is associated with discounting of monetary rewards by physical effort. Schizophrenia Bulletin,41(2), 503-512.
[50]	Hartmann M. N., Hager O. M., Tobler P. N., & Kaiser S . (2013). Parabolic discounting of monetary rewards by physical effort. Behavioural Processes,100 192-196.
[51]	Hayakawa S. . (1987). Choose the right word: A modern guide to synonyms . New York: Harper & Row.
[52]	Heatherton T.., &Wagner D.D . (2011). Cognitive neuroscience of self-regulation failure. Trends in Cognitive Sciences,15(3), 132-139. doi: 10.1016/j.tics.2010.12.005
[53]	Heckhausen H., Schmalt H. D., &Schneider K , (1985) . Achievement motivation in perspective. Orlando: Academic Press.
[54]	Hernandez Lallement J., Kuss K., Trautner P., Weber B., Falk A., & Fliessbach K . (2014). Effort increases sensitivity to reward and loss magnitude in the human brain. Social Cognitive and Affective Neuroscience,9(3), 342-349. doi: 10.1093/scan/nss147
[55]	Hess T.., &Ennis G.E . (2012). Age differences in the effort and costs associated with cognitive activity. Journals of Gerontology Series B: Psychological Sciences and Social Sciences,67(4), 447-455.
[56]	Hill B.., &Aita S.L . (2018). The positive side of effort: A review of the impact of motivation and engagement on neuropsychological performance. Applied Neuropsychology: Adult,25(4), 312-317.
[57]	Hill B. D., Rohling M. L., Boettcher A. C., & Meyers J. E . (2013). Cognitive intra-individual variability has a positive association with traumatic brain injury severity and suboptimal effort. Archives of Clinical Neuropsychology,28(7), 640-648. doi: 10.1093/arclin/act045
[58]	Holsen L.., &Goldstein J.M . (2015). Valuation and cognitive circuitry in anorexia nervosa: Disentangling appetite from the effort to obtain a reward. Biological Psychiatry,77(7), 604-606.
[59]	Hosking J. G., Floresco S. B., & Winstanley C. A . (2014). Dopamine antagonism decreases willingness to expend physical, but not cognitive, effort: A comparison of two rodent cost/benefit decision-making tasks. Neuropsychopharmacology,40(4), 1005-1015.
[60]	Hughes D. M., Yates M. J., Morton E. E., & Smillie L. D . (2015). Asymmetric frontal cortical activity predicts effort expenditure for reward. Social Cognitive and Affective Neuroscience,10(7), 1015-1019.
[61]	Hull C. . (1943). Principles of behavior: An introduction to behavioral theory.Oxford, England:Appleton-Century.
[62]	Husain M. &Roiser J.P . (2018). Neuroscience of apathy and anhedonia: A transdiagnostic approach. Nature Reviews Neuroscience,19(8), 470-484.
[63]	Inzlicht M., Bartholow B. D., & Hirsh J. B . (2015). Emotional foundations of cognitive control. Trends in Cognitive Sciences,19(3), 126-132.
[64]	Inzlicht M. &Schmeichel B.J . (2012). What is ego depletion? Toward a mechanistic revision of the resource model of self-control. Perspectives on Psychological Science,7(5), 450-463. doi: 10.1177/1745691612454134
[65]	Inzlicht M., Schmeichel B. J., & Macrae C. N . (2014). Why self-control seems (but may not be) limited. Trends in Cognitive Sciences,18(3), 127-133. doi: 10.1016/j.tics.2013.12.009
[66]	Inzlicht M., Shenhav A., & Olivola C. Y . (2018). The effort paradox: Effort is both costly and valued. Trends in Cognitive Sciences,22(4), 337-349.
[67]	Johnson A.., &Gallagher M., (2011). Greater effort boosts the affective taste properties of food. Proceedings of the Royal Society B: Biological Sciences,278(1711), 1450-1456.
