Extended Visual Fixation in Young Infants: Look Distributions, Heart Rate Changes, and Attention

Visual fixation in in ants from 3 to 6 months of age was examined for its fit to the theory of "attentional inertia." This theory posits that during the progression of a look there is increasing attention toward the stimulus and an "inertia" to continue looking. An extended audiovisual stimulus was presented for 20 min to infants while fixation was videotaped and heart rate (HR) was recorded. Consistent with the attentional inertia theory, look duration toward the stimulus had a lognormal distribution. Hazard functions describing these distributions showed a decreasing conditional probability of looking away with increases in look duration. Look onset and stimulus changes that occurred within a look were accompanied by HR deceleration. The average HR level continued to decrease over the duration of a look and returned to prestimuls level immediately look and returned to prestimulus level immediately prior to the fixation offset. Infant fixation has characteristics similar to fixation in children and adults, and attention appears to increase over to the course of a look in young infants.     

Extended visual fixation and distractibility in children from six to twenty-four months of age

Distractibility during extended visual fixations in children 6 months to 2 years of age was examined. A children's Sesame Street movie (Follow That Bird) was presented to children (N = 40) for a minimum of 20 min while fixation was videotaped and heart rate was recorded. Distractors (computer-generated patterns or another Sesame Street movie) were presented on an adjacent television screen. Consistent with prior research with older preschool-age children, the latency to turn toward the distractor was a function of the length of the look occurring before distractor onset. For the period immediately before distractor onset, children had a greater sustained lowered heart rate for the trials on which they continued looking at the center television monitor than for the trials on which they looked toward the distractor. This pattern of distractibility suggests attention increases over the course of a look toward the television, and that heart rate changes reflect this increase in attention.     

Extended visual fixation in the early preschool years: look duration, heart rate changes, and attentional inertia

Visual fixation in infants from 6 months to 2 years of age was examined for its fit to the theory of "attentional inertia." A children's movie ("Sesame Street" movie, "Follow that Bird") or an extended audiovisual stimulus (computer-generated patterns) was presented to 40 children for a minimum of 20 min while fixation was videotaped and heart rate (HR) was recorded. Consistent with attentional inertia theory, fixations toward the stimuli had a lognormal distribution, HR decreased over the course of a look, and HR returned to prestimulus levels immediately before look offset. Older children (18 months, 24 months) showed a distinction in the parameters describing the lognormal distribution for the "Sesame Street" movie and the audiovisual patterns, whereas younger children (6 months, 12 months) responded similarly to the two stimulus types. Fixation patterns of children in this age range suggest attention increases over the course of a look, and parameters consistent with attentional inertia theory differentially develop in this age range.     

A smartcard conditional access interface scheme for conditional access subsystem separation in digital TV broadcasting

INTRODUCTION With the introduction of digital TV broadcasting in China, TV operators can deliver their TV programs and value-added services to their subscribers more efficiently and conveniently than the analog coun-terpart. Most main technical components of digital TV broadcasting have been adopted by the Chinese government as the de facto national standards. For example, the standards relating to the programs’ source coding are MPEG-2 (ISO/IEC 13818, 1996~ 2004) or MPEG-4 (I…     

A developmental study of filtering in visual attention

Children aged 4, 5, and 7 years and adults aged 20 years performed a speeded classification task designed to isolate several sources of interference in visual selective attention. On each trial, observers responded to 1 of 4 targets which were mapped to 2 responses. On some trials the targets were also flanked by distractor stimuli, which observers were asked to ignore. The interference measures examined the effects of attentional set, increases in feature number, increases in feature type, response competition, and stimulus generalization. All but 1 of the measures (stimulus generalization) produced reliable interference in the adult observers. However, only 2 of the measures (attentional set, increases in feature number) produced reliable interference in children. The implications of these findings for theories of attentional development are discussed.     

