The Degrees of Freedom of Partial Least Squares Regression

The derivation of statistical properties for Partial Least Squares regression can be a challenging task. The reason is that the construction of latent components from the predictor variables also depends on the response variable. While this typically leads to good performance and interpretable models in practice, it makes the statistical analysis more involved. In this work, we study the intrinsic complexity of Partial Least Squares Regression. Our contribution is an unbiased estimate of its Degrees of Freedom. It is defined as the trace of the first derivative of the fitted values, seen as a function of the response. We establish two equivalent representations that rely on the close connection of Partial Least Squares to matrix decompositions and Krylov subspace techniques. We show that the Degrees of Freedom depend on the collinearity of the predictor variables: The lower the collinearity is, the higher the Degrees of Freedom are. In particular, they are typically higher than the naive approach that defines the Degrees of Freedom as the number of components. Further, we illustrate how the Degrees of Freedom approach can be used for the comparison of different regression methods. In the experimental section, we show that our Degrees of Freedom estimate in combination with information criteria is useful for model selection.Comment: to appear in the Journal of the American Statistical Associatio

The Shorter the Better? Effects of Privacy Policy Length on Online Privacy Decision-Making

Privacy policies provide Internet users with the possibility to inform themselves about websites’ usage of their disclosed personal data. Strikingly, however, most people tend not to read privacy policies because they are long and cumbersome, indicating that people do not wish to expend much (cognitive) effort on reading such policies. The present study aimed to examine whether shorter privacy policies can be beneficial in informing users about a social networking site’s (SNS) privacy practices, and to investigate associations between variables relevant for privacy decision-making using one theory-based integrative model. In an online experiment, participants (N = 305) were asked to create a personal account on an SNS after being given the option to read the privacy policy. Privacy policy length and the SNS’s level of privacy were varied, creating a 2 (policy length) x 2 (level of privacy) between-subjects design. The results revealed that participants who saw short policies spent less time on reading but gained higher knowledge about the SNS’s privacy practices - due to the fact that they spent more reading time per word. Factual privacy policy knowledge was found to be an indicator for participants’ subjective privacy perception. The perception and evaluation of the specific SNS´s privacy level influenced the assessment of privacy costs and benefits. Particularly when benefits were perceived as high, self-disclosure was increased

Age-related differences in the evaluation of a virtual health agent’s appearance and embodiment in a health-related interaction: Experimental lab study

Straßmann C, Krämer NC, Buschmeier H, Kopp S. Age-related differences in the evaluation of a virtual health agent’s appearance and embodiment in a health-related interaction: Experimental lab study. Journal of Medical Internet Research. 2020;22(4): e13726.**Background:** Assistive technologies have become more important owing to the aging population, especially when they foster healthy behaviors. Because of their natural interface, virtual agents are promising assistants for people in need of support. To engage people during an interaction with these technologies, such assistants need to match the users´ needs and preferences, especially with regard to social outcomes. **Objective:** Prior research has already determined the importance of an agent’s appearance in a human-agent interaction. As seniors can particularly benefit from the use of virtual agents to maintain their autonomy, it is important to investigate their special needs. However, there are almost no studies focusing on age-related differences with regard to appearance effects. **Methods:** A 2×4 between-subjects design was used to investigate the age-related differences of appearance effects in a human-agent interaction. In this study, 46 seniors and 84 students interacted in a health scenario with a virtual agent, whose appearance varied (cartoon-stylized humanoid agent, cartoon-stylized machine-like agent, more realistic humanoid agent, and nonembodied agent [voice only]). After the interaction, participants reported on the evaluation of the agent, usage intention, perceived presence of the agent, bonding toward the agent, and overall evaluation of the interaction. **Results:** The findings suggested that seniors evaluated the agent more positively (liked the agent more and evaluated it as more realistic, attractive, and sociable) and showed more bonding toward the agent regardless of the appearance than did students. In addition, interaction effects were found. Seniors reported the highest usage intention for the cartoon-stylized humanoid agent, whereas students reported the lowest usage intention for this agent. The same pattern was found for participant bonding with the agent. Seniors showed more bonding when interacting with the cartoon-stylized humanoid agent or voice only agent, whereas students showed the least bonding when interacting with the cartoon-stylized humanoid agent. **Conclusions:** In health-related interactions, target group–related differences exist with regard to a virtual assistant’s appearance. When elderly individuals are the target group, a humanoid virtual assistant might trigger specific social responses and be evaluated more positively at least in short-term interactions

