Clifford Nass

Stanford University | SU · Department of Communication

Advertisers on Social Network Sites often use recommendations by others in a user's networks to endorse products. While these familiar others are hypothesized to be more effective in influencing users than unfamiliar others, there is a catch: familiarity does not necessarily ensure similarity to the familiar person, a potential problem because the...

Behavior monitoring is an important part of many recommender systems; however, its effects on users' perceptions of such systems are not well understood. We describe a 2x2 factorial experiment that manipulates a simulated recommender system's monitoring of user behavior (monitoring: present vs. absent) and whom the system is perceived to benefit (b...

As the popularity of online shopping grows, concerns about identity theft and fraud are increasing. While stronger customer authentication procedures may provide greater protection and thus benefit customers and retailers, security is often traded off against convenience. To provide insight into this security-convenience trade-off in customer authe...

We describe a social visualization system that monitors the vocal arousal levels of the participants in a simulated two-party employment negotiation. In a 3x2 factorial experiment (N = 84), we manipulate two variables of interest for social visualization systems: the feedback configuration of the system's display (participants receive self feedback...

Promoting dependents' perceptions of point-of-injury care robots as social actors may elicit feelings of companionship and diminish stress. However, numerous rescuers may control these robots and communicate with dependents through the robot, creating communication and interaction challenges that may be best addressed by creating a pure medium robo...

Driving is a challenging task because of the physical, attentional, and emotional demands. When drivers become frustrated by events their negative emotional state can escalate dangerously. This study examines behavioral and attitudinal effects of cognitively reframing frustrating events. Participants (N = 36) were asked to navigate a challenging dr...

We describe two experiments on whether individual thoughtful effort during online commenting is shaped by situational norms derived from the behavior of social others and the design of the environment, respectively. By measuring the length of participants' comments on a news website, the time taken to write them, and the number of issue-relevant th...

A system for tracking driver facial features aims to enhance the predictive accuracy of driver-assistance systems. The authors identify key facial features at varying pre-accident intervals and use them to predict minor and major accidents.

This paper describes an open source speech translator toolkit created as part of the "Survivor Buddy" project which allows written or spoken word from multiple independent controllers to be translated into either a single synthetic voice, synthetic voices for each controller, or unchanged natural voice of each controller. The human controllers can...

Increasingly, our emotional connections, artistic experiences and playful escapes are migrating to the virtual world. Virtual environments and online communities are growing and becoming more commonplace in society; for many, they are already a primary means of social interaction. This experiment is a preliminary investigation into the underlying e...

In this experiment we intend to discover characteristics of stories that make them effective and utilize the findings to teach engineers and designers effective storytelling to create inventive action. One central research question organized the study: How do ineffective stories predict disengagement? A paper and pencil test and a projective cue me...

One critical question suggested by Web 2.0 is as follows: When is it better to leverage the knowledge of other users vs. rely on the product characteristic-based metrics for online product recommenders? Three recent and notable changes of recommender systems have been as follows: (1) a shift from characteristic-based recommendation algorithms to so...

Likert-type scales are used extensively during usability evaluations, and more generally evaluations of interactive experiences, to obtain quantified data regarding attitudes, behaviors, and judgments of participants. Very often this data is analyzed using parametric statistics like the Student t-test or ANOVAs. These methods are chosen to ensure h...

We investigate how initial mental models of a photo sharing website are shaped by observing the behavior of existing users. We manipulate experimentally whether content with critical or popular appeal is highlighted as the best content on the website. Despite interacting with uniform site content and interface design, user's mental models are signi...

As their abilities improve, robots will be placed in roles of greater responsibility and specialization. In these contexts, robots may attribute blame to humans in order to identify problems and help humans make sense of complex information. In a between-participants experiment with a single factor (blame target) and three levels (human blame vs. t...

This paper describes the Survivor Buddy human-robot interaction project and how it was used by four middle-school girls to illustrate the scientific process for an episode of "SciGirls", a Public Broadcast System science reality show. Survivor Buddy is a four degree of freedom robot head, with the face being a MIMO 740 multi-media touch screen moni...

Communication mediating technologies are throwing our voices away from our bodies in situations ranging from voice conference meetings to mass presentations. Physical height is known to influence dominance in interactions between people (1, 8, 13, 16). This study explores how audio projection technologies also influence dominance behaviors between...

This paper describes the Survivor Buddy human-robot interaction project and how it was used by four middle-school girls to illustrate the scientific process for an episode of "SciGirls", a Public Broadcast System science reality show. Survivor Buddy is a four degree of freedom robot head, with the face being a MIMO 740 multi-media touch screen moni...