Tracking of the expected time to reinforcement in temporal conditioning procedures

In one experiment, the rate and pattern of responding (head entry into the food cup) under different distributions of intervals between food deliveries were examined. Separate groups of rats received fixed-time (45, 90, 180, or 360 sec), random-time (45, 90, 180, or 360 sec), or tandem fixed-time (45 or 90 sec) random-time (45 or 90 sec) schedules of reinforcement. Schedule type affected the pattern of responding as a function of time, whereas mean interval duration affected the mean rate of responding. Responses occurred in bouts with characteristics that were invariant across conditions. Packet theory, which assumes that the momentary probability of bout occurrence is negatively related to the conditional expected time remaining until the next reinforcer, accurately predicted global and local measures of responding. The success of the model advances the prediction of multiple measures of responding across different types of time-based schedules.     

Postdiscrimination generalization as a function of interresponse time

Following 20 sessions of variable-interval 20-sec reinforcement in the presence of a single 45-deg line-tilt stimulus, three pigeons were trained to discriminate between line tilts of 45 deg correlated with variable-interval 20-sec reinforcement and line tilts of 15 deg correlated with extinction. A generalization test along the line-tilt dimension was administered following a criterion discrimination performance. Gradients derived in terms of relative frequency of response as a function of line tilt indicated strong external stimulus control and exhibited clear peak shift. From the interresponse time (IRT) distributions generated for responding to each test stimulus, probability of response conditional upon IRT (IRTs/Op) was derived as a joint function of line tilt and IRT. The IRTs/Op functions for responses following IRTs in 0.2-sec-wide classes from 0.2 to 1.0 sec and for responses following IRTs in the interval of 1.0 to 2.0 sec were similar to the relative generalization gradients and also exhibited peak shift. Few IRTs were greater than 2.0 sec. External stimulus control was established over responses terminating IRTs both longer and shorter than 1.0 sec.     

Heart Rate and Behavioral measures of Attention in Six-, Nine-, and Twelve-Month-Old Infants during Object Exploration

In this study we examined the effect of heart rate and behavioral measures of attention on distractibility of 6-, 9-, and 12-month-old infants. The infants were presented with a toy, and a distractor was presented while they attended to the toy. The distractor was presented during heart rate changes indicating sustained attention or attention termination, or during periods of time when behavioral ratings indicated the infant was in focused or casual attention. There were longer distraction latencies during attentional engagement as defined by heart rate changes or behavioral ratings than for periods of inattention. Infants had the longest distraction latencies when heart rate and behavior measures were congruent with respect to attention engagement (heart rate deceleration and focused attention). Conversely, latencies were shortes for congruent values of inattention (heart rate acceleration and casual attention). Infant information processing may be greatest when a heart rate deceleration occurs simultaneously with an episode of focused attention.     

Infant Gaze Following During Parent–Infant Coviewing of Baby Videos

A total of 122 parent–infant dyads were observed as they watched a familiar or novel infant‐directed video in a laboratory setting. Infants were between 12–15 and 18–21 months old. Infants were more likely to look toward the TV immediately following their parents' look toward the TV. This apparent social influence on infant looking at television was not solely due to the common influence of the television program on looking behavior. Moreover, infant looks that were preceded by parent looks tended to be longer in length than those that were not preceded by parent looks, suggesting that infants assign greater value to media content attended to by their parents. Thus, parental patterns of attention to television may influence early viewing behavior.     

A comparison of the short-term memory performances of pigeons and jackdaws

Two experiments employed a delayed conditional discrimination procedure in which half the trials began with the presentation of food and half with no food; following a retention interval, subjects were presented with a choice between red and green keys, a response to one of which was reinforced according to whether the trial had started with food or no food. In Experiment 1, after 38 training sessions during which the retention interval was gradually increased, pigeons performed at a moderate level with intervals of 5 to 7.5 sec. A final test produced a steep forgetting function for food trials, but not for no-food trials; performance was unaffected by the duration of the intertriai interval (10 or 40 sec). Experiment 2 used the delayed conditional discrimination procedure to compare short-term memory in jackdaws (Corvus monedulus) with that in pigeons. Although the performance of the jackdaws was below that of the pigeons at the start of training, they showed more rapid learning over long delays, and, in the final test, a shallower forgetting function for food trials than that shown by pigeons. The results suggested superior short-term memory in jackdaws, which may help to explain the better performance of corvids in general when compared with that of pigeons in certain complex learning tasks.     

