Alexander Toet

• Ph.D.
• Retired at TNO, Soesterberg, The Netherlands

Highlights • Unspeeded response time (URT) is negatively correlated with absolute valence and arousal. • URT is larger for food images with ambiguous valence. • URT is shorter for food images eliciting more arousing or intense affective responses. • The URT may be an implicit evaluation measure that complements self-report measures.

Camouflage evaluation typically involves human visual search and detection experiments that are time-consuming and expensive. Hence, there is a need for models that compute camouflage effectiveness from digital imagery. Convolutional neural networks are a powerful tool for automatic object detection and recognition. We investigated whether such a n...

Camouflage evaluation typically involves human visual search and detection experiments that are time-consuming and expensive. Hence, there is a need for models that compute camouflage effectiveness from digital imagery. Convolutional neural networks are a powerful tool for automatic object detection and recognition. We investigated whether such a n...

Introduction Understanding how food neophobia affects food experience may help to shift toward sustainable diets. Previous research suggests that individuals with higher food neophobia are more aroused and attentive when observing food-related stimuli. The present study examined whether electrodermal activity (EDA), as index of arousal, relates to...

We examined the effects of informative pitch and multisensory context as potential factors influencing individuals' experience of tofu with soy sauce and the amount consumed outside the lab. Two hundred and sixteen participants watched one of two pitches (promoting either vegetarian diets or exercise) and were guided into one of three multisensory...

To monitor adherence to diets and to design and evaluate nutritional interventions, it is essential to obtain objective knowledge about eating behavior. In most research, measures of eating behavior are based on self-reporting, such as 24-h recalls, food records (food diaries) and food frequency questionnaires. Self-reporting is prone to inaccuraci...

To monitor adherence to diets and to design and evaluate nutritional interventions, it is essential to obtain objective knowledge about eating behavior. In most research, measures of eating behavior are based on self-reporting, such as 24-h recalls, food records (food diaries) and food frequency questionnaires. Self-reporting is prone to inaccuraci...

To monitor adherence to diets and to design and evaluate nutritional interventions it is essential to obtain objective knowledge about eating behavior. In most research, measures of eating behavior are based on self-reporting, such as 24-h recalls, food records (food diaries), and food frequency questionnaires. Self-reporting is prone to inaccuraci...

Recent improvements in extended reality (XR) technology created an increase in XR products and solutions in the industry while raising new requirements for new or improved architectural concepts. This need can be particularly complex as XR applications often relate both to 3D geometric rendering and multimedia paradigms. This article outlines the m...

Visual search, with or without the aid of optical or electro-optical instruments, plays a significant role in various types of military and civilian operations (e.g., reconnaissance, surveillance, and search and rescue). Advance knowledge of human visual search and target acquisition performance is often required to prepare flight scenarios (e.g.,...

Natural scenes are typically highly heterogeneous, making it difficult to assess camouflage effectiveness for moving objects since their local contrast varies with their momentary position. Camouflage performance is usually assessed through visual search and detection experiments involving human observers. However, such studies are time-consuming a...

Modern immersive multisensory communication systems can provide compelling mediated social communication experiences that approach face-to-facecommunication. Existing methods to assess the quality of mediated social communication experiences are typically targeted at specific tasks or communication technologies. As a result, they do not address all...

Telemeetings such as audiovisual conferences or virtual meetings play an increasingly important role in our professional and private lives. For that reason, system developers and service providers will strive for an optimal experience for the user, while at the same time optimizing technical and financial resources. This leads to the discipline of...

IntroductionOur visual, auditory, and tactile perception is not solely determined by what we process at a given moment in time, but also determined by what we perceived recently. These sequential effects can either be negative (repulsive) or positive (assimilative). Here, we investigated whether such sequential effects also occur in odor perception...

