Mind the sheep! User experience evaluation & brain-computer interface games

A brain-computer interface (BCI) infers our actions, intentions and psychological states (e.g. emotion, attention) solely by interpreting our brain signals. It uses the inferences it makes to manipulate a computer. Although BCIs have long been used exclusively to support disabled people (e.g. through brain-controlled wheelchairs, spellers), with the emerging low-cost and portable hardware, they have started to be considered for a variety of human-computer interaction applications for non-disabled people as well. Among these, games have been receiving the interest of researchers and practitioners.\ud In BCI research, games have been used solely to demonstrate the performance of signal processing and analysis methods. Therefore, they have been evaluated only for their performance (e.g. recognition accuracy, information transfer rate). However, games are not meant to satisfy our practical needs. They satisfy our hedonic needs. They challenge us, let us make our fantasies true, evoke our memories, and so on. We look for these experiences while playing games. Thus, rather than the performance of the controller used, the user experience of the game is essential.\ud In my work, I investigated how the BCI control can influence the user experience of a computer game. My work consisted of three studies in each of which I evaluated different user experience related concepts and used different data collection methods. In all the studies, participants played an experimental multimodal game that we had developed, called ‘Mind the Sheep!’. They controlled 3 dogs to herd 10 sheep across a meadow. Their goal was to pen all the sheep as quickly as possible.\ud My work shows that the challenge, cognitive involvement and novelty offered by BCI can improve emotional social interaction, enhance the sense of immersion and satisfy hedonic human needs. Based on the findings of my studies, in my work, I provide guidelines for building enjoyable BCI games

Classifying motor imagery in presence of speech

In the near future, brain-computer interface (BCI) applications for non-disabled users will require multimodal interaction and tolerance to dynamic environment. However, this conflicts with the highly sensitive recording techniques used for BCIs, such as electroencephalography (EEG). Advanced machine learning and signal processing techniques are required to decorrelate desired brain signals from the rest. This paper proposes a signal processing pipeline and two classification methods suitable for multiclass EEG analysis. The methods were tested in an experiment on separating left/right hand imagery in presence/absence of speech. The analyses showed that the presence of speech during motor imagery did not affect the classification accuracy significantly and regardless of the presence of speech, the proposed methods were able to separate left and right hand imagery with an accuracy of 60%. The best overall accuracy achieved for the 5-class separation of all the tasks was 47% and both proposed methods performed equally well. In addition, the analysis of event-related spectral power changes revealed characteristics related to motor imagery and speech

Document ranking by graph based lexical cohesion and term proximity computation

Ankara : The Department of Computer Engineering and the Institute of Engineering and Science of Bilkent University, 2008.Thesis (Master's) -- Bilkent University, 2008.Includes bibliographical references leaves 48-52.During the course of reading, the meaning of each word is processed in the context of the meaning of the preceding words in text. Traditional IR systems usually adopt index terms to index and retrieve documents. Unfortunately, a lot of the semantics in a document or query is lost when the text is replaced with just a set of words (bag-of-words). This makes it mandatory to adapt linguistic theories and incorporate language processing techniques into IR tasks. The occurrences of index terms in a document are motivated. Frequently, in a document, the appearance of one word attracts the appearance of another. This can occur in forms of short-distance relationships (proximity) like common noun phrases as well as long-distance relationships (transitivity) defined as lexical cohesion in text. Much of the work done on determining context is based on estimating either long-distance or short-distance word relationships in a document. This work proposes a graph representation for documents and a new matching function based on this representation. By the use of graphs, it is possible to capture both short- and long-distance relationships in a single entity to calculate an overall context score. Experiments made on three TREC document collections showed significant performance improvements over the benchmark, Okapi BM25, retrieval model. Additionally, linguistic implications about the nature and trend of cohesion between query terms were achieved.Gürkök, HayrettinM.S

Modality switching and performance in a thought and speech controlled computer game

Providing multiple modalities to users is known to improve the overall performance of an interface. Weakness of one modality can be overcome by the strength of another one. Moreover, with respect to their abilities, users can choose between the modalities to use the one that is the best for them. In this paper we explored whether this holds for direct control of a computer game which can be played using a brain-computer interface (BCI) and an automatic speech recogniser (ASR). Participants played the games in unimodal mode (i.e. ASR-only and BCI-only) and multimodal mode where they could switch between the two modalities. The majority of the participants switched modality during the multimodal game but for the most of the time they stayed in ASR control. Therefore multimodality did not provide a significant performance improvement over unimodal control in our particular setup. We also investigated the factors which influence modality switching. We found that performance and peformance-related factors were prominently effective in modality switching