浅谈当代电视纪录片的创意和构思

目前我国多数电视纪录片的叙事技巧和拍摄形式还处于比较低的水平,拍摄手法单一、模仿成风,新的模式化以及僵化的“定义”使纪录片失去了创新和发展的原动力,不能适应当前电视产业的迅猛发展。本文试图通过纪录片创意的主体、电视纪录片的创意、纪录片的艺术构思三个方面的论述探索电视纪录片创作的基本规律,拓展新时期电视纪录片创作思路的新途径。     

电大班主任日常管理有效性提升的动力机制

沿袭普通高校的班主任管理模式在以远程教育形式为主的电大教育中显得并不适用,日常管理工作存在大量无用功,难以发挥班主任对远程教育的组织引导作用.因此,通过分析电大学生的一般性特征,围绕电大班主任日常管理工作的几点重心,提出日常管理工作有效性的提升策略,以期为提高电大班主任日常管理水平提供借鉴参考.     

Effects of prior response-contingent reinforcement on superstitious behavior

Three pigeons were exposed to fixed-time (FT) 15 sec, fixed-interval (FI) 15 sec for performing an arbitrary response, a reversal back to FT 15 sec, and then extinction (no reinforcement). During each phase, a computer-controlled tracking system continuously recorded the position of the bird’s head as it moved freely in the experimental chamber. During the first exposure to FT 15 sec, all 3 birds developed a pattern of feeder-wall-directed behavior with occasional circular excursions from the feeder immediately following reinforcement. During FI 15 sec, all birds performed the arbitrary operant, which consisted of contacting a virtual target sphere near the rear of the chamber, and did not engage in feeder-wall-directed behavior. During the reversal back to FT 15 sec, the birds developed a behavior sequence consisting of moving in the direction of the target sphere after reinforcement, followed by feeder-wall-directed behavior prior to the next reinforcement. During extinction, either moves toward the target sphere or wall-directed behavior occurred separately, interspersed with reappearance of the two as a sequence, followed by cessation of both members of the behavior sequence. These findings indicate that prior reinforcement of an arbitrary response can affect the location and form of superstitious behavior that develops near the beginning of the interreinforcement interval, but that other factors (e.g., immediacy of reinforcement) affect the location and form of the behavior near the end of the interval. The findings can be interpreted in the context of superstitious chaining.     

Effect of intertrial interval on variable-interval discrete-trial barpressing

In seven experiments, an effect of the intertriai interval (ITI) duration on barpressing by rats was studied. A stimulus signaled a 15-sec variable-interval trial. The first response after the interval elapsed turned the stimulus off and was rewarded with food. Trials were separated by long (about 300 sec) or short (about 10 sec) ITIs. A within-subjects design established that response rate on trials after long ITIs was lower than that after short ITIs (Experiments 1 and 3–7). The effect was not cumulative (the effect of one and five consecutive short ITIs was the same). Response rate after short and long ITIs was the same when a between-subjects design was used (Experiment 2). Response rate was higher after 160-sec ITIs than after 300-sec ITIs, suggesting that the ITI duration at which all longer ITIs are treated the same (i.e., the upper limit) is greater than 160 sec (Experiment 3). When food, the trial stimulus, a novel stimulus, or a familiar stimulus never paired with food, was presented 10 sec before the next trial during some of the long ITIs, response rate on the next trial was similar to that found after 10-sec ITIs (Experiments 4–6). This similarity suggested that these events could mark the start of the ITI. However, the familiar stimulus did so only when it reliably predicted that the next trial would occur after a short interval. The effect of ITI duration on responding was apparently attributable to response latency. Response latency was greater after long ITIs, but once responding began, it was similar after long and short ITIs (Experiment 7).     