Reflecting the two main prevailing and opposing views on the nature of emotions, emotional responses to food and beverages are typically measured using either (a) a categorical (lexicon-based) approach where users select or rate the terms that best express their food-related feelings or (b) a dimensional approach where they rate perceived food item...

In recent years, there has been a significant increase in research on mediated communication via social touch. Previous studies indicated that mediated social touch (MST) can induce similar positive outcomes to interpersonal touch. However, studies investigating the user experience of MST technology predominantly involve brief experiments that are...

Recent improvements in Extended Reality (XR) technology created an increase in XR products and solutions in the industry, while raising new requirements for new or improved architectural concepts. This need can be particularly complex as XR applications often relate both to 3D geometric rendering and multimedia paradigms. This paper outlines the ma...

Cognitive biases are systematic cognitive dispositions or inclinations in human thinking and reasoning that often do not comply with the tenets of logic, probability reasoning, and plausibility. These intuitive and subconscious tendencies are at the basis of human judgment, decision making, and the resulting behavior. Psychological frameworks consi...

Effective interpersonal communication is important to maintain relationships and build trust, empathy, and confidence. In this digital age, communication has become mediated, which filters out many of the social cues that are essential to facilitate interpersonal communication. This paper investigates the extent to which social cues influence socia...

Cognitive biases are systematic cognitive dispositions or inclinations in human thinking and reasoning that often do not comply with the tenets of logic, probability reasoning, and plausibility. These intuitive and subconscious tendencies are at the basis of human judgment, decision making, and the resulting behavior. Psychological frameworks consi...

We recently developed the Holistic Social Presence Questionnaire (HSPQ) to measure the quality of mediated social communication experiences. Initial research confirmed the content and face validity of the HSPQ. This study investigates the convergent validity and sensitivity of the HSPQ. Participants completed a decision-making task in groups, using...

In our digital age, human social communication is increasingly mediated. However, mediated social communication (MSC) systems will only become a viable alternative for in-person social interactions when they reliably and intuitively convey all relevant social and spatial cues needed by communication partners to establish effective communication, co...

Immersive communication systems provide increasingly realistic virtual environments, which may afford immersive social interactions that approach the quality of face-to-face (F2F) meetings by eliciting a sense of social presence; the feeling of being physically together with another person and having an affective and intellectual connection. To opt...

Recent improvements in Extended Reality (XR) technology created an increase in XR products and solutions in the industry, while raising new requirements for new or improved architectural concepts. This need can be particularly complex as XR applications often relate both to 3D geometric rendering and multimedia paradigms. This paper outlines the ma...

How we perceive the world is not solely determined by our experiences at a given moment in time, but also by what we have experienced in our immediate past. Here, we investigated whether such sequential effects influence the affective appraisal of food images. Participants from 16 different countries (N = 1278) watched a randomly presented sequence...

How we perceive the world is not solely determined by what we sense at a given moment in time, but also by what we processed recently. Here we investigated whether such serial dependencies for emotional stimuli transfer from one modality to another. Participants were presented a random sequence of emotional sounds and images and instructed to rate...

While the sense of presence in VR has been extensively studied, there are currently no scales available to measure the sense of presence in AR and MR. Here we propose a general Holistic Presence Questionnaire (HPQ), that measures presence through the sense of telepresence, internal and external plausibility and perceived behavioral and cognitive af...

While the sense of presence in VR has been extensively studied, there are currently no scales available to measure the sense of presence in AR and MR. Here we propose a general Holistic Presence Questionnaire (HPQ), that measures presence through the sense of telepresence, internal and external plausibility and perceived behavioral and cognitive af...

Cognitive biases can adversely affect human judgment and decision making and should therefore preferably be mitigated, so that we can achieve our goals as effectively as possible. Hence, numerous bias mitigation interventions have been developed and evaluated. However, to be effective in practical situations beyond laboratory conditions, the bias m...

Modern immersive multisensory communication systems can provide compelling mediated social communication experiences that approach face-to-face (F2F) communication. Existing frameworks to assess the quality of mediated social communication experiences are typically targeted at specific communication technologies and do not address all relevant aspe...