[68]	Kacelnik A. &Marsh B., (2002). Cost can increase preference in starlings. Animal Behaviour,63(2), 245-250.
[69]	Kahneman D. (1973). Attention and effort (Vol. 1063). Englewood Cliffs, NJ: Prentice-Hall.
[70]	Kaplan S. (2016). Meditation, restoration, and the management of mental fatigue. Environment and Behavior,33(4), 480-506.
[71]	Kaplan S. &Berman M.G . (2010). Directed attention as a common resource for executive functioning and self-regulation. Perspectives on Psychological Science,5(1), 43-57.
[72]	Klein-Flügge M. C., Kennerley S. W., Saraiva A. C., Penny W. D., & Bestmann S . (2015). Behavioral modeling of human choices reveals dissociable effects of physical effort and temporal delay on reward devaluation. PLoS Computational Biology,11(3), e1004116.
[73]	Kool W. &Botvinick M., (2013). The intrinsic cost of cognitive control. Behavioral and Brain Sciences,36(6), 697-698. doi: 10.1017/S0140525X1300109X
[74]	Kool W. &Botvinick M., (2014). A labor/leisure tradeoff in cognitive control. Motivation Science,143(1), 131-141.
[75]	Kurniawan I. T., Guitart-Masip M., Dayan P., & Dolan R. J . (2013). Effort and valuation in the brain: The effects of anticipation and execution. Journal of Neuroscience,33(14), 6160-6169.
[76]	Kurzban R. (2016). The sense of effort. Current Opinion in Psychology,7 67-70.
[77]	Kurzban R., Duckworth A., Kable J. W., & Myers J . (2013). An opportunity cost model of subjective effort and task performance. Behavioral and Brain Sciences,36(6), 661-679. doi: 10.1017/S0140525X12003196
[78]	Ma Q., Meng L., Wang L., & Shen Q . (2014). I endeavor to make it: Effort increases valuation of subsequent monetary reward. Behavioural Brain Research,261 1-7.
[79]	Massar S. A., Libedinsky C., Weiyan C., Huettel S. A., & Chee M. W . (2015). Separate and overlapping brain areas encode subjective value during delay and effort discounting. NeuroImage,120 104-113.
[80]	McGuire J.., &Botvinick M.M . (2010). Prefrontal cortex, cognitive control, and the registration of decision costs. Proceedings of the National Academy of Sciences,107(17), 7922-7926.
[81]	Metcalfe J. &Mischel W., (1999). A hot/cool-system analysis of delay of gratification: Dynamics of willpower. Psychological Review,106(1), 3-19.
[82]	Milyavskaya M., Inzlicht M., Johnson T., & Larson M. J . (2019). Reward sensitivity following boredom and cognitive effort: A high-powered neurophysiological investigation. Neuropsychologia, 123, 159-168.
[83]	Mochon D., Norton M. I., & Ariely D . (2012). Bolstering and restoring feelings of competence via the IKEA effect. International Journal of Research in Marketing,29(4), 363-369. doi: 10.1016/j.ijresmar.2012.05.001
[84]	Muehlbacher S. &Kirchler E., (2009). Origin of endowments in public good games: The impact of effort on contributions. Journal of Neuroscience, Psychology, and Economics, 2( 1), 59-67.
[85]	Muraven M. &Baumeister R.F . (2000). Self-regulation and depletion of limited resources: Does self-control resemble a muscle? Psychological Bulletin,126(2), 247-259.
[86]	Musslick S., Dey B., Ozcimder K., Patwary M. M. A., Willke T., & Cohen J. D . (2016). Parallel processing capability versus efficiency of representation in neural networks. Network,8 7.
[87]	Musslick S., Shenhav A., Botvinick M. M., & Cohen J. D . (2015). A computational model of control allocation based on the Expected Value of Control., Paper presented at the meeting of the 2nd multidisciplinary conference on reinforcement learning and decision making, Edmonton,Canada.
