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Cogn Dev 15:185–214Ĭerella J (1980) The pigeon's analysis of pictures. Child Dev 70:1314–1324Ĭallaghan TC (2000) Factors affecting children's graphic symbol use in the third year: language, similarity, and iconicity. J Comp Psychol 101:82–89Ĭallaghan TC (1999) Early understanding and production of graphic symbols. J Exp Psychol: Anim Behav Proc 14:219–234īoysen ST, Bernston GG, Prentice J (1987) Simian scribbles: a reappraisal of drawing in the chimpanzee ( Pan troglodytes). Thus, the calculated chance level was 25%.īhatt RS, Wasserman EA, Reynolds WF, Knauss KS (1988) Conceptual behavior in pigeons: categorization of both familiar and novel examples from four classes of natural and artificial stimuli. In the same way, the number of images chosen from the other three categories will be calculated as follows: tree: 165, grass: 165, and others: 165. If the subject randomly chooses three items among the presented items in 220 trials, the subject will choose a total of 165 correct images. In these cases, the subject chose 108 correct images in total (108×1). There are 108 ways in which the subject chose one flower and two from the other categories (i.e., 3C 1× 9C 2). In these cases, the subject chose 54 correct images in total (27×2). There are 27 ways in which the subject chose two flowers and one item from the other three categories (i.e., 3C 2× 9C 1). In this case, the subject chose three correct images in total (1×3). Among the combination of the chosen items, there is one combination wherein all three items are flowers. There are 220 ways in which the subject chose three items among the 12 different presented items (i.e., 12C 3=220). The results of this study suggest a relationship between pictorial competence and symbolic one.Ĭalculation of chance level in test trials.

Her learning history might have aided her in acquiring this skill. Only one adult chimpanzee, who had acquired skill in recognizing visual symbols, also recognized pictures aside from the juvenile chimpanzees. The results also suggest “critical period” in acquisition of skill in recognizing pictures in chimpanzees. The results revealed that not all chimpanzees could recognize pictures used by humans without training. The other three adult chimpanzees’ performance level did not exceed the chance level in terms of choosing nonphotographic images although they showed good transfer skills to novel photographs. One adult and all three juvenile chimpanzees were able to choose any style of the nonphotographic images of flowers significantly above the chance level, whereas none could choose the correct Kanji characters corresponding to a flower significantly above the chance level. As a generalization test, the following five types of images were presented: (1) novel photographs, (2) colored sketches (more realistic), (3) a colored clip art (cartoon-like images), (4) black-and-white line drawings, and (5) Kanji characters (as the control images). Four adults and three juvenile chimpanzees were trained to choose images of photographs of flowers among 12 items belonging to four categories on a touch-sensitive monitor. In this study, I investigated chimpanzees’ ability to recognize pictorial representations.

Chimpanzee drawing