Pigeon perception and discrimination of rapidly changing texture stimuli.

Abstract

The perception and discrimination of rapidly changing texture stimuli by pigeons was examined in a target localization task. Five experienced pigeons were rewarded for finding and pecking at a randomly placed odd target block of small repeated elements embedded in a larger rectangular array of contrasting distractor elements. On dynamic color test trials, the color of the target, distractor, or both of these regions changed at rates of 100, 250, 500, or 1000 ms per frame. The number of colors appearing within such trials also varied. Pigeons performed well above chance in all test conditions, with target-associated changes producing the best discrimination. The results suggest: (a) global relational information can exclusively guide target localization behavior, (b) pigeons can perceptually group and segregate colored textured differences quite rapidly (-<100 ms), and (c) pigeons may possess automatic search control processes that can be captured by stimulus-driven changes in the display.The research described in this article is part of our ongoing efforts to understand the mechanisms of visual perception and cognition in pigeons, and their comparative relations to mammalian visual perception and cognition. Our overall goal is to discern the perceptual (Cook, 1992a) and decisional processes (Cook & Wixted, 1997) involved from the point when external visual information first impinges on the animal to its final behavioral reaction to this information. By looking in detail at each aspect of how pigeons accomplish complex visual discriminations, we hope to uncover the cognitive and neural mechanisms used by these visually sophisticated animals and to compare them with those mechanisms found in other types of animals, including humans.One way we have investigated these questions is by examining in detail how pigeons process and discriminate visual textures

Scene gist categorization by pigeons.

“…Kramer (2010) examined rapid discrimination of simple geometric stimuli and naturalistic slides (containing humans vs. non-humans) with randomly intermixed exposure times of 0.1-10 s. Discrimination accuracy was reduced with display times of 1 s or less, but some birds were able to perform above-chance at durations less than 0.5 s. In addition, pigeons have been shown to engage in texture segregation with as little as .1 s of exposure time (R. G. Cook, Cavoto, Katz, & Cavoto, 1997). Finally, pigeons have been shown to be able to discriminate same versus different scene image sequences (e.g., AAA vs. ABA vs.…”

Figure-ground assignment in pigeons: Evidence for a figural benefit

“…Pigeons trained to discriminate the odd region in a texture display do so more accurately when the visual elements come from the same dimension (e.g., color) than when the visual elements are represented by a conjunction of features (e.g., color and shape). Moreover, pigeons were able to detect texture differences within 100 msec, implying that texture discrimination and perceptual grouping are early processes in pigeon vision, just as they are in human vision (Cook, B. R. Cavoto, Katz, & K. K. Cavoto, 1997;Cook, K. K. Cavoto, & B. R. Cavoto, 1996). Although there seem to be differences in later visual processing in pigeons and people (e.g., perception of 2-D occlusion; see DiPietro, Wasserman, & Young, 2002;Fujita, 2001;Sekuler, Lee, & Shettleworth, 1996), we believe that a visual process as fundamental as figure-ground assignment is likely to be similar for pigeons and people.…”

Surface texture and priming play important roles in predator recognition by the red-backed shrike in field experiments

“…Laboratory studies with trained pigeons have shown that the presence of a geometric texture results in very quick differentiation of objects from background, which is enabled by grouping perceptually similar elements within the object (Cook 1992a, b). Pigeons were also able to utilize the texture for categorization of natural (Troje et al 1999;Nicholls et al 2011) as well as artificial (Cook 1993;Cook et al 1995Cook et al , 1996Cook et al , 1997Katz and Cook 2000;Kelly and Cook 2003;Young et al 2001) objects occurring in digital photographs. However, it is not evident whether the surface texture is also important in the recognition of ecologically relevant stimuli by wild birds.…”