Area-matching strategies used by young children

Across three studies, conditions were varied under which children aged 4–5 years matched the area of a rectangle with a given width (or height) to that of a square. In the first study, subjects observed the rectangle being changed in height from trial to trial and had access to their immediately preceding response. Under these conditions, rectangle width (the dimension under subject control) was a linear decreasing function of rectangle height. This function was interpreted as evidence for a hypothetical addition/subtraction strategy for maintaining equality in area between the comparison rectangle and the standard square. As a test of this hypothesis, in a second experiment the subjects were denied access to their immediately previous response, and in a third study they were also unable to observe the rectangle as it was altered by the experimenter between trials. The purpose of these changes was to remove the information necessary for readily implementing an addition/subtraction strategy. In both studies, area matches seemed to be based on a side-matching strategy, such that subjects matched one dimension of the rectangle to one side of the standard square. It was suggested that young children use different cues or strategies with different variants of the matching task because they do not possess a fixed, specific concept of area.     

The causal psycho-logic of choice

Choices do not merely identify one option among a set of possibilities; choosing is an intervention, an action that changes the world. As a result, good decision making generally requires a model specifying how actions are causally related to outcomes. Interventions license different inferences than observations because an event whose state has been determined by intervention is not diagnostic of the normal causes of that event. We integrate these ideas into a causal framework for decision making based on causal Bayes nets theory, and suggest that deliberate decision making is based on simplified causal models and imaginary interventions. The framework is consistent with what we know so far about how people make decisions.     

Review article

A History of Pagan Europe PRUDENCE JONES & NIGEL PENNICK London and New York: Routledge, 1995 262 pp., £25.00 ISBN 0–415–09136–5     

The Punishment Gap: Racial/Ethnic Comparisons in School Infractions by Objective and Subjective Definitions

This research examines the differences between ethnic groups when school infractions are subjective/objective. Using school discipline incident data, eight categories of infractions are analyzed: disobedience, violence, substance abuse, vandalism, theft, truancy, safety, and miscellaneous. Within these eight categories there are 32 specific infractions. Specific infractions were then classified as either subjective or objective by a committee. Population proportion criteria (PPC; minus or plus 10% of a group’s overall population) is used. Findings indicated that only black students exceeded the criteria with infractions having subjective definitions. All other groups only exceeded PPC with infractions having objective definitions.     

Category transfer in sequential causal learning: the unbroken mechanism hypothesis

The goal of the present set of studies is to explore the boundary conditions of category transfer in causal learning. Previous research has shown that people are capable of inducing categories based on causal learning input, and they often transfer these categories to new causal learning tasks. However, occasionally learners abandon the learned categories and induce new ones. Whereas previously it has been argued that transfer is only observed with essentialist categories in which the hidden properties are causally relevant for the target effect in the transfer relation, we here propose an alternative explanation, the unbroken mechanism hypothesis. This hypothesis claims that categories are transferred from a previously learned causal relation to a new causal relation when learners assume a causal mechanism linking the two relations that is continuous and unbroken. The findings of two causal learning experiments support the unbroken mechanism hypothesis.     

The Changing Age of Individuals Seeking Presymptomatic Genetic Testing for Huntington Disease

Huntington disease (HD) is a progressive neurodegenerative disorder. Presymptomatic genetic testing allows at-risk individuals to clarify their risk status. Understanding the characteristics and motivations of individuals seeking HD presymptomatic genetic testing better equips genetic counselors and other healthcare professionals to provide comprehensive and personalized care. The aims of this study were to (1) determine whether the average age when individuals seek presymptomatic HD genetic testing has decreased over time, (2) assess motivations for seeking testing, (3) explore whether there is a relationship between age and motivations, and (4) explore genetic counselors’ perceptions of the shift in age. Data from the US HD testing centers (N?=?4) were analyzed. A small but statistically significant decrease in age of individuals seeking presymptomatic testing was observed (p?=?0.045). HD community members (N?=?77) were surveyed regarding presymptomatic testing motivations. Younger individuals were more likely than older individuals to cite “To learn whether or not you would develop HD” and “To make choices about further education or a career” compared to older individuals (p?<?0.05). Conversely, older individuals more frequently cited “To give children a better idea of their risk” (p?<?0.002). Sixteen percent of genetic counselors surveyed (6/37) perceived a change in age of testing. All of these respondents had provided HD testing for ten or more years and anecdotally believed the age at testing has decreased over time. Study results help providers personalize counseling based on patient’s age and serve as a starting point for more research into the relationship between age at testing and motivations for testing.     

Estimating causal strength: the role of structural knowledge and processing effort.

The strength of causal relations typically must be inferred on the basis of statistical relations between observable events. This article focuses on the problem that there are multiple ways of extracting statistical information from a set of events. In causal structures involving a potential cause, an effect and a third related event, the assumed causal role of this third event crucially determines whether it is appropriate to control for this event when making causal assessments between the potential cause and the effect. Three experiments show that prior assumptions about the causal roles of the learning events affect the way contingencies are assessed with otherwise identical learning input. However, prior assumptions about causal roles is only one factor influencing contingency estimation. The experiments also demonstrate that processing effort affects the way statistical information is processed. These findings provide further evidence for the interaction between bottom-up and top-down influences in the acquisition of causal knowledge. They show that, apart from covariation information or knowledge about mechanisms, abstract assumptions about causal structures also may affect the learning process.