As their abilities improve, robots will be placed in roles of greater responsibility and specialization. In these contexts, robots may attribute blame to humans in order to identify problems and help humans make sense of complex information. In a between-participants experiment with a single factor (blame target) and three levels (human blame vs. t...

Designers of embodied agents constantly strive to create agents that appear more human-like, with the belief that increasing the human-likeness of agents will improve users’ interactions with agents. While designers have focused on visual realism, less attention has been paid to the effects of agents’ behavioral realism on users’ responses. This pa...

Chronic media multitasking is quickly becoming ubiquitous, although processing multiple incoming streams of information is considered a challenge for human cognition. A series of experiments addressed whether there are systematic differences in information processing styles between chronically heavy and light media multitaskers. A trait media multi...

Increasingly, people interact with others via digital representations, or avatars, that feature indicators of race. Nonetheless, little is known about the effects of avatar race on attitudes and behaviors. We conducted a study to determine how people's implicit racial bias is affected by the race of their avatar in an immersive virtual environment...

This article presents the results of two experimental laboratory studies that establish relationships between displays and people's attitudes, beliefs, and behaviors toward self, others, and social situations. Experiment I investigates how participants (N = 40) engaging in a trivia game respond when their answers and performance feedback evaluation...

Access to information technology in developing countries is often indirect, involving human intermediaries. A computer kiosk is a typical instance of three-way interaction between user, kiosk operator, and kiosk technology. We describe a pilot experimental study that investigates whether manipulating the social prominence of the intermediary versus...

As computational agents become more sophisticated, it will frequently be necessary for the agents to disagree with users. In these cases, it might be useful for the agent to use politeness strategies that defuse the person's frustrations and preserve the human-computer relationship. One such strategy is distancing, which we implemented by spatially...

Though legislation is increasingly discouraging drivers from holding on to their mobile phones while talking, hands-free devices do not improve driver safety. We offer two design alternatives to improve driver safety in the contexts of voice-based user interfaces and mobile phone conversations in cars' side tones (auditory feedback used in landline...

As robots become more pervasive, operators will develop richer relationships with them. In a 2 (robot form: humanoid vs. car) x 2 (assembler: self vs. other) between-participants experiment (N=56), participants assembled either a humanoid or car robot. Participants then used, in the context of a game, either the robot they built or a different robo...

This chapter will discuss the Connector service. The goal was to build a mobile communication system that could help people better manage the risk of untimely interruptions in an always-on world, where we can reach each other anytime and anyplace. In an iterative process of design, we have developed technologies that intelligently and nondisruptive...

This study investigated the possibility of using interactive media to help drowsy drivers wake up, thereby enabling them to drive more safely. Many studies have investigated the negative impacts of driver drowsiness and distraction in cars, separately. However, none has studied the potentially positive effects of slightly interactive media for rous...

Driving requires focused attention and timely decision making for appropriate maneuvers. This relies on well-timed and accurate information. Designing an in-vehicle information system it is important to ensure that the information for the driver does not negatively affect cognitive processing and driving performance. This study investigates levels...

We present a study of people's attitudes toward robot workers, identifying the characteristics of occupations for which people believe robots are qualified and desired. We deployed a web-based public-opinion survey that asked respondents (n=250) about their attitudes regarding robots' suitability for a variety of jobs (n=812) from the U.S. Departme...

Cars have changed from pure transportation devices to fully interactive, voice-based systems. While voice interaction in the car has previously required on-board processing, the growing speed and ubiquity of wireless technologies now enable interaction with a distant source. Will the perceived source of the information influence driver safety, resp...

Advances in mobile communication technologies have allowed people in more places to reach each other more conveniently than ever before. However, many mobile phone communications occur in inappropriate contexts, disturbing others in close proximity, invading personal and corporate privacy, and more broadly breaking social norms. This paper presents...

The team has become a popular model to organize joint human-robot behavior. Robot teammates are designed with high-levels of autonomy and well-developed coordination skills to aid humans in unpredictable environments. In this paper, we challenge the assumption that robots will succeed as teammates alongside humans. Drawing from the literature on hu...

This paper brings together two important aspects of the human-machine interaction in cars: the psychological aspect and the engineering aspect. The psychologically motivated part of this study addresses questions such as why it is important to automatically assess the driver’s affective state, which states are important and how a machine’s response...

In a balanced between-participants experiment (N = 96) American and Swedish participants listened to tourist information on a website about an American or Swedish city presented in English with either an American or Swedish accent and evaluated the speakers' knowledge of the topic, the voice characteristics, and the information characteristics. Use...

