The Time-course Of Novelty And Appropriateness Processing In Creative Idea Generation And Evaluation

Novelty is the core of creativity,a novel idea which is not appropriate could still be regarded as an ordinary idea.The processing of novelty and appropriateness are required in both creative idea generation and evaluation.As previous studies revealed,there are different neural networks underlying novelty and appropriateness processing,but the time-course of these two characteristics processing remains unknown.Moreover,most of the current creativity researches focused on creative ideageneration.They ignored the evaluation of creative ideas,which is of equal importance and helpful to explore how creative ideas or products are accepted by public.Therefore,this study aims to further separate novelty and appropriateness processing of creative ideageneration and evaluation.To explore the time-course of these twocharacteristics,highly time-accurate electroencephalogram(EEG)technology were adopted.We analyzed the spectrums and event-related potentials which were induced by novelty and appropriateness processing and compared the temporal sequence of these twocharacteristics.Experiment 1 aimed to reveal the time-course of novelty and appropriateness processing in creative idea generation.Participants were askedto independently come up with correct answers to achieve Chinese character chunk decomposition according to the prior presented requirement.There was only one answer to each question.One-quarter of the questions can be solved by novel solutions,one-quarter can be solved by familiar solutions,while the other two quarters have no novel or familiar solutions.Thus,four categories,novel-appropriate,familiar-appropriate,novel-inappropriate,familiar-inappropriate,were filtered from the answers offered by participants.The behavioral results showed that compared with the familiar and appropriate condition,the response time was longer and the correct rate was lower in the novel and inappropriate condition.As the EEG results revealed,novel answers induced a stronger theta-ERS in 200-300 ms since the stimulus than familiar answers in anterior-frontal,frontal,frontal-central,central,central-parietal and parietal areas.The evoked theta-ERS after stimulation reflected the brain's early detection ofconflicts between novel and familiar answers.To explore the more relevant time sequence of novelty and appropriateness processing in creative idea generation,we also analyzed the EEG data in 1250 ms and 250 ms before response.We found that in-850 to-250 ms,compared with familiar and appropriate answers,both the generation of novel and inappropriate answers induced stronger alpha-ERD in anterior-frontal,frontal,frontal-central,central,central-parietal and parietal areas.The current alpha-ERD may be an index of attention adjustment after the conflict was realized.More executive functions which inhibited strongly activated but unhelpful associations and promoted weakly-activated but original associations were invloved.The alpha-ERD between inappropriate and appropriate ideas may reflect the memory retrieval and the continuous updating of working memory to confirm the appropriate degree of current novel idea.Therefore,we conclude that in creative ideageneration,our brains are more sensitive to the conflict evoked by novelty compared to appropriateness,and attention strategies are adopted to ensure the survival of novel ideas.Experiment2 aimed to reveal the time-course of novelty and appropriateness processing in creative idea evaluation.The catalytic paradigm was adopted,subjects were asked to evaluate whether each presented answer was appropriate or not.There werealso four categories of the presented answers: novel-appropriate,familiar-appropriate,novel-inappropriate,familiar-inappropriate.The response time in novel and inappropriate condition was significantly longer than that in familiar and appropriate condition,while the correct rate on novel and inappropriate condition was lower than that in familiar and appropriate condition.As ERP results revealed,compared with familiar answers,the evaluation of novel answers induced a frontal N2 in 220-320 ms and N400 in 420-520 ms since the stimulus was presented.Compared with appropriate answers,the evaluation of inappropriate answers evoked a more positive LPC in 800-2000 ms since the stimulus,in left-frontal and central area.We contend that N2 and N400 may be an index of conflict detection and inhibition which was evoked by novel associations.LPC may reflect higher executive control and processing requirements,more memory retrieval and working memory updating were implemented to evaluate whether the current novel idea was appropriate.This suggests that our brains are still more sensitive to the cognitive conflict induced by novelty in creative idea evaluation.As the results of the spectrums and ERP components revealed,our brains are more sensitive to novelty in both creative idea evaluation and generation.Comparedwith creative idea evaluation,to generate creative ideas,people may pay more executive control to ensure novel associations survival from the constraints of existing knowledge,then the most novel and appropriate idea can be selected from them.