The Effect of Delayed Responding on Stroop-Like Task Performance Among Preschoolers

Forty-four preschoolers completed 2 conditions of a Stroop-like procedure (e.g., saying “boat” for car and “car” for boat) that differed in whether a 3-s delay was imposed before responding. The test card was visible during the delay period for half of the children and occluded for the other children. Preschoolers’ interference control was significantly improved in the delay condition. There was no difference between the two delay variants (test card visible or occluded). Children were more prone to interference as testing progressed regardless of whether the delay was present. These results suggest that delays effectively reduce interference by reducing the potency of the competing response during test trials, although memory demands may moderate the effectiveness of delays.     

The Influence of Stimulus Discriminability on Young Children's Interference Control in the Stroop-Like Happy–Sad Task

The day–night paradigm, where children respond to a pair of pictures with opposite labels for a series of trials, is a widely used measure of interference control. Recent research has shown that a happy–sad variant of the day–night task was significantly more difficult than the standard day–night task. The present research examined whether the perceptual discriminability of the happy–sad task pictures impacts young children's interference control. When test card pairs were equally distinct between conditions, children performed similarly regardless of whether the happy–sad or day–night response terms were employed (Experiment 1). Two versions of the happy–sad task were administered in Experiment 2, and children experienced significantly more interference when the stimuli were perceptually similar than when they were distinct. Theoretical implications for the role attentional demands play in interference control in Stroop-like tasks for pre-readers are discussed.     

Effects of manipulating incentive visibility during the baiting phase of delayed-response problems

Rhesus monkeys were given 960 delayed response (DR) problems. The incentive was either visible or not visible during the baiting phase of each problem, and a 0-, 5-, 10-, or 20-sec intraproblem delay was imposed. Performance was substantially better when the incentive could be seen during the baiting phase. When the incentive was visible during baiting, at all stages of training performance decreased as a function of increased chance levels after short delays, and the rate of improvement with training was comparable after each of the four intraproblem delays. When the incentive was not visible during the baiting phase, an inverse relationship between performance and delay duration became evident only during the later stages of training. On the initial problems performance was at chance levels, and although improvement with training was evident, the rate of this improvement was inversely related to delay duration. The findings were interpreted in terms of Fletcher's orienting response analysis of DR performance.     

Acoustic Interference in a Recognition Task

Phonetic or acoustic characteristics of stimuli in recall studies have consistently been shown to generate more interference over short intervals than semantic characteristics. We performed three experiments to determine whether this characteristic also applied to recognition processes over short intervals. Subjects were shown study lists of eight words and were asked to recognize which of those words recurred on subsequent eight-word lists. Delays varied from 0 to 100 s between study and test, with a rehearsal-preventing task inserted during the delays. Phonetic distractors generated greater interference than semantic distractors at all delay levels, and semantic distractors generated greater interference than random distractors. These distractor-type differences were not present in long-term recognition tasks. The deterioration in performance over time was considerably slower in these recognition experiments than in previous recall studies.     

Acoustic interference in a recognition task

Phonetic or acoustic characteristics of stimuli in recall studies have consistently been shown to generate more interference over short intervals than semantic characteristics. We performed three experiments to determine whether this characteristic also applied to recognition processes over short intervals. Subjects were shown study lists of eight words and were asked to recognize which of those words recurred on subsequent eight-word lists. Delays varied from 0 to 100 s between study and test, with a rehearsal-preventing task inserted during the delays. Phonetic distractors generated greater interference than semantic distractors at all delay levels, and semantic distractors generated greater interference than random distractors. These distractor-type differences were not present in long-term recognition tasks. The deterioration in performance over time was considerably slower in these recognition experiments than in previous recall studies.     

Long delay learning in the T-maze

Rats were trained to go to one side of a T-maze with delays of reward lasting 1, 20, or 60 min in Expt 1 and 1 or 60 min in Expt 2. Mediation by secondary reward was prevented by administering the same delay treatment regardless of whether the response was correct or incorrect: after a response, the rat was removed from the choice alley and placed in its home cage to spend the delay. Feedback for the response was given in the startbox after the delay interval ended. The rats learned and there were no significant differences in performance among groups trained with different delays. These results had been expected on the basis of Revusky's (1971) hypothesis that removal of the rat from the learning situation to spend the delay elsewhere facilitates long delay learning by reducing associative interference. In Expt 3, this notion was tested explicitly by varying the amount of a 2-min delay to be spent in the experimental situation. Different groups of rats were left in the choice alley after the response for 0, 15, or 60 sec; then the rats were removed to spend the remainder of the 2-min delay in the home cage As predicted, the level of performance decreased as the length of time in the choice alley was increased.     

