Distortions in predicted motion: Pitch and direction influence imagined speed for a visual object during occlusion

<p>Visual motion prediction is essential for making key judgements about objects in the environment. These judgements are typically investigated using a time-to-contact (TTC) task, in which an object travels along a straight trajectory and disappears behind an occluder. Participants make a response coinciding with the moment the object would have contacted a visual landmark. The assumption is that the motion continues behind the occluder. This task is used to measure how we perceive and predict the arrival-time of objects. The addition of sound to TTC tasks generally enhances visual judgements. One characteristic which may affect how sound influences visual motion judgements is pitch. A rising pitch is associated with speeded motion and a falling pitch with slowed motion. Pitch change could therefore lead to biases in visual motion judgements; however, this has not yet been investigated. Furthermore, TTC tasks can utilise horizontal or vertical motion. In vertical motion, an additional variable that may be critical for TTC estimations is gravity. It is postulated that humans possess an internal model of gravity that allows us to make accurate predictions for downward motion. This model assumes faster downward than upward motion. However, this model can be wrongfully applied in constant speed tasks, producing faster speed estimations for downward stimuli when there is no acceleration. Therefore, vertical motion could lead to additional biases in visual motion judgements. This thesis investigated whether pitch and gravity could affect the imagined speed of an object under occlusion. Specifically, a rising pitch was hypothesised to produce speeded predicted motion and falling pitch, slowed predicted motion. I investigated the influence of pitch change in vertical and horizontal planes. I also investigated two different aspects of pitch change, since dynamic pitch is a novel addition to TTC paradigms. Experiment 1A explored gradual pitch change and Experiment 1B used sudden pitch change. The hypothesised pitch effects were observed for a gradual, but not a sudden pitch change. However, a gravity effect was observed across both Experiments 1A and 1B, suggesting the presence of sound does not moderate this effect. I also examined the cortical substrates of the audio-visual TTC task components by using transcranial magnetic stimulation (TMS) in Experiment 2. The superior temporal sulcus (STS) was targeted in this experiment, as it has been implicated in audio-visual integration. TMS causes neuronal inhibition, and as such, can be used to determine whether an area is involved in a task. If the STS is responsible for audio-visual integration in a TTC task, then TMS to the STS should disrupt the pitch effects evidenced in Experiment 1A. That is, a change in pitch should have no effect on TTC judgements compared to a constant tone. This result was evident only for rising tones, suggesting the involvement of the STS in the generating speeded predicted motion. The pitch effects observed in Experiment 1A and Experiment 2 implicate pitch in the production of biases in motion imagery for visual motion judgements, particularly for visual stimuli under occlusion.</p>

Distortions in predicted motion: Pitch and direction influence imagined speed for a visual object during occlusion

<p>Visual motion prediction is essential for making key judgements about objects in the environment. These judgements are typically investigated using a time-to-contact (TTC) task, in which an object travels along a straight trajectory and disappears behind an occluder. Participants make a response coinciding with the moment the object would have contacted a visual landmark. The assumption is that the motion continues behind the occluder. This task is used to measure how we perceive and predict the arrival-time of objects. The addition of sound to TTC tasks generally enhances visual judgements. One characteristic which may affect how sound influences visual motion judgements is pitch. A rising pitch is associated with speeded motion and a falling pitch with slowed motion. Pitch change could therefore lead to biases in visual motion judgements; however, this has not yet been investigated. Furthermore, TTC tasks can utilise horizontal or vertical motion. In vertical motion, an additional variable that may be critical for TTC estimations is gravity. It is postulated that humans possess an internal model of gravity that allows us to make accurate predictions for downward motion. This model assumes faster downward than upward motion. However, this model can be wrongfully applied in constant speed tasks, producing faster speed estimations for downward stimuli when there is no acceleration. Therefore, vertical motion could lead to additional biases in visual motion judgements. This thesis investigated whether pitch and gravity could affect the imagined speed of an object under occlusion. Specifically, a rising pitch was hypothesised to produce speeded predicted motion and falling pitch, slowed predicted motion. I investigated the influence of pitch change in vertical and horizontal planes. I also investigated two different aspects of pitch change, since dynamic pitch is a novel addition to TTC paradigms. Experiment 1A explored gradual pitch change and Experiment 1B used sudden pitch change. The hypothesised pitch effects were observed for a gradual, but not a sudden pitch change. However, a gravity effect was observed across both Experiments 1A and 1B, suggesting the presence of sound does not moderate this effect. I also examined the cortical substrates of the audio-visual TTC task components by using transcranial magnetic stimulation (TMS) in Experiment 2. The superior temporal sulcus (STS) was targeted in this experiment, as it has been implicated in audio-visual integration. TMS causes neuronal inhibition, and as such, can be used to determine whether an area is involved in a task. If the STS is responsible for audio-visual integration in a TTC task, then TMS to the STS should disrupt the pitch effects evidenced in Experiment 1A. That is, a change in pitch should have no effect on TTC judgements compared to a constant tone. This result was evident only for rising tones, suggesting the involvement of the STS in the generating speeded predicted motion. The pitch effects observed in Experiment 1A and Experiment 2 implicate pitch in the production of biases in motion imagery for visual motion judgements, particularly for visual stimuli under occlusion.</p>

