Negations and natural sampling in data selection: Ecological versus heuristic explanations of matching bias

Matching bias occurs when people ignore negations when testing a hypothesis--for example, if A, then not 2--and select possible data types that are named in the hypothesis (i.e., A and 2; Evans & Lynch, 1973). There are two explanations of this bias: the heuristic account and the contrast class account. The latter is part of Oaksford and Chater's (1994) ecological approach to data selection. On this account, a contrast set (i.e., birds that are not ravens) has a higher probability than the original set (i.e., birds that are ravens). This article reports two experiments in which these accounts make divergent predictions. The same materials were used as those in Yama (2001), who found more support for the heuristic approach. Experiment 1 replicated Yama with Western participants. Experiment 2 used a procedure introduced by Oaksford and Wakefield (2003). Rather than present participants with one of each of the four possible data types all at once, 50 were presented one at a time. The proportions of each data type reflected the relevant probabilities. The results supported the ecological approach, showing that people constructed contrast sets that strongly influenced their data selection behavior. The results were not consistent with the heuristic approach.     

The development of the still-face effect: Mothers do matter

The Face-to-Face Still-Face paradigm (FFSF) has been used to investigate how infants react to stressful events. However, there is little developmental data on the FFSF effect, and whether it connects to a specific relationship (e.g., to a mother versus a stranger). This prospective longitudinal study aims to evaluate developmental changes in infant reaction to the FFSF presented by the mother or a stranger at 2, 4, 6, and 8 months of age (n = 39). Results show that infant negativity was expressed less in relation to a stranger, the identity effect. Results further suggest that from 6 to 8 months of age, stranger induced protest flattens out; whereas mother induced protest decreases. The results are discussed in relation to different theories regarding infant responsiveness.     

The media do matter: comment on Steinberg and Monahan (2011)

Steinberg and Monahan's (2011) reanalysis of the Teen Media longitudinal survey of adolescents does not meet prevailing standards for propensity score analysis and therefore does not undermine the original conclusions of the Brown, L'Engle, Pardun, Guo, Kenneavy, and Jackson (2006) analysis. The media do matter in the sexual socialization of adolescents.     

Rich stimulus sampling for between-subjects designs improves model selection

The choice of stimulus values to test in any experiment is a critical component of good experimental design. This study examines the consequences of random and systematic sampling of data values for the identification of functional relationships in experimental settings. Using Monte Carlo simulation, uniform random sampling was compared with systematic sampling of two, three, four, or N equally spaced values along a single stimulus dimension. Selection of the correct generating function (a logistic or a linear model) was improved with each increase in the number of levels sampled, with N equally spaced values and random stimulus sampling performing similarly. These improvements came at a small cost in the precision of the parameter estimates for the generating function.     

Inspection times and the selection task: What do eye-movements reveal about relevance effects?

Three experiments are reported that used eye-movement tracking to investigate the inspection-time effect predicted by Evans' (1996) heuristic-analytic account of the Wason selection task. Evans' account proposes that card selections are based on the operation of relevance-determining heuristics, whilst analytic processing only rationalizes selections. As such, longer inspection times should be associated with selected cards (which are subjected to rationalization) than with rejected cards. Evidence for this effect has been provided by Evans (1996) using computer- presented selection tasks and instructions for participants to indicate (with a mouse pointer) cards under consideration. Roberts (1998b) has argued that mouse pointing gives rise to artefactual support for Evans' predictions because of biases associated with the task format and the use of mouse pointing. We eradicated all sources of artefact by combining careful task constructions with eye-movement tracking to measure directly on-line attentional processing. All three experiments produced good evidence for the robustness of the inspection-time effect, supporting the predictions of the heuristic-analytic account.     

Cardiovascular reactivity during social and nonsocial stressors: do children's personal goals and expressive skills matter?