Great Expectations? Relation of Previous Experiences With Social Robots in Real Life or in the Media and Expectancies Based on Qualitative and Quantitative Assessment

Social robots, which mostly look and behave like humans, are often perceived as somehow alive and treated similar to humans, despite the fact that they are non-living electronic devices. Based on considerations of the uncertainty reduction theory, the question arises what expectancies regarding social robots people have and what sources they use to achieve these expectancies. To receive an in-depth understanding of people’s expectancies regarding social robots and particularly how these expectancies are influenced by people’s experiences with real robots but also with fictional robots from media, thirteen semi-structured interviews and a quantitative online study (n = 433) were conducted. Results indicate that people’s experiences with robots in the media lead to high expectations regarding the skills of robots, which in turn increase people’s general expectancies regarding social robots being part of the society as well as their personal lives. Furthermore, knowledge of negatively perceived fictional robots increases negative expectancies of robots becoming a threat to humans, while technical affinity reduces general robot anxiety

There’s More to Humanity Than Meets the Eye: Differences in Gaze Behavior Toward Women and Gynoid Robots

Based on evolutionary psychological theories, numerous eye-tracking studies have demonstrated how people visually perceive a potential mate in order to efficiently estimate the person’s mate value. Companies are currently working on sexualized robots that provide numerous human-like visual cues which foster the visual resemblance to humans. To gain more elaborated knowledge on how people react to sexualized robots compared with humans, the present study empirically investigated whether heterosexual males transfer deep-rooted evolutionary psychological processes of mate perception to human-like and machine-like sexualized robots. Moreover, we aimed to learn more about the processes of orienting responses toward human and non-human stimuli and about potential predictors of visual attention to robots. Therefore, we conducted an eye-tracking study in which 15 heterosexual men, 12 homosexual men, and 18 heterosexual women were confronted with stimuli showing women, human-like gynoid robots and machine-like gynoid robots. For the sample as a whole, there was no difference in the amount of time spent looking at the human and non-human breasts. However, the results for the heterosexual males supported the assumption that human breasts attract more visual attention than do the breast areas of human-like and machine-like robots. The pelvic region yielded an unexpected gaze pattern, as all participants spent more time looking at the robotic pelvic area than at the human one, with more visual attention paid to the machine-like robots than to the human-like robots. The results of the viewing times toward the head revealed that all participants had a stronger need to gain visual information about the human head in comparison to the robotic heads, underlining the importance of authenticity in terms of emotions and motivations that can only be decoded in humans. Moreover, the study showed that individuals more frequently switched their visual attention toward different body parts of the robots in comparison to the female stimuli, implying that non-human sexualized representations evoked a higher need for visual exploration

Als Chef hat man nichts zu lachen – Eine Studie zur Wirkung von durch Führungspersonen genutzten Emoticons in berufsbezogenen Emails

