Form perception and attention in pigeons

Abstract

This report selectively reviews the authors' research on stimulus control by visual forms. Most studies employed visual search of computer-generated displays, and the main behavioral measure was search reaction time. Pigeons classify simple line forms much as do humans, and there was some evidence for feature extraction, though a search asymmetry probe failed to identify several putative features. Dimensional analysis revealed a new quantitative relation between similarity and the probability of detecting a target. It also identified candidates for integral and separable stimulus dimensions. Similarity and set-size variables influenced the extent to which attention was engaged. Further studies addressed the manner in which attention is focused, revealing relationships between priming and search images. In these cases, attention to a selected form is probably driven by a top-down assessment of predictability.Birds seem to interact with their visual world much as do humans, and it is easy to assume that they see things as we do. Psychophysical studies of basic' visual functions provide some support for this view, though such things as avian acuity, temporal resolution, and color vision are also unique in suggestive ways (Donovan, 1978;Granda & Maxwell, 1979). More complex aspects ofbirds' visual perception have been less well understood, but recent studies ofsuch matters as visual categorization, texture discrimination, and visual illusions are beginning to scratch the surface ofour ignorance (cf. Stebbins & Berkley, 1990;Wasserman, 1993;Zentall, 1993). It is not our purpose to review this literature but rather to summarize some ofour own contributions to it. The present paper concentrates on processes revealed by visual search for targets defined by shape or form. Naturally, the extensive literature on human form perception influenced the course ofthis research, but it also has roots in other areas, such as foraging, and has developed its own logic over time. Our goal has been the general understanding of relevant perceptual processes; pigeon-human comparison is considered where it serves that purpose.The bird's natural reliance on visual information recommends it for perceptual research. About 20 years ago, we began to harness the pigeon's skillful foraging to a visual search paradigm in which displays and search reaction times (RTs) were computer controlled and recorded (D. S. Blough, 1979). Inthe research reviewed here, we used thisThe preparation of this report was supported in part by National Science Foundation Grant BNS-9407269. The authors thank many long-term members ofthe psychology department staffat Brown University for their help over the 18-year course of this research. Correspondence should be addressed to either author at Department of Psychology, Campus Box 1853, Brown University, Providence, RI 02912 (e-mail: donald_blough@brown.edu, or patricia_blough@brown.edu).Note: This article is one of those occasionally invited by the editor in which authors have the opportunity to provide an overview of ...

Anticipating by Pigeons Depends on Local Statistical Information in a Serial Response Time Task.

“…There are many striking similarities between pigeon and human visual cognition (D. S. Blough, 1984;Cook, 2001), and the present results suggest that there may be an additional similarity in terms of local temporal dynamics of serial response time performances. This similarity in the dynamics of serial response time performances strengthens the likelihood that the neurobiological foundation of, and evolution of, human attentional processes can be studied indirectly through the use of invasive techniques with pigeons.…”

Perceptual completion in rhesus monkeys (Macaca mulatta) and pigeons (Columba livia)

“…When humans perceive a complete circle in Figure 1, they perceive the triangle as being closer to them than the "circle." Pigeons are known to have difficulty recognizing depth from 2-D drawings (e.g., Blough, 1984;Cerella, 1990), unless they are specially trained to recognize rotating 2-D representations of figures (Cook & Katz, 1999). In contrast, humans start to recognize 3-D when they are only a few months old (see, e.g., Granrud & Yonas, 1984;Yonas & Arterberry, 1994), as may macaque monkeys (Gunderson, Yonas, Sargent, & Grant-Webster, 1993) and domestic hens (Forkman, 1998).…”

Orthogonal stimulus variation and attention in dimensional contrast

“…A stimulus that is potentially analyzable may not be analyzed or filtered out in a given task. Hence, it may be difficult to arrange contingencies that simply and clearly distinguish between integral and separable dimensions for animals-a point noted by others (e.g., D. S. Blough, 1991; D. S. Blough & P. M. Blough, 1997). Furthermore, stimulus organization that is potentially available may not be used by pigeons the way in which it is used by humans.…”