Serge Caparos

Bouba and Kiki in Namibia? A remote culture make similar shape―sound matches, but different shape―taste matches to Westerners

Western participants consistently match certain shapes with particular speech sounds, tastes, and flavours. Here we demonstrate that the Bouba-Kiki effect, a well-known shape-sound symbolism effect commonly observed in Western participants, is also observable in the Himba of Northern Namibia, a remote population with little exposure to Western cultural and environmental influences, and who do not use a written language. However, in contrast to Westerners, the Himba did not map carbonation (in a sample of sparkling water) onto an angular (as opposed to a rounded) shape. Furthermore, they also tended to match less bitter (i.e., milk) chocolate samples to angular rather than rounded shapes; the opposite mapping to that shown by Westerners. Together, these results show that cultural-environmental as well as phylogenetic factors play a central role in shaping our repertoire of crossmodal correspondences.

Exposure to an urban environment alters the local bias of a remote culture

There is substantial evidence that populations in the Western world exhibit a local bias compared to East Asian populations that is widely ascribed to a difference between individualistic and collectivist societies. However, we report that traditional Himba - a remote interdependent society - exhibit a strong local bias compared to both Japanese and British participants in the Ebbinghaus illusion and in a similarity-matching task with hierarchical figures. Critically, we measured the effect of exposure to an urban environment on local bias in the Himba. Even a brief exposure to an urban environment caused a shift in processing style: the local bias was reduced in traditional Himba who had visited a local town and even more reduced in urbanised Himba who had moved to that town on a permanent basis. We therefore propose that exposure to an urban environment contributes to the global bias found in Western and Japanese populations.

The Spatial Focus of Attention Is Controlled at Perceptual and Cognitive Levels.

Selective attention has been hypothesized to reduce distractor interference at both perceptual and postperceptual levels (Lavie, 2005), respectively, by focusing perceptual resources on the attended location and by blocking at postperceptual levels distractors that survive perceptual selection. This study measured the impact of load on these selection mechanisms using a flanker paradigm (Eriksen & St. James, 1986) and indexing distractor interference as a function of separation. It distinguished changes in the extent of focus of the distractor-interference function of separation (reflecting perceptual selection) from changes in the amplitude of distractor interference not accompanied by changes in focus (reflecting postperceptual selection). It showed that: (1) the spatial profile of perceptual resources is shaped like a Mexican hat (Müller et al., 2005); (2) increasing perceptual load focuses perceptual resources (Caparos & Linnell, 2009); (3) increasing cognitive load defocuses perceptual resources; and (4) participants with reduced working-memory span show reduced postperceptual blocking of distractors. While these findings are consistent with two levels of selective attention, they show that the first perceptual level is affected not only by perceptual but also by cognitive-control mechanisms.

Do Local and Global Perceptual Biases Tell Us Anything About Local and Global Selective Attention

Local, as opposed to global, perceptual bias has been linked to a lesser ability to attend globally. We examined this proposed link in Himba observers, members of a remote Namibian population who have demonstrated a strong local bias compared with British observers. If local perceptual bias is related to a lesser ability to attend globally, Himba observers, relative to British observers, should be less distracted by global information when performing a local-selection task but more distracted by local information when performing a global-selection task. However, Himba observers performed better than British observers did on both a local-selection task and a global-selection task (both of which used local/global hierarchical figures as stimuli), which suggests that they possessed greater control over attentional selection in response to task demands. We conclude that local and global perceptual biases must be distinguished from local and global selective attention.

Reduced Distractibility in a Remote Culture

Background In visual processing, there are marked cultural differences in the tendency to adopt either a global or local processing style. A remote culture (the Himba) has recently been reported to have a greater local bias in visual processing than Westerners. Here we give the first evidence that a greater, and remarkable, attentional selectivity provides the basis for this local bias. Methodology/Principal Findings In Experiment 1, Eriksen-type flanker interference was measured in the Himba and in Western controls. In both groups, responses to the direction of a task-relevant target arrow were affected by the compatibility of task-irrelevant distractor arrows. However, the Himba showed a marked reduction in overall flanker interference compared to Westerners. The smaller interference effect in the Himba occurred despite their overall slower performance than Westerners, and was evident even at a low level of perceptual load of the displays. In Experiment 2, the attentional selectivity of the Himba was further demonstrated by showing that their attention was not even captured by a moving singleton distractor. Conclusions/Significance We argue that the reduced distractibility in the Himba is clearly consistent with their tendency to prioritize the analysis of local details in visual processing.