网络思维方式及其对电视传播的影响

多媒体的传播形态将成为未来人们信息接受的普遍方式，因此，不同发媒介接受行为所形成的思维方式之间就有了相互影响的可能。从电视的角度看，我们可以将网民看成是喜允上网的观众。而网络的运作规则对网民的思维方式产生了潜移默化的影响。长时间上网形成的思维方式，直接影响到他们对电视信息的接受，因此，为了顺应这一趋势，电视传播必须要进行相应的改革。     

Color television and educational TV

Conclusions Color television is so new that there is little concrete information on the subject. However, it seems logical to doubt that color will provide any general increased effectiveness to educational TV. In some areas, such as art and medicine, the impact may be great; but for the greater proportion of educational subjects, it will not contribute a great deal. In view of this, together with the present high cost of color TV, it would seem foolish for educational TV to delay development because color television is coming. The transition to color can always be made after the piomeering is done, when costs have gone down, when color receiver circulation is large enough to make color worth while, and when the numerous problems of color programming and production have been solved. What effect will color TV have upon educational TV programs? How expensive will color TV be for educational use? How will educational TV stations use color TV? What competition will commercial color TV offer to educational black and white TV stations? These questions are answered and an overview of the implications of color for educational TV is presented. E. G. Sherburne, Jr., was formerly Television Coordinator at the U. S. Navy Special Devices Center, Port Washington, Long Island, New York.     

Habituation as a function of similarity and temporal location of target and distractor stimuli

Three experiments examined the habituation of rats’ neophobia to novel flavors, and the disruption of that habituation by presentation of a distractor flavor either immediately before or immediately after the target flavor. Habituation of neophobia to lemon solution was more seriously disrupted by presentation of saline as a distractor than by presentation of coffee as a distractor, and this was true whether the distractor was presented before or after the target on each habituation trial. Two further experiments established that the relative ineffectiveness of coffee as a distractor could not be attributed to its lack of salience, and was probably related to its greater similarity to the target lemon flavor. These results do not fully accord with those reported by Robertson and Garrud (1983), but are readily explained in terms of generalization of habituation between distractor and target flavors.     

Effects of discriminability, probability of reinforcement, and handling cost on visual search and prey choice

Pigeons searched for two targets that varied in similarity to items in the background. The targets, simulating “prey,” were small alphabetic characters presented on computer monitors among distractor characters. In the first experiment, the probability of reinforcement for pecking at the targets was manipulated. In the second experiment, the response requirement for one of the targets was varied. Changing the probability of reinforcement led to more efficient search and increased choice for the more reinforced item. This effect carried over to subsequent equal reinforcement baseline conditions. Increasing the response requirement for one item increased response time for that item and reduced choice of the item. This effect did not carry over to a subsequent baseline condition. The results suggested that a high probability of reinforcement resulted in improved detection of the item, perhaps through perceptual learning, and increased the incentive that motivated response to the item, but that high response requirement resulted only in an incentive shift.     

探寻近年我国电视剧中民族精神表述的蜕变

通过对各种类型电视剧剧情探索与研究,认为民族精神是我国电视剧精神架构的核心。民族精神的内涵在我国不同类型电视剧中都有所体现。但随着近几年我国电视创作观念的不断更新,电视剧在民族精神的表述上发生着一系列的变化,从人性美的彰显到纪实主义的挥发,从传承历史到贴近时代特色,从爱国到爱家,这些变化使我国电视剧在民族精神的表述上不断呈现新的面貌。     

Attending to spatial locations: a developmental study

In 2 experiments, 7- and 8-year-old children and college students performed a letter-detection task in which reaction time was the dependent variable. Expectancy was manipulated by varying the probability the stimulus would appear at the center of an imaginary circle rather than along the perimeter. Although both age groups responded consistently faster to stimuli presented in expected locations than to stimuli presented in unexpected locations, this expectancy effect was larger for the children than it was for the college students. In a third experiment, these results were replicated using a luminance-detection task with 5-year-olds, 8-year-olds, and college students as subjects. It was concluded that children as well as adults are able to expand or contract the breadth of their attentional focus in accordance with task demands and that there is a developmental change in the efficiency with which a stimulus presented in an otherwise empty field can be located. Furthermore, it was suggested that children may be more disrupted by the occurrence of an unexpected event than adults are.