User expectations and experiences of a speech and thought controlled computer game

Brain-computer interfaces (BCIs) are often evaluated in terms of performance and seldom for usability. However in some application domains, such as entertainment computing, user experience evaluation is vital. User experience evaluation in BCI systems, especially in entertainment applications such as games, can be biased due to the novelty of the interface. However, as the novelty will eventually vanish, what matters is the user experience related to the unique features offered by BCI. Therefore it is a viable approach to compare BCI to other novel modalities, such as a speech or motion recogniser, rather than the traditional mouse and keyboard. In the study which we present in this paper, our participants played a computer game with a BCI and an automatic speech recogniser (ASR) and they rated their expectations and experiences for both modalities. Our analysis on subjective ratings revealed that both ASR and BCI were successful in satisfying participants' expectations in general. Participants found speech control easier to learn than BCI control. They indicated that BCI control induced more fatigue than they expected

Meeting the expectations from brain-computer interfaces

Brain-computer interfaces (BCIs) are often evaluated in terms of performance and seldom for usability. However in some application domains, such as entertainment computing, user experience evaluation is vital. User experience evaluation in BCI systems, especially in entertainment applications such as games, can be biased due to the novelty of the interface.However, as the novelty will eventually vanish, whatmatters is the user experience related to the unique features offered by BCI. Therefore it is a viable approach to compare BCI to other novel modalities, such as a speech or motion recognizer, rather than the traditional mouse and keyboard. In the study that we present in this article, our participants played a computer game with a BCI and an automatic speech recognizer (ASR), and they rated their expectations and experiences for both modalities. Our analysis on subjective ratings revealed that both ASR and BCI were successful in satisfying participants' expectations in general. Participants found speech control easier to learn than BCI control. They indicated that BCI control induced more fatigue than they expected

User Experience Evaluation in BCI:Mind the Gap!

Generally brain-computer interface (BCI) systems are evaluated based on the assumption that the user is trying to perform a specific task in the most efficient way. BCI for entertainment yields interesting applications for both patients and healthy users. Then the purpose is to create positive experiences that enrich our lives. To evaluate such systems, the user experience needs to be taken into account to understand how a system can satisfy these needs. This paper points at the gap in user experience evaluation currently in BCI research, and shows how user experience evaluation could benefit BCI, through increased user acceptance, enjoyment, BCI task performance, enhanced human-computer interaction, and improved selection of suitable mental tasks in a given context

Experiencing BCI control in a popular computer game

Brain–computer interfaces (BCIs) are not only being developed to aid disabled individuals with motor substitution, motor recovery, and novel communication possibilities, but also as a modality for healthy users in entertainment and gaming. This study investigates whether the incorporation of a BCI in the popular game World of Warcraft (WoW) has effects on the user experience. A BCI control channel based on parietal alpha band power is used to control the shape and function of the avatar in the game. In the experiment, participants , a mix of experienced and inexperienced WoW players, played with and without the use of BCI in a within-subjects design. Participants themselves could indicate when they wanted to stop playing. Actual and estimated duration was recorded and questionnaires on presence and control were administered. Afterwards, oral interviews were taken. No difference in actual duration was found between conditions. Results indicate that the difference between estimated and actual duration was not related to user experience but was person specific. When using a BCI, control and involvement were rated lower. But BCI control did not significantly decrease fun. During interviews, experienced players stated that they saw potential in the application of BCIs in games with complex interfaces such as WoW. This study suggests that BCI as an additional control can be as much fun and natural to use as keyboard/mouse control, even if the amount of control is limited

Human-Computer Interaction for BCI Games: Usability and User Experience

Brain-computer interfaces (BCI) come with a lot of issues, such as delays, bad recognition, long training times, and cumbersome hardware. Gamers are a large potential target group for this new interaction modality, but why would healthy subjects want to use it? BCI provides a combination of information and features that no other input modality can offer. But for general acceptance of this technology, usability and user experience will need to be taken into account when designing such systems. This paper discusses the consequences of applying knowledge from Human-Computer Interaction (HCI) to the design of BCI for games. The integration of HCI with BCI is illustrated by research examples and showcases, intended to take this promising technology out of the lab. Future research needs to move beyond feasibility tests, to prove that BCI is also applicable in realistic, real-world settings