Individual Observer Differences in the Use of Form and Motion to Perceive the Actor’s Sex in Biological Motion Displays

Recent research has shown that the perception of biological motion may be influenced by aspects of the observer’s personality. In this study, we sought to determine how participant characteristics (including demographics, response inhibition, autism spectrum quotient, empathy, social anxiety, and motion imagery) might influence the use of form and motion to identify the actor’s sex in biological motion displays. We varied the degree of form and motion in biological motion displays and correlated 76 young adult participants’ performances for identifying the actor’s sex in these varied conditions with their individual differences on variables of interest. Differences in the separate use of form and motion cues were predictive of participant performance generally, with use of form most predictive of performance. Female participants relied primarily on form information, while male participants relied primarily on motion information. Participants less able to visualize movement tended to be better at using form information in the biological motion task. Overall, our findings suggest that similar group level performances across participants in identifying the sex of the actor in a biological motion task may result from quite different individual processing.

Citraan pada Kumpulan Puisi Bertema Musim Gugur Karya Goethe

<p><strong>Imagery plays an important role in literary works, and poetry is no exception. In Goethe's poetry, the romantic era which tries to describe the beauty of nature as the main object is very strong. One of the natural beauties that are trying to be described and famous is autumn in Germany. This natural phenomenon is trying to be described through imagery, so readers need to understand the imagery in poetry to get a clear picture and understand the intent or message in the poem. This study aims to describe the meaning related to imagery and the types of imagery contained in Goethe's poems. The research method used is qualitative with the theory of Pradopo. The results showed that in the process of understanding the images or images contained in poetry, an understanding of the meaning contained in the poem as a whole was needed to get a clear picture. Meanwhile, based on the results of the analysis, found 4 types of imagery in Goethe's autumn-themed poetry, namely visual imagery, auditory imagery, tactile imagery, and motion imagery. The number of each image is 8 visual images, 2 auditory images, 2 tactile images, and 3 motion images.</strong></p><p><strong><strong><em>Keywords</em></strong>–</strong><em>Goethe, Imagery, Poetry</em><em>, Herbsgedichte</em></p>

Reducing Response Time in Motor Imagery Using A Headband and Deep Learning

Electroencephalography (EEG) signals to detect motor imagery have been used to help patients with low mobility. However, the regular brain computer interfaces (BCI) capturing the EEG signals usually require intrusive devices and cables linked to machines. Recently, some commercial low-intrusive BCI headbands have appeared, but with less electrodes than the regular BCIs. Some works have proved the ability of the headbands to detect basic motor imagery. However, all of these works have focused on the accuracy of the detection, using session sizes larger than 10 s, in order to improve the accuracy. These session sizes prevent actuators using the headbands to interact with the user within an adequate response time. In this work, we explore the reduction of time-response in a low-intrusive device with only 4 electrodes using deep learning to detect right/left hand motion imagery. The obtained model is able to lower the detection time while maintaining an acceptable accuracy in the detection. Our findings report an accuracy above 83.8% for response time of 2 s overcoming the related works with both low- and high-intrusive devices. Hence, our low-intrusive and low-cost solution could be used in an interactive system with a reduced response time of 2 s.