Gap Task Research Articles

Classroom Learning, Teaching, and Research: A Task‐Based Perspective

In an increasing number of second language (L2) classrooms, teachers and researchers are taking on new roles and responsibilities. From these new perspectives, they are developing similar concerns about L2 learning processes, which they typically express in ways that reflect their different backgrounds and goals. To support learning, teaching, and research in the L2 classroom, researchers and teachers have attempted to develop activities that both address their concerns and accommodate their differences on a long‐term basis. This article reflects my participation as a researcher in this context and presents the ways in which the teachers and students with whom I have worked have turned to information gap tasks to serve many of our needs. The first part of the article describes the contributions of information gap tasks as seen from our learning, teaching, and research perspectives. The second part describes the issues and challenges we have faced in integrating and implementing them. Then the third part presents an approach that we have developed for designing information gap tasks both as authentic activities for teaching and learning and as reliable instruments for research. Examples of our tasks are provided, together with excerpts from the discourse of their classroom implementation. These excerpts reveal the effectiveness of the tasks in drawing students' attention to form, function, and meaning in ways that we considered vital to students' L2 learning.

Short-term visual deprivation alters neural processing of tactile form

Blindness is known to alter the responsiveness of visual cortex. Recently, reversible visual deprivation by blindfolding has been shown to affect non-visual abilities as well as visual cortical function. Here we investigated the effect of 2 h of blindfolding on cerebral cortical activation patterns during tactile form perception, using functional magnetic resonance imaging. Two form tasks were used, one requiring discrimination of global stimulus form and the other, detection of a gap in a bar. Blindfolded subjects showed significant deactivation during these tasks in regions that are intermediate in the hierarchy of visual shape processing: probable V3A and ventral intraparietal sulcus (vIPS). These regions lacked signal changes in controls. There were also task-specific increases in activation in blindfolded relative to control subjects, favoring the form over the gap task, along the IPS and in regions of frontal and temporal cortex. We also found alterations of functional connectivity that corresponded to the activity differences, with the emergence of correlated activity between the vIPS and V3A in blindfolded subjects. We conclude that blindfolding sighted individuals for a 2-h period induces significant changes in the neural processing of tactile form, probably reflecting short-term neural plasticity.

The effect of transcranial magnetic stimulation on the latencies of vertical saccades

In this study, we investigated the effect of transcranial magnetic stimulation (TMS) over the right posterior parietal cortex (PPC) on the latency of two different types of visually-guided vertical saccades: reflexive saccades triggered by the sudden onset of a target, and saccades towards target locations known in advance. For this reason, we used two oculomotor tasks: a gap and a delay task, respectively. Nine normal subjects performed vertical saccades at +/-7.5 and +/-15 degrees . TMS was applied at 80 and 100 ms after target onset in the gap task, and after fixation offset in the delay task. Without TMS, we confirmed a latency asymmetry in the gap task favouring upward saccades at the lower eccentricity (7.5 degrees ), and a latency symmetry in the delay task. TMS increased the latencies of all saccades in the delay task, when delivered at 100 ms. This effect was mostly pronounced for downward saccades at 7.5 degrees . As a result, saccade latencies showed an asymmetry in this condition, similar to the one observed in the gap task without TMS. The gap task with TMS resulted in a variable latency distribution and no significant overall effect on saccade latency. Our results indicate that the right PPC is involved in the initiation of vertical saccades in the delay task, and that this involvement appears to be enhanced for downward saccades. A conclusion for the involvement of this area in the gap task could not be drawn from this study.