During the COVID-19 pandemic, many nursing homes had to restrict visitations. This had a major negative impact on the wellbeing of residents and their family members. In response, residents and family members increasingly resorted to mediated communication to maintain social contact. To facilitate high-quality mediated social contact between reside...

Family visiting restrictions in nursing homes due to COVID-19-related measures have a major impact on elderly and their families. As an alternative communication means, TNO is developing an augmented reality (AR)-based solution to realize high-quality virtual social contact. To investigate its suitability for remote family visits in nursing homes,...

While AR has successfully been deployed in the military air domain for decades, its use in the ground domain poses serious challenges. Some of these challenges result from technological limitations. However, others are more difficult or even impossible to resolve since they reflect fundamental human characteristics. The toughest-to-solve limitation...

Background: In this study we measured the affective appraisal of sounds and video clips using a newly developed graphical self-report tool: the EmojiGrid. The EmojiGrid is a square grid, labeled with emoji that express different degrees of valence and arousal. Users rate the valence and arousal of a given stimulus by simply clicking on the grid. Me...

Cognitive biases can adversely affect human judgement and decision making and should therefore preferably be mitigated, so that we can achieve our goals as effectively as possible. Hence, numerous bias mitigation interventions have been developed and evaluated. However, to be effective in practical situations beyond laboratory conditions, the bias...

The present study investigated the potential of implicit physiological measures to provide objective measures of affective food experience in contrast to explicit self-report ratings in a cross-cultural context. Dutch and Thai participants viewed 120 food images portraying universal food image categories (regular and molded food) and cultural food...

Targets that are well camouflaged under static conditions are often easily detected as soon as they start moving. We investigated and evaluated ways to design camouflage that dynamically adapts to the background and conceals the target while taking the variation in potential viewing directions into account. In a human observer experiment, recorded...

Communication through modern immersive systems that afford the representation of a wide range of multisensory (visual, auditory, haptic, olfactory) social and ambient (environmental) affective cues can provide compelling experiences that approach face-to-face communication. The quality of a mediated social communication experience (QoE) can be defi...

We trained a model to distinguish an extreme high arousal, unpleasant drink from regular drinks based on a range of implicit behavioral and physiological responses to naturalistic tasting. The trained model predicted arousal ratings of regular drinks, highlighting the possibility to estimate affective experience without having to rely on subjective...

Introduction he main purpose of this study was to investigate the overall relation between the mean (at the nomothetic or group level) subjective valence and arousal ratings for odors. Although well established in other sensory modalities (e.g., visual, auditory, gustatory, tactile), this relation has not previously been investigated for odors cove...

Immersive 360° virtual reality (VR) movies can effectively evoke a wide range of different emotional experiences. To this end, they are increasingly deployed in entertainment, marketing and research. Because emotions influence decisions and behavior, it is important to assess the user's affective appraisal of immersive 360° VR movies. Knowledge of...

Emotional state during food consumption is expected to affect food pleasantness. We hypothesize that a negative emotional state reduces food pleasantness and more so for novel foods than for familiar foods because novel foods have not yet been associated with previous emotions. Furthermore, we expect this effect to be stronger when judging the food...

In this study we evaluate the convergent validity of a new graphical self-report tool (the EmojiGrid) for the affective appraisal of perceived touch events. The EmojiGrid is a square grid labeled with facial icons (emoji) showing different levels of valence and arousal. The EmojiGrid is language independent and efficient (a single click suffices to...

We evaluated the convergent validity of the new language-independent EmojiGrid rating tool for the affective appraisal of perceived touch events. The EmojiGrid is a rectangular response grid, labeled with facial icons (emoji) that express different degrees of valence and arousal. We previously showed that participants can intuitively and reliably r...

