A comparison of the efficacy of different decay functions in geographical profiling for a sample of US serial killers

Many studies have shown that distributions of the distances that offenders travel in the commission of their offences are typically characterised by a decay function. However, there are few empirical comparisons of the different mathematical functions which may characterise such distributions. Further, there has been little consideration of what different forms of function may reflect about the underlying factors and psychological processes governing this aspect of the journey to crime. With the increasing use of geographical profiling systems which incorporate decay functions into their calculations, it is particularly of value to explore the most appropriate mathematics for describing the frequencies of crime journeys and to determine the impact of different decay functions on the effectiveness of a geographical profiling system. A two‐stage study was therefore carried out using data derived from 96 US serial killers. In the first stage three different decay functions were examined, in terms of the extent to which they fitted a distribution of the distances travelled to offend for the sample; logarithmic, in accordance with Steven's ‘Power Law’ for distance estimation; negative exponential as an estimate based on the ‘friction’ generated by journeys; and quadratic, which reflects key principles found from journey to crime research. A ‘control’ function, simple negative linear, was also tested against the data. It was found the logarithmic function provided the closest approximation to the journey to crime distances of offenders in the present sample (R² = 0.81, p < 0.001), suggesting that distance estimations may be an important part of the explanation for the length of the crime trips that offenders make. In the second stage, all four functions were utilised within a geographical profiling system (Dragnet) and their impact on the search cost for locating an offender established for the whole sample. In general it was found that the search cost function, which relates the proportion of the sample to the search cost, was positively monotonic with a distinct change in gradients around 58% of the sample, indicating that the software was producing useful results in the majority of cases. However, although the logarithmic function produced the best results overall, and the linear function the worst, as hypothesised, no significant differences between the search costs were found when each of the different functions was utilised. The implications for the robustness of the software and the possible influence of the low precision of the raw data are discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

Relating different perspectives on how outcomes of behavior influence behavior

Many researchers have tackled the question of how behavior is influenced by its outcomes. Some have adopted a nonmechanistic (functional) perspective that attempts to describe the influence of outcomes on behavior. Others have adopted a mechanistic (cognitive) perspective that attempts to explain the influence of outcomes on behavior. Orthogonal to this distinction, some have focused on the influence of outcomes that a behavior had in the past, whereas others also consider the influence of outcomes that a behavior might have in the future. In this article, we relate these different perspectives with the goal of reducing misunderstandings and fostering collaborations between researchers who adopt different perspectives on the common question of how behavior is influenced by its outcomes.     

Features and feedback: enhancing metamnemonic knowledge at retrieval reduces source-monitoring errors

Three experiments explored the issue of whether enhanced metamnemonic knowledge at retrieval can improve participants' ability to make difficult source discriminations in the context of the eyewitness suggestibility paradigm. The 1st experiment documented differences in phenomenal experience between veridical and false memories. Experiment 2 revealed that drawing participants' attention to these differences by pairing the ratings of the features with instructions about their utility was successful in reducing source misattributions of suggested items to the event. The results of Experiment 3 showed that participants can make online adjustments in the types of evidence used to make source judgments, as participants who received correct feedback during the training portion of the test reduced misattribution errors on the remainder of the test where feedback was not provided. Altogether, these studies suggest that people can discover and benefit from updated knowledge of the types of memorial evidence that discriminate between sources of information in memory.     

How Do You Say Nature?: Opening the Design Space with a Knowledge Environment

In this paper, we describe a design study on how families in Los Angeles experience nature, with a particular focus on how using alternative formats for research analysis and presentation can enrich a design research inquiry. Conducted in Pasadena, CA as a part of Super Studio, the year-long design research class emphasized knowledge building and sharing through design methods of analysis, exhibition, and concept prototypes. After conducting interviews and engaging participants with probes, the class built the results into an open-ended knowledge environment. The main observation from the exhibition – that Angelenos have a limited vocabulary for describing nature and their interaction with it – helped to define the opportunity for design intervention that created connection points between Angelenos and nature. There are few attempts to describe how probe returns evolve into design concepts. Showcased is a process that depends on the unique affordances of design as the vehicle for discovery and invention.     