Differential effects of target probability on saccade latencies in gap and warning tasks

Saccade latencies are significantly reduced by extinguishing a foveal fixation stimulus before the appearance of a saccade target. It has been shown recently that this "fixation offset effect" (FOE) can be modulated by varying target probability. Cortico-collicular top-down effects have been assumed to mediate this strategic FOE modulation. Here, we have investigated strategic FOE modulation in 14 healthy human subjects performing gap and warning tasks. In the former task, the central fixation point was extinguished 200 ms before target onset. In the latter task, the central fixation point changed its colour 200 ms before target onset, but remained illuminated until the target appeared. Target probability was varied block-wise between 25 and 75%. In both tasks, mean latencies decreased with increasing target probability. However, in contrast with what can be expected from preceding studies, we found no differential modulation of mean latencies by target probability between tasks. Instead, we observed differential probability-dependent changes in latency distributions. In the gap task, discrete changes of saccade latencies were found, with a probability-dependent change in frequency of express and regular latencies. By contrast, in the warning task a shift of the entire latency distribution towards longer latencies with low target probability was found. We conclude that strategic modulation of saccade latencies by target probability may be mediated by two distinct neural mechanisms. Selection of either mechanism seems to depend critically on activation of the fixation system.

Saccadic eye movement changes in Parkinson's disease dementia and dementia with Lewy bodies

Neurodegeneration in Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) affect cortical and subcortical networks involved in saccade generation. We therefore expected impairments in saccade performance in both disorders. In order to improve the pathophysiological understanding and to investigate the usefulness of saccades for differential diagnosis, saccades were tested in age- and education-matched patients with PDD (n = 20) and DLB (n = 20), Alzheimer's disease (n = 22) and Parkinson's disease (n = 24), and controls (n = 24). Reflexive (gap, overlap) and complex saccades (prediction, decision and antisaccade) were tested with electro-oculography. PDD and DLB patients had similar impairment in all tasks (P > 0.05, not significant). Compared with controls, they were impaired in both reflexive saccade execution (gap and overlap latencies, P < 0.0001; gains, P < 0.004) and complex saccade performance (target prediction, P < 0.0001; error decisions, P < 0.003; error antisaccades: P < 0.0001). Patients with Alzheimer's disease were only impaired in complex saccade performance (Alzheimer's disease versus controls, target prediction P < 0.001, error decisions P < 0.0001, error antisaccades P < 0.0001), but not reflexive saccade execution (for all, P > 0.05). Patients with Parkinson's disease had, compared with controls, similar complex saccade performance (for all, P > 0.05) and only minimal impairment in reflexive tasks, i.e. hypometric gain in the gap task (P = 0.04). Impaired saccade execution in reflexive tasks allowed discrimination between DLB versus Alzheimer's disease (sensitivity > or =60%, specificity > or =77%) and between PDD versus Parkinson's disease (sensitivity > or =60%, specificity > or =88%) when +/-1.5 standard deviations was used for group discrimination. We conclude that impairments in reflexive saccades may be helpful for differential diagnosis and are minimal when either cortical (Alzheimer's disease) or nigrostriatal neurodegeneration (Parkinson's disease) exists solely; however, they become prominent with combined cortical and subcortical neurodegeneration in PDD and DLB. The similarities in saccade performance in PDD and DLB underline the overlap between these conditions and underscore differences from Alzheimer's disease and Parkinson's disease.

Visuomotor dependency on an initial fixation target involved in the disorder of visually-guided manual movement in Parkinson's disease

Role of a central fixation target on the latencies of visually guided manual movement was analyzed on young healthy subjects, age-matched control subjects and patients with Parkinson's disease (Hoehn and Yahr stages II, III, and IV). Two paradigms were used: overlap paradigm where a central fixation target was lighted throughout the test, and gap paradigm where a central fixation target was turned off 200 ms before a peripheral target was lighted. The subject was first asked to fixate the central target then instructed to locate a peripheral target with a laser beam spot, operated with wrist flexion or extension as quickly as possible. Latencies of gap paradigm are always shorter than those of overlap task in all the groups. Latencies of both overlap and gap tasks prolonged from young to elder, from elder to PD II, from PD II to PD III and from PD III to PD IV. Also latencies were extremely prolonged in the overlap tasks and correlated with disease severity. Latencies in the gap tasks were less prolonged as compared with those in the overlap tasks. The visual fixation target prolonged the visuo-motor latency in association with severity of Parkinson's disease.