Background: In this study we measured the affective appraisal of sounds and video clips using a newly developed graphical self-report tool: the EmojiGrid. The EmojiGrid is a square grid, labeled with emoji that express different degrees of valence and arousal. Users rate the valence and arousal of a given stimulus by simply clicking on the grid. Me...

The affective appraisal of odors is known to depend on their intensity (I), familiarity (F), detection threshold (T), and on the baseline affective state of the observer. However, the exact nature of these relations is still largely unknown. We therefore performed an observer experiment in which participants (N = 52) smelled 40 different odors (var...

In this study we evaluate the convergent validity of a new graphical self-report tool (the EmojiGrid) for the affective appraisal of perceived touch events. The EmojiGrid is a square grid labeled with facial icons (emoji) showing different levels of valence and arousal. The EmojiGrid is language independent and efficient (a single click suffices to...

Telerobotics aims to transfer human manipulation skills and dexterity over an arbitrary distance and at an arbitrary scale to a remote workplace. A telerobotic system that is transparent enables a natural and intuitive interaction. We postulate that embodiment (with three sub-components: sense of ownership, agency, and self-location) of the robotic...

The ways that extraneous visual and auditory stimuli impair human performance are reviewed with aim of distinguishing those sensory, perceptual and cognitive effects relevant to the design of human-machine systems. Although commonly regarded as disruptive, distractions reflect the adaptability of the organism to changing circumstances. Depending on...

Cognitive biases are systematic cognitive dispositions or inclinations in human thinking and reasoning that often do not comply with the tenets of logic, probability reasoning, and plausibility. These intuitive and subconscious tendencies are at the basis of human judgment, decision making, and the resulting behavior. Psychological frameworks consi...

Probing food experience or liking through verbal ratings has its shortcomings. We compare explicit ratings to a range of (neuro)physiological and behavioral measures with respect to their performance in distinguishing drinks associated with different emotional experience. Seventy participants tasted and rated the valence and arousal of eight regula...

Immersive 360° VR systems are increasingly used in entertainment, marketing and design and development processes. Many of these applications involve emotional experiences. Since momentary emotions significantly determine a user’s response and decisions, it is essential to understand the influence of media content and technological factors on the us...

In a recent study on food-evoked emotions, we observed that people often misunderstood the currently available affective self-report tools. We, therefore, developed a new intuitive and language-independent self-report instrument called the EmojiGrid: a rectangular response grid labeled with facial icons (emoji) that express different degrees of val...

In military operations signature reduction techniques such as camouflage nets, low-emissive paints, and camouflage patterns are typically deployed to optimize the survivability of high value assets by minimizing their detectability. Various methods have been developed to assess the effectiveness of these camouflage measures. There are three main ap...

Viewing images of food triggers the desire to eat and this effect increases when images represent food in a more vivid way. Cinemagraphs are a new medium that is intermediate between photographs and videos: most of the frame is static, while some details are animated in a seamless loop, resulting in a vivid viewing experience. On social media cinem...

We present CROCUFID: a CROss-CUltural Food Image Database that currently contains 840 images, including 479 food images with detailed metadata and 165 images of non-food items. The database includes images of sweet, savory, natural, and processed food from Western and Asian cuisines. To create sufficient variability in valence and arousal we includ...

Research on food experience is typically challenged by the way questions are worded. We therefore developed the EmojiGrid: a graphical (language-independent) intuitive self-report tool to measure food-related valence and arousal. In a first experiment participants rated the valence and the arousing quality of 60 food images, using either the EmojiG...

We investigated how different graphical representations convey the underlying uncertainty distribution in ensemble predictions. In ensemble predictions, a set of forecasts is produced, indicating the range of possible future states. Adopting a use case from life sciences, we asked non-expert participants to compare ensemble predictions of the growt...

Modern night-time cameras are designed to expand the conditions under which human observers can operate. A functional piece of equipment must therefore provide an image that leads to good perceptual awareness in most environmental and operational conditions (to "Own the weather" or "Own the night"). The two most common night-time imaging systems ei...

