Effect of between-category similarity on basic level superiority in pigeons

Abstract

Children categorize stimuli at the basic level faster than at the superordinate level. We hypothesized that between-category similarity may affect this basic-level superiority effect. Dissimilar categories may be easy to distinguish at the basic level but be difficult to group at the superordinate level, whereas similar categories may be easy to group at the superordinate level but be difficult to distinguish at the basic level. Consequently, similar basic-level categories may produce a superordinate-before-basic learning trend, whereas dissimilar basic-level categories may result in a basic-before-superordinate learning trend. We tested this hypothesis in pigeons by constructing superordinate-level categories out of basic-level categories with known similarity. In Experiment 1, we experimentally evaluated the between-category similarity of four basic-level photographic categories using multiple fixed interval-extinction training (Astley & Wasserman, 1992). We used the resultant similarity matrices in Experiment 2 to construct two superordinate-level categories from basic-level categories with high between-category similarity (cars and persons; chairs and flowers). We then trained pigeons to concurrently classify those photographs into either the proper basic-level category or the proper superordinate-level category. Under these conditions, the pigeons learned the superordinate-level discrimination faster than the basic-level discrimination, confirming our hypothesis that basic-level superiority is affected by between-category similarity. Keywordspigeons; categorization; basic category; superordinate category; visual discrimination; stimulus similarity Categories are often considered to be organized at multiple hierarchical levels, such as the subordinate, basic, and superordinate levels. The subordinate-level categories office chair and dining chair are included in the basic-level category chair which, in turn, is included in the superordinate-level category furniture.Send correspondence to: Olga F. Lazareva, olga.lazareva@drake.edu, telephone: (515) 271-4801, fax: (515) 316 Olin Hall, Department of Psychology, Drake University, Des Moines, IA 50311-4505. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptBehav Processes. Author manuscript; available in PMC 2011 October 1. Published in final edited form as:Behav Processes. 2010 October ; 85(3): 236-245. doi:10.1016/j.beproc.2010.014. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptStarting with the pioneering research of Rosch and colleagues (Rosch & Merv...

Scene gist categorization by pigeons.

“…In addition, Lazareva, Soto and Wasserman (2010) showed that pigeons demonstrate a superordinate level categorization advantage if the basiclevel categories are similar, but the opposite pattern if the basic-level categories are very distinct. This suggests that the discriminability of different scene categories should be considered when making such comparisons.…”

Natural category discrimination in chimpanzees (Pan troglodytes) at three levels of abstraction

“…This chimpanzee also appeared to acquire the most abstract discriminations the most slowly, consistent with the idea that more abstract discriminations, in which exemplars share fewer perceptual features, should be the most difficult for nonverbal organisms to acquire. Within-category variance may have been more important than between-category variance for these chimpanzees (Lazareva et al, 2004;Lazareva et al, 2010). Although Marsh and MacDonald (2008) examined the features used by orangutans to perform concrete level discriminations, the factors underlying more abstract level concepts have yet to be identified.…”

“…In addition, given that very distantly related species, such as honeybees, have been shown to categorize at reasonably abstract levels (Benard, Stach, & Giurfa, 2006), the extent to which the process is an analogue to abstraction in humans has been questioned. Lazareva, Soto, and Wasserman (2010) have suggested that even abstract concepts may be readily discriminated because, although the exemplars within categories are perceptually diverse, there is also much greater variance and less overlap between the categories. The category discrimination tasks traditionally presented to pigeons and other animals may, therefore, allow even the more abstract categories to be discriminated on a perceptual basis (Vonk & Povinelli, 2012).…”

Conceptualization in pigeons: The evolution of a paradigm

“…Left-right reflection had no effect on pigeons' classification behavior, whereas top-bottom inversion, blurring, and quartering/scrambling of the photographs differentially impaired their categorization of natural and artificial stimuli. In addition, Lazareva, Soto, and Wasserman (2010) reported that betweencategory similarity affects the relative speeds of pigeons' learning basic-level and superordinatelevel tasks; these data may help to explain the occasionally contradictory results that have been reported in the developmental literature (e.g., Mandler & Bauer, 1988;Mareschal & Quinn, 2001;Oakes & Rakison, 2003;Rosch et al, 1976).…”