Language teaching

Language teaching

Human temporal auditory acuity as assessed by envelope following responses

Temporal auditory acuity, the ability to discriminate rapid changes in the envelope of a sound, is essential for speech comprehension. Human envelope following responses (EFRs) recorded from scalp electrodes were evaluated as an objective measurement of temporal processing in the auditory nervous system. The temporal auditory acuity of older and younger participants was measured behaviorally using both gap and modulation detection tasks. These findings were then related to EFRs evoked by white noise that was amplitude modulated (25% modulation depth) with a sweep of modulation frequencies from 20 to 600 Hz. The frequency at which the EFR was no longer detectable was significantly correlated with behavioral measurements of gap detection (r = -0.43), and with the maximum perceptible modulation frequency (r = 0.72). The EFR techniques investigated here might be developed into a clinically useful objective estimate of temporal auditory acuity for subjects who cannot provide reliable behavioral responses.

Predisposition to choose: the language of an information gap task in a multilingual primary classroom

This paper focuses on an information gap task that was part of a larger critical action research project that sought to expand talk opportunities for children in multilingual classrooms. Little of the previous research on tasks and language learning has focused on children learning English as an additional language in the context of diverse, urban, multilingual mainstream classrooms. It is important therefore that these sites are investigated for the way tasks might be utilized to assist both language development, and crucially, academic content learning. The information gap task was investigated to determine the extent to which it predis-posed children to use particular patterns of language. Six groups of children were videotaped doing the task and the interactions transcribed. These transcripts were then analysed using aspects of systemic functional grammar in conjunction with a concordance tool. Across the resulting corpus there was a strong regularity in the language choices made by the children. Furthermore, the structure of the task pre-disposed the children to use patterns of language that might later be utilized in writing information reports. The task could be considered a bridge from the generally situated nature of spoken language to the more decontextualized nature of written language.

The Relationship between the Negotiation of Meaning and Language Learning: A Longitudinal Study

For over 20 years, SLA research has been investigating the role of negotiation in second language acquisition. While much attention has been given to an examination of the conditions that are necessary for acquisition and the factors that can facilitate opportunities for negotiation, limited attention has been given to a longitudinal study of the relationship between negotiation and language learning. This paper reports on a study which investigated the extent to which successfully negotiated linguistic features were retained over a period of 12 weeks. The 30 pre-intermediate ESL learners who participated in the study were asked to repeat two different communication tasks (information gap and decision-making) 1 week and 12 weeks after their first performance. Vocabulary items, particularly concrete nouns in the information gap task, were negotiated more often than pronunciation and grammar items. Noticing the gap between their problematic utterances and the feedback they received from their conversational partners, the participants immediately modified close to two-thirds of these utterances, indicating that learning may have occurred. There was a high retention rate both one week and 12 weeks later for these negotiated items.

How laminar frontal cortex and basal ganglia circuits interact to control planned and reactive saccades

How does the brain learn to balance between reactive and planned behaviors? The basal ganglia (BG) and frontal cortex together allow animals to learn planned behaviors that acquire rewards when prepotent reactive behaviors are insufficient. This paper proposes a new model, called TELOS, to explain how laminar circuitry of the frontal cortex, exemplified by the frontal eye fields, interacts with the BG, thalamus, superior colliculus, and inferotemporal and parietal cortices to learn and perform reactive and planned eye movements. The model is formulated as fourteen computational hypotheses. These specify how strategy priming and action planning (in cortical layers III, Va and VI) are dissociated from movement execution (in layer Vb), how the BG help to choose among and gate competing plans, and how a visual stimulus may serve either as a movement target or as a discriminative cue to move elsewhere. The direct, indirect and hyperdirect pathways through the BG are shown to enable complex gating functions, including deferred execution of selected plans, and switching among alternative sensory-motor mappings. Notably, the model can learn and gate the use of a What-to-Where transformation that enables spatially invariant object representations to selectively excite spatially coded movement plans. Model simulations show how dopaminergic reward and non-reward signals guide monkeys to learn and perform saccadic eye movements in the fixation, single saccade, overlap, gap, and delay (memory-guided) saccade tasks. Model cell activation dynamics quantitatively simulate seventeen established types of dynamics exhibited by corresponding real cells during performance of these tasks.

