Increasing capacity: practice effects in absolute identification

In most of the long history of the study of absolute identification--since Miller's (1956) seminal article--a severe limit on performance has been observed, and this limit has resisted improvement even by extensive practice. In a startling result, Rouder, Morey, Cowan, and Pfaltz (2004) found substantially improved performance with practice in the absolute identification of line lengths, albeit for only 3 participants and in a somewhat atypical paradigm. We investigated the limits of this effect and found that it also occurs in more typical paradigms, is not limited to a few virtuoso participants or due to relative judgment strategies, and generalizes to some (e.g., line inclination and tone frequency) but not other (e.g., tone loudness) dimensions. We also observed, apart from differences between dimensions, 2 unusual aspects of improvement with practice: (a) a positive correlation between initial performance and the effect of practice and (b) a large reduction in a characteristic trial-to-trial decision bias with practice.     

Purely relative models cannot provide a general account of absolute identification

Unidimensional absolute identificatio—identifying a presented stimulus from an ordered set—is a common component of everyday tasks. Laboratory investigations have mostly used equally spaced stimuli, and the theoretical debate has focused on the merits of purely relative versus purely absolute models. Absolute models incorporate substantial knowledge of the complete set of stimuli, whereas relative models allow only partial knowledge and assume that each stimulus is compared with recently observed stimuli. We test and refute a general prediction made by relative models, that accuracy is very low for some stimulus sequences when the stimuli are unequally spaced. We conclude that, although relative judgment processes may occur in absolute identification, a model must incorporate long-term referents to explain performance with unequally spaced stimuli. This implies that purely relative models cannot provide a general account of absolute identification.     

Avoiding Empty Rhetoric: Engaging Publics in Debates About Nanotechnologies

Despite the amount of public investment in nanotechnology ventures in the developed world, research shows that there is little public awareness about nanotechnology, and public knowledge is very limited. This is concerning given that nanotechnology has been heralded as 'revolutionising' the way we live. In this paper, we articulate why public engagement in debates about nanotechnology is important, drawing on literature on public engagement and science policy debate and deliberation about public policy development. We also explore the significance of timing in engaging the public, and we make some suggestions concerning how to effectively engage publics. Our conclusions indicate the significance of scientific researchers, policy makers and representative consumer groupings in public reasoning towards a better public policy framework for debate about technological development.     

Perhaps Unidimensional Is Not Unidimensional

Miller (1956) identified his famous limit of 7 ± 2 items based in part on absolute identification—the ability to identify stimuli that differ on a single physical dimension, such as lines of different length. An important aspect of this limit is its independence from perceptual effects and its application across all stimulus types. Recent research, however, has identified several exceptions. We investigate an explanation for these results that reconciles them with Miller’s work. We find support for the hypothesis that the exceptional stimulus types have more complex psychological representations, which can therefore support better identification. Our investigation uses data sets with thousands of observations for each participant, which allows the application of a new technique for identifying psychological representations: the structural forms algorithm of Kemp and Tenenbaum (2008) . This algorithm supports inferences not possible with previous techniques, such as multidimensional scaling.     

The Biological Roots of Complex Thinking: Are Heritable Attitudes More Complex?

ABSTRACT Are highly heritable attitudes more or less complex than less heritable attitudes? Over 2,000 participant responses on topics varying in heritability were coded for overall integrative complexity and its 2 subcomponents (dialectical complexity and elaborative complexity). Across different heritability sets drawn from 2 separate prior twin research programs, the present results yielded a consistent pattern: Heritability was always significantly positively correlated with integrative complexity. Further analyses of the subcomponents suggested that the manner in which complexity was expressed differed by topic type: For societal topics, heritable attitudes were more likely to be expressed in dialectically complex terms, whereas for personally involving topics, heritable attitudes were more likely to be expressed in elaboratively complex terms. Most of these relationships remained significant even when controlling for measurements of attitude strength. The authors discuss the genetic roots of complex versus simple attitudes, implications for understanding attitude development more broadly, and the contribution of these results to previous work on both heritability and complexity.     

Attribute centrality and imaginative thought

Participants' representations of the concept human were examined to differentiate three types of associations between concepts and their component attributes: the capacity of concepts to cue attributes (attribute accessibility), the capacity of attributes to cue concepts (instance accessibility), and the extent to which attributes are thought of as central to concepts (attribute centrality). The findings provide information about the concept human itself and, more generally, about the functionally distinct roles those different attribute-concept associations play in guiding imaginative thought. College students listed attributes that differentiate humans from other animals, rated the centrality of those attributes, and listed animals that possess those attributes. Other students drew and described extraterrestrials that possessed some of the attributes that were found to vary across those listing and rating tasks. Rated centrality was the most important determinant of an attribute's impact on imaginative generation. When the imagined extraterrestrials were supposed to possess attributes that had been rated as central to humans (intelligence, emotional complexity, or opposable thumbs), participants projected more aspects of human form onto them than when the creatures were supposed to possess less central attributes or when attributes were unspecified.     

Chinese teenagers' concerns about the future: a cross-national comparison.

Teenagers in the U.S., U.S.S.R., Eastern Europe, Western Europe, and New Zealand have consistently rated death of a parent and nuclear war as their greatest concerns about the future. In the present study, however, Chinese teenagers rated overpopulation and environmental pollution as their greatest concerns; these were usually rated quite low by teenagers in other countries. While still of concern to Chinese teenagers, nuclear war seemed more remote to them than it did to U.S. and U.S.S.R. teenagers and therefore more survivable. Speculation is offered as to how teenagers' concerns reflect those of a country's general population.     

Two ways to be complex and why they matter: implications for attitude strength and lying

Integrative complexity broadly measures the structural complexity of statements. This breadth, although beneficial in multiple ways, can potentially hamper the development of specific theories. In response, the authors developed a model of complex thinking, focusing on 2 different ways that people can be complex within the integrative complexity system and subsequently developed measurements of each of these 2 routes: Dialectical complexity focuses on a dialectical tension between 2 or more competing perspectives, whereas elaborative complexity focuses on complexly elaborating on 1 singular perspective. The authors posit that many variables have different effects on these 2 forms of complexity and subsequently test this idea in 2 different theoretical domains. In Studies 1a, 1b, and 2, the authors demonstrate that variables related to attitude strength (e.g., domain importance, extremism, domain accessibility) decrease dialectical complexity but increase elaborative complexity. In Study 3, the authors show that counterattitudinal lying decreases dialectical complexity but increases elaborative complexity, implicating a strategic (as opposed to a cognitive strain) view of the lying-complexity relationship. The authors argue that this dual demonstration across 2 different theoretical domains helps establish the utility of the new model and measurements as well as offer the potential to reconcile apparent conflicts in the area of cognitive complexity.