Adult age differences in interference from a prospective-memory task: a diffusion model analysis

People often slow down their ongoing activities when they must remember an intended action, known as the cost or interference effect of prospective memory (PM). Only a few studies have examined adult age differences in PM interference, and the specific reasons underlying such differences are not well understood. The authors used a model-based approach to reveal processes underlying PM interference and age differences in these processes. Older and younger adults first performed a block of an ongoing lexical decision task alone. An embedded event-based PM task was added in a second block. Simultaneously accounting for the changes in response time distributions and error rates induced by the PM task, Ratcliff’s (Psychological Review 85:59–108, 1978) diffusion model was used to decompose the nonlinear combination of speed and accuracy into psychologically meaningful components. Remembering an intention not only reduced processing efficiency in both age groups, but also prolonged peripheral nondecision times and induced response cautiousness. Overall, the findings suggest that there are multiple, but qualitatively similar factors underlying PM task interference in both age groups.     

Theory and Analysis of Total,Direct, and Indirect Causal Effects

Mediation analysis, or more generally models with direct and indirect effects, are commonly used in the behavioral sciences. As we show in our illustrative example, traditional methods of mediation analysis that omit confounding variables can lead to systematically biased direct and indirect effects, even in the context of a randomized experiment. Therefore, several definitions of causal effects in mediation models have been presented in the literature (Baron &; Kenny, 1986 Baron, R.M., &; Kenny, D.A. (1986). The moderator-mediator variable distinction in social psychological research: Conceptual, strategic and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182. doi:10.1037/0022-3514.51.6.1173[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Imai, Keele, &; Tingley, 2010 Imai, K., Keele, L., &; Tingley, D. (2010). A general approach to causal mediation analysis. Psychological Methods, 15, 309–334. doi:10.1037/a0020761[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Pearl, 2012 Pearl, J. (2012). The causal mediation formula: A guide to the assessment of pathways and mechanisms. Prevention Science, 13, 426–436. doi:10.1007/s11121-011-0270-1[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). We illustrate the stochastic theory of causal effects as an alternative foundation of causal mediation analysis based on probability theory. In this theory we define total, direct, and indirect effects and show how they can be identified in the context of our illustrative example. A particular strength of the stochastic theory of causal effects are the causality conditions that imply causal unbiasedness of effect estimates. The causality conditions have empirically testable implications and can be used for covariate selection. In the discussion, we highlight some similarities and differences of the stochastic theory of causal effects with other theories of causal effects.     

Silencing the experience of change

Perceptual illusions have often served as an important tool in the study of perceptual experience. In this paper I argue that a recently discovered set of visual illusions sheds new light on the nature of time consciousness. I suggest the study of these silencing illusions as a tool kit for any philosopher interested in the experience of time and show how to better understand time consciousness by combining detailed empirical investigations with a detailed philosophical analysis. In addition, and more specifically, I argue against an initially plausible range of views that assume a close match between the temporal content of visual experience and the temporal layout of experience itself. Against such a widely held structural matching thesis I argue that which temporal changes we are experiencing bears no close relation to how our experience itself is changing over time. Explanations of the silencing illusions that are compatible with the structural matching thesis fail.     

Does it always feel good to get what you want? Young children differentiate between material and wicked desires

One line of research on children's attributions of guilt suggests that 3‐year‐olds attribute negative emotion to self‐serving victimizers, slightly older children attribute happiness, and with increasing age, attributions become negative again (i.e., a three‐step model; Yuill et al., 1996, Br. J. Dev. Psychol., 14, 457). Another line of research provides reason to expect that 3‐year‐olds may be predisposed to view self‐serving moral transgression as leading to positive emotion; this is a linear developmental model in which emotion attributions to transgressors become increasingly negative over the course of childhood (e.g., Nunner‐Winkler & Sodian, 1988, Child Dev., 59, 1323). However, key differences in methodology make it difficult to compare across these findings. The present study was designed to address this problem. We asked how 3‐ to 9‐year‐old children (n = 111) reason about transgression scenarios that involve satisfying wicked desires (wanting to cause harm and doing so successfully) versus material desires (wanting an object and getting it successfully via harmful behaviour). Three‐year‐old children reasoned differently about desire and emotion across these two types of transgressions, attributing negative emotion in the case of wicked desires and positive emotion in the case of material desires. This pattern of emotion attribution by young children provides new information about how young children process information about desires and emotions in the moral domain, and it bridges a gap in the existing literature on this topic.     

Bigger knows better: Young children selectively learn rule games from adults rather than from peers

Preschoolers' selective learning from adult versus peer models was investigated. Extending previous research, children from age 3 were shown to selectively learn simple rule games from adult rather than peer models. Furthermore, this selective learning was not confined to preferentially performing certain acts oneself, but more specifically had a normative dimension to it: children understood the way the adult demonstrated an act not only as the better one, but as the normatively appropriate/correct one. This was indicated in their spontaneous normative interventions (protest, critique, etc.) in response to third party acts deviating from the one demonstrated by the adult model. Various interpretations of these findings are discussed in the broader context of the development of children's social cognition and cultural learning.     

Extrinsic rewards undermine altruistic tendencies in 20-month-olds

The current study investigated the influence of rewards on very young children's helping behavior. After 20-month-old infants received a material reward during a treatment phase, they subsequently were less likely to engage in further helping during a test phase as compared with infants who had previously received social praise or no reward at all. This so-called overjustification effect suggests that even the earliest helping behaviors of young children are intrinsically motivated and that socialization practices involving extrinsic rewards can undermine this tendency.     

Logic programs, iterated function systems, and recurrent radial basis function networks

Graphs of the single-step operator for first-order logic programs—displayed in the real plane—exhibit self-similar structures known from topological dynamics, i.e., they appear to be fractals, or more precisely, attractors of iterated function systems. We show that this observation can be made mathematically precise. In particular, we give conditions which ensure that those graphs coincide with attractors of suitably chosen iterated function systems, and conditions which allow the approximation of such graphs by iterated function systems or by fractal interpolation. Since iterated function systems can easily be encoded using recurrent radial basis function networks, we eventually obtain connectionist systems which approximate logic programs in the presence of function symbols.