What does syntax say about space? 2-year-olds use sentence structure to learn new prepositions

Children as young as two use sentence structure to learn the meanings of verbs. We probed the generality of sensitivity to sentence structure by moving to a different semantic and syntactic domain, spatial prepositions. Twenty-six-month-olds used sentence structure to determine whether a new word was an object-category name (This is a corp!) or a spatial-relational term (This is acorp my box!). We argue that children rely on the intimate relationship between nouns in sentences and semantic arguments of predicate terms: Noting that a new word takes noun arguments identifies the new word as a predicate term, and directs the child's attention to relations among its arguments.     

A likelihood ratio test for mixture effects

Under certain circumstances, it is theoretically important to decide whether a difference between two conditions in mean reaction time (RT) results from a relatively uniform slowing of all the responses in the slower condition or from a mixture of some slowed trials with some unslowed ones. This article describes a likelihood ratio test that can be used to differentiate between these two possibilities and reports computer simulations examining the power and Type I error rate of the test under conditions similar to those encountered in RT research. A freely available computer program, called MIXTEST, can be used both to carry out the likelihood ratio test and to conduct simulations evaluating the performance of the test within various settings.     

Simon congruency effects based on stimulus and response numerosity

Three choice reaction time experiments documented a Simon-type congruence effect involving the numbers of stimuli and responses. In Experiment 1 the stimulus consisted of one or two high- or low-pitch tones, and participants were required to respond with one or two taps of a response key depending on stimulus pitch. Responses were faster when the number of tones matched the required number of response taps than when these numbers mismatched. Experiment 2 showed that a weaker version of this effect can also be obtained using visual stimuli, and Experiment 3 showed that the analogous effect can even be obtained, albeit very weakly, with bimodal stimuli. There was also evidence that the number of stimuli affected the rate of emitting the two-tap response. These results indicate that stimulus numerosity is processed automatically to the level at which it can affect the selection and possibly the execution of a varying number of responses.     

Being bad isn't always good: affective context moderates the attention bias toward negative information

Research has demonstrated that people automatically devote more attention to negative information than to positive information. The authors conducted 3 experiments to test whether this bias is attenuated by a person's affective context. Specifically, the authors primed participants with positive and negative information using traditional (e.g., subliminal semantic priming) and nontraditional (e.g., social interactions) means and measured the amount of attention they allocated to positive and negative information. With both event-related brain potentials (Experiment 1) and the Stroop task (Experiments 2 and 3), results suggest that the attention bias to negative information is attenuated or eliminated when positive constructs are made accessible. The implications of this result for other biases to negative information and for the self-reinforcing nature of emotional disorders are discussed.     

A brief account of statistical tests for single-case research with persons with developmental disabilities

Education and rehabilitation research with persons with developmental disabilities is often based on single-case designs (with small numbers of ordinal data points collected at irregular intervals) and relies upon graphic display and visual inspection of the data. This paper (a) provides a brief account of some statistical tests, which may serve to supplement the visual inspection process and (b) underlines some of their strengths and limitations to help education and rehabilitation personnel make a reasonable choice among them.     

Teaching 'Yes' and 'No' responses to children with multiple disabilities through a program including microswitches linked to a vocal output device

The present study introduced two children (a boy and a girl of 9.2 and 12.3 yr. of age, respectively, with multiple disabilities) to an intervention program for establishing Yes and No responses in relation to preferred and nonpreferred stimuli and assessed the acquisition and generalization of those responses. The program involved the use of microswitches, which monitored the nonverbal Yes and No responses performed by the children and ensured that these responses produced the matching verbal utterances via a vocal output device. Analysis showed children acquired Yes and No responses in relation to the stimuli used for the intervention and, to a comparable degree, to the stimuli used for generalization checks as well. An interview of 30 educational staff of a center for persons with multiple disabilities indicated that they considered the presence of Yes and No verbal utterances preferable to the absence of such utterances, and thought that the utterances could be helpful for the children's response acquisition and would be useful and pleasing for staff and parents. General implications of the findings were discussed.     

The physics of optimal decision making: a formal analysis of models of performance in two-alternative forced-choice tasks

In this article, the authors consider optimal decision making in two-alternative forced-choice (TAFC) tasks. They begin by analyzing 6 models of TAFC decision making and show that all but one can be reduced to the drift diffusion model, implementing the statistically optimal algorithm (most accurate for a given speed or fastest for a given accuracy). They prove further that there is always an optimal trade-off between speed and accuracy that maximizes various reward functions, including reward rate (percentage of correct responses per unit time), as well as several other objective functions, including ones weighted for accuracy. They use these findings to address empirical data and make novel predictions about performance under optimality.     

Terror Management and Trait Empathy: Evidence that Mortality Salience Promotes Reactions of Forgiveness among People with High (vs. low) Trait Empathy

Terror management research has typically found that people respond harshly toward offending others when reminded of their mortality. In the current research we examined whether mortality salience would increase attitudes of forgiveness toward such individuals, especially among those with high trait empathy. Consistent with prior research, Study 1 showed that mortality salience increased forgiveness of a violent hockey player, but only if this person was a member of the ingroup. Study 2 showed that mortality (vs. dental pain) salience led persons high in trait empathy to forgive the same violent hockey player regardless of his group membership. Implications for increasing forgiveness and prosocial behavior in intergroup contexts are briefly discussed.

Research ethics for mental health science involving ethnic minority children and youths

In response to U.S. Public Health Service projects promoting attention to disparities in the outcomes of mental health treatments, in July 2001, the American Psychological Association, the National Institute of Mental Health, and the Fordham University Center for Ethics Education convened a group of national leaders in bioethics, multicultural research, and ethnic minority mental health to produce a living document to guide ethical decision making for mental health research involving ethnic minority children and youths. This report summarizes the key recommendations distilled from these discussions.