Vivian C. Paulun

Vivian C. Paulun
Massachusetts Institute of Technology | MIT · Department of Brain and Cognitive Sciences

Dr.rer.nat., Psychology

About

38
Publications
10,382
Reads
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331
Citations
Citations since 2016
28 Research Items
320 Citations
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2016201720182019202020212022020406080
Introduction
Vivian C. Paulun currently works as a postdoctoral fellow at the Department of Psychology, Justus-Liebig-Universität Gießen. Vivian does research in Vision Science, Psychophysics and Experimental Psychology.

Publications

Publications (38)
Article
Full-text available
Common everyday materials such as textiles, foodstuffs, soil or skin can have complex, mutable and varied appearances. Under typical viewing conditions, most observers can visually recognize materials effortlessly, and determine many of their properties without touching them. Visual material perception raises many fascinating questions for vision r...
Article
Full-text available
How humans visually select where to grasp objects is determined by the physical object properties (e.g., size, shape, weight), the degrees of freedom of the arm and hand, as well as the task to be performed. We recently demonstrated that human grasps are near-optimal with respect to a weighted combination of different cost functions that make grasp...
Preprint
Full-text available
How humans visually select where to grasp objects is determined by the physical object properties (e.g., size, shape, weight), the degrees of freedom of the arm and hand, as well as the task to be performed. We recently demonstrated that human grasps are near-optimal with respect to a weighted combination of different cost functions that make grasp...
Article
Full-text available
We rarely experience difficulty picking up objects, yet of all potential contact points on the surface, only a small proportion yield effective grasps. Here, we present extensive behavioral data alongside a normative model that correctly predicts human precision grasping of unfamiliar 3D objects. We tracked participants’ forefinger and thumb as the...
Article
Full-text available
Visually inferring the elasticity of a bouncing object poses a challenge to the visual system: The observable behavior of the object depends on its elasticity but also on extrinsic factors, such as its initial position and velocity. Estimating elasticity requires disentangling these different contributions to the observed motion. We created 2-secon...
Article
Full-text available
When haptically exploring softness, humans use higher peak forces when indenting harder versus softer objects. Here, we investigated the influence of different channels and types of prior knowledge on initial peak forces. Participants explored two stimuli (hard vs. soft) and judged which was softer. In Experiment 1 participants received either sema...
Article
Full-text available
Humans exhibit spatial biases when grasping objects. These biases may be due to actors attempting to shorten their reaching movements and therefore minimize energy expenditures. An alternative explanation could be that they arise from actors attempting to minimize the portion of a grasped object occluded from view by the hand. We reanalyze data fro...
Article
Full-text available
The material-weight illusion (MWI) occurs when an object that looks heavy (e.g., stone) and one that looks light (e.g., Styrofoam) have the same mass. When such stimuli are lifted, the heavier-looking object feels lighter than the lighter-looking object, presumably because well-learned priors about the density of different materials are violated. W...
Preprint
Full-text available
Humans exhibit spatial biases when grasping objects. These biases may be due to actors attempting to shorten their reaching movements and therefore minimize energy expenditures. An alternative explanation could be that they arise from actors attempting to minimize the portion of a grasped object occluded from view by the hand. We re-analyze data fr...
Preprint
Full-text available
We rarely experience difficulty picking up objects, yet of all potential contact points on the surface, only a small proportion yield effective grasps. Here, we present extensive behavioral data alongside a normative model that correctly predicts human precision grasping of unfamiliar 3D objects. We tracked participants’ forefinger and thumb as the...
Article
Full-text available
We report an illusion in which the felt weight of an object changes depending on whether a previously manipulated object was lighter or heavier. The illusion is not modulated by visual weight cues, yet it transfers across hands.
Chapter
When estimating the softness of an object by active touch, humans typically indent the object’s surface several times with their finger, applying higher peak indentation forces when they expect to explore harder as compared to softer stimuli [1]. Here, we compared how different types of prior knowledge differentially influence exploratory forces in...
Article
Full-text available