Developmental differences in the use of task goals in a cued version of the stroop task

The ability of children (M= 8.8 years) and adults (M= 25.6 years) to maintain task goals was examined by comparing their performance on a cued version of the Stroop colour‐word task. The experimental task presented a cue on each trial that instructed the participant to either read aloud the forthcoming word or name the colour of the word's lettering. Participants were tested with each of two cue‐stimulus delays (1,000 and 5,000 ms). Analysis of error rates in the colour‐naming condition revealed that children experienced greater interference than adults at each of the cue‐stimulus delays. In an effort to separate the relative contributions of colour‐naming and word‐reading processes, additional analyses were performed based on the process dissociation procedure of Lindsay and Jacoby (1994) . While colour‐naming process estimates did not vary with age group or cue‐stimulus delay, word‐reading process estimates were found to vary with age group and cue‐stimulus delay. Specifically, adults were superior to children in the inhibition of irrelevant word information only during a long cue‐stimulus delay. Collectively, these findings indicate that children have difficulty maintaining task goals in order to suppress stronger, goal‐irrelevant responses.     

Sources of Dual-Task Interference: Evidence From Human Electrophysiology

When an individual attempts to perform two tasks at the same time, the tasks often interfere with each other. This interference has been studied for several decades with the psychological refractory period paradigm, in which two targets that require independent responses are presented on each trial, separated by a variable delay period; interference typically takes the form of increased response times for the second target at short interstimulus delays. The present study used electrophysiological recordings to determine whether a specific index of perception and categorization (the P3 wave) is delayed in the same manner as response times. Although response times for the second target were found to be greatly delayed at short interstimulus intervals, the P3 wave was not substantially delayed. This finding indicates that there was minimal interference during target identification and categorization and that the prolongation of response times in this paradigm primarily reflects a delay in a relatively late process, such as response selection.     

Is perseveration caused by inhibition failure? Evidence from preschool children's inferences about word meanings

Four studies examined the relation between children's cognitive inhibition and flexibility in a lexical inference task. Children's linguistic flexibility was assessed by the Flexible Induction of Meaning (FIM) test (Deák, 2000a), which requires that children shift inferences about the meanings of several words for novel objects. In Study 1, 54 3-year-olds either were trained between blocks of problems, for a delay of 3 min, or received no training or delay. Training delays did not influence perseveration. In Study 2 (N=72 3- and 4-year-olds') novel word problems were grouped either to increase the frequency of cue switches (i.e., reduce response "set") or minimize the interval between problems about the same objects. Again, no effect was found. In Study 3, 48 3- and 4-year-olds completed 6 preliminary trials; in a high interference group these trials generated a response set to be inhibited upon the first switch to a new cue context. This group did not perseverate more than a control group. There was no association between FIM perseveration and a Stroop-like test of verbal inhibition though both were marginally related to receptive vocabulary. In study 4 (48 3- and 4-year-olds), FIM was again unrelated to Stroop performance, but was related to the ability to tell whether a situation or problem is indeterminate. Thus, flexibility across semantic inferences is not influenced by timing, order, and number of pre-switch problems and is not predicted by individual differences in a test of verbal inhibition. However previously reported age and individual differences in flexible induction of word meanings are robust and related to vocabulary and logical ability.     

Object boundaries influence toddlers' performance in a search task

Previous research has shown that young children have difficulty searching for a hidden object whose location depends on the position of a partly visible physical barrier. Across four experiments, we tested whether children's search errors are affected by two variables that influence adults' object-directed attention: object boundaries and proximity relations. Toddlers searched for a car that rolled down a ramp behind an occluding panel and stopped on contact with a barrier. The car's location on each trial depended on the placement of the barrier behind one of two doors in the panel. In Experiment 1, when a part of the car (a pompom on an antenna) was visible at the same distance from the object as the barrier wall in past research, search performance was above chance but below ceiling. In Experiments 2 and 3, when the visible part was close to the hidden body of the car and could be seen through one of two windows in the doors of the occluding panel, performance was near ceiling. In Experiment 4, when only the barrier was visible through one of the same windows, performance was at chance. Toddlers' search for a hidden object therefore is affected by the proximity of a visible part of the object, though not by the proximity of a separate visible landmark. These findings suggest a parallel between the object representations of young children and those of adults, whose attention is directed to objects and spreads in a gradient-like fashion within an object.     