Because of the globalization of world food markets there is a growing need for valid and language independent self-assessment tools to measure food-related emotions. We recently introduced the EmojiGrid as a language-independent, graphical affective self-report tool. The EmojiGrid is a Cartesian grid that is labeled with facial icons (emoji) expres...

Human decision-making shows systematic simplifications and deviations from the tenets of rationality (‘heuristics’) that may lead to suboptimal decisional outcomes (‘cognitive biases’). There are currently three prevailing theoretical perspectives on the origin of heuristics and cognitive biases: a cognitive-psychological, an ecological and an evol...

Besides sensory characteristics of food, food-evoked emotion is a crucial factor in predicting consumer's food preference and therefore in developing new products. Many measures have been developed to assess food-evoked emotions. The aim of this literature review is (i) to give an exhaustive overview of measures used in current research and (ii) to...

Cinemagraphs are a new medium that is intermediate between photographs and videos: most of the frame is static, while some details are animated in a seamless loop. Given their vivid appearance we expected that food cinemagraphs evoke stronger affective and appetitive responses than their static counterparts (stills). In this study we measured the L...

Despite of the ongoing interest in the fusion of multi-band images for surveillance applications and a steady stream of publications in this area, there is only a very small number of static registered multi-band test images (and a total lack of dynamic image sequences) publicly available for the development and evaluation of image fusion algorithm...

We tested the hypothesis that, either through training or selection, military personnel is more resilient to stress than civilians, as indicated by several subjective and physiological measures. In addition, we examined the effect of stress on the perceived trustworthiness of faces in these two groups. Stress was induced in 45 civilian participants...

Previously, we presented two color mapping methods for the application of daytime colors to fused nighttime (e.g., intensified and longwave infrared or thermal (LWIR)) imagery. These mappings not only impart a natural daylight color appearance to multiband nighttime images but also enhance their contrast and the visibility of otherwise obscured det...

Human decision making shows systematic simplifications and deviations from the tenets of rationality (‘heuristics’) that may lead to suboptimal decisional outcomes (‘cognitive biases’). There are currently three prevailing theoretical perspectives on the origin of heuristics and cognitive biases: a cognitive-psychological, an ecological and an evol...

The Triangle Orientation Discrimination (TOD) methodology includes i) a widely applicable, accurate end-to-end EO/IR sensor test, ii) an image-based sensor system model and iii) a Target Acquisition (TA) range model. The method has been extensively validated against TA field performance for a wide variety of well-and under-sampled imagers, systems...

Social touch forms an important aspect of the human non-verbal communication repertoire, but is often overlooked in human-robot interaction. In this study, we investigated whether robot-initiated touches can induce physiological, emotional, and behavioral responses similar to those reported for human touches. 39 Participants were invited to watch a...

The fusion and enhancement of multiband nighttime imagery for surveillance and navigation has been the subject of extensive research for over two decades. Despite the ongoing efforts in this area there is still only a small number of static multiband test images available for the development and evaluation of new image fusion and enhancement method...

We have tested whether natural dynamic backgrounds affect perceived facial dominance. Facial evaluation is based on just two fundamental dimensions of facial appearance: valence and dominance. Perceived facial valence has been shown to be biased towards background valence. However, it is currently unknown, if the perception of facial dominance is a...

Cognitive biases and heuristics are pervasive simplifications and distortions in judgement and reasoning that systematically affect human decision making. Knowledge in this area may enable us to foresee and reduce detrimental effects of biases or to influence others more effectively. We therefore performed a literature study to assess the influence...

We introduce a multiscale image fusion scheme based on guided filtering. Guided filtering can effectively reduce noise while preserving detail boundaries. When applied in an iterative mode, guided filtering selectively eliminates small scale details while restoring larger scale edges. The proposed multi-scale image fusion scheme achieves optimal sp...