Treatment Choice and Placebo Expectation Effects

Placebo expectations can have a strong influence on physical and mental health outcomes. In prior research examining placebo expectation effects, participants have been assigned placebo treatments rather than being actively involved in selecting their treatment. In modern health care, however, individuals are often involved in health care decisions. We review relevant literature regarding choice and placebo expectation effects and conclude that exercising choice over a treatment should strengthen placebo effects. Data relevant to this hypothesis is reviewed. Next, we provide a framework for understanding the key variables involved in mediating and moderating the influence of treatment choice on placebo expectation effects. Finally, theoretical and practical issues revolving around treatment choice in the context of placebo effects are raised.     

Perceptual categories and the computation of “grandmother”

Abstract

Recent theoretical approaches to understanding face recognition have used converging evidence from studies of normal face processing, everyday errors and patterns of neuropsychological impairment to suggest how different face processing modules are related to each other. This paper disuses four issues that arise from this body of work. These concern the nature of representations involved in face recognition, the existence of parallel pathways for processing different types of information, the relationship between recognition and awareness, and the question of how faces become familiar. Current research provoked by these issues is reviewed in the paper and suggestions are made about the ways in which such research will help refine theories of face processing.     

Spatial problem solving and functional relations

Three experiments investigated the role of object knowledge on participants' ability to solve a spatial arrangement problem. The task was to rearrange six real-world three-dimensional objects so that their relative locations agreed with a given set of rules. The aim of the experiments was to tease out the relative extent to which object association, orientation, and object-specific functional relations affect performance on arrangement tasks. When the problem was presented vertically (objects arranged in piles), participants solved functional canonical versions of the problem significantly quicker than functional non-canonical versions both between (Experiments 1a and 2), and within subjects (Experiment 3). When the arrangement problem was presented horizontally (objects arranged flat in two rows), no significant differences in solution times were found between conditions (Experiments 1b and 2). Overall the results provide evidence for the importance of object-specific functional relations as a predictor of the solution time of spatial arrangement problems, although some differences were noted between single and multiple presentation of problems when specific rules within problems were rotated. The importance of functional information in memory as a constraint on the building of mental models and problem spaces is discussed.     

Age and age of acquisition: An evaluation of the cumulative frequency hypothesis

An important determinant of picture and word naming speed is the age at which the names were learned (age of acquisition). Two related interpretations of these effects are that they reflect differences between words in their cumulative frequency of use, or that they reflect differences in the amount of time early and lateacquired words have spent in lexical memory. Both theories predict that differences between early and late-acquired words will be less apparent in older than younger adults. Two experiments are reported in which younger and older adults read words varying in age of acquisition or frequency, or named objects varying in age of acquisition. There was an observed effect of word frequency only for young adults' word naming. In contrast, strong age of acquisition effects were found for both the young and the old participants. The implications of these results for theories of how age of acquisition might affect lexical processing are discussed.     

Behavioral versus Behavioral and Pharmacological Treatment in ADHD Children Attending a Summer Treatment Program

As part of the behavioral treatment in the Multimodal Treatment Study of Children with ADHD (MTA), children participated in an intensive summer treatment program (STP). This study examined the differences between 57 children in the combined treatment (Comb) group, who were medicated, and 60 children in the behavioral treatment (Beh) group, who were unmedicated throughout the STP. Comb children were significantly better than Beh on 5 measures: rule following, good sportsmanship, peer negative nominations, and STP teacher posttreatment ratings of inattention/overactivity. Groups did not differ on any of the other 30 measures, and responded similarly to the STP over time. Comparisons to normative data revealed that Comb children were more likely to fall within the normative range on 6 measures. The differences between these results and the main MTA results, in which Comb was always superior to Beh, are discussed in terms of the relative intensity of combined treatments. The implications for future studies of pharmacological and behavioral treatment for ADHD are discussed.     

Memory and executive function impairments after frontal or posterior cortex lesions

Free recall and recognition, memory for temporal order, spatial memory and prospective memory were assessed in patients with frontal lobe lesions, patients with posterior cortex lesions and control subjects. Both patient groups showed equivalent memory deficits relative to control subjects on a range of free recall and recognition tasks, on memory for temporal order and on a prospective memory task. The patient groups also performed equivalently on the spatial memory task although only patients with frontal lobe lesions were significantly impaired. However, the patients with frontal lobe lesions showed an increased false alarm rate and made more intrusion errors relative not only to the control subjects, but also to the patients with poster or cortex lesions. These memory problems are discussed in relation to deficits in executive function and basic memory processes.     

The power law repealed: The case for an exponential law of practice

The power function is treated as the law relating response time to practice trials. However, the evidence for a power law is flawed, because it is based on averaged data. We report a survey that assessed the form of the practice function for individual learners and learning conditions in paradigms that have shaped theories of skill acquisition. We fit power and exponential functions to 40 sets of data representing 7,910 learning series from 475 subjects in 24 experiments. The exponential function fit better than the power function in all the unaveraged data sets. Averaging produced a bias in favor of the power function. A new practice function based on the exponential, the APEX function, fit better than a power function with an extra, preexperimental practice parameter. Clearly, the best candidate for the law of practice is the exponential or APEX function, not the generally accepted power function. The theoretical implications are discussed.     

The development of implicit attitudes. Evidence of race evaluations from ages 6 and 10 and adulthood

To understand the origin and development of implicit attitudes, we measured race attitudes in White American 6-year-olds, 10-year-olds, and adults by first developing a child-oriented version of the Implicit Association Test (Child IAT). Remarkably, implicit pro-White/anti-Black bias was evident even in the youngest group, with self-reported attitudes revealing bias in the same direction. In 10-year-olds and adults, the same magnitude of implicit race bias was observed, although self-reported race attitudes became substantially less biased in older children and vanished entirely in adults, who self-reported equally favorable attitudes toward Whites and Blacks. These data are the first to show an asymmetry in the development of implicit and explicit race attitudes, with explicit attitudes becoming more egalitarian and implicit attitudes remaining stable and favoring the in-group across development. We offer a tentative suggestion that mean levels of implicit and explicit attitudes diverge around age 10.