1 Theoretische Vorüberlegungen Im face-to-face (ftf) Kontext spielt das nonverbale Verhalten eine entscheidende Rolle bei der Wahrnehmung von Personen und der Interpretation des Gesagten [1,2]. Der Gesichtsausdruck [3], im Besonderen das Lächeln,nimmt in der interpersonalen Kommunikation eine essentielle Bedeutungein. So werden lächelnde Menschen in der Regel positiver, z.B.als glücklicher, höflicher und unbekümmerter, kompetenter und aufrichtiger beurteilt [4], allerdings auch als unterwürfiger [5,6]. Hinsichtlich der Bewertung von Männern und Frauen gibt es zudem stereotypbasierte Erwartungen an das Lächeln, die zu unterschiedlichen Bewertungen von Männern und Frauen bei gleichem Verhalten führen und in der Regel eine negative Bewertung von nicht lächelnden Frauen hervorrufen[7]. In der computervermittelten Kommunikation haben sich Smilies (Grafiken: J) und Emoticons (Zeichenketten wie :-)) mittlerweile als nonverbale, digitale Substitute für das Lächelnverbreitet, so dass auch im Netz sozusagen gelächelt werden kann. Verschiedene Studien untersuchten bisher die Wirkung von Smilies und Emoticons auf die Interpretation von Nachrichten und die Wahrnehmung des Smilienutzers. So kann zum Beispiel die Verwendung eines solchen Cues Zweideutigkeit reduzieren oder erzeugen, die Bedeutung einer Nachricht verstärken [8,9] oder aber die Stimmung des Lesers [10] und dessen Wahrnehmung vom Schreiber einer Nachricht [11] beeinflussen

A New Design Paradigm for Secure Full-Duplex Multiuser Systems

We consider a full-duplex (FD) multiuser system where an FD base station (BS) is designed to simultaneously serve both downlink (DL) and uplink (UL) users in the presence of half-duplex eavesdroppers (Eves). The problem is to maximize the minimum (max-min) secrecy rate (SR) among all legitimate users, where the information signals at the FD-BS are accompanied with artificial noise to debilitate the Eves' channels. To enhance the max-min SR, a major part of the power budget should be allocated to serve the users with poor channel qualities, such as those far from the FD-BS, undermining the SR for other users, and thus compromising the SR per-user. In addition, the main obstacle in designing an FD system is due to the self-interference (SI) and co-channel interference (CCI) among users. We therefore propose an alternative solution, where the FD-BS uses a fraction of the time block to serve near DL users and far UL users, and the remaining fractional time to serve other users. The proposed scheme mitigates the harmful effects of SI, CCI and multiuser interference, and provides system robustness. The SR optimization problem has a highly nonconcave and nonsmooth objective, subject to nonconvex constraints. For the case of perfect channel state information (CSI), we develop a low-complexity path-following algorithm, which involves only a simple convex program of moderate dimension at each iteration. We show that our path-following algorithm guarantees convergence at least to a local optimum. Then, we extend the path-following algorithm to the cases of partially known Eves' CSI, where only statistics of CSI for the Eves are known, and worst-case scenario in which Eves can employ a more advanced linear decoder. The merit of our proposed approach is further demonstrated by extensive numerical results.Comment: Accepted for publication in IEEE Journal on Selected Areas in Communications (JSAC), 201

Empathische Reaktionen gegenüber einem Roboter

Es ist bereits bekannt, dass Menschen soziale Reaktionen auf Computer und artifizielle Wesen wie virtuelle Agenten zeigen. Auch für die Mensch-Roboter-Interaktion konnten erste Studien zeigen, dass Menschen Verhalten zeigen, das man lediglich in der Mensch-Mensch-Kommunikation erwarten würde. Ob auch empathische Reaktionen gegenüber Robotern gezeigt werden, wurde bislang nicht untersucht. In einem 2x2 laborexperimentellen Design betrachteten die Probanden (N=40) zwei Filme, in denen ein Spielzeugroboter in Dinosaurierform entweder gequält oder gestreichelt wird (Treatmentfaktor 1, within subjects). Der einen Hälfte der Probanden wurde der Roboter vorab vorgestellt und 10 Minuten zum Kennenlernen überlassen, während der anderen Hälfte der Probanden der Roboter vollkommen fremd war (Treatment Faktor 2, between subjects). Nach jedem Video wurde das emotionale Befinden mit Hilfe der PANAS erhoben und die Probanden füllten am Ende einen Fragebogen zur Bewertung des Roboters aus. Nach der Rezeption des Videos, in dem der Roboter gequält wird, fühlten die Probanden sich signifikant schlechter (F(1/39)=26,946; p=.000). Die Bedingungsvariation der vorherigen Interaktion zeigte jedoch keinen Einfluss auf das emotionale Befinden nach der Rezeption des Videos oder die empfundene Empathie. Somit konnte gezeigt werden, dass eine negative Behandlung eines Roboters das eigene Empfinden beeinflusst, dass eine kurzzeitige Interaktion mit dem Roboter das Mitleiden aber nicht verstärkt