Second-order beliefs about intention and children's attributions of sociomoral judgment

Predicting how another person will evaluate the intention underlying an action involves consideration of second-order mental states. Children (ages 5-10 years) and college students (N=105) predicted an observer's belief about an actor's intention and evaluated the actor from both their own perspectives and the perspective of the observer. Younger children were more likely than older children and adults to attribute a belief to the observer that mismatched the actor's prior intention. Attributed beliefs about intention were more likely to match negative prior intentions than to match positive prior intentions and were also more likely to match prior intentions when the observer knew the actor's prior intention than when the observer did not know the actor's prior intention. The judgments attributed to the observer were based on the beliefs about intention attributed to the observer, showing use of second-order mental states to infer another's sociomoral judgments.     

Liminal Subjectivities and Religious Change: Circumscribing Giddens for the Study of Contemporary American Religion

Observers of American religion have noted significant changes in the last 50 years. Many of the current theories interpreting these changes cite the writings of the British social theorist Anthony Giddens. Such works suggest that we are living in a post-traditional, ‘late modern’ society in which self-identity, community, and the codes we live by are no longer ascribed, but reflexively made and re-made in continuous ‘projects of the self’. This article seeks to circumscribe late modernity theory for the study of contemporary religion, examining its usefulness and limitations. I argue that the disembedding structures of late modernity—while uneven in their effects on individuals from different social locations—create ‘liminal subjectivities’ among certain classes and groups. This state of being ‘betwixt and between’ social locations places individuals into new and sometimes ephemeral social networks, which in turn may result in them seeking out and experimenting with new religious groups, beliefs, and practices.     

The Social Production of Altruism: Motivations for Caring Action in a Low-Income Urban Community

Contemporary social science paints a bleak picture of inner-city relational life. Indeed, the relationships of low-income, urban-residing Americans are represented as rife with distress, violence and family disruption. At present, no body of social scientific work systematically examines the factors that promote loving or selfless interactions among low-income, inner-city American individuals, families and communities. In an effort to fill that gap, this ethnographic study examined the motivations for altruism among a sample of adults (n = 40) who reside in an economically distressed housing community (i.e., housing project) in New York City. Content analyses of interviews indicated that participants attributed altruism to an interplay between 14 motives that were then ordered into four overarching categories of motives: (1) needs-centered motives, (2) norm-based motives deriving from religious/spiritual ideology, relationships and personal factors, (3) abstract motives (e.g., humanism), and (4) sociopolitical factors. The implications of these findings are discussed.     

Development of cultural strategies of attention in North American and Japanese children

Recent studies suggest that North American adults exhibit a focused strategy of attention that emphasizes focal information about objects, whereas Japanese adults exhibit a divided strategy of attention that emphasizes contextual information about objects. The current study investigated whether 4- and 5-, 6- to 8-, and 9- to 13-year-old North American and Japanese children exhibit these divergent attention strategies. Two experiments suggest that those older than 6 years of age exhibit measurable cultural differences in attention, whereas 4- to 6-year-olds do not. We suggest that sociocognitive development and socialization experiences that occur around 5 to 7 years of age may foster the development of cultural strategies of attention.     

Origins of the stuttering stereotype: stereotype formation through anchoring-adjustment

The stereotype of people who stutter is predominantly negative, holding that stutterers are excessively nervous, anxious, and reserved. The anchoring–adjustment hypothesis suggests that the stereotype of stuttering arises from a process of first anchoring the stereotype in personal feelings during times of normal speech disfluency, and then adjusting based on a rapid heuristic judgment. The current research sought to test this hypothesis, elaborating on previous research by [White, P. A., & Collins, S. R. (1984). Stereotype formation by inference: A possible explanation for the “stutterer” stereotype. Journal of Speech and Hearing Research, 27, 567–570]. Participants provided ratings of a hypothetical typical person who stutters, a person suffering from normal speech disfluency and a typical male on a 25-item semantic differential scale. Results showed a stereotype of people who stutter similar to that found in previous research. The pattern of results is consistent with the anchoring–adjustment hypothesis. Ratings of a male stutterer are very similar to a male experiencing temporary disfluency, both of which differ from ratings of a typical male. As expected, ratings of a stutterer show a small but statistically significant adjustment on several traits that makes the stereotype of stutterers less negative and less emotionally extreme than the temporarily disfluent male. Based on the results of this research, it appears that stereotype formation is a result of generalization and adjustment from personal experience during normal speech disfluency.

Educational objectives: The reader will be able to: (1) explain how the negative stereotype of people who stutter arises; (2) discuss the negative implications of stereotypes in the lives of people who stutter; and (3) summarize why the stereotype of people who stutter is so consistent and resistant to change.