Teemu Ahmaniemi

Emotional responses to thermal stimuli

The present aim was to study if thermal stimuli presented to the palm can affect emotional responses when measured with emotion related subjective rating scales and changes in skin conductance response (SCR). Two target temperatures, cold and warm, were created by either decreasing or increasing the temperature of the stimulus 4 °C in respect to the participants current hand temperature. Both cold and warm stimuli were presented by using two presentation methods, i.e., dynamic and pre-adjusted. The results showed that both the dynamic and pre-adjusted warm stimuli elevated the ratings of arousal and dominance. In addition, the pre-adjusted warm and cold stimuli elevated the SCR. The results suggest that especially pre-adjusted warm stimuli can be seen as effective in activating the autonomic nervous system and arousal and dominance dimensions of the affective rating space.

Design of Dynamic Vibrotactile Textures

This paper describes a method for creating virtual textures without force feedback by using a simple motion sensor and a single vibrotactile actuator. It is based on wavetable synthesis driven by the users hand movements. The output of the synthesis is rendered with the tactile actuator attached in a hand-held box together with the motion sensor. The method provides a solution for creating tangible properties for virtual objects which can be explored by pointing at them with the sensor-actuator device. The study introduces 12 virtual textures which were based on three different envelope ridge lengths, two spatial densities, and were either regularly or irregularly organized. To evaluate the role of each design parameter in the perception of the texture, a series of experiments was conducted. The perceived similarity was assessed in a pairwise comparison test and the outcome was analyzed by using multidimensional scaling. The analysis revealed that envelope ridge length and spatial density were distinguishable design parameters while regularity was not. The textures were also rated according to five attribute scales previously determined in the pilot experiment. The results show that ridge length and spatial density influence perceived roughness and flatness similarly as with real textures.

The Role of Gesture Types and Spatial Feedback in Haptic Communication

The sense of touch is a fundamental part of social interaction as even a short touch from another person can elicit emotional experiences. Previous studies on haptic communication indicate that the benefits of interpersonal touch exist even when touch is artificially mediated between people that are physically apart. In the current study an evaluation of three input gestures (i.e., moving, squeezing, and stroking) was conducted to identify preferred methods for creating haptic messages using a hand-held device. Furthermore, two output methods (i.e., one or four haptic actuators) were investigated in order to determine whether representing spatial properties of input gestures haptically provides additional benefit for communication. Participants created haptic messages in four example communication scenarios. The results of subjective ratings, postexperimental interviews, and observations showed that squeezing and stroking were the preferred ways to interact with the device. Squeezing was an unobtrusive and quick way to create haptic content. Stroking, on the other hand, enabled crafting of more detailed haptic messages. Spatial haptic output was appreciated especially when using the stroking method. These findings can help in designing haptic communication methods for hand-held devices.

Enhancing personal communication with spatial haptics: Two scenario-based experiments on gestural interaction

Haptic gestures and sensations through the sense of touch are currently unavailable in remote communication. There are two main reasons for this: good quality haptic technology has not been widely available and knowledge on the use of this technology is limited. To address these challenges, we studied how users would like to, and managed to create spatial haptic information by gesturing. Two separate scenario-based experiments were carried out: an observation study without technological limitations, and a study on gesturing with a functional prototype with haptic actuators. The first study found three different use strategies for the device. The most common gestures were shaking, smoothing and tapping. Multimodality was requested to create the context for the communication and to aid the interpretation of haptic stimuli. The second study showed that users were able to utilize spatiality in haptic messages (e.g., forward-backward gesture for agreement). However, challenges remain in presenting more complex information via remote haptic communication. The results give guidance for communication activities that are usable in spatial haptic communication, and how to make it possible to enable this form of communication in reality.

