Distributed and massed practice: from laboratory to classroom

The benefit to memory of spacing presentations of material is well established but lacks an adequate explanation and is rarely applied in education. This paper presents three experiments that examined the spacing effect and its application to education. Experiment 1 demonstrated that spacing repeated presentations of items is equally beneficial to memory for a wide range of ages, contrary to some theories. Experiment 2 introduced ‘clustered’ presentations as a more relevant control than massed, reflecting the fact that massed presentation of material is uncommon in education. The scheduling of clustered presentations was intermediate between massed and distributed, yet recall was no different than for massed. Experiment 3, a classroom‐based study, demonstrated the benefit of distributed over clustered teaching of reading through modification of the scheduling of everyday lessons. Thus, the effectiveness of teaching may be improved by increasing the degree to which lessons are distributed. Copyright © 2004 John Wiley & Sons, Ltd.     

Effects of voluntary wheel running on heart rate, body temperature, and locomotor activity in response to acute and repeated stressor exposures in rats

Stress often negatively impacts physical and mental health but it has been suggested that voluntary physical activity may benefit health by reducing some of the effects of stress. The present experiments tested whether voluntary exercise can reduce heart rate, core body temperature and locomotor activity responses to acute (novelty or loud noise) or repeated stress (loud noise). After 6 weeks of running-wheel access, rats exposed to a novel environment had reduced heart rate, core body temperature, and locomotor activity responses compared to rats housed under sedentary conditions. In contrast, none of these measures were different between exercised and sedentary rats following acute 30-min noise exposures, at either 85 or 98 dB. Following 10 weeks of running-wheel access, both groups displayed significant habituation of all these responses to 10 consecutive daily 30-min presentations of 98 dB noise stress. However, the extent of habituation of all three responses was significantly enhanced in exercised compared to sedentary animals on the last exposure to noise. These results suggest that in physically active animals, under some conditions, acute responses to stress exposure may be reduced, and response habituation to repeated stress may be enhanced, which ultimately may reduce the negative and cumulative impact of stress.     

Nicotine trained as a negative feature passes the retardation-of-acquisition and summation tests of a conditioned inhibitor

Nicotine functions as a negative feature in a Pavlovian discriminated goal-tracking task. Whether withholding of responding to the conditional stimulus (CS) reflects nicotine functioning as a conditioned inhibitor is unknown. Accordingly, the present research sought to determine whether nicotine trained as a negative feature passed the retardation-of-acquisition and summation tests, thus characterizing it as a pharmacological (interoceptive) conditioned inhibitor. In the retardation test, rats received either nicotine (0.4 mg/kg) or chlordiazepoxide (5 mg/kg) negative feature training in which the drug state signaled when a 15-sec light CS would not be paired with sucrose; light was paired with sucrose on intermixed saline sessions. Following acquisition of the discrimination, both groups received nicotine CS training in which sucrose was intermittently available on nicotine but not intermixed saline sessions. Acquisition of conditioned responding to the nicotine CS was slower in the nicotine negative feature group than in the chlordiazepoxide negative feature group. In the summation test, rats were assigned to either the nicotine negative feature group or a pseudoconditioning control. In this control, the light CS was paired with sucrose on half the nicotine and half the saline sessions. Both groups also received excitatory training in which a white noise CS was paired with sucrose. The summation test consisted of presenting the white noise in conjunction with nicotine. Conditioned responding evoked by the white noise was decreased in the negative feature but not the pseudoconditioning group. Combined, the results provide the first evidence that an interoceptive stimulus (nicotine) can become a conditioned inhibitor.     

Constraints on infants' musical rhythm perception: effects of interval ratio complexity and enculturation

Effects of culture-specific experience on musical rhythm perception are evident by 12 months of age, but the role of culture-general rhythm processing constraints during early infancy has not been explored. Using a habituation procedure with 5- and 7-month-old infants, we investigated effects of temporal interval ratio complexity on discrimination of standard from novel musical patterns containing 200-ms disruptions. Infants were tested in three ratio conditions: simple (2:1), which is typical in Western music, complex (3:2), which is typical in other musical cultures, and highly complex (7:4), which is relatively rare in music throughout the world. Unlike adults and older infants, whose accuracy was predicted by familiarity, younger infants were influenced by ratio complexity, as shown by their successful discrimination in the simple and complex conditions but not in the highly complex condition. The findings suggest that ratio complexity constrains rhythm perception even prior to the acquisition of culture-specific biases.     

