Short-term memory effects on visual global/local processing in tufted capuchin monkeys (Sapajus spp.).

Abstract

All authors contributed equally to the paper.We wish to thank the three anonymous reviewers for their valuable suggestions and constructive comments on the manuscript. We acknowledge Massimiliano Bianchi and Simone Cartarinacci for help with animal management and Ludovica Cazzato for help with data collection. We also thank the Comune di Roma-Museo Civico Zoologia and Non-human primates, differently from humans, are less proficient at processing 6 global properties of visual compound stimuli. It has been suggested that humans 7 preferentially process stimuli globally because this enables a more economical encoding 8 of the stimuli. In this study we assessed the role of short-term memory in global/local 9 processing by presenting tufted capuchin monkeys with Navon-type hierarchical figures 10 in both simultaneous and delayed matching-to-sample tasks. Capuchins' ability to 11 discriminate hierarchical stimuli was evaluated as a function of increasing delay intervals 12 (0.0, 0.5, 1.0, 2.0 and 3.0 sec) between the disappearance of the sample and the 13 presentation of the comparison stimuli. The results showed that recognition accuracy for 14 local features was above chance level with delays of up to 3.0 sec, as previously reported 15 when capuchins were faced with non-hierarchical stimuli. By contrast, the recognition of 16 global configurations was above chance level in simultaneous, 0.0 and 0.5 sec delay 17 conditions but not at delay intervals of 1.0 sec or longer. These findings indicate that 18 capuchins' propensity to process the local properties of visual stimuli can be observed 19 when a delay is interposed between the presentation of sample and comparison stimuli 20 and was not reversed by increasing the delay. Moreover, our results show that capuchins' 21 local propensity was not reversed by increasing stimulus size. Overall, our study 22 confirms crucial differences between human and non-human primates and adds new 23 insights into the comparative research on visual grouping functions of these species. 24 25

Are you as fooled as I am? Visual illusions in human (Homo) and nonhuman (Sapajus, Gorilla, Pan, Pongo) primate species.

“…If we assume that nonhuman primates are less globally oriented than humans, an assumption that is supported by empirical evidence (Fagot & Deruelle, 1997;Fagot & Tomonaga, 1999), our results are consistent because humans, especially older children and adults, showed much stronger illusionary effects than any of the primate species. However, if we focus exclusively on nonhuman primates and assume that chimpanzees process stimuli more globally than monkeys, again something that has received some empirical support (Fagot & Deruelle, 1997;Hopkins & Washburn, 2002;Truppa et al, 2016), our data do not support the global-local precedence as an explanation for interspecific differences. First of all, despite the putative differences in global-local processing between monkeys and apes, we found no significant differences between species in most tests.…”

“…Interestingly, a prevalence of global over local feature processing—the so-called global precedence effect (Navon, 1977)—that was shown in (western) humans could not be found in baboons (Fagot & Deruelle, 1997). Data from capuchin monkeys also suggest a more locally oriented processing style (Spinozzi et al, 2006; Truppa et al, 2016, 2017). Whereas these monkey subjects primarily process the local features of a stimulus array, chimpanzees seem to fall in between humans and monkeys depending on the presentation format used.…”

Global/local processing of hierarchical visual stimuli in a conflict–choice task by capuchin monkeys (Sapajus spp.)

“…For example, paradigms may 100 inadvertently differ in their memory requirements with possible consequences for the type of 101 visual system and resources that need to be recruited for the analysis of the stimuli. brief delays which require the short-term retention of stimulus structure (Truppa et al 2016). …”

Investigation of preference for local and global processing of Capuchin-monkeys (Sapajus spp.) in shape discrimination of mosaic arrangements

“…Numerous studies exploring perceptual grouping processes with visual stimuli reveal variations in the precedence of global or local cues across different species, including humans [ 9 – 11 ], chimpanzees [ 3 , 11 , 12 ], baboons [ 10 ], rhesus monkeys [ 12 ], cotton top tamarins [ 13 ], and capuchin monkeys [ 6 , 9 , 14 ]. In the context of platyrrhine monkeys, investigations into global and local processing have predominantly focused on capuchin monkeys [ 1 , 5 , 6 , 9 , 14 – 19 ]. Several of these experiments utilized matching-to-sample (MTS) procedures, and their outcomes consistently demonstrated an advantage for local level of hierarchical processing [ 1 , 14 , 16 , 18 , 19 ].…”