The interacting effect of load and space on visual selective attention

In the study of visual attention, two major determinants of our ability to ignore distracting information have been isolated, namely, (1) the spatial separation from the focus of attention and (2) perceptual load. This study manipulated both factors using a dual-task adaptation of the flanker paradigm (Eriksen & Hoffman, 1973). It showed that (1) although attention followed a gradient profile under low perceptual load it followed a Mexican-hat profile under high perceptual load, consistent with the idea that increasing load focuses spatial attention; and (2) increasing perceptual load did not improve overall selectivity: Though selectivity improved at near separations, it was impaired at far ones. Load and spatial separation exert interacting effects.

Urbanization decreases attentional engagement

Exposure to the urban environment has been shown dramatically to increase the tendency to process contextual information. To further our understanding of this effect of urbanization, we compared performance on a local-selection task of a remote people, the Himba, living traditionally or relocated to town. We showed that (a) spatial attention was defocused in urbanized Himba but focused in traditional Himba (Experiment 1), despite urbanized Himba performing better on a working memory task (Experiment 3); (b) imposing a cognitive load made attention as defocused in traditional as in urbanized Himba (Experiment 2); and (c) using engaging stimuli/tasks made attention as focused in urbanized Himba, and British, as in traditional Himba (Experiments 4 and 5). We propose that urban environments prioritize exploration at the expense of attentional engagement and cognitive control of attentional selection.

Perceptual and cognitive load interact to control the spatial focus of attention

Caparos and Linnell (2009, 2010) used a variable-separation flanker paradigm to show that (a) when cognitive load is low, increasing perceptual load causes spatial attention to focus and (b) when perceptual load is high, decreasing cognitive load causes spatial attention to focus. Here, we tested whether the effects of perceptual and cognitive load on spatial focus remain when, respectively, cognitive load is high and perceptual load is low. We found that decreasing cognitive load only causes spatial attention to focus when perceptual load is high and the stimulus encourages this. Moreover, and contrary to the widely held assumption that perceptual load focuses attention automatically (Lavie, Hirst, de Fockert, & Viding, 2004), perceptual load exerts its focusing effect only with the engagement of cognitive resources when cognitive load is low. In sum, perceptual and cognitive mechanisms exert interacting effects and operate in concert to focus spatial attention.

When emotions improve reasoning: The possible roles of relevance and utility

New paradigms in the psychology of reasoning have included a consideration for general contextual factors that may impact on the reasoning process, including individuals’ goals and motivations. We suggest that emotions are one such important contextual factor that influences reasoning. The classic literature on thinking and reasoning has typically ignored the possible influence of emotion, except to consider it a source of disruption. We review findings from studies where participants were asked to reason about personally relevant emotional experiences such as sexual abuse, war, and terrorist attacks. While some findings are consistent with the view that incidental emotions have a deleterious effect on reasoning, a number of findings also suggest a beneficial impact of emotion. For instance, veterans reasoned more logically about combat-related syllogisms than structurally identical syllogisms with neutral contents; victims of sexual abuse reporting more negative emotions following the events also reasoned more logically on abuse-related contents, relative to neutral contents. This may be associated with integral emotions, when the affective reaction is relevant to the semantic contents reasoned about. We propose that the positive impact of integral emotions on reasoning can be explained by increased utility of problem content and increased utility of reasoning.

Perceptual load and early selection: an effect of attentional engagement?

The selection of task-relevant information from amongst task-irrelevant or distracting information is key to successful performance, and much debate has focused on the processing stage(s) at which this selection takes place. Early-selection theory claimed that the selection of task-relevant information occurs at an early perceptual level of processing, so that only targets are perceptually encoded (Cherry, 1953; Broadbent, 1958). In contrast, late-selection theory claimed that both targets and distractors are perceptually encoded and that target selection occurs at a late post-perceptual level of processing (DeutSch and DeutSch, 1963). Lavie (1995) attempted to reconcile these theories by suggesting that early and late selection occur, respectively, when the perceptual load associated with the selection of the target is high and low.