Cognitive precedence for local information in hierarchical stimulus processing by pigeons.

Abstract

Four experiments investigated the processing of hierarchical stimuli by pigeons. Using a 4 alternative divided-attention task, 4 pigeons were food-reinforced for accurately identifying letters arranged as either hierarchical global- or local-relevant stimuli or as size-matched filled stimuli. Experiment 1 found that task acquisition was faster with local-relevant than global-relevant stimuli. This difference was not due to letter size. Experiment 2 demonstrated successful transfer to a novel irrelevant letter configuration. Experiments 3 and 4 tested pigeons' responses to conflict probe stimuli composed of equally discriminable relevant letters at each level. These tests revealed that all of the pigeons showed a cognitive precedence for local information early in processing, with the pigeons using different cues to initiate the processing of global information. This local advantage contrasts with previously reported results for humans and pigeons but is similar to that reported for nonhuman primates. Alternatives attempting to reconcile these contrasting comparative results are considered.

Scalar effects in the visual discrimination of numerosity by pigeons

“…A common finding is that humans tend to show a "global precedence effect," focusing on the overall stimulus configuration (see, e.g., J. Miller, 1981;Navon, 1977), whereas pigeons have shown a bias toward discriminating local features over global ones (Cavoto & Cook, 2001;Fremouw, Herbranson, & Shimp, 2002). There are exceptions to these general findings in both species.…”

Global and local processing of hierarchical visual stimuli in tufted capuchin monkeys (Cebus apella).

“…Although very convincing claims concerning the adaptive value of global precedence in the processing of visual information have been put forward (Navon, 1977), and there is clear evidence that priority is given to the processing of the overall spatial structure of the environment over the analysis of the featural details of the objects included in it (see, e.g., Cheng, 1986), results like ours (Cavoto & Cook, 2001;Fagot & Deruelle, 1997) challenge the generality of early claims concerning the adaptive value of global precedence in the processing of hierarchical figures (Navon, 1977).…”

“…However, given that the procedure adopted here involved a lengthy presentation of the stimuli in each trial, some inferences can be drawn concerning the relative stability of the local advantage in this species. The only study of which we are aware that addressed directly the problem of the stability of the priority of particular forms of processing in hierarchical stimuli in animals was recently conducted on pigeons and provided some evidence for a shift from local to global advantage when the duration of the stimulus presentation was increased from 750 ms to 5s (Cavoto & Cook, 2001). In our study, the duration of the presentation of the stimuli was much in excess of 5 s. It seems, therefore, that the local advantage exhibited by our subjects was relatively stable and immune from the variability that can be generated by the protracted exposure to the stimuli.…”

Integration of spatial maps in pigeons

“…They had prior experience with visual-choice discrimination touch-screen tasks (two from Cavoto and Cook 2001; one from Katz and Cook, unpublished data), but were naive to the task employed here. Subjects were maintained at 85% of their free-feeding weight during testing with free access to water and grit in their home cages, which were housed in a colony room with a 12-h light-dark cycle.…”