[88]	Nishiyama R. (2014). Response effort discounts the subjective value of rewards. Behavioural Processes,107 175-177.
[89]	Nishiyama R. (2016). Physical, emotional, and cognitive effort discounting in gain and loss situations. Behavioural Processes,125 72-75.
[90]	Norman D.., &Bobrow D.G . (1975). On data-limited and resource-limited processes. Cognitive Psychology,7(1), 44-64.
[91]	Norton M. I., Mochon D., & Ariely D . (2012). The IKEA effect: When labor leads to love. Journal of Consumer Psychology,22(3), 453-460. doi: 10.1016/j.jcps.2011.08.002
[92]	Oberauer K., Farrell S., Jarrold C., & Lewandowsky S . (2016). What limits working memory capacity? Psychological Bulletin,142(7), 758.
[93]	Pattyn N., Neyt X., Henderickx D., & Soetens E . (2008). Psychophysiological investigation of vigilance decrement: Boredom or cognitive fatigue? Physiology & Behavior,93(1-2), 369-378.
[94]	Pompilio L., Kacelnik A., & Behmer S. T . (2006). State-dependent learned valuation drives choice in an invertebrate. Science,311(5767), 1613-1615.
[95]	Prévost C., Pessiglione M., Météreau E., Cléry-Melin M. L., & Dreher J. C . (2010). Separate valuation subsystems for delay and effort decision costs. Journal of Neuroscience,30(42), 14080-14090.
[96]	Rzepa E., Fisk J., & McCabe C . (2017). Blunted neural response to anticipation, effort and consummation of reward and aversion in adolescents with depression symptomatology. Journal of Psychopharmacology,31(3), 303-311.
[97]	Salamone J. D., Correa M., Farrar A., & Mingote S. M . (2007). Effort-related functions of nucleus accumbens dopamine and associated forebrain circuits. Psychopharmacology, 191( 3), 461-482.
[98]	Sandra D.., &Otto A.R . (2018). Cognitive capacity limitations and Need for Cognition differentially predict reward-induced cognitive effort expenditure. Cognition,172 101-106.
[99]	Sarstedt M., Neubert D., & Barth K . (2017). The IKEA effect. A conceptual replication. Journal of Marketing Behavior,2(4), 307-312.
[100]	Schmidta B., Mussel P., Osinsky R., Rasch B., Debener S., & Hewig J . (2017). Work first then play: Prior task difficulty increases motivation-related brain responses in a risk game. Biological Psychology,126 82-88.
[101]	Schouppe N., Demanet J., Boehler C. N., Ridderinkhof K. R., & Notebaert W . (2014). The role of the striatum in effort-based decision-making in the absence of reward. Journal of Neuroscience,34(6), 2148-2154. doi: 10.1523/JNEUROSCI.1214-13.2014
[102]	Shenhav A., Botvinick M. M., & Cohen J. D . (2013). The expected value of control: An integrative theory of anterior cingulate cortex function. Neuron,79(2), 217-240.
[103]	Shenhav A., Musslick S., Lieder F., Kool W., Griffiths T. L., Cohen J. D., & Botvinick M. M . (2017). Toward a rational and mechanistic account of mental effort. Annual Review of Neuroscience,40 99-124.
[104]	Silvestrini N. (2017). Psychological and neural mechanisms associated with effort-related cardiovascular reactivity and cognitive control: An integrative approach. International Journal of Psychophysiology,119 11-18.
[105]	Tan H., Pogosyan A., Anzak A., Ashkan K., Bogdanovic M., Green A. L., .. Brown P . (2013). Complementary roles of different oscillatory activities in the subthalamic nucleus in coding motor effort in Parkinsonism. Experimental Neurology,248 187-195.
[106]	Tangney J. P., Baumeister R. F., & Boone A. L . (2004). High self-control predicts good adjustment, less pathology, better grades, and interpersonal success. Journal of Personality,72(2), 271-324.