The effects of interference and retention delay on temporal generalization performance

This study investigated the effect of forgetting of the standard duration on temporal discrimination in a generalization task. In two experiments, participants were given a temporal generalization task with or without a retention delay between the learning of the standard duration and the testing of the comparison durations. During this delay, they either performed or did not perform an interference task. Results failed to reveal any effect of 15-min and 24-h retention delays on time judgments (Experiment 1). However, when an interference task was performed during the 15-min delay (Experiment 2), there was a subjective shortening effect, indicating that the standard duration was judged shorter with than without an interference task. These findings suggest that when an interference task occurs immediately after initial temporal encoding, it affects the process of consolidation in reference memory.     

Performance on the dimensional change card sort and backward digit span by young children with autism without intellectual disability

The early development of executive function (EF) and its relation to autism symptom expression is of considerable theoretical interest, particularly in children without general cognitive delay. Executive function was tested in 23 children with autism spectrum disorders (ASD) without intellectual disability and 20 age- and IQ-matched typically developing children. Even though performance was equivalent between the two groups on tests of general intelligence, flexibility in card sorting was lower for children with ASD. Verbal working memory during the backward digit span did not differ between groups. Among children with ASD, poorer performance on card sorting distinguished a subgroup with worse social-communication functioning above and beyond IQ. Controlling for IQ social and repetitive symptoms of ASD did not differ based on card sorting ability.     

The occlusion illusion: partial modal completion or apparent distance?

In the occlusion illusion, the visible portion of a partly occluded object (eg a semicircle partly hidden behind a rectangle) appears to be significantly larger than a physically identical region that is fully visible. This illusion may occur either because the visual system 'fills in' a thin strip along the occluded border (the partial-modal-completion hypothesis) or because the partly occluded object is perceived as farther away (the apparent-distance hypothesis). We measured the magnitude of the occlusion illusion psychophysically in several experiments to investigate its causes. The results of experiments 1-3 are consistent with the general proposal that the magnitude of the illusion varies with the strength of the evidence for occlusion, supporting the inference that it is due to occlusion. Experiment 4 provides a critical test between apparent-distance and partial-modal-completion explanations by determining whether the increase in apparent size of the occluded region results from a change in its perceived shape (due to the modal extension of the occluded shape along the occluding edge, as predicted by the partial-modal-completion hypothesis) or from a change in its perceived overall size (as predicted by the apparent-distance hypothesis). The results more strongly support the partial-modal-completion hypothesis.     

Dissipation of retroactive interference in human infants

In 3 experiments with 85 human 3-month-olds, the authors asked whether retroactive interference with their memory of the original training stimulus is temporary or permanent. Infants learned to move a mobile by kicking and then were exposed to a different mobile (Experiment 1) or context (Experiment 2) immediately or 3 days afterward (Experiment 3). They were tested after increasing delays with the original stimulus, the exposed stimulus, or a completely novel stimulus. Retroactive interference was temporary and unrelated to the exposure delay. The data are consistent with a retrieval-based account of interference. Memory updating (i.e., responding to the interfering stimulus) was coincident with retroactive interference, suggesting that retroactive interference is an adaptive mechanism that facilitates memory updating within a narrow time window.     

Disjunctive Concept Utilization in Preschool Children

Summary

Twenty-four children, eight each in three age groups, were asked to “play a game” which required them to utilize disjunctive concepts such as “blue or car.” The disjunctive concepts used were the nine which can be formed by combining one value from among three possibilities on the color dimension (green, blue, red) with one value from among three possibilities on the form dimension (car, boat, airplane). The task consisted of 18 five-choice trials with each of the nine disjunctive concepts represented twice—once with the color mentioned first and once with the form mentioned first. Ss were required to pick the positive instance card. All three groups performed significantly better than chance (ps. < .0001) on the task. A significant relation between age and performance on this task was found (Rho = .65, p < .05). There were no sex differences. The results are discussed in relation to task variables and an associative view of cognitive development.     

