Better than average: alternatives to statistical summary representations for rapid judgments of average size

People can perceive the individual features of an object by focusing attention on it and binding the features together at a location. Some perceptual processing can occur without focusing attention on each object, though; people may even be able to extract summary information about the sizes of all the objects in a display, essentially computing the mean size at a glance. Evidence that people can judge the mean size of an array efficiently and accurately has been used to support the strong claim that people use a global, parallel process to extract a statistical summary of the average size of the objects in the display. Such claims are based both on the accuracy of performance and on the supposition that performance exceeds what would be possible with serial, focused attention. However, these studies typically have not examined the limits of performance with focused-attention strategies. Through experiments and simulations, we show that existing evidence for mean size perception can be explained through various focused-attention strategies, without appealing to a new mechanism of average size perception. Although our evidence does not eliminate the possibility that people do perceive the average size of all the objects in a display, it suggests that simpler mechanisms can accommodate the existing data.     

Forgetting in immediate serial recall: decay, temporal distinctiveness, or interference?

Three hypotheses of forgetting from immediate memory were tested: time-based decay, decreasing temporal distinctiveness, and interference. The hypotheses were represented by 3 models of serial recall: the primacy model, the SIMPLE (scale-independent memory, perception, and learning) model, and the SOB (serial order in a box) model, respectively. The models were fit to 2 experiments investigating the effect of filled delays between items at encoding or at recall. Short delays between items, filled with articulatory suppression, led to massive impairment of memory relative to a no-delay baseline. Extending the delays had little additional effect, suggesting that the passage of time alone does not cause forgetting. Adding a choice reaction task in the delay periods to block attention-based rehearsal did not change these results. The interference-based SOB fit the data best; the primacy model overpredicted the effect of lengthening delays, and SIMPLE was unable to explain the effect of delays at encoding. The authors conclude that purely temporal views of forgetting are inadequate.     

On use of student samples for scale construction

This research note responds to the question of whether a convenience sample of undergraduate students may be successfully utilized in concept development and in scale construction, and in what way the results are comparable to the findings of a representative national sample. The results of a Mokken analysis in both samples support the hypothesis that convenience samples have utility in concept development and in developing measures that can also be used in representative samples.     

Variation in the serotonin transporter gene modulates selective attention to threat

The 5-HTTLPR is an insertion/deletion polymorphism in the promoter region of the serotonin transporter gene. Prior research has revealed associations between the short-allele variant of this polymorphism, enhanced self-reported negative emotionality, and hypersensitivity of fear relevant neural circuits. In a sample of 50 healthy women we examined the role of 5-HTTLPR for cognitive-affective processing of phylogenetical fear-relevant stimuli (spiders) in a dot probe task. In contrast to homozygote long-allele carriers (ll), participants carrying at least 1 short allele (ss and sl) selectively shifted attention toward pictures of spiders, when these were presented for a duration of 2,000 ms. These results argue for an involvement of 5-HTTLPR in cognitive processing of threatening stimuli and thus, underpin its general role for individual differences in negative affect.     

Neural mechanisms supporting flexible performance adjustment during development

Feedback processing is crucial for successful performance adjustment following changing task demands. The present event-related fMRI study was aimed at investigating the developmental differences in brain regions associated with different aspects of feedback processing. Children age 8–11, adolescents age 14–15, and adults age 18–24 performed a rule switch task resembling the Wisconsin Card Sorting Task, and analyses focused on different types of negative and positive feedback. All age groups showed more activation in lateral orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), and superior parietal cortex following negative relative to positive performance feedback, but the regions contributed to different aspects of feedback processing and had separable developmental trajectories. OFC was adultlike by age 8–11, whereas parietal cortex was adultlike by age 14–15. DLPFC and ACC, in contrast, were still developing after age 14–15. These findings demonstrate that changes in separable neural systems underlie developmental differences in flexible performance adjustment. Supplementary data from this study are available online at the Psychonomic Society Archive of Norms, Stimuli, and Data, atwww.psychonomic.org/archive.     

Spiritual needs: Gender differences among professional spiritual care providers

The current study explored gender differences regarding spirituality by comparing the relative frequency with which male (n = 85) and female (n = 103) professional chaplains experience various facets of the spiritual experience. The women in the sample reported experiencing five of the seven spiritual constructs examined significantly more often than men, including the need for (1) belonging, (2) meaning, (3) hope, (4) beauty, and (5) acceptance of death. No significant gender differences were found for spiritual needs related to morality concerns or religious practices.     

Finger flexor motor control patterns during active flexion: an in vivo tendon force study

An in vivo tendon force measurement system was used to evaluate index finger flexor motor control patterns during active finger flexion. During open carpal tunnel release surgery (N=12) the flexor digitorum profundus (FDP) and flexor digitorum superficilias (FDS) tendons were instrumented with buckle force transducers and participants performed finger flexion at two different wrist angles (0 degrees or 30 degrees ). During finger flexion, there was concurrent change of metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint angles, but the FDP and FDS tendon force changes were not concurrent. For the FDS tendon, no consistent changes in force were observed across participants at either wrist angle. For the FDP tendon, there were two force patterns. With the wrist in a neutral posture, the movement was initiated without force from the finger flexors, and further flexion (after the first 0.5s) was carried out with force from the FDP. With the wrist in a flexed posture, the motion was generally both initiated and continued using FDP force. At some wrist postures, finger flexion was initiated by passive forces which were replaced by FDP force to complete the motion.     

Parsing the relations between SES and stress reactivity: examining individual differences in neonatal stress response

In an effort to further delineate the reported relations between socioeconomic status (SES) and stress reactivity in children, associations between three domains of perinatal risk: socio-demographic, obstetrical complications, and maternal psychological factors during the perinatal period, and cortisol and behavioral reactivity were examined in 100 healthy African American neonates whose families resided in low-income environments. Behavioral and cortisol response to a heel stick and the Neonatal Behavioral Assessment Scale (NBAS) was measured within the first 2 days of life. Significant associations were found between socio-demographic risk, obstetrical complications, and maternal psychological factors and neonatal behavior and cortisol in the context of the NBAS; few significant associations were found in the context of the heel stick. Greater magnitude of perinatal risk was associated with both higher and lower than average neonatal stress reactivity. The results provide preliminary data on the types of perinatal experiences that may have significant effects on stress reactivity in humans, especially in the context of families living in poverty. Application of these data to the hypothesis that prenatal stress results in programming of the fetal/neonatal stress response system is discussed.     

Temperamental contributions to children's performance in an emotion-word processing task: a behavioral and electrophysiological study

Seven-year-old children (N=65) participating in a study of the influence of infant temperament on socioemotional development performed an auditory selective attention task involving words that varied in both affective (positive vs. negative) and social (social vs. nonsocial) content. Parent report of contemporaneous child temperament was also collected, and individual differences in self-regulation in the affective (soothability) and cognitive (attentional control) domains were noted. Overall, children showed slower responses to stimuli that were either social or negative in content, with the largest effect elicited by words that possessed both traits. Children rated high in soothability and attentional control showed slower responses to social negative words. The other children showed little to no differential response patterns across the word categories. ERPs collected during the task indicated that processing differences were evident in the later more cognitive components of the ERP, especially in children low in attentional control. These findings indicate that performance on an auditory selective attention task can assist in identifying underlying patterns of affective processing.