Color and size interactions in a real 3D object similarity task

Abstract

In the natural world, objects are characterized by a variety of attributes, including color and shape. The contributions of these two attributes to object recognition are typically studied independently of each other, yet they are likely to interact in natural tasks. Here we examine whether color and size (a component of shape) interact in a real three-dimensional (3D) object similarity task, using solid domelike objects whose distinct apparent surface colors are independently controlled via spatially restricted illumination from a data projector hidden to the observer. The novel experimental setup preserves natural cues to 3D shape from shading, binocular disparity, motion parallax, and surface texture cues, while also providing the flexibility and ease of computer control. Observers performed three distinct tasks: two unimodal discrimination tasks, and an object similarity task. Depending on the task, the observer was instructed to select the indicated alternative object which was "bigger than," "the same color as," or "most similar to" the designated reference object, all of which varied in both size and color between trials. For both unimodal discrimination tasks, discrimination thresholds for the tested attribute (e.g., color) were increased by differences in the secondary attribute (e.g., size), although this effect was more robust in the color task. For the unimodal size-discrimination task, the strongest effects of the secondary attribute (color) occurred as a perceptual bias, which we call the "saturation-size effect": Objects with more saturated colors appear larger than objects with less saturated colors. In the object similarity task, discrimination thresholds for color or size differences were significantly larger than in the unimodal discrimination tasks. We conclude that color and size interact in determining object similarity, and are effectively analyzed on a coarser scale, due to noise in the similarity estimates of the individual attributes, inter-attribute attentional interactions, or coarser coding of attributes at a "higher" level of object representation.

Toward a new computer-based and easy-to-use tool for the objective measurement of motivational states in humans: a pilot study

“…First, differently from what initially expected, the geometric figures used in our study, were overestimated in size as the food images, especially under fasting, when compared to their respective devalued counterparts. This finding is consistent with earlier studies showing that the color of a stimulus affects its size perception (Tedford et al 1977;Ling and Hurlbert 2004). Relationships between the color and the emotional reaction elicited by the presentation of a stimulus have also been established (Valdez and Mehrabian 1994).…”

“…The tasks were based on the discrimination of the size (Task A, Figure 3A) or of the time of presentation (Task B, Figure 3B) of food ("F", food picture) or control ("C", geometric image) stimuli and their devalued counterpart ("D") in grayscale. Devalued images were used since earlier studies demonstrated that the visual characteristics, particularly in terms of colors, have an impact on the affective reaction to salient cues, thereby influencing the size and time perception (Smets 1969;Tedford et al 1977;Ling and Hurlbert 2004;Valdez and Mehrabian 1994;Gil et al 2009). Images were chosen within a library containing 70 photographs of various food categories (snacks, meats, fish, pizzas, sandwiches, cheeses, fruits, and cakes) and the same number of geometric shapes.…”

Object Knowledge Modulates Colour Appearance

“…On the neuropsychological level this would imply that information about colour is processed by cortical cells that are functionally separable from those that process other visual attributes (Wandell 1995, page 334). The question of whether the later cortical stages that are at the basis of our final visual impression of the environment are functionally segregated is in the focus of today's colour research (Bloj et al 1999; Ling and Hurlbert 2004; Miceli et al 2001; Naor-Raz et al 2003, page 677; Werner 2007). …”

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“…Pelz et al [2001] monitored participants' eye-movements during the familiar complex task of hand washing, which revealed a novel perceptual strategy involving task-dependent lookahead fixation. More recently, Ling et al [2004] showed that color and size interact in a real 3D object similarity task.…”