Investigating local and global effects of surface colours and contours in amodal completion

ABSTRACT

We studied interpretations of partly occluded shapes. Models that account for amodal completion mostly deal with local and global contour characteristics. In the current study, we were interested in the effects of colour on local and global contour completions. In our stimuli, local contour completions comprised simple linear extensions of the partly occluded contours, whereas global contour completions accounted for global shape regularities. Our stimuli were designed such that the visible surface colour could also be completed in a local or global fashion, being consistent or inconsistent with contour completions. We tested the preferred interpretations of the partly occluded shapes by using a sequential matching task. Participants had to judge whether a test shape could be a previously shown partly occluded shape. We found that interpretations of partly occluded shapes depend on both colour and contour characteristics. Additional time bin analyses revealed that for fast responses colour and contour completions already depend on the visible context of the partly occluded shapes, while for slow responses the congruency between colour and contour completions play a role as well.     

Pigeons' memory for number of events: Effects of intertrial interval and delay interval illumination

In Experiment 1, pigeons were trained at a 0-s baseline delay to discriminate sequences of light flashes (illumination of the feeder) that varied in number but not time (2f/4s and 8f/4s). During training, the intertrial interval was illuminated by the houselight for Group Light, but it was dark for Group Dark. Testing conducted with dark delay intervals produced a strong choose-small bias in both groups. All birds then received baseline training with a 5-s dark delay and were subsequently tested at shorter and longer dark delays. A choose-small bias was again observed at delays longer than the training delay, while a choose-large bias occurred at delays shorter than the training delay. Differentiating the ambient chamber illumination during the intertrial interval and the delay interval did not attenuate choose-small or choose-large effects. In Experiment 2, all birds received baseline training with a 5-s illuminated delay and were subsequently tested at shorter and longer illuminated delays. A choose-large bias was observed at delays longer than the training delay, while a choose-small bias occurred at delays shorter than the training delay. In Experiment 3, on intermittent test trials, when the duration of the second flash on small-sample trials was equal to the total flash duration on large-sample trials (i.e., 1600 ms), accuracy fell to approximately chance. These results suggest that pigeons discriminated the sequences of light flashes that varied in number but not in total duration of the sequence by relying on other temporal properties of the sequence rather than by using an event switch to count flashes.     

Interference control in preschoolers: factors influencing performance on the day–night task

Two experiments investigated preschoolers' interference control in variants of the day–night task. The day–night task involves instructing children across 16 trials to say the word ‘day’ when viewing a card depicting a nighttime sky and to say ‘night’ when shown a picture of the daytime sky. The purpose of the experiments was to investigate whether the depiction on each card distracts children because it is semantically associated with the instructed response or because the depicted item cues the alternative (incorrect) response within the response set. The results in the first study (N=23, M=52.65 months) and second study (N=54, M=50.81 months) indicate that a close semantic relation between the picture and the target response does not pose substantial interference for preschoolers. In contrast, the pictured item poses a significant challenge for preschoolers when it depicts the interfering alternative in the response set. Theoretical implications of these results for the development of interference control are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

TEACHERS' GENERALIZED USE OF DELAY AS A STIMULUS CONTROL PROCEDURE TO INCREASE LANGUAGE USE IN HANDICAPPED CHILDREN

In Experiment 1, classroom teachers were taught to delay their offers of help in naturally occurring situations, and thereby to provide additional opportunities for language use by six moderately retarded language-delayed children. The teachers introduced this delay technique in a multiple-baseline design across the six children. As delays were used, child verbal initiations increased. Follow-up assessment showed that teachers were maintaining greater than baseline levels of the delay technique after 10 weeks. Experiment 2 replicated the findings of Experiment 1, and included a more thorough maintenance assessment, while focusing on teachers' generalization of the delay technique. Teachers were found to generalize their use of delay to 56% of their monitored untaught opportunities. The two experiments show that (a) the delay technique is quick to teach and simple to implement, (b) delays do provide opportunities for children to initiate, (c) teachers can generalize their use of delay to novel self-selected situations, and (d) teachers can maintain their use of delays over time.     

Interference processes in monkey auditory list memory

A rhesus monkey’s memory was tested for single items and four-item lists of natural and environmental sounds. Memory items were presented from a center speaker, followed by a retention delay and then a choice response to a test sound presented simultaneously from two side speakers. Recognition of the last item of four-item lists was much poorer than that of single items at 0-, 1-, and 2-sec delays, despite there being the same temporal relations between study and test. This result showed that the first three items proactively interfered with memory of the last list item. Proactive interference dissipated after 2 sec, revealing a recency effect that eventually equaled single-item performance. Recognition of the first item of four-item lists was much poorer than single items at 20- and 30-sec delays, showing that the last three items retroactively interfered with memory of the first list item. The results point to the critical nature of interference processes in the understanding of serial position functions.