With the increasing number of cars on the road, longer commutes, and the proliferation of complex information and entertainment features, there is a greater need for careful interaction design in the car. The automobile is a challenging environment for designing and deploying good user interfaces. Interaction designers must balance brand identity,...

In this paper, we present a study concerning psychological ownership for digital entities in the context of collaborative working environments. In the first part of the paper we present a conceptual framework of ownership: various issues such as definition, effects, target factors and behavioral manifestation are explicated. We then focus on owners...

In this thriving world of mobile communications, the difficulty of communication is no longer contacting someone (the receiver), but rather con- tacting them in a socially appropriate manner. Ideally, senders should have some understanding of a receiver's availability in order to make contact at the right time, in the right contexts, and with the o...

This paper explores the relationship between display of feedback (public vs. private) by a computer system and the basis for evaluation (present vs. absent) of that feedback. We employ a social interpersonal context (speed-dating) in a controlled laboratory setting. Participants (in male-female pairs) receive real-time performance feedback, either...

People display adaptive language behaviors in face-to-face conversations, but will computer users do the same during HCI? We report an experiment (N=20) demonstrating that users' use of language (in terms of lexical choice) is influenced by their beliefs and expectations about a system: When users believe that the system is unsophisticated and rest...

There is a long tradition in psychology asking the question, "how does a body affect how people think and respond?" There is a much smaller literature addressing the question, "how does having a body affect how people think about us and respond to us?" In this talk, I will discuss a series of experimental studies that are guided by the idea that an...

A 2x2 mixed design experiment (N=52) was conducted to examine the effects of search interface and task complexity on participants’ information-seeking performance and affective experience. Keyword vs. natural language search was the within-participants factor; simple vs. complex tasks was the between-participants factor. There were cross-over inter...

This study examines the effect of colearner agent performance and social behavior on learner performance and subjective satisfaction in an interactive learning environment. In this 2 (high- or low-performing colearner) by 2 (socially supportive or competitive colearner) experiment (N=44), participants learned Morse Code alongside an agent colearner...

Older adult drivers have more difficulty than the general driving public in attending to driving tasks especially in complex traffic situations. This study examines whether a speech based in-car information system can positively influence driver attitudes, driving performance and safety. Eighteen participants between the ages of 55 and 73 used a dr...

When devices become less visible and recede to the background, what kinds of influences would they have on users'? This paper presents two experiments (N=48 and N=96) that examine the effects of four different types of microphones (and voice vs. text output) on user's behaviors and attitudes. The microphones differ with respect to their visibility...

This study examines whether characteristics of a car voice can affect driver performance and affect. In a 2 (driver emotion: happy or upset) x 2 (car voice emotion: energetic vs. subdued) experimental study, participants (N=40) had emotion induced through watching one of two sets of 5-minute video clips. Participants then spent 20 minutes in a driv...

We demonstrate, via 2 experiments (N = 72 and N = 80) done in e-commerce contexts, that social responses to technology influence feelings of social presence. Users feel stronger social presence when they hear a computer-synthesized voice that manifests a personality that (a) is similar to the user (especially to the extrovert user) as compared to d...

It is a desirable goal to balance information given to the user with the potential adverse effects on cognitive processing and perception of information systems. In this experiment, we investigated the minimum level of information accuracy necessary in an in-car information system to elicit positive behavioral and attitudinal responses from the dri...

This article investigates whether source credibility theory can support reputation mechanisms in business-to-business (B2B) electronic commerce. In contrast to consumer electronic marketplaces, the raters in B2B communities are skilled and connected, necessitating a reputation mechanism to account for the relationship between the user and the rater...

Even though social intelligence has not been clearly defined yet, consideration of this new type of intelligence should be important for realizing a new generation of human-machine collaborative systems based on human-centered system design policy. In this article, social intelligence and mind model for implementing socially intelligent agents are...

Key concerns of automobile interface designers are driving performance and safety. As cars include voices for telematics, command and control, warning messages, etc., these voices become an opportunity to affect drivers and their performance. In this experimental study, participants (N=36) spent 20 minutes in a driving simulator. The car presented...

As much as people crave more human like computers, experimental evidence shows that people do display polite behavior towards computers, preceiving human qualities they don't actually have. The difficulty of explaining why people are polite to dogs opened up an opportunity for a fundamental insight into human computer interaction. If people are pol...

Traditionally, an optimal embodied conversational agent (ECA) has the same capabilities and appearance as an actual person. This chapter proposes a ‘user as assessor’ approach to evaluating ECAs that focuses on how ECAs manifest human capabilities independent of actual capabilities that an ECA may possess. Literatures on humans as producers of beha...

