Conceptual behavior in pigeons: Categorization of both familiar and novel examples from four classes of natural and artificial stimuli.

Abstract

Two new procedures-a four-key choice procedure and a four-ply multiple fixed ratio schedule procedure-were used to train pigeons to categorize color slides depicting natural (cat, person, flower) and human-made (car, chair) objects. In Experiments IA, IB, 2A, and 2fl, 16 pigeons trained with 10 slides from each of four categories reliably classified novel examples from these categories. However, performance was more accurate on training than on novel stimuli. In Experiment 3, 8 pigeons learned to classify 2,000 nonrepeating slides. Thus, repetitive training with a limited number of stimuli is not necessary for pigeons to learn a four-category classification task. In Experiment 4, 4 pigeons were trained with a set of repeating slides while concurrently being trained with novel stimuli. As in Experiments IA, IB, 2A, and 2e, performance here was more discriminative on repeatedly seen stimuli than on novel ones. Thus, repetition facilitates categorization, whether or not the pigeons are concurrently exposed to novel stimuli. The implications of these results for models of categorization are discussed. We conclude that the conceptual abilities of pigeons are more advanced than hitherto suspected.

Influence of reward motivation on human declarative memory

“…Dunsmoor et al, 2009Dunsmoor et al, , 2012Dunsmoor et al, , 2013Maren et al, 2013), generalization of reward conditioning may partly rely on physical properties of the stimuli. Conditioned responses (CRs) can extend to stimuli that resemble the CS+ along some basic perceptual dimensions, such as tone pitch, size, or color (Honig and Urcuioli, 1981), or generalize to stimuli sharing more abstract characteristics, such as belonging to a specific visual category like 'cars' or 'flowers' (Bhatt et al, 1988).…”

Concept Learning in Animals

“…Instead of requesting verbal behavior from their subjects (an obvious impossibility), the researchers asked their birds to report members of four different categories --cats, flowers, cars, and chairs --by pecking four circular keys surrounding a square viewing screen (Figure 1). In one experiment (Bhatt, Wasserman, Reynolds, & Knauss, 1988;Experiment 1B), for example, pigeons were shown color slides depicting 10 different examples from each of the four categories. Within each category, the slides differed from each other in the number, size, color, brightness, orientation, location, and context of the stimulus object, to capture a broad range of category instances in those places where humans would ordinarily find them.…”

“…These results (and those of Edwards & Honig, 1987, Herrnstein & de Villiers, 1980, and Pearce, 1988 implicate differential within-versus betweenclass generalization as a key feature of visual categorization in animals. Wasserman et al (1988, Experiment 2) used a new technique to explore the stimuli that to pigeons constitute a class or category of objects. In any particular 40-trial session, pigeons were given a split-category discrimination, in which they viewed 20 cat slides and 20 flower slides (or 20 cat slides and 20 chair slides, or 20 car slides and 20 flower slides, or 20 car slides and 20 chair slides).…”

Applying Bubbles to Localize Features That Control Pigeons' Visual Discrimination Behavior.

“…Researchers have discovered that animals readily categorize objects according to their perceptual similarity (Bhatt, Wasserman, Reynolds, & Knauss, 1988;Herrnstein, Loveland, & Cable, 1976;Lea, Lohmann, & Ryan, 1993). Such perceptual category learning is an important process that allows animals to respond flexibly to a variable environment.…”