The relationships between social competence and cardiovascular reactivity were evaluated in 180 children (ages 8-17; 52% female; 53% Caucasian). Participants performed a social task (Social Competence Interview [SCI]) and 2 nonsocial tasks while reactivity measures were obtained. Social competence was coded from SCI audiotapes. Among adolescents, higher scores on the Acceptance-Affiliation subscale were associated with increased heart rate (HR) and blood pressures and with decreased HR variability during the SCI. Among boys, greater Acceptance-Affiliation scores were associated with increased vascular reactivity during the SCI. During the nonsocial tasks, higher Self-Defensiveness and Expressiveness scores were associated with increased cardiac output and stroke volume among African American children. Personal strivings and expressive skills do matter for understanding cardiovascular responses in children.     

Revising Probabilities and Full Beliefs

Journal of Philosophical Logic - A new formal model of belief dynamics is proposed, in which the epistemic agent has both probabilistic beliefs and full beliefs. The agent has full belief in a...     

Taurek, Numbers and Probabilities

In his paper, “Should the Numbers Count?" John Taurek imagines that we are in a position such that we can either save a group of five people, or we can save one individual, David. We cannot save David and the five. This is because they each require a life-saving drug. However, David needs all of the drug if he is to survive, while the other five need only a fifth each. Typically, people have argued as if there was a choice to be made: either numbers matter, in which case we should save the greater number, or numbers don't matter, but rather there is moral value in giving each person an equal chance of survival, and therefore we should toss a coin. My claim is that we do not have to make a choice in this way. Rather, numbers do matter, but it doesn't follow that we should always save the greater number. And likewise, there is moral value in giving each person an equal chance of survival, but it doesn't follow that we should always toss a coin. In addition, I argue that a similar approach can be applied to situations in which we can save one person or another, but the chances of success are different.     

Counterfactuals,Probabilities, and Information: Response to Critics

In earlier work we proposed an account of information grounded in counterfactual conditionals rather than probabilities, and argued that it might serve philosophical needs that more familiar probabilistic alternatives do not. Demir [2008] and Scarantino [2008] criticize the counterfactual approach by contending that its alleged advantages are illusory and that it fails to secure attractive desiderata. In this paper we defend the counterfactual account from these criticisms, and suggest that it remains a useful account of information.     

Bets and Boundaries: Assigning Probabilities to Imprecisely Specified Events

Uncertainty and vagueness/imprecision are not the same: one can be certain about events described using vague predicates and about imprecisely specified events, just as one can be uncertain about precisely specified events. Exactly because of this, a question arises about how one ought to assign probabilities to imprecisely specified events in the case when no possible available evidence will eradicate the imprecision (because, say, of the limits of accuracy of a measuring device). Modelling imprecision by rough sets over an approximation space presents an especially tractable case to help get one’s bearings. Two solutions present themselves: the first takes as upper and lower probabilities of the event X the (exact) probabilities assigned X’s upper and lower rough-set approximations; the second, motivated both by formal considerations and by a simple betting argument, is to treat X’s rough-set approximation as a conditional event and assign to it a point-valued (conditional) probability. With rough sets over an approximation space we get a lot of good behaviour. For example, in the first construction mentioned the lower probabilities are n-monotone, for every . When we examine other models of approximation/imprecision/vagueness, and in particular, proximity spaces, we lose a lot of that good behaviour. In the literature there is not (even) agreement on the definition of upper and lower approximations for events (subsets) in the underlying domain. Betting considerations suggest one choice and, again, ways to assign upper and lower and point-valued probabilities, but nothing works well. Special Issue on Vagueness Edited by Rosanna Keefe and Libor Bêhounek     

Conditionals Right and Left: Probabilities for the Whole Family

The fact that the standard probabilistic calculus does not define probabilities for sentences with embedded conditionals is a fundamental problem for the probabilistic theory of conditionals. Several authors have explored ways to assign probabilities to such sentences, but those proposals have come under criticism for making counterintuitive predictions. This paper examines the source of the problematic predictions and proposes an amendment which corrects them in a principled way. The account brings intuitions about counterfactual conditionals to bear on the interpretation of indicatives and relies on the notion of causal (in)dependence.