Decisional role of the dorsolateral prefrontal cortex in ocular motor behaviour.

Three patients with a unilateral cortical lesion affecting the dorsolateral prefrontal cortex (DLPFC), i.e. Brodmann area 46, were tested using different paradigms of reflexive saccades (gap and overlap tasks), intentional saccades (antisaccades, memory-guided and predictive saccades) and smooth pursuit movements. Visually guided saccades with gap and overlap, latency of correct antisaccades and memory-guided saccades and the gain of smooth pursuit were normal, compared with controls. These results confirm our anatomical data showing that the adjacent frontal eye field (FEF) was unimpaired in these patients. The specific pattern of abnormalities after a unilateral DLPFC lesion, compared with that of the FEF lesions previously reported, consists mainly of: (i) a bilateral increase in the percentage of errors in the antisaccade task (misdirected reflexive saccades); (ii) a bilateral increase in the variable error in amplitude, without significant decrease in the gain, in the memory-guided saccade task; and (iii) a bilateral decrease in the percentage of anticipatory saccades in the predictive task. Taken together, these results suggest that the DLPFC plays a crucial role in the decisional processes, preparing saccades by inhibiting unwanted reflexive saccades (inhibition), maintaining memorized information for ongoing intentional saccades (short-term spatial memory) or facilitating anticipatory saccades (prediction), depending upon current external environmental and internal circumstances.

Effects of Stimulus Predictability and Interstimulus Gap on Saccades in Alzheimer’s Disease

Objectives: Studies of saccadic eye movement impairment in Alzheimer’s disease (AD) have largely focused on simple reflexive eye movements and the antisaccade task. The effects of manipulating stimulus timing have been little studied. Methods: Fourteen patients with mild to severe AD and 11 age-matched controls were studied on the antisaccade task, while latencies on simultaneous, gap and predictable tasks were recorded from 11 patients and 11 controls. Dementia severity was assessed with the Mini-Mental State Examination. Results: As a group, patients’ latencies were significantly higher and more variable on the simultaneous and gap tasks. Predictable task performance was similar in mean but significantly more variable. Grossly anticipatory responses by patients were common on the predictable, simultaneous and gap tasks. Exclusion of these from subject means revealed that AD patients, when making target-driven saccades, demonstrated a gap effect of similar magnitude to normal subjects. Patients made significantly fewer correct antisaccades and significantly more reflexive errors not followed by a corrective antisaccade than did controls. Conclusions: The frequent presence of grossly anticipatory saccades may reflect dysfunction of fixation mechanisms possibly involving projections from frontal lobe to superior colliculus. The less frequently seen, marked prolongation of latency may reflect changes in posterior parietal mechanisms mediating reflexive saccade generation. The presence of the gap effect demonstrates a continued ability to benefit from externally controlled stimulus disengagement. Patients’ ability to make appropriately timed saccades to targets of known locations was particularly impaired, but the target sequence itself was at least grossly correctly learned. Larger studies may be able to identify clinically distinct populations of AD patients.

The attentional disengagement processing reflected by ERPs and saccade reaction times during a gap task

In this study, we examined cerebral process of attentional disengagement using ERPs and saccade reaction time (SRT) during a saccadic eye movement task to produce the gap effect. Ten healthy adults participated in this study. Subjects were required to execute saccadic eye movement when the target appeared. In the gap condition, a fixation point disappeared 200 ms prior to the target stimulus presentation. In the overlap condition, a fixation point remained after the target stimulus presentation. ERPs were analyzed separately for target stimulus and saccadic eye movement. SRT in the gap condition was significantly shorter than that in the overlap condition. For the target-locked ERPs in the gap condition, central positivity appeared around 60 ms before the onset of the target stimulus. This would reflect an automatic processing of attentional disengagement elicited by the offset of a fixation point. For the saccade-locked ERPs, pre-saccadic positivities were observed in both conditions. In the overlap condition, it appeared earlier and higher than that in the gap condition. It reflects a processing of attentional disengagement to the fixation point. These results indicated that the cerebral processing of attentional disengagement would be differentiated by the existence of gap.

