Multi-mode Measurement Methods For User Experience

New product development is a critical factor in market competition,and the success of new product development depends on the capacity to satisfy users.In the experience era,pragmatic aspects of product are not the only thing that users care about.Whether the product can bring them good feelings and emotional experience becomes an important factor in purchase decision.How to design a product with higher UX(user experience)is a pending problem in industry as well as a frontier issue in human factor/ergonomics filed and so on.There are many issues in UX research,but the multiple definitions and measurement of user experience are two thorny issues should be solved in tandem.As Law(2014)pointed out that measurement and definition of UX are two foundational issues currently.Accurate measurement is the basis of design and evaluation of UX.However,with the characteristics of vague,subjective,dynamic and environment depended,measuring user experience is difficult.Especially subjective evaluation methods are mostly used for measuring UX of tangible products.Based on the definition of UX,UX is divided into emotional experience and interactive experience.And the cognition process and content of each phase are analyzed.According to these,taking the smartphone as example,subjective evaluation,eye-tracking,ERPs/EEG are used to explore the measurement of emotional experience,interactive experience and intention for future experience.And the difference of visual processing and brain cognition are analyzed to give a measurement method of UX.The content contains following aspects:(1)Stage division,cognition of UX and construction of framework for measurement.UX is divided into emotional experience,interactive experience.Based on the perception of user experience,intention for future experience is analyzed.Corresponding cognition models of different stage are promoted based on the process and characters of each stage.Then the contents of user experience in each phase are analyzed.At last,the framework of UX measurement is given.All of these provide foundation for the following research.(2)Mearsuremnt of emotional experience based on eye-tracking technique.In the process of emotional experience,vision is the first channel to obtain information,and directly impact user's future behaviour and intention to experience with the product.Hence,eye movements in emotional experience are explored to discover the inner evaluation of emotional experience.First,smartphones were screened out for subjective evaluation.Second,considering the mechanism of visual attention,two tasks are designed in the experiment of eye movement to find out the indexes which can be used to measure emotional experience.In the browsing task,participants had shorter time to first fixation for the smart phone picture with higher level of emotional experience than the lower.And pupil dilated significantly when participants browse smart phone picture with lower level of emotional experience.In evaluation task,participants' attentions were dominated by visual perception of task driven,mainly reflected on longer fixation time and larger pupil diameter when looking at the smart phone with higher level of emotional experience.(3)Measurement of emotional experience based on ERPs.Correspondingly,two experiments(low attention and evaluation tasks)are designed to explore the mechanism of brain responses when users evaluate emotional experience of products.In the experiment,participants are asked to respond as quickly as possible with the fingers on the left mouse button only to the randomly occurring target stimuli(landscapes with 25%probability)among a series of nontarget stimuli(smartphone pictures randomly presented with 75%probability).The smartphone pictures with lower scores of emotional experience can elicit more negative N100/N200 than the higher in the frontal sites.In experiment two,participants were asked to click the left mouse button when they evaluate the one product form as higher emotional experience,else the right button for lower.The results showed that smartphones with higher emotional experience can evoke enhanced N2,P2 and P3.(4)Measurement of interactive experience based on EEG.In this process,data from questionnaire,behavioral performance and EEG are combined to measure interactive experience.For the measurement of interactive experience,electroencephalography(EEG)is applied to investigate the brain responses when users interact with smartphones.And the brain signals obtained are processed by using EEGlab,matlab and Curry 7.0.Five rhythm waves(i.e.alpha,beta,delta,gamma and theta)are analyzed with the feature extraction.Power spectrum is applied to quantify each rhythm wave,and the relation between powers of rhythm waves with subjective evaluation of interactive experience and behavioural performance are investigated.Subjective data was obtained by using questionnaire after the experiment.The results show that gamma at occipital,beta at the bilateral sites of central,and theta at frontal and parietal sites have significant correlation with subjective scores of interactive experience,which can used as indexes to measure interactive experience.(5)Intention for future experience based on ERPs.At last,ERPs is used to explore the intention for future experience on smartphones(stimuli chosen from the experiment of emotional experience and interactive experience).In the experiment,participants are asked to click the left mouse button when certain picture gives them a feeling of behavioural intention to experience,else nothing to do.The results show that pictures with an ability to arouse participants' behavioural intention for further experience can evoke smaller N2 and P3 in fronto-central sites,and enhanced N300 and LPPs(late positive potentials)in central-parietal,parietal and occipital regions.This study promotes a phase division for user experience measurement,and pertinent method for each stage of user experience is provided based the features of user experience.The methods promoted in this paper can not only provide new ideas for the study of user experience,but methods for enterprises to measure and evaluate user experience to improve their product and ability of product development.