Effects of television exposure on developmental skills among young children

BackgroundLiterature addressing the effects of television exposure on developmental skills of young children less than 36 months of age is scarce. This study explored how much time young children spend viewing television and investigated its effects on cognitive, language, and motor developmental skills.MethodsData were collected from the Pediatric Clinics at University Medical Center in Southern Taiwan. The participants comprised 75 children who were frequently exposed to television and 75 children who were not or infrequently exposed to television between 15 and 35 months old. The age and sex were matched in the two groups. The Bayley Scales of Infant Development-second edition and Peabody Developmental Motor Scales-second edition were used to identify developmental skills. Independent t-tests, χ² tests, and logistic regression models were conducted.ResultsAmong 75 children who were frequently exposed to television, young children watched a daily average of 67.4 min of television before age 2, which was excessive according to the American Academy of Pediatrics. Viewing television increased the risk of delayed cognitive, language, and motor development in children who were frequently exposed to television. Cognitive, language, and motor delays in young children were significantly associated with how much time they spent viewing television. The type of care providers was critical in determining the television-viewing time of children.ConclusionWe recommend that pediatric practitioners explain the impacts of television exposure to parents and caregivers to ensure cognitive, language, and motor development in young children. Advocacy efforts must address the fact that allowing young children to spend excessive time viewing television can be developmentally detrimental.     

Effects of signaled versus unsignaled delay of reinforcement on choice

Pigeons chose between 5-s and 15-s delay-of-reinforcement alternatives. The first key peck to satisfy the choice schedule began a delay timer, and food was delivered at the end of the interval. Key pecks during the delay interval were measured, but had no scheduled effect. In Experiment 1, signal conditions and choice schedules were varied across conditions. During unsignaled conditions, no stimulus change signaled the beginning of a delay interval. During differential and nondifferential signal conditions, offset of the choice stimuli and onset of a delay stimulus signaled the beginning of a delay interval. During differential signal conditions, different stimuli were correlated with the 5-s and 15-s delays, whereas the same stimulus appeared during both delay durations during nondifferential signal conditions. Pigeons showed similar, extreme levels of preference for the 5-s delay alternative during unsignaled and differentially signaled conditions. Preference levels were reliably lower with nondifferential signals. Experiment 2 assessed preference with two pairs of unsignaled delays in which the ratio of delays was held constant but the absolute duration was increased fourfold. No effect of absolute duration was found. The results highlight the importance of delayed primary reinforcement effects and challenge models of choice that focus solely on conditioned reinforcement.     

Briefly delayed reinforcement: An interresponse time analysis

Key-peck responding of pigeons was compared under VI or DRL schedules arranging immediate reinforcement and briefly (.5 sec) delayed reinforcement. Delays were either signaled by a blackout in the chamber, unsignaled, or unsignaled with an additional requirement that responding not occur during the .5 sec interval immediately preceding reinforcement (response delay). Relative to the immediate reinforcement condition, response rates increased during the unsignaled delay, decreased during the signaled delay, and were inconsistent during the response delay condition. An analysis of interresponse times (IRTs) under the different conditions revealed a substantial increase in the frequency of short (0 to .5 sec) IRTs during the unsignaled condition and generally during the response delay conditions compared to that during the immediate reinforcement baseline. Signaled delays decreased the frequency of short (0 to .5 sec) IRTs relative to the immediate reinforcement condition. The results suggest that brief unsignaled delays and, in many instances, response delays increase the frequency of short IRTs by eliminating constraints on responding.     

Examining children's ability to delay reward: Is the delay discounting task a suitable measure?

Discounting the value of delayed rewards has primarily been measured in children with the delay of gratification task and in adolescents and adults with the delay discounting task. In the present study, we assessed the suitability of the delay discounting task as a measure of temporal discounting in children. A sample of 7- to 9-year-olds (N = 98) completed a delay discounting task, a delay of gratification task, a sensation seeking measure, and IQ measures. In addition, teacher-based assessments of attention-deficit/hyperactivity disorder traits were measured. The results indicated that the majority of children produced meaningful data on the discounting task and discounted rewards hyperbolically. Children with an elevated risk of attention-deficit/hyperactivity disorder showed a trend towards discounting future rewards on the delay discounting task more steeply than did those at low risk. However, delay discounting was unrelated to either delay of gratification or sensation seeking. We interpret these results as providing some support for the use of delay discounting as a measure of intertemporal choice in children, although the results also suggest that delay discounting and delay of gratification tasks may tap different processes in this population.     

