Beyond Likeability: Investigating Social Interactions with Artificial Agents and Objective Metrics

Loth S. Beyond Likeability: Investigating Social Interactions with Artificial Agents and Objective Metrics. Frontiers in Psychology. 2017;8: 1662

Congruency and typicality effects in lexical decision

This thesis describes basic research into visual word recognition and decision making. Determining the best matching lexical representation for a given stimulus involves interactions between representations. The standard task for studying these processes is the lexical decision task (LDT), but there is still debate regarding the factors that affect how individuals make lexical decisions. The nature of lexical interactions and the processes underlying lexical decision-making were addressed here by testing response congruency effects in the masked priming variant of the LDT. The results of seven masked priming experiments showed a robust response congruency effect that depends on the difficulty of the word-nonword discrimination. This finding resolved apparent inconsistencies in previous research. The experiments were simulated using the Bayesian Reader and the Spatial Coding Model (SCM). The probability based Bayesian Reader model failed to accommodate the findings. However, a good fit to the data was provided by a modified version of the SCM in which the assumptions regarding the nature of lexical interactions were changed such that word nodes inhibit only (closely) related competitors. The model also assumes that the difficulty of the word-nonword discrimination affects the degree to which stimulus typicality informs lexical decisions. A critical issue for these experiments involved the definition of orthographic typicality. An algorithm for measuring orthographic typicality and for generating nonwords with a specific level of orthographic typicality (OT3) was developed. An unprimed LDT experiment showed that OT3 affected decision latency even when other standard measures of orthographic typicality were controlled. Two additional masked priming experiments showed that highly typical primes lead to faster word responses and slower nonword responses than less typical primes. Overall, the results of this research enhance our understanding of the processes underlying visual word recognition and lexical decision making, and also have important methodological implications for the field

Automatic detection of service initiation signals used in bars

Loth S, Huth K, de Ruiter J. Automatic detection of service initiation signals used in bars. Frontiers in Psychology. 2013;4: 557.Recognizing the intention of others is important in all social interactions, especially in the service domain. Enabling a bartending robot to serve customers is particularly challenging as the system has to recognize the social signals produced by customers and respond appropriately. Detecting whether a customer would like to order is essential for the service encounter to succeed. This detection is particularly challenging in a noisy environment with multiple customers. Thus, a bartending robot has to be able to distinguish between customers intending to order, chatting with friends or just passing by. In order to study which signals customers use to initiate a service interaction in a bar, we recorded real-life customer-staff interactions in several German bars. These recordings were used to generate initial hypotheses about the signals customers produce when bidding for the attention of bar staff. Two experiments using snapshots and short video sequences then tested the validity of these hypothesized candidate signals. The results revealed that bar staff responded to a set of two non-verbal signals: first, customers position themselves directly at the bar counter and, secondly, they look at a member of staff. Both signals were necessary and, when occurring together, sufficient. The participants also showed a strong agreement about when these cues occurred in the videos. Finally, a signal detection analysis revealed that ignoring a potential order is deemed worse than erroneously inviting customers to order. We conclude that (a) these two easily recognizable actions are sufficient for recognizing the intention of customers to initiate a service interaction, but other actions such as gestures and speech were not necessary, and (b) the use of reaction time experiments using natural materials is feasible and provides ecologically valid results

Structural and magnetic properties of FeMnx_x (x=x=1...6) chains supported on Cu2_2N / Cu (100)

Heterogeneous atomic magnetic chains are built by atom manipulation on a Cu$_2$N/Cu (100) substrate. Their magnetic properties are studied and rationalized by a combined scanning tunneling microscopy (STM) and density functional theory (DFT) work completed by model Hamiltonian studies. The chains are built using Fe and Mn atoms ontop of the Cu atoms along the N rows of the Cu$_2$N surface. Here, we present results for FeMn$_x$ ($x$=1...6) chains emphasizing the evolution of the geometrical, electronic, and magnetic properties with chain size. By fitting our results to a Heisenberg Hamiltonian we have studied the exchange-coupling matrix elements $J$ for different chains. For the shorter chains, $x \leq 2$, we have included spin-orbit effects in the DFT calculations, extracting the magnetic anisotropy energy. Our results are also fitted to a simple anisotropic spin Hamiltonian and we have extracted values for the longitudinal-anisotropy $D$ and transversal-anisotropy $E$ constants. These parameters together with the values for $J$ allow us to compute the magnetic excitation energies of the system and to compare them with the experimental data.Comment: 10 pages 8 figure