Race preferences in children: insights from South Africa

Minority-race children in North America and Europe often show less own-race favoritism than children of the majority (White) race, but the reasons for this asymmetry are unresolved. The present research tested South African children in order to probe the influences of group size, familiarity, and social status on children's race-based social preferences. We assessed South African children's preferences for members of their country's majority race (Blacks) compared to members of other groups, including Whites, who ruled South Africa until 1994 and who remain high in status. Black children (3-13 years) tested in a Black township preferred people of their own gender but not race. Moreover, Black, White, and multiracial children (4-9 years) tested in a racially diverse primary school showed in-group bias by gender but not by race: all favored people who were White. Relative familiarity and numerical majority/minority status therefore do not fully account for children's racial attitudes, which vary with the relative social status of different racial groups.     

Effects of a history of differential reinforcement on preference for choice

The effects of a history of differential reinforcement for selecting a free-choice versus a restricted-choice stimulus arrangement on the subsequent responding of 7 undergraduates in a computer-based game of chance were examined using a concurrent-chains arrangement and a multiple-baseline-across-participants design. In the free-choice arrangement, participants selected three numbers, in any order, from an array of eight numbers presented on the computer screen. In the restricted-choice arrangement, participants selected the order of three numbers preselected from the array of eight by a computer program. In initial sessions, all participants demonstrated no consistent preference or preference for restricted choice. Differential reinforcement of free-choice selections resulted in increased preference for free choice immediately and in subsequent sessions in the absence of programmed differential outcomes. For 5 participants, changes in preference for choice were both robust and lasting, suggesting that a history of differential reinforcement for choice may affect preference for choice.     

Effects of the Positive Action programme on problem behaviours in elementary school students: a matched-pair randomised control trial in Chicago

This study examined the effects of the Positive Action (PA) programme in Chicago Public Schools on problem behaviours among a cohort of elementary school students from grade three through grade five. Using a matched-pair, randomised control design with 14 elementary schools, approximately 510 fifth-graders self-reported lifetime substance use, serious violence-related behaviour, and current bullying and disruptive behaviours. Three-level (i.e. students nested within schools within school pairs) overdispersed Poisson models were used to examine programme effects on the number of items endorsed for each of the four outcomes. Findings indicated that students in the intervention endorsed 31% fewer substance use behaviours (incidence rate ratio [IRR] = 0.69), 37% fewer violence-related behaviours (IRR = 0.63) and 41% fewer bullying behaviours (IRR = 0.59), respectively, compared to students in the control schools. Reduction in reported disruptive behaviours was of a similar magnitude (27%, IRR = 0.73), but was not statistically significant. These results replicate findings of an earlier randomised trial of the PA programme and extend evidence of its effectiveness to youth attending large urban school systems.     

Verbal ability and executive functioning development in preschoolers at head start

Research suggests that executive functioning skills may enhance the school readiness of children from disadvantaged homes. Questions remain, however, concerning both the structure and the stability of executive functioning among preschoolers. In addition, there is a lack of research addressing potential predictors of longitudinal change in executive functioning during early childhood. This study examined the structure of executive functioning from fall to spring of the preschool year using a multimethod battery of measures. Confirmatory factor analyses revealed a unidimensional model fit the data well at both time points, and tests of measurement invariance across time points indicated that children's mean latent executive functioning scores significantly improved over time. Verbal ability was a significant predictor of longitudinal change in executive functioning. Theoretical implications and directions for future research are discussed.     

Infants learn about objects from statistics and people

In laboratory experiments, infants are sensitive to patterns of visual features that co-occur (e.g., Fiser & Aslin, 2002). Once infants learn the statistical regularities, however, what do they do with that knowledge? Moreover, which patterns do infants learn in the cluttered world outside of the laboratory? Across 4 experiments, we show that 9-month-olds use this sensitivity to make inferences about object properties. In Experiment 1, 9-month-old infants expected co-occurring visual features to remain fused (i.e., infants looked longer when co-occurring features split apart than when they stayed together). Forming such expectations can help identify integral object parts for object individuation, recognition, and categorization. In Experiment 2, we increased the task difficulty by presenting the test stimuli simultaneously with a different spatial layout from the familiarization trials to provide a more ecologically valid condition. Infants did not make similar inferences in this more distracting test condition. However, Experiment 3 showed that a social cue did allow inferences in this more difficult test condition, and Experiment 4 showed that social cues helped infants choose patterns among distractor patterns during learning as well as during test. These findings suggest that infants can use feature co-occurrence to learn about objects and that social cues shape such foundational learning in distraction-filled environments.