Delay discounting of monetary gains and losses in adolescents with ADHD: Contribution of delay aversion to choice

Adolescents with attention-deficit/hyperactivity disorder (ADHD) are known to have stronger preferences for smaller immediate rewards over larger delayed rewards in delay discounting tasks than their peers, which has been argued to reflect delay aversion. Here, participants performed a delay discounting task with gains and losses. In this latter condition, participants were asked whether they were willing to wait in order to lose less money. Following the core assumption of the delay aversion model that individuals with ADHD have a general aversion to delay, one would predict adolescents with ADHD to avoid waiting in both conditions. Adolescents (12–17 years) with ADHD (n = 29) and controls (n = 28) made choices between smaller immediate and larger delayed gains, and between larger immediate and smaller delayed losses. All delays (5–25 s) and gains/losses (2–10 cents) were experienced. In addition to an area under the curve approach, a mixed-model analysis was conducted to disentangle the contributions of delay duration and immediate gain/delayed loss amount to choice. The ADHD group chose the immediate option more often than controls in the gain condition, but not in the loss condition. The contribution of delay duration to immediate choices was stronger for the ADHD group than the control group in the gain condition only. In addition, the ADHD group scored higher on self-reported delay aversion, and delay aversion was associated with delay sensitivity in the gain condition, but not in the loss condition. In sum, we found no clear evidence for a general aversion to delay in adolescents with ADHD.     

职业延迟满足研究述评

职业延迟满足强调人们为了实现长期职业目标, 克服职业生涯中即时满足的冲动和诱惑的选择倾向, 并为审视和解释个体职业生涯发展提供了新的视角。国外研究者一般从工作伦理的范畴来考察职业延迟满足, 而在中国, 职业延迟满足则成为一个明确的组织行为学概念得以发展。虽然国内外研究者从个体、组织和社会等多个层面考察了职业延迟满足的相关因素及其效果, 但由于该领域的研究起步较晚, 现有研究并不深入。未来应重点关注职业延迟满足的本土化研究、概念发展、测量方法的改进, 并纵向研究其对个体职业成长的影响机制与效果。     

The Problem of the Condition of Arousal of the Pure Sensation of Cutaneous Pain

In order to develop scales representing curiosity-arousing components of pictures (slides) of either common objects or random shapes, a total of 56 college student Ss rated both sets of material on nine dimensions. Factor analyses indicated that the nine dimensions could be reduced to two factors. In order to test the ability of these factors to predict memorial performance and exploratory behavior, an additional 80 undergraduates were then tested for recognition or free looking time (FLT) of either object or random shape slides. Separate regression equations, using FLT and recognition performance as criterion measures, were computed. The present results not only indicate stability in visual exploratory scaling plus redundancy among various attributes of visual stimuli, but also suggest that behavior can be considered as elicited by two separate attributes of visual stimuli.     

延迟满足情境中2岁儿童对行为的自我控制能力和延迟策略的使用

以2岁儿童为被试,探讨其在延迟满足情境中的自我控制能力发展的状况。结果表明:(1)2岁儿童已具有一定程度的自我控制能力,个体差异显著,性别差异不显著;(2)2岁儿童已能使用一定的延迟策略,包括问题解决、分心、寻求安慰、消极等待、寻求他人帮助、回避等,其中使用频率最高的是分心策略;(3)不同的策略对延迟时间有着不同的影响;(4)儿童对策略的使用不会因延迟满足情境的不同而出现显著差异。     

Impulsive choice and pre‐exposure to delays: iv. effects of delay‐ and immediacy‐exposure training relative to maturational changes in impulsivity