Der Aufbau sozialer Beziehungen mit einem Roboter. Eine Beobachtungsstudie im Feld

Roboter nehmen in letzter Zeit vermehrt Einzug in verschiedene Lebensbereiche. Es werden nicht nur Haushaltsroboter, die staubsaugen, oder Roboter, die vorrangig Entertainment-Zwecken dienen, angeboten, sondern in einigen Altenheimen werden Roboter bereits eingesetzt, um Senioren Gesellschaft zu leisten. Vor diesem Hintergrund untersucht die Studie als Teil des EU Forschungsprojektes SERA (Social Engagement with Robots and Agents), ob und inwiefern soziale Beziehungen zu Robotern aufgebaut werden. In einer Beobachtungsstudie und einem anschließenden qualitativen Interview wurden drei weibliche Teilnehmer (zwischen 50 und 65 Jahren) über eine Woche in der Interaktion mit einem Nabaztag beobachtet. Dieser Roboter in Hasenform wurde für die Studie so programmiert, dass er mit den Untersuchungsteilnehmerinnen Dialoge rund um das Thema Gesundheit und Fitness führen konnte. Der Roboter nutzte Sprachoutput, der Input von Seiten der Teilnehmerinnen wurde über Ja/Nein Knöpfe vorgenommen. Mit einer Webcam wurden 66 Interaktionen aufgezeichnet. Die kategorienbasierte Auswertung der Transkripte zeigte z.B., dass der Nabaztag häufig natürlich-sprachlich adressiert wurde und ihm beispielsweise alltägliches Verhalten erklärt wurde, obwohl die Probandinnen wussten, dass der Roboter sie nicht verstehen kann, da eine Interaktion nur über die Knöpfe möglich war. Die Ergebnisse zeigen, dass durchaus Beziehungen aufgebaut werden und lassen Schlüsse über die soziale Natur des Menschen zu

Sexual interaction in digital contexts and its implications for sexual health: a conceptual analysis

Based on its prevalence, there is an urgent need to better understand the mechanisms, opportunities and risks of sexual interaction in digital contexts (SIDC) that are related with sexual arousal. While there is a growing body of literature on SIDC, there is also a lack of conceptual clarity and classification. Therefore, based on a conceptual analysis, we propose to distinguish between sexual interaction (1) through , (2) via , and (3) with digital technologies. (1) Sexual interactions through digital technologies are face-to-face sexual interactions that (a) have been started digitally (e.g., people initiating face-to-face sexual encounters through adult dating apps) or (b) are accompanied by digital technology (e.g., couples augmenting their face-to-face sexual encounters through filming themselves during the act and publishing the amateur pornography online). (2) Sexual interactions via digital technology are technology-mediated interpersonal sexual interactions (e.g., via text chat: cybersex; via smartphone: sexting; via webcam: webcam sex/camming). (3) Sexual interactions with digital technology occur when the technology itself has the role of an interaction partner (e.g., sexual interaction with a sex robot or with a media persona in pornography). The three types of SIDC and their respective subtypes are explained and backed up with empirical studies that are grouped according to two major mediators: consent and commerce. Regarding the causes and consequences of the three types of SIDC we suggest a classification that entails biological, psychological, social, economic, and technological factors. Regarding implications of SIDC we suggest to focus on both opportunities and risks for sexual health. The proposed conceptual framework of SIDC is meant to inform future research