Getting involved: Testing the effectiveness of a volunteering intervention on young adolescents' future intentions

Past research has identified a host of benefits associated with volunteering and community involvement, yet involvement appears to be on the decline in recent years. We tested the effectiveness of an intervention designed to encourage involvement. We provided young adolescents with information about volunteer opportunities, benefits and ways to overcome barriers to involvement. Adolescents who participated in the volunteering intervention reported greater involvement intentions than control participants. In addition, mediation analyses indicated that adolescents in the volunteering intervention based their self‐worth to a greater degree on virtuous behaviour, which in turn predicted their involvement intentions, especially in the helping domain. Copyright © 2008 John Wiley & Sons, Ltd.     

Distinct neural mechanisms mediate olfactory memory formation at different timescales

Habituation is one of the oldest forms of learning, broadly expressed across sensory systems and taxa. Here, we demonstrate that olfactory habituation induced at different timescales (comprising different odor exposure and intertrial interval durations) is mediated by different neural mechanisms. First, the persistence of habituation memory is greater when mice are habituated on longer timescales. Second, the specificity of the memory (degree of cross-habituation to similar stimuli) also depends on induction timescale. Third, we demonstrate a pharmacological double dissociation between the glutamatergic mechanisms underlying short- and long-timescale odor habituation. LY341495, a class II/III metabotropic glutamate receptor antagonist, blocked habituation only when the induction timescale was short. Conversely, MK-801, an N-methyl-D-aspartate (NMDA) receptor antagonist, prevented habituation only when the timescale was long. Finally, whereas short-timescale odor habituation is mediated within the anterior piriform cortex, infusion of MK-801 into the olfactory bulbs prevented odor habituation only at longer timescales. Thus, we demonstrate two neural mechanisms underlying simple olfactory learning, distinguished by their persistence and specificity, mediated by different olfactory structures and pharmacological effectors, and differentially utilized based solely on the timescale of odor presentation.     

Material properties determine how force and position signals combine in haptic shape perception

When integrating estimates from redundant sensory signals, humans seem to weight these estimates according to their reliabilities. In the present study, human observers used active touch to judge the curvature of a shape. The curvature was specified by positional and force signals: When a finger slides across a surface, the finger's position follows the surface geometry (position signal). At the same time, it is exposed to patterns of forces depending on the gradient of the surface (force signal; Robles-de-la-Torre, G., & Hayward, V. (2001). Force can overcome object geometry in the perception of shape through active touch. Nature, 412, 445-448). We show that variations in the surface's material properties (compliance, friction) influence the sensorily available position and force signals, as well as the noise associated with these signals. Along with this, material properties affect the weights given to the position and force signals for curvature judgements. Our findings are consistent with the notion of an observer who weights signal estimates according to their reliabilities. That is, signal weights shifted with the signal noise, which in the present case resulted from active exploration.     

Free-ranging rhesus monkeys spontaneously individuate and enumerate small numbers of non-solid portions

Fundamental questions in cognitive science concern the origins and nature of the units that compose visual experience. Here, we investigate the capacity to individuate and store information about non-solid portions, asking in particular whether free-ranging rhesus monkeys (Macaca mulatta) quantify portions of a non-solid substance presented in discrete pouring actions. When presented with portions of carrot pieces poured from a cup into opaque boxes, rhesus picked the box with the greatest number of portions for comparisons of 1 vs. 2, 2 vs. 3, and 3 vs. 4, but not for comparisons of 4 vs. 5 and 3 vs. 6. Additional experiments indicate that rhesus based their decisions on both the number of portions and the total amount of food. These results show that the capacity to individuate non-solid portions is not unique to humans, and does not depend on structures of natural language. Further, the fact that rhesus' ability to represent non-solid portions is constrained by the same 4-item limit typically ascribed to the system of parallel individuation that operates over solid objects suggests that the visual system recruits common working memory processes for retaining information about solid objects and non-solid portions. We discuss our results with respect to theories of visual processing, as well as to the role that the human language faculty may have played in both the evolution and development of quantification.     

The SNARC effect in the processing of second-language number words: further evidence for strong lexico-semantic connections

We present new evidence that word translation involves semantic mediation. It has been shown that participants react faster to small numbers with their left hand and to large numbers with their right hand. This SNARC (spatial-numerical association of response codes) effect is due to the fact that in Western cultures the semantic number line is oriented from left (small) to right (large). We obtained a SNARC effect when participants had to indicate the parity of second-language (L2) number words, but not when they had to indicate whether L2 number words contained a particular sound. Crucially, the SNARC effect was also obtained in a translation verification task, indicating that this task involved the activation of number magnitude.     

The Temporally Extended Self: The Relation of Past and Future Selves to Current Identity,Motivation, and Goal Pursuit

People's current identity is constructed not only in the present moment but also by looking back to past selves and forward to future selves. In this article, we review research on the temporally extended self, with a focus on recent work informed by temporal self‐appraisal theory. People often recall the past and imagine the future in ways that contribute to a favorable current identity. Subjective temporal distance (how near or distant a point in time feels) plays a powerful role in determining temporal self‐appraisals. In turn, people's judgments of subjective distance can shift when considering temporal selves with good or bad implications for current identity. We will describe research exploring the complex interconnections between past, present, and future identity. In addition, we consider some of the unique implications that people's constructions of future selves might have for their plans and goals, and how predicted selves might influence goal‐pursuit motivation and behavior.     

Age-of-acquisition and subjective frequency estimates for all generally known monosyllabic French words and their relation with other psycholinguistic variables

Ratings for age of acquisition (AoA) and subjective frequency were collected for the 1,493 monosyllabic French words that were most known to French students. AoA ratings were collected by asking participants to estimate in years the age at which they learned each word. Subjective frequency ratings were collected on a 7-point scale, ranging from never encountered to encountered several times daily. The results were analyzed to address the relationship between AoA and subjective frequency ratings with other psycholinguistic variables (objective frequency, imageability, number of letters, and number of orthographic neighbors). The results showed high reliability ratings with other databases. Supplementary materials for this study may be downloaded from the Psychonomic Society’s Archive of Norms, Stimuli, and Data, www.psychonomic.org/archive.     

Instructional effects on performance in a matching-to-sample study

Conducting studies using an undergraduate participant pool is fraught with difficulties. Among them are problems with adequately motivating subjects both to come to the study, and once there, to actively engage the experimental task. Thirty-one college students participated in a matching-to-sample (MTS) study involving substantial training, testing, retraining, and retesting of conditional discriminations and equivalence relations among four 4-member classes of nonsensical words. The study was conducted during the end of the semester, when performance often had been observed to be poorer than at other points in the semester. Eleven of the participants, in addition to standard instructions about the task, received additional instructions specifying molar consequences for high rates of "correct" responses throughout the procedure. This subset of participants displayed markedly improved performance as compared to those who did not receive the additional instructions. Results suggest that specification of molar contingencies improves participants' sensitivity to molecular contingencies within the study. Instructions that specify and increase the consequential functions of feedback provided during MTS trials may be one means of reducing unwanted variability in human MTS performance.