A tale of two simples

A material simple is a material object that has no proper parts. Some philosophers have argued for the possibility of extended simples. Some have even argued for the possibility of heterogeneous simples or simples that have intrinsic variations across their surfaces. There is a puzzle, though, that is meant to show that extended, heterogeneous simples are impossible. Although several plausible responses have been given to this puzzle, I wish to reopen the case against extended, heterogeneous simples. In this paper, I briefly canvass responses to this puzzle which may be made in defense of extended, heterogeneous simples. I then present a new version of this puzzle which targets simples that occupy atomic yet extended regions of space. It seems that none of the traditional responses can be used to successfully save this particular kind of extended simple from the new puzzle. I also consider some non-traditional defenses of heterogeneous extended simples and argue that they too are unsuccessful. Finally, I will argue that a substantial case can be made against the possibility of extended heterogeneous simples of any kind.     

Properties of long-range illusory contours produced by offset-arcs

Researchers have used several different types of illusory contours to investigate properties of human perception. One rarely used illusory contour is a combination of the abutting grating and Kanizsa illusions. We call this the offset-arcs illusion and provide an empirical investigation of the illusion. Through a series of four experiments, using different methods of measurement, we show that changes to the phase of the abutting-grating part of the inducing stimulus can dramatically change the perceived strength and clarity of the long-range illusory contour. The easy manipulation of illusion strength should make the offset-arcs illusion applicable to a wide range of studies that utilize long-range illusory contours. The lack of a brightness component to the illusion should allow the offset-arcs illusion to help separate perceptual grouping from surface brightness effects that are often confounded in other illusory contours.     

Attentional capture under high perceptual load

Attentional capture by abrupt onsets can be modulated by several factors, including the complexity, or perceptual load, of a scene. We have recently demonstrated that observers are less likely to be captured by abruptly appearing, task-irrelevant stimuli when they perform a search that is high, as opposed to low, in perceptual load (Cosman & Vecera, 2009), consistent with perceptual load theory. However, recent results indicate that onset frequency can influence stimulus-driven capture, with infrequent onsets capturing attention more often than did frequent onsets. Importantly, in our previous task, an abrupt onset was present on every trial, and consequently, attentional capture might have been affected by both onset frequency and perceptual load. In the present experiment, we examined whether onset frequency influences attentional capture under conditions of high perceptual load. When onsets were presented frequently, we replicated our earlier results; attentional capture by onsets was modulated under conditions of high perceptual load. Importantly, however, when onsets were presented infrequently, we observed robust capture effects. These results conflict with a strong form of load theory and, instead, suggest that exposure to the elements of a task (e.g., abrupt onsets) combines with high perceptual load to modulate attentional capture by task-irrelevant information.     

A probabilistic model of theory formation

Concept learning is challenging in part because the meanings of many concepts depend on their relationships to other concepts. Learning these concepts in isolation can be difficult, but we present a model that discovers entire systems of related concepts. These systems can be viewed as simple theories that specify the concepts that exist in a domain, and the laws or principles that relate these concepts. We apply our model to several real-world problems, including learning the structure of kinship systems and learning ontologies. We also compare its predictions to data collected in two behavioral experiments. Experiment 1 shows that our model helps to explain how simple theories are acquired and used for inductive inference. Experiment 2 suggests that our model provides a better account of theory discovery than a more traditional alternative that focuses on features rather than relations.     

Making Meaning of Trauma: Trauma Exposure Doesn’t Tell the Whole Story

Although traumatic experiences are relatively common, there is wide variability in individuals’ responses to them. This study examined trauma exposure, meaning making efforts (indexed by post-traumatic cognitions), and post-traumatic stress symptoms (PTS) in a non-clinical volunteer student sample (N = 631). We further examined the moderating role of gender, the importance of trauma type (interpersonal vs. non-interpersonal), and the impact of cumulative traumatic experiences. About 75% of the sample reported past trauma (n = 475). Women reported more interpersonal trauma than did men. For both genders, trauma exposure was associated with more PTS. A dose–response relationship was found between the extent of trauma exposure and negative post-traumatic cognitions. Importantly, post-traumatic cognitions predicted PTS controlling for amount of trauma exposure. It appears that it is not merely exposure to negative events that matters, but how we construe and make sense of these experiences. This study extends our understanding of gender differences, meaning-making, and responses to trauma exposure, and suggests avenues of clinical treatment.     

When animals attack: The effects of mortality salience, infrahumanization of violence, and authoritarianism on support for war

Terror management theory (TMT) suggests that people are motivated to elevate themselves above other animals as a way of denying their creatureliness and mortality. Based on this reasoning, the present study assessed whether infrahumanizing violence by emphasizing its similarities to animal aggression would lead to reduced support for war, especially when mortality is salient. This hypothesis was supported among participants high in right-wing authoritarianism (RWA), who are especially prone to infrahumanize outgroup members and are generally more supportive of military action against outgroups. RWA was associated with greater support for war against Iran, except when primed with thoughts of death and violence as an infrahuman behavior. These data suggest that by portraying violence as something instinctual and creaturely, it may be possible to reduce inter-group hostility and aggression among individuals who tend to be more dispositionally aggressive, particularly in the context of the death awareness that often exacerbates inter-group conflict.