Perceived physicality in audio-enhanced force input

This paper investigates how the perceived physicality of the action of applying force with a finger on a rigid surface (such as on a force-sensing touch screen) can be enhanced using real-time synthesized audio feedback. A selection of rich and evocative audio designs was used. Additionally, audio-tactile cross-modal integration was encouraged, by observing that the main rules of multisensory integration were supported. The study conducted showed that richness of perceived physicality increased considerably, mostly in its auditory expression (what pressing sounded like). In addition, in many instances it was observed that the haptic expression of physicality also increased (what pressing felt like), including some perception of compliance. This last result was particularly interesting as it showed that audio-tactile cross-modal integration might be present.

Effect of Dynamic Vibrotactile Feedback on the Control of Isometric Finger Force

This study investigates how controllability of force is influenced by concurrent vibrotactile feedback that is generated proportionally to the applied force. Three different models to provide tactile feedback are introduced: amplitude and frequency modulation and granular synthesis. Then, an experiment investigating the effect of the feedback models on force control is reported. The tactile feedback conditions were compared to each other and to a condition with no feedback in a force repetition and a force hold tasks. In the force repetition task, all the feedback conditions yielded significantly better accuracy compared to no feedback condition. In the force hold task, there was no difference in the accuracy between the conditions including the no feedback condition. The results suggest that dynamic vibrotactile feedback assists the force control in force repetition tasks.

Tactile modulation of emotional speech samples

Traditionally only speech communicates emotions via mobile phone. However, in daily communication the sense of touch mediates emotional information during conversation. The present aim was to study if tactile stimulation affects emotional ratings of speech when measured with scales of pleasantness, arousal, approachability, and dominance. In the Experiment 1 participants rated speech-only and speech-tactile stimuli. The tactile signal mimicked the amplitude changes of the speech. In the Experiment 2 the aim was to study whether the way the tactile signal was produced affected the ratings. The tactile signal either mimicked the amplitude changes of the speech sample in question, or the amplitude changes of another speech sample. Also, concurrent static vibration was included. The results showed that the speech-tactile stimuli were rated as more arousing and dominant than the speech-only stimuli. The speech-only stimuli were rated as more approachable than the speech-tactile stimuli, but only in the Experiment 1. Variations in tactile stimulation also affected the ratings. When the tactile stimulation was static vibration the speech-tactile stimuli were rated as more arousing than when the concurrent tactile stimulation was mimicking speech samples. The results suggest that tactile stimulation offers new ways of modulating and enriching the interpretation of speech.

Vocal sketching: a prototype tool for designing multimodal interaction

Dynamic audio feedback enriches the interaction with a mobile device. Novel sensor technologies and audio synthesis tools provide infinite number of possibilities to design the interaction between the sensory input and audio output. This paper presents a study where vocal sketching was used as prototype method to grasp ideas and expectations in early stages of designing multimodal interaction. We introduce an experiment where a graspable mobile device was given to the participants and urged to sketch vocally the sounds to be produced when using the device in a communication and musical expression scenarios. The sensory input methods were limited to gestures such as touch, squeeze and movements. Vocal sketching let us to examine closer how gesture and sound could be coupled in the use of our prototype device, such as moving the device upwards with elevating pitch. The results reported in this paper have already informed our opinions and expectations towards the actual design phase of the audio modality.

MARSUI: malleable audio-reactive shape-retaining user interface

MARSUI is a hardware deformable prototype exhibiting plastic (shape-retaining) behavior. It can track the shape that the user creates when deforming it. We envision that a set of predefined shapes could be mapped onto particular applications and functions. In its current implementation, we present three shapes that MARSUI can be deformed into: circular band, flat surface and sharp bent. These shapes map respectively onto the following applications: wristwatch, mobile phone and media player. Since the malleable interface can also take other forms, feedback plays an important role in guiding the user towards the predefined shapes. In this paper, we focus on investigating the possibilities that auditory feedback could offer in guiding the user towards reaching the intended shapes.

Squeeze vs. tilt: a comparative study using continuous tactile feedback

This paper presents an investigation into the performance of squeezing as a manipulative interaction technique in comparison to tilting with an aim to answer two questions: is squeezing an effective input technique for mobile devices and can tactile feedback improve performance? The experiment results show that both input methods are viable but squeezing is significantly faster and more sustainable than tilting (with and without tactile feedback).