Impulsive choice describes preference for smaller, sooner rewards over larger, later rewards. Excessive delay discounting (i.e., rapid devaluation of delayed rewards) underlies some impulsive choices, and is observed in many maladaptive behaviors (e.g., substance abuse, gambling). Interventions designed to reduce delay discounting may provide therapeutic gains. One such intervention provides rats with extended training with delayed reinforcers. When compared to a group given extended training with immediate reinforcers, delay‐exposed rats make significantly fewer impulsive choices. To what extent is this difference due to delay‐exposure training shifting preference toward self‐control or immediacy‐exposure training (the putative control group) shifting preference toward impulsivity? The current study compared the effects of delay‐ and immediacy‐exposure training to a no‐training control group and evaluated within‐subject changes in impulsive choice across 51 male Wistar rats. Delay‐exposed rats made significantly fewer impulsive choices than immediacy‐exposed and control rats. Between‐group differences in impulsive choice were not observed in the latter two groups. While delay‐exposed rats showed large, significant pre‐ to posttraining reductions in impulsive choice, immediacy‐exposed and control rats showed small reductions in impulsive choice. These results suggest that extended training with delayed reinforcers reduces impulsive choice, and that extended training with immediate reinforcers does not increase impulsive choice.     

Evaluation of an islandwide screening,assessment and treatment program

This article reports on the effectiveness of the Islandwide Screening, Assessment, and Treatment Program of the Child Development Project in Bermuda. From 1982 to 1984, approximately 1100 families with 2-year-old children were screened for children's cognitive and language delay, for behaviour management problems and for other home characteristics that put children at risk for later school failure. Children who failed the screening and subsequent assessment procedures (of whom random samples received treatment) and samples of others who passed screening and assessment were evaluated from 1984 to 1986 at 4 years of age. This article focuses on the results of the cognitive and language programs; the more problematic behaviour management analyses were reported elsewhere (Miller and Scarr, 1988). The screening procedures and assessment measures developed for this project were themselves evaluated and adjusted to maximize efficiency and costeffectiveness. The screening and assessment procedures proved effective in bringing to the attention of the Child Development Project those families and children who need developmental services, and in not overidentifying normal children as potentially delayed in development. Two kinds of treatment services were compared: The Mother-Child Home Program (MCHP), administered by paraprofessional toy demonstrators, and other interventions tailored by professionals to the language and cognitive problems of the child (called ‘tailored programs’). Children who were not extremely delayed or disturbed were randomly assigned either to the MCHP or to a tailored program. Neither intervention program was preferable to the other. Even though improved, the 4-year-olds identified as developmentally delayed at 24 months still lagged behind children who passed all parts of screening and those who failed screening but passed assessment 2 years earlier. The screening and assessment procedures were very effective in the early identification of children with developmental problems, but the treatment programs failed to bring most children to normal levels of cognitive and language functioning.     

The effects of a seatbelt-gearshift delay prompt on the seatbelt use of motorists who do not regularly wear seatbelts

A seatbelt-gearshift delay was evaluated in two U.S. and three Canadian vehicles using a reversal design. The seatbelt-gearshift delay required unbelted drivers either to buckle their seatbelts or to wait a specified time before they could put the vehicle in gear. After collecting behavioral prebaseline data, a data logger was installed in all five vehicles to collect automated data on seatbelt use. Next the seatbelt-gearshift delay was introduced. The results showed that the delay increased all 5 drivers' seatbelt use, and that the duration of the delay that produced relatively consistent seatbelt use varied across drivers from 5 to 20 s. When the device was deactivated in four of the five vehicles, behavior returned to baseline levels.     

On the functions of the changeover delay

The function of changeover delays in producing matching was examined with pigeons responding on concurrent variable-interval variable-interval schedules. In Experiment 1, no changeover delay was compared to two different types of changeover delay. One type, designated generically as response-response but in the present example as peck-peck, was timed from the first response on the switched-to key; the other, designated generically as pause-response but in the present example as pause-peck, was timed from the last response on the switched-from key. High changeover rates occurred with no changeover delay. Peck-peck and pause-peck changeover delays produced low and intermediate changeover rates, respectively. In Experiment 2, pause-peck and peck-peck changeover delays were compared across a range of relative reinforcement rates. Similar matching relations developed despite differences in the changeover rates and local response patterns as a function of the type of changeover delay. In Experiment 3, both types of changeover delay yielded similar changeover rates when their obtained durations were equal via yoking. The results suggest that changeover delays function to separate responses on one key from reinforcers on the other or to delay reinforcement for changing over. In addition, the distribution of responding during and after the changeover delay may vary considerably without affecting matching.     

