The tune in-and-out model: A random walk and its application to a presidential election survey

The stochastic model for the evolution of preferences proposed by Falmagne, Regenwetter, and Grofman [1997. Journal of Mathematical Psychology, 41, 129-143] and tested by Regenwetter, Falmagne, and Grofman [1999. Psychological Review, 106, 362-384], as well as the alternative Thurstonian model of Böckenholt [Falmagne, J.-C., Regenwetter, M., & Grofman, B. (1997). A stochastic model for the evolution of preferences. In A. A. J. Marley (Ed.), Choice, decision and measurement: Essays in honor of R. Duncan Luce (pp. 113-131). Mahwah, NJ: Lawrence Erlbaum.], gave a good statistical account of attitudinal panel data from the 1992 US presidential election. We show, however, that both models have the defect of underestimating the number of respondents who did not change their order of preference for the candidates across different polls. We present a generalization of Falmagne et al.'s model based on the idea that some individuals may become momentarily impervious to all matters related to the campaign and ‘tune out.’ This behavior could be triggered by some personal reason or by some external event related to the campaign. Like the original model, the resulting model is a random walk, but on an augmented set of states. A respondent in a ‘live’ state behaves as in the previous model, except when receiving a ‘tune-out’ token, which effectively freezes the respondent's preference state until it is reversed by a ‘tune-in’ token. We describe and successfully test the new model on the same 1992 National Election Study panel data as those used by Böckenholt (2002) and Regenwetter et al. (1999).     

Self-organizing individual differences in brain development

Brain development is self-organizing in that the unique structure of each brain evolves in unpredictable ways through recursive modifications of synaptic networks. In this article, I review mechanisms of neural change in real time and over development, and I argue that change at each of these time scales embodies principles of self-organizing systems. I demonstrate how corticolimbic configurations that emerge within occasions lay down synaptic structure across occasions, giving rise to individual trajectories that become entrenched with age. Emotions have a powerful influence on this process.This is because the neural processes mediating emotion consolidate patterns of activation across the brain, through their enhancement of inter-regional coordination in real time and their contribution to synaptic shaping over development. The loss of corticolimbic plasticity with age is an unfortunate fact of development, but it is compensated in part by transitional phases and individual learning experiences through which habits are modified or replaced. I emphasize variations in inter-systemic coupling as a key mediator of developing individual differences, and I discuss the acquisition of anxious/depressive appraisals as an example.     

Unsignaled delay of reinforcement, relative time, and resistance to change

Two experiments with pigeons examined the effects of unsignaled, nonresetting delays of reinforcement on responding maintained by different reinforcement rates. In Experiment 1, 3-s unsignaled delays were introduced into each component of a multiple variable-interval (VI) 15-s VI 90-s VI 540-s schedule. When considered as a proportion of the preceding immediate reinforcement baseline, responding was decreased similarly for the three multiple-schedule components in both the first six and last six sessions of exposure to the delay. In addition, the relation between response rates and reinforcement rates was altered such that both parameters of the single-response version of the matching law (i.e., k and Re) were decreased. Experiment 2 examined the effects of unsignaled delays ranging from 0.5 s to 8.0 s on responding maintained by a multiple VI 20-s VI 120-s schedule of reinforcement. Response rates in both components increased with brief unsignaled delays and decreased with longer delays. As in Experiment 1, response rates as a proportion of baseline were affected similarly for the two components in both the first six and last six sessions of exposure to the delay. Unlike delays imposed between two stimulus events, the effects of delays between responses and reinforcers do not appear to be attenuated when the average time between reinforcers is longer. In addition, the disruptions produced by unsignaled delays appear to be inconsistent with the general finding that responding maintained by higher rates of reinforcement is less resistant to change.     

Gricean Belief Change

One of the standard principles of rationality guiding traditional accounts of belief change is the principle of minimal change: a reasoner's belief corpus should be modified in a minimal fashion when assimilating new information. This rationality principle has stood belief change in good stead. However, it does not deal properly with all belief change scenarios. We introduce a novel account of belief change motivated by one of Grice's maxims of conversational implicature: the reasoner's belief corpus is modified in a minimal fashion to assimilate exactly the new information. In this form of belief change, when the reasoner revises by new information p ∨ q their belief corpus is modified so that p∨q is believed but stronger propositions like p∧q are not, no matter what beliefs are in the reasoner's initial corpus. We term this conservative belief change since the revised belief corpus is a conservative extension of the original belief corpus given the new information.     

Might We Practice What We'ved Preached? Thoughts on the Special Issue Papers

Commentary on the papers of the special issue identifies and discusses four themes: 1) strategies to bridge the gap between science and practice, 2) sources of community science questions of interest, 3) choice and quality of methods, and 4) epistemology and useful language for community science. The commentary identifies some limitations in the models proposed by the special issue authors, and proposes renewed attention to ecology, context and process in community change initiatives, calling for a common set of community level measures as one strategy to advance a community centered science agenda.     

Systematic Changes in Families Following Prevention Trials

A selective prevention design was applied to 238 recently separated families. Of these, 153 mothers randomly assigned to the experimental (E) group participated in 14 group sessions focused on Parent Management Treatment (PMT). Prior analyses showed that, over time, the group of families in the untreated group deteriorated in both parenting practices and in child outcomes. In keeping with the classic prevention pattern, families in the E group showed modest improvements in parenting and in child outcomes. Improvements in parenting were associated with significant reductions in problem behavior. The data showed that those mothers who improved their parenting skills during the first 12 months also showed significant reductions in maternal depression during that same interval. A cross-lagged panel analysis showed that a reduction in maternal depression during the first year of the study was a significant predictor of maintenance or improvements over the next 18 months. The findings are consistent with the concept of the family as a system.     

Action, verbal response and spatial reasoning

Studies have shown that perception of distance, orientation and size can be dissociated from action tasks. The action system seems to possess more veridical, unbiased information than the perceptual/verbal system. The current study examines the nature of the distinction between action and verbal responses in a spatial reasoning task. Participants imagined themselves facing different orientations and either pointed to where other objects would be, or verbally reported their egocentric directions (e.g., "50 degrees to my left"). When using pointing responses, RT and error increased as a function of the angular disparity between the imagined heading and their actual heading. However, when using verbal responses, performance was not affected by angular disparity, suggesting that participants knew the direction of the targets from the imagined perspective but could not point to them directly. The verbal and action systems have fundamentally different information or processes rather than quantitatively different ones.     

The efficacy of videotape feedback for enhancing the effects of exposure-based treatment for social anxiety disorder: a controlled investigation

Correcting patients' faulty beliefs concerning social evaluative threats is the hallmark of cognitive-behavioral treatment of social anxiety disorder. The current study examined the efficacy of two videotape feedback procedures as adjuncts to exposure-based treatment. Participants suffering from social phobia (N=77) were randomly assigned to one of four conditions: (a) credible placebo treatment (PLA); (b) exposure + no feedback (EXP); (c) exposure + videotape feedback of performance (PER); or (d) exposure + videotape feedback of audience responses (AUD). Contrary to prediction, the videotape feedback procedures did not enhance the effects of exposure-based treatment. Clinical and theoretical implications are discussed.