As robot technology is evolving and creating a social community between humans and robots, it is necessary to research and develop a new type of intelligence, which we refer to as "social intelligence''. Social intelligence enables natural and socially appropriate interactions. Its importance is gaining a growing interest among not just the human-c...

As machine evolution continues, human-machine collaboration systems are increasing their importance. In this paper, a social and intelligent agent is discussed as a strategy for improving the effectiveness and efficiency of human-machine collaboration. The proposed approach uses an embedded mind model, which enables agents to interact with the huma...

Disclosure of personal information is valuable to individuals, governments, and corporations. This experiment explores the role interface design plays in maximizing disclosure. Participants (N = 100) were asked to disclose personal information to a telephone-based speech user interface (SUI) in a 3 (recorded speech vs. synthesized speech vs. text-b...

In consumer electronic markets, rating mechanisms are important facilitators of trust between market participants. This paper investigates whether source credibility theory can support the evaluation of bidders in architecture/engineering/construction (AEC) electronic market places. In contrast to consumer electronic marketplaces, the raters in AEC...

This panel brings together usability and voting experts to discuss voting user experience in American governmental elections. Technological improvements and voting debacles have made this a special time for improving voting user experience. Can technologists improve the confidence citizens have in the voting system? What are the roles of teaching m...

People tend to mirror the syntax used by their interlocutors in dialogue. Given that people treat computers as "social actors" in many ways, we might expect them to mirror computers' syntax as well. We report an experiment in which naïve participants played a dialogue game in which they believed that they were interacting with either a person or a...

Speech has recently made headway towards becoming a more mainstream interface modality. For example, there is an increasing number of call center applications, especially in the airline and banking industries. However, speech still has many properties that cause its use to be problematic, such as its inappropriateness in both very quiet and very no...

This study examines the effects of interface adaptation on user performance in HCI and CMC. No studies to date have explored the psychological effects of a combination of software performance monitoring and adaptation. This combination is the focus of the present study. Two competing possible effects of adaptive interfaces are presented: 1) Social...

this article will attempt a fresh conceptualization of source. It will first explicate the concept of source as used in past communication research. It will identify key conceptions of source in the literature and use them to create a typology. The strength of the resulting typology will be evaluated along three criteria: (a) It should apply to all...

This study examines the effects of interface adaptation on user performance in HCI and CMC. No studies to date have explored the psychological effects of a combination of software performance monitoring and adaptation. This combination is the focus of the present study. Two competing possible effects of adaptive interfaces are presented: 1) Social...

Designing interactive computer systems to be efficient and easy to use is important so that people in our society may realize the potential benefits of computer-based tools .... Although modern cognitive psychology contains a wealth of knowledge of human ...

Speech has recently made headway towards becoming a more mainstream interface modality. For example, there is an increasing number of call center applications, especially in the airline and banking industries. However, speech still has many properties that cause its use to be problematic, such as its inappropriateness in both very quiet and very no...

Would people exhibit similarity-attraction and consistency-attraction toward unambiguously computer-generated speech even when personality is clearly not relevant? In Experiment 1, participants (extrovert or introvert) heard a synthesized voice (extrovert or introvert) on a book-buying Web site. Participants accurately recognized personality cues i...

This study examines the effects of interacting with voice interfaces in an ingroup or an outgroup accent, for both native and non-native but competent English speakers. In a balanced, between-subjects experiment, (N = 96), ingroup and outgroup participants were randomly paired with one of two types of computer speech outputs: 1) computer speech out...

This study attempts a new conceptualization of communication ‘sources’ by proposing a typology of sources that would apply not only to traditional media but also to new online media. Ontological rationale for the distinctions in the typology is supplemented by psychological evidence via an experiment that investigated the effects of different types...

This study examines whether emotion conveyed in recorded and synthesized voices affects perceptions of emotional valence of content, perceptions of suitability of content, liking of content, and credibility of content as well as whether recorded or synthesized speech influences perceptions differently. Participants heard two news stories, two movie...

How do people respond to voice user interfaces (VUIs) that use first-person pronouns as opposed to those that use thepassive voice? We addressed this question in the context of a phone-based auction via a 2 (first person vs. passive voice) X 2 (recorded vs. synthesized speech) between-participants experiment (N=48). There were significant cross-ove...

When individuals apply social rules and social expectations while working on a computer, are they directly interacting with the computer as an independent social actor or source (the CAS model), or are they orienting to an unseen programmer or imagined person in another room (the CAM model)? Two studies provide critical tests of these competing mod...

This study examined whether people would interpret and respond to verbal