Processing of contour closure by baboons (Papio papio).

Abstract

This study investigated the Gestalt law of closure in baboons. Using a computer-controlled self-testing procedure, we trained baboons (Papio papio) to discriminate open versus closed shapes presented on a touch screen with a two-alternative forced choice procedure. Ten baboons (OPEN + group) were trained with the open shapes serving as the positive stimulus (S+), and nine others (CLOSE + group) were trained with the closed shape serving as S+. The OPEN + group obtained higher discrimination performance than the CLOSE + group (Exp 1), but its scores declined when new line segments were added to the stimuli (Exp 2) and after smoothing the end points of the open shapes (Exp 3). The CLOSE + group was less affected by the above manipulations of local stimulus dimension, but its performance was disrupted when the collinearity end points was reduced (Exp 3). Use of a visual search task revealed that the search for an open shape among closed distractors was less attention demanding in baboons than the search for a closed shape among open ones (Exp 4). It is concluded that (1) end lines rather than closeness per se are perceptual primitives for the open versus closed discrimination in baboons, and (2) the relative emphasis on local or configural cues when processing contour closure depends on experiential factors in baboons and is thus subject to interindividual variations.

Age-dependant behavioral strategies in a visual search task in baboons (Papio papio) and their relation to inhibitory control.

“…That is, there was a positive association between RT and the bits of information processing demand. This finding converges with previous reports also showing that RTs increased in visual search tasks with display size in baboons (Barbet & Fagot, 2011;Deruelle & Fagot, 1998) and chimpanzees (Fagot & Tomonaga, 1999), and that the RTs also follow Hick's law in similar test conditions in pigeons (Vickrey & Neuringer, 2000). Noticeably, the RT slope of the baboons (54 ms/bit) is close to that initially reported in humans (e.g., from 34 to 44 ms/bit in Vickrey & Neuringer, 2000), suggesting similar modes of processing in the two species.…”

“…These microchips served the self-identification procedure (see below). All baboons were already familiar with the Hick task from previous unpublished studies and other visual search tasks (e.g., Barbet & Fagot, 2011), but have never received the Hick task using the ϩ-shaped and ϫ-shaped stimuli involved in the current research. Automated learning device for monkeys test systems.…”

Automated cognitive testing of monkeys in social groups yields results comparable to individual laboratory-based testing

“…Andrews and Rosenblum (1994), Wallen (Hasset et al 2007), and Fagot (2009) have created cognitive testing systems that use RFID chips to identify individual monkeys as they complete computerized motor, perceptual, and cognitive tasks. Monkeys living in small groups have been found to perform motor and cognitive tasks (motor: Andrews and Rosenblum 1994; visual search: Barbet and Fagot 2011; Bonte et al 2011; Fagot and Bonte 2010; working memory: Fagot and De Lillo 2011; complex matching: Fagot and Paleressompoulle 2009; orthographic processing: Grainger et al 2012), indicating the feasibility of this method of testing.…”

Animal Camouflage: Disentangling Disruptive Coloration from Background Matching

“…2.3) (Anderson et al, 2002, Kellman and Shipley, 1991, Anderson, 2013. Because decision making during instances of incomplete visual information is a ubiquitous problem, it is not surprising that contour completion is another common mechanism of shape perception shared by humans and non-humans (mammals (Barbet and Fagot, 2011, Parron and Fagot, 2007, Deruelle et al, 2000, Sato et al, 1997, Kurylo, 2008, Fujita, 2001, Kanizsa et al, 1993, birds (Nakamura et al, 2010, Nagasaka et al, 2005, Cavoto and Cook, 2006, Regolin and Vallortigara, 1995 and fishes (Truppa et al, 2010, Sovrano andBisazza, 2008), but see (Burke et al, 2001)). The final stage of object recognition is to utilize shape information for object identification.…”

“…A common challenge in shape perception is recognising incomplete shapes, such as objects that are occluded. Such objects can still be accurately recognised based on incomplete shape information in mammals (Barbet and Fagot, 2011, Parron and Fagot, 2007, Deruelle et al, 2000, Sato et al, 1997, Kurylo, 2008, Fujita, 2001, Kanizsa et al, 1993, birds (Nakamura et al, 2010, Nagasaka et al, 2005, Cavoto and Cook, 2006, Regolin and Vallortigara, 1995 and fishes (Truppa et al, 2010, Sovrano andBisazza, 2008) (but see (Burke et al, 2001)). These results are particularly strong in ecologically meaningful experiments; for instance, blue tits (Parus caeruleus) can recognise and elicit antipredator behaviour towards occluded models of their predators (Tvardikova and Fuchs, 2010).…”