The Mona Lisa Illusion—scientists see her looking at them though she isn’t

Horstmann G, Loth S. The Mona Lisa Illusion—scientists see her looking at them though she isn’t. i-Perception. 2019;10(1): 2041669518821702.If the person depicted in an image gazes at the camera or painter, a viewer perceives this as being gazed at. The viewers’ perception holds irrespectively of their position relative to image. This is the Mona Lisa effect named after the subject of Leonardo’s famous painting La Gioconda. The effect occurs reliably but was not tested with Mona Lisa herself. Remarkably, viewers judged Mona Lisa’s gaze as directed to their right-hand side irrespectively of the image zoom, its horizontal position on screen, and the distance of the ruler that was used for measuring the gaze direction

Editorial: Understanding Social Signals: How Do We Recognize the Intentions of Others?

Loth S, de Ruiter J. Editorial: Understanding Social Signals: How Do We Recognize the Intentions of Others? Frontiers in Psychology. 2016;7: 281

Do syllables matter in visual word recognition? – German evidence extended and reviewed.

Loth S, Davis CJ. Do syllables matter in visual word recognition? – German evidence extended and reviewed. Presented at the Experimental Psychology Society - London Meeting, London, UK.Although research has established the phonologicalsyllable as a processing unit in speech production (e.g., Levelt & Wheeldon, 1994), its role in recognition is somewhat controversial. There was no clear syllabic effect in speech perception in English (e.g., Cutler, Mehler, Norris, & Segui, 1986), and also no clear-cut effects in visual word recognition in English (Macizo & van Petten, 2006). However, inhibitory effects of syllable frequency have been reported in German visual word recognition (Conrad, Stenneken, & Jacobs, 2006). In this poster we examine the latter effects more closely, and conclude that they find their basis in morphological processing rather than in syllabification processes. This criticism is applicable to (virtually) all items in German syllable frequency research (Hutzler, Conrad, & Jacobs, 2005; Conrad & Jacobs, 2004; Conrad, Stenneken, & Jacobs, 2006). We report a new experiment that shows no effect of first syllable frequency in a lexical decision task in German. These data challenge the claim that syllabic units affect visual word recognition

Response congruency effects in masked primed lexical decision

Loth S, Davis CJ. Response congruency effects in masked primed lexical decision. Presented at the Experimental Psychology Society - London Meeting, London, UK.Response priming occurs when prime and target are members of the same category in categorisation tasks. Prior research has demonstrated these effects, e.g. in number magnitude categorisation tasks, but has failed to establish a congruency priming effect in masked primed lexical decision. We present a series of five experiments that demonstrate clear prime congruency effects in lexical decision. The data show that the size ofthe congruency priming effect is influenced by the difficulty of the word-nonword discrimination. This sensitivity can explain the failure to find prime congruency effects in previous studies. Furthermore, the data suggest that the lexical decision is dependent on an evidence accumulating process, allowing the prime to bias speed and accuracy. We discuss the implications of these results for computational models of visual word identification and lexical decision

Non-locally sensing the magnetic states of nanoscale antiferromagnets with an atomic spin sensor

The ability to sense the magnetic state of individual magnetic nano-objects is a key capability for powerful applications ranging from readout of ultra-dense magnetic memory to the measurement of spins in complex structures with nanometer precision. Magnetic nano-objects require extremely sensitive sensors and detection methods. Here we create an atomic spin sensor consisting of three Fe atoms and show that it can detect nanoscale antiferromagnets through minute surface-mediated magnetic interaction. Coupling, even to an object with no net spin and having vanishing dipolar stray field, modifies the transition matrix element between two spin states of the Fe-atom-based spin sensor that changes the sensor's spin relaxation time. The sensor can detect nanoscale antiferromagnets at up to three nanometers distance and achieves an energy resolution of 10 micro-electronvolts surpassing the thermal limit of conventional scanning probe spectroscopy. This scheme permits simultaneous sensing of multiple antiferromagnets with a single spin sensor integrated onto the surface.Comment: 30 pages main text, 6 figures, Supplementary materials not inculde