The Cognitive And Neural Mechanism Of Time Perspective Effect On Procrastination

Procrastination is the phenomenon that individuals are to voluntarily delay an intended course of action despite expecting to be worse off for the delay.Procrastination is very widespread in the general population,chronically affecting some 15%–20% of adults.And approximately 75% of college students engage in procrastination,even some of them become trait procrastinators.Procrastination appears to be a troubling phenomenon which being bad,harmful to individual emotion,performance,achievments,and heath or well-being.Therefore,there are amounts of researches hasve been done on definition,impacting factors,causes and correlates of procrastination.Previous research has explored that the Future Time Perspective is negatively correlated with procrastination.Many behavioral studies have demonstrated that procrastinators usually had a low level of Future Time Perspective.However,little is known about the cognitive mechanism and neural substrates underlying the relationship between procrastination and time perspective.Combining the behavioral research and fMRI neuroimaging,the study systemically examed the cognitive processes and neural substrates of the effect of time perspective on procrastination.In the study 1,we used the GPS(General Procrastination Scale),ZIPI(Zimbardo Time Perspective Inventory)and SCS(the Self-control Scale)to measure the procrastination,time perspective and self-control of participants(303 subjects)respectively,we explored the behavioral correlation of procrastination and Future Time perspective(FTP).In line with previous studies,the results showed a significantly negatively correlation between procrastination and Future Time Perspective,a significantly negatively correlation between procrastination and self-control,and a significantly positive correlation between Future Time perspective and self-control.And the stepwise multiple regression analysis and the dominance analysis showed that Future Time Perspective in the prediction of procrastination contribution is the largest.Then,the mediation effect analysis showed that the self-control plays a partial mediation effect in Future Time perspective affecting procrastination.Finally we used voxel-based morphometry(VBM)to explore the neural substrates underlying the processes how FTP affecting procrastination.Brain imaging results showed the FTP score was significantly positively correlated with the gray matter volume(GMV)of the right dorsol prefrontal cortex(R.dlPFC),and significantly negatively correlated with the ventral medial prefrontal cortex(vmPFC)and hippocampal gyrus(PHG).And both FTP and self-control are significantly related to the GMV of the overlapping dLPFC.The mediation effect analysis showed that this overlapping dLPFC plays a partial mediation effect in Future Time perspective affecting procrastination.It suggests that DLPFC might be Neural substrates underlying the effect of FTP on procrastination.In the study 2,behavioral and VBM approaches are used to further examine the possible pathways of FTP affecting procrastination and and the neural basis.First,behavioral data of 207 subjects(ZTPI,GPS and Episodic Futuer Thinking(EFT))conducted correlation analysis and mediation analysis to explore whether the EFT has a mediating effect between FTP and procrastination;The results found that the FTP and procrastination were significantly negatively correlated,confirming the results of Study 1;FTP was significantly positively correlated with the EFT ability,while the EFT and procrastination were significant negative correlation.And the mediation effect of EFT in FTP and procrastination is significant and EFT plays a partial intermediary role.Then VBM and mediation effect analysis were used to analyze the behavior and brain structure data of 144 subjects,to explore the neural bases of FTP affecting procrastination.Brain imaging results verified the resules of study 1 and showed that both FTP and EFT are significantly negatively related to the GMV of the overlapping vmPFC and PHG.Furthermore,the mediating effect of the vmPFC between FTP and procrastination scores was not significant,but the mediation effect of PHG in FTP affecting procrastination is significant and plays a partial intermediary role.These results show that the EFT can negatively predict the procrastination behavior,suggesting the individuals with strong insights in the future have better EFT,and the FTP can also influence the procrastination behavior through the EFT,the neural basis underlying this influence is the PHG.In order to further explore the neural basis of the impact of FTP on procrastination,and to verify the preliminary findings of Study 1 and Study 2,Study 3 used a whole brain functional connection and a large-scale brain network to examine the neural basis of FTP affecting procrastination.Firstly,the behavioral data of 276 subjects and the whole brain resting state function connection data were analyzed to explore the predictability of the functional connection between the brain region and the whole brain related to FTP.The results showed that the functional connection between the hippocampus and the right dorsolateral prefrontal cortex(dlPFC-PHG),hippocampus and upper gyrus(SFG)(PHG-SFG),ventromedial prefrontal cortex and the dorsolateral prefrontal cortex(dlPFC-vmPFC)were all significantly negatively correlated with procrastination.Then behavioral and resting state data of 132 subjects were tested for large-scale brain network analysis and correlation analysis to identify large-scale brain networks associated with FTP and procrastination,to provide direct neurological evidence.The results showed that FTP is significantly negatively correlated with functional connections within the subcortical network(SCN),while procrastination is significantly positively correlated with the functional connections within the SCN.And the mediation effect analysis showed that the mediation effect of functional connectivity within SCN in FTP and procrastination is significant.These results indicate that the stronger the functional connection between the dorsolateral prefrontal cortex and the hippocampal gyrus(dlPFC-PHG)or between the hippocampus and the frontal gyrus(PHG-SFG),the less procrastination behavior;the weaker the functional connection withhe dorsolateral prefrontal cortex and the ventral medial prefrontal cortex(dlPFC-vmPFC),the more prone to procrastination.The stronger the individual's insight in the future,the stronger the self-regulation ability of the target value,behavioral plan and future imagination,and the less delay.In addition,the stronger the functional connections within the subcortical network,the weaker the individual's future time insights,and the more serious individual delays.On the whole,the study found that:(1)there is a stable negative correlation between FTP and procrastination behavior,that is,the stronger FTP individuals have less delay;(2)the impact of FTP on iindividuals procrastination involves two pathways at least: one is the FTP through the self-control to influence the procrastination behavior,the core brain area responsible for self-control-the dorsolateral prefrontal lobe(dlPFC)is the neural basis of FTP affecting procrastination.The other way is that the FTP also affects the procrastination behavior through the EFT.The main brain area of the hippocampus(PHG),which is responsible for the EFT,may be another neural basis for the impact of FTP on procrastination;(3)functional connections between the dorsolateral prefrontal cortex and the hippocampal gyrus(dlPFC-PHG),between the hippocampus and the frontal gyrus(PHG-SFG),and between the dorsolateral prefrontal and the ventral medial prefrontal(dlPFC-vmPFC)negatively predict procrastination behavior,which further confirms that the impact of FTP on individual procrastination behavior mainly involves the brain regions and brain networks responsible with core cognitive abilities such as self-control(dlPFC,SFG),episodic futuer thinking(PHG)and value characterization(vmPFC);(4)spontaneous functional connectivity activities within the subcortical network(SCN)associated with FTP are positive predictive of procrastination,which indicates that the stronger the functional connections within the SCN,that are closely related to impulsiveness,make it easier for individuals to pursue timely satisfaction and abandon long-term goals,which is also a typical manifestation of self-regulation failure.