Express saccades: is bimodality a result of the order of stimulus presentation?

Subjects undertook a saccadic gap task, in which the fixation target is extinguished for a period before the appearance of the peripheral stimulus. The majority showed a population of short-latency express saccades in addition to the main, slower, distribution. However, closer analysis showed that nearly all of this bimodality was due to the order in which trials were performed: the faster responses came almost entirely from trials in which the target was on the opposite side from the preceding trial, slower ones when it was on the same side. Further experiments using a novel two-gap task demonstrated that this inter-trial effect is due to the return eye movement of one trial conditioning the first saccade of the next. Consequently, in a two-gap task the latency of the second saccade falls into the faster category if it is in the same direction as the immediately preceding one: this may be the result of the oculomotor system predicting target direction, saccades in the expected direction having a shorter latency. It seems therefore that the bimodality is not primarily the result of some kind of randomising process within the oculomotor system: rather, it is a consequence of the way in which saccadic experiments are normally conducted.

Negotiation of Meaning in Conversational and Information Gap Activities: A Comparative Discourse Analysis

This article reports an investigation of how meaning is negotiated in two different types of interactions between native speakers (NSs) and nonnative speakers (NNSs): a relatively unstructured conversation and a two-way information-gap task. Three NS-NNS dyads were recorded as they engaged in these two activities, and the data were examined in detail. Negotiation exchanges, lexical and syntactic complexity, and various pragmatic issues were examined and compared qualitatively and quantitatively. The results suggest that conversational interaction has the potential to offer substantial learning opportunities at multiple levels of interaction even though it offered fewer instances of repair negotiation in the traditional sense than did the information gap activity. In addition, the NNS participants stated in subsequent interviews that they found the conversational activity to be more challenging than the information-gap activity because they had to pay attention to the entire discourse in the former but mainly focused on lexical items in the latter. This study thus raises questions about claims that conversational interactions do not provide learners with as much challenging language practice as do more highly structured interactional activities, such as information gap tasks.

The Difference in Saccadic Parameters Among Several Visually Guided Tasks

Purpose: The present study was undertaken to establish the effects of the five different paradigms (simultaneous, gap, overlap, delayed-memory, and anti-saccade tasks) on saccade dynamics (duration, peak velocity, and amplitude). Methods: We recorded ocular movements in 7 normal subjects, using infrared oculography with a visual stimulation system. Results: The distribution of saccade accuracy in gap and overlap tasks had about the same steepness as that in simultaneous tasks, but that in delayed-memory and anti-saccade tasks was broader than that in simultaneous tasks. The distribution in anti-saccade tasks had a marked intersubject variability, and the average values of accuracy were hypermetric in four subjects. The peak velocity/amplitude ratio in simultaneous and gap tasks were higher than those of other tasks. The relationship between average of peak velocity of abduction and adduction was different, adduction was higher than abduction in simultaneous and gap tasks, and abduction was lower than adduction in delayed-memory and anti-saccade tasks. Conclusions: The dynamics in simultaneous tasks had about the same characteristics as in gap tasks, but were different from those in overlap, delayed-memory, and anti-saccade tasks. These results indicated that the marked differences in dynamic properties among different saccade types may reflect processes in the visuomotor system.

The Difference in Saccadic Parameters among Several Visually Guided Tasks—Saccadic Reaction Time

Purpose: The saccadic reaction time (SRT) was measured as a saccadic movement parameter using visually guided tasks. Subjects and Method: The SRT was measured for nine healthy adult subjects aged from 28 to 49 years. The visually guided tasks for saccadic movement induction were simultaneous, gap, overlap, delayed-memory, and anti-SM tasks. Results: The median of the SRT (msec) for each task in the actual measurements was as follows: 216 for the simultaneous task, 180 for the gap task, 240 for the overlap task, 234 for the delayed-memory task, and 292 for the anti-SM task. The SRT distribution of each subject exhibited two peaks for the gap task but mostly one peak for each of the other tasks. The first peak, observed in the SRT distribution for the gap task was an eysress saccade. Conclusion: The SRT for the gap task was the shortest