Evaluating the effect of delay spacing on delay discounting: carry‐over effects on steepness and the form of the discounting function

Most delay discounting studies use tasks that arrange delay progressions in which the spacing between consecutive delays becomes progressively larger. To date, little research has examined delay discounting using other progressions. The present study assessed whether the form or steepness of discounting varied across different delay progressions. Human participants completed three discounting tasks with delay progressions that varied in the time between consecutive delays: a standard (increasing duration between delays), linear (equal duration between delays), and an inverse progression (decreasing duration between delays). Steepness of discounting was generally reduced, and remained so, following experience with the inverse progression. Effects of the delay progression on the best fitting equation were order‐dependent. Overall the hyperbola model provided better fits, but the exponential model performed better with data from the inverse progression. Regardless, differences in which model fit best were often small. The finding that the best fitting model was dependent, in some cases, on the delay progression suggests that a single quantitative model of discounting may not be applicable to describe discounting across all procedural contexts. Ultimately, changes in steepness of discounting following experience with the inverse progression appeared similar to anchoring effects, whose mechanism will require further study to delineate.     

INCREASING AUTISTIC CHILDREN'S SPONTANEOUS VERBALIZATIONS OF AFFECTION: AN ASSESSMENT OF TIME DELAY AND PEER MODELING PROCEDURES

We assessed the efficacy of time delay and peer modeling procedures in increasing autistic children's spontaneous verbalizations of affection. Four autistic children were taught to spontaneously say “I like (love) you” in response to a hug from a familiar person and their mother. Generalization from a free play training setting to free play outdoors and at home was assessed. Ancillary social and affection behaviors were also observed. Results indicated that the time delay was a quick and effective procedure for all the children. Peer modeling was unsuccessful in teaching the target behavior.     

Probability and delay in commitment

In the first stage of a two-stage choice, human subjects chose between probabilistic access to a second choice (between a small high-probability reward and a large low-probability reward) and commitment to the large low-probability reward. When confronted with the second-stage choice, subjects strongly preferred the small high-probability reward. When the first-stage probability (of access to the second stage) was high, subjects strongly preferred the path leading to the choice in the second stage. But when the first-stage probability was low, subjects committed themselves to the large low-probability reward. These results parallel those obtained by Rachlin and Green (1972) with pigeons and constitute some evidence that probabilities may be interpreted as delays.     

AN EVALUATION OF TWO METHODS FOR INCREASING SELF-INITIATED VERBALIZATIONS IN AUTISTIC CHILDREN

Three children with autism and mental retardation were treated for deficits in self-initiated speech. A novel treatment package employing visual cue fading was compared with a graduated time-delay procedure previously shown to be effective for increasing self-initiated language. Both treatments included training multiple self-initiated verbalizations using multiple therapists and settings. Both treatments were efffective, with no differences in measures of acquisition of target phrases, maintenance of behavioral gains, acquisition with additional therapists and settings, and social validity.     

Delay discounting in the pigeon: In search of a magnitude effect

The magnitude effect, where larger outcomes are discounted proportionally less than smaller outcomes, is a well‐established phenomenon in delay discounting by human participants. To this point in the literature magnitude effects have not been reliably evidenced in nonhuman animals. , however, used a concurrent‐chains arrangement with pigeon and found evidence for a magnitude effect. Grace et al. suggested that in many delay discounting experimental arrangements with nonhuman animals (e.g., adjusting amount, adjusting delay) the organism is not given the opportunity to directly compare outcomes of different sizes. They suggest that because of the lack of direct comparison it is difficult for the organism to determine the relative size of each outcome, which in turn mutes the effect of the amount differences between outcomes. As a test of this “comparison hypothesis,” the present experiment was conducted to assess whether the magnitude effect would be evidenced in pigeon when using an adjusting amount procedure where outcomes of different amounts were presented proximally. In the present arrangement, pigeons were presented two choice panels in an operant chamber where each panel was associated with an independent adjusting amount delay discounting task, but with differing outcome amounts (i.e., a 32‐food pellet panel and an 8‐food pellet panel). In this arrangement the choice panels alternated in their availability within a session from trial block to trial block. The present findings indicate no reliable effect of amount, even when the outcomes were proximal and thus readily comparable. This result suggests that the lack of magnitude effect is not driven by the organism's ability to compare the difference in amount between choice alternatives.