Successfully interacting with objects requires choosing appropriate grasp locations. By taking into account an object's shape, material properties, and the desired action, humans identify stable, comfortable grasp points that minimize slippage and torsion. The "contact point selection model" (Kleinholdermann et al., 2013) successfully predicts prec...
Article
Full-text available
Visually inferring the stiffness of objects is important for many tasks but is challenging because, unlike optical properties (e.g., gloss), mechanical properties do not directly affect image values. Stiffness must be inferred either (a) by recognizing materials and recalling their properties (associative approach) or (b) from shape and motion cues...
Article
Full-text available
Nonrigid materials, such as jelly, rubber, or sponge move and deform in distinctive ways depending on their stiffness. Which cues do we use to infer stiffness? We simulated cubes of varying stiffness and optical appearance (e.g., wood, metal, wax, jelly) being subjected to two kinds of deformation: (a) a rigid cylinder pushing downwards into the cu...
Conference Paper
Non-rigid materials such as rubber or jelly respond to external forces by bending, bulging and wobbling in distinctive ways. These characteristic motions and shape changes could provide visual cues to the material's stiffness. However, there is an inherent ambiguity between the amount of force applied and the physical parameters of the object, as b...
Article
Full-text available
Successfully picking up and handling objects requires taking into account their physical properties (e.g., material) and position relative to the body. Such features are often inferred by sight, but it remains unclear to what extent observers vary their actions depending on the perceived properties. To investigate this, we asked participants to gra...
Conference Paper
Knowledge about the material properties of objects is essential for successful manual interactions. Vision can provide useful information about features such as weight or friction even before interaction, allowing us to prepare the action appropriately, e.g. adjusting initial forces applied to an object when lifting it. But visual information can a...
Article
Full-text available
We present an apparatus that allows independent stimulation of rods and short (S)-, middle (M)-, and long (L)-wavelength-sensitive cones. Previously presented devices allow rod and cone stimulation independently, but only for a spatially invariant stimulus design (Pokorny, Smithson, & Quinlan, 2004; Sun, Pokorny, & Smith, 2001b). We overcame this l...
Article
When we search for visual targets in a cluttered background we systematically move our eyes around to bring different regions of the scene into foveal view. We explored how visual search behavior changes when the fovea is not functional, as is the case in scotopic vision. Scotopic contrast sensitivity is significantly lower overall, with a function...
Article
Full-text available
Perceiving material properties can be crucial for many tasks-such as determining food edibility, or avoiding getting splashed-yet the visual perception of materials remains poorly understood. Most previous research has focussed on optical characteristics (e.g., gloss, translucency). Here, however, we show that shape also provides powerful visual cu...
Conference Paper
A precision grip of index finger and thumb is often used to interact with objects in our environment. To successfully accomplish this everyday task we adapt our grip depending on various extrinsic and intrinsic properties of the object to be grasped. For example, the grasping movement needs to be adjusted if we want to grasp a wooden spoon or a wet...
Conference Paper
In everyday life, we usually have no problem distinguishing liquids with different viscosities, such as water, honey and tar. However, it is not known exactly how we achieve this and which image measurements have most influence on our perception of viscosity. Here, we investigated how stable visual estimates of viscosity are over time, as liquids p...
Article
Full-text available
Choosing appropriate grasp points is necessary for successfully interacting with objects in our environment. We brought two possible determinants of grasp point selection into conflict: the attempt to grasp an object near its center of mass to minimize torque and ensure stability and the attempt to minimize movement distance. We let our participant...
Conference Paper
Choosing appropriate grasp points is necessary for successfully interacting with objects in our environment. Humans place their grasp axis near the center of mass (Lederman & Wing, 2003) to avoid large torques when lifting the object. Humans also generally attempt to minimize energetic costs (Alexander, 1997). We brought these two possible determin...
Conference Paper
Liquids with different viscosities, such as milk, honey and hair-gel, respond to forces in radically different ways. Low viscosity fluids, like water, tend to flow and splash easily, whereas high viscosity fluids, like melting glass, tend to ooze slowly into distinctive clumps. These tendencies lead to strikingly different visual appearances, and i...

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