VISITING DEAD ANCESTORS: SHAMANS AS INTERPRETERS OF RELIGIOUS TRADITIONS

Abstract. Religious traditions enable ancestors to encourage proper social behavior in their distant descendants. Although traditional myths and rituals can provide basic values, these values must be interpreted in light of the specific circumstances encountered by later generations. In tribal societies the task of interpreting religious traditions falls upon religious leaders known as shamans. Shamans, perhaps universally, are claimed to obtain instructions from dead ancestors on how to deal with social disruptions. This paper argues that a focus on the more exotic aspects of shamanism has kept previous studies from realizing the crucial role of shamans as interpreters of religious traditions.     

LOCAL AND GLOBAL PROCESSES IN VISUAL COMPLETION

In the natural environment, objects are frequently occluded, and people continuously complete partly occluded objects Do local processes or global processes control the completion of partly occluded objects? To answer this question, most previous studies simply asked subjects to draw the completions they "saw" Such drawing tasks are highly subjective, and they provide equivocal results Our studies are the first to use an objective, implicit paradigm (primed matching) to determine the extent to which local or global processes underlie the visual completion of partly occluded objects Our results suggest that global processes dominate perceptual completion, whereas local processes do not play a large role Therefore, local theories of completion, or theories in which local processes dominate, cannot be entirely correct     

Hierarchical structure in perceptual representation

A theoretical framework for perceptual representation is presented which proposes that information is coded in hierarchical networks of nonverbal propositions. The hierarchical structure of the representations implies selective organization: Some subsets of a figure will be encoded as integral, structural units of that figure, while others will not. A context-sensitive metric for the “goodness” of a part within a figure is developed, corresponding to the probability that the subset will be encoded as a structural unit. Converging evidence supporting this position is presented from four different tasks using simple, straight-line figures. The tasks studied are (a) dividing figures into “natural” parts, (b) rating the “goodness” of parts within figures, (c) timed verification of parts within figures, and (d) timed mental synthesis of spatially separated parts into unitary figures. The results are discussed in terms of the proposed theory of representation, the processes that operate on those representations, and the general implications of the data for perceptual theories.     

Do Internet‐Based Support Interventions Change Perceptions of Social Support?: An Experimental Trial of Approaches for Supporting Diabetes Self‐Management

Internet-based support groups are a rapidly growing segment of mutual aid programs for individuals with chronic illnesses and other challenges. Previous studies have informed us about the content of online exchanges between support group members, but we know little about the ability of these interventions to change participants' perceptions of support. A randomized trial of 160 adult Type 2 diabetes patients provided novice Internet users with computers and Internet access to 1 of 4 conditions: (a) diabetes information only, (b) a personal self-management coach, (c) a social support intervention, or (d) a personal self-management coach and the support intervention. After 3 months, individuals in the 2 support conditions reported significant increases in support on a diabetes-specific support measure and a general support scale. Participants' age was significantly related to change in social support, but intervention effects were still significant after accounting for this relationship. This report is a critical first step in evaluating the long-term effects of Internet-based support for diabetes self-management. The discussion identifies directions for future research.     

Top-down influences on perceptual grouping

Observers are faster to find and discriminate a target pair of adjacent, same-shaped objects that are within the same perceptual group (within group) versus within adjacent perceptual groups. Manipulating the probability of a within-group pair modulated this grouping effect such that it increased as the percentage of within-group trials (25%, 50%, or 75%) increased. This probability effect was stronger for extrinsic grouping factors (common region and connectedness) than for intrinsic factors (proximity and color similarity). Further experiments, however, suggested that this extrinsic-intrinsic difference was due to differences in overall speed with which the target pair was found. The results are interpreted as indicating that grouping is sensitive to top-down influences as long as there is sufficient time for feedback to operate.     

The role of type and token frequency in using past tense morphemes correctly

Type and token frequency have been thought to be important in the acquisition of past tense morphology, particularly in differentiating regular and irregular forms. In this study we tested the role of frequency in two ways: (1) in bilingual children, who typically use and hear either language less often than monolingual children and (2) cross-linguistically: French and English have different patterns of frequency of regular/irregular verbs. Ten French-English bilingual children, 10 French monolingual and 10 English monolingual children between 4 and 6 years watched a cartoon and re-told the story. The results demonstrated that the bilingual children were less accurate than the monolingual children. Their accuracy in both French and English regular and irregular verbs corresponded to frequency in the input language. These results are consistent with the hypothesis that children learn past tense morphemes by analogy with other words in their vocabularies. We propose a developmental sequence based on conservative generalization across a growing set of verbs.     

The occlusion illusion: partial modal completion or apparent distance?

In the occlusion illusion, the visible portion of a partly occluded object (eg a semicircle partly hidden behind a rectangle) appears to be significantly larger than a physically identical region that is fully visible. This illusion may occur either because the visual system 'fills in' a thin strip along the occluded border (the partial-modal-completion hypothesis) or because the partly occluded object is perceived as farther away (the apparent-distance hypothesis). We measured the magnitude of the occlusion illusion psychophysically in several experiments to investigate its causes. The results of experiments 1-3 are consistent with the general proposal that the magnitude of the illusion varies with the strength of the evidence for occlusion, supporting the inference that it is due to occlusion. Experiment 4 provides a critical test between apparent-distance and partial-modal-completion explanations by determining whether the increase in apparent size of the occluded region results from a change in its perceived shape (due to the modal extension of the occluded shape along the occluding edge, as predicted by the partial-modal-completion hypothesis) or from a change in its perceived overall size (as predicted by the apparent-distance hypothesis). The results more strongly support the partial-modal-completion hypothesis.