[107]	Thaler R. (1981). Some empirical evidence on dynamic inconsistency. Economics Letters,8(3), 201-207.
[108]	Todman M. (2003). Boredom and psychotic disorders: Cognitive and motivational issues. Psychiatry,66(2), 146-167.
[109]	Treadway M. T., Bossaller N. A., Shelton R. C., & Zald D. H . (2012). Effort-based decision-making in major depressive disorder: A translational model of motivational anhedonia. Journal of Abnormal Psychology,121(3), 553-558. doi: 10.1037/a0028813
[110]	Treadway M. T., Buckholtz J. W., Schwartzman A. N., Lambert W. E., & Zald D. H . (2009). Worth the 'EEfRT'? The effort expenditure for rewards task as an objective measure of motivation and anhedonia. PLoS One,4(8), e6598.
[111]	Vadillo M. A., Gold N., & Osman M . (2016). The bitter truth about sugar and willpower: The limited evidential value of the glucose model of ego depletion. Psychological Science,27(9), 1207-1214.
[112]	Vassena E., Holroyd C. B., & Alexander W. H . (2017). Computational models of anterior cingulate cortex: At the crossroads between prediction and effort. Frontiers in Neuroscience,11(316), 316.
[113]	Vassena E., Silvetti M., Boehler C. N., Achten E., Fias W., & Verguts T . (2014). Overlapping neural systems represent cognitive effort and reward anticipation. PLoS One,9(3), e91008.
[114]	Wallis J. D., &Rushworth M. F. S. ,(2014) .Integrating benefits and costs in decision making. In P. W. Glimcher & E. Fehr (Eds.), Neuroeconomics (Second Edition) (pp. 411-433). San Diego: Academic Press.
[115]	Wang J., Huang J., Yang X-H., Lui S. S. Y Cheung E. F. C., &Chan R. C. K ., (2015). Anhedonia in schizophrenia: Deficits in both motivation and hedonic capacity. Schizophrenia Research,168(1-2), 465-474.
[116]	Wang L., Zheng J., & Meng L . (2017). Effort provides its own reward: Endeavors reinforce subjective expectation and evaluation of task performance. Experimental Brain Research,235(4), 1107-1118.
[117]	Wardle M. C., Treadway M. T., Mayo L. M., Zald D. H., & de Wit H . (2011). Amping up effort: Effects of d-amphetamine on human effort-based decision-making. Journal of Neuroscience,31(46), 16597-16602. doi: 10.1523/JNEUROSCI.4387-11.2011
[118]	Westbrook A. &Braver T.S . (2015). Cognitive effort: A neuroeconomic approach. Cognitive,Affective, & Behavioral Neuroscience, 15(2), 395-415.
[119]	Westbrook A., Kester D., & Braver T. S . (2013). What is the subjective cost of cognitive effort? Load, trait, and aging effects revealed by economic preference. PLoS One,8(7), e68210.
[120]	Yang X-H., Huang J., Lan Y., Zhu C-Y., Liu X-Q., Wang Y-F., Liu X-Q., .. Chan R. C. K .(2016). Diminished caudate and superior temporal gyrus responses to effort-based decision making in patients with first-episode major depressive disorder. Progress in Neuro-Psychopharmacology and Biological Psychiatry,64 52-59.
[121]	Zénon A., Solopchuk O., & Pezzulo G . (2019). An information-theoretic perspective on the costs of cognition. Neuropsychologia,123 5-18.
[122]	Zentall T. . (2016). Cognitive dissonance or contrast? Animal Sentience: An Interdisciplinary Journal on Animal Feeling,12(1), 1.
[123]	Zhang Y., Li Q., Wang Z., Liu X., & Zheng Y . (2017). Temporal dynamics of reward anticipation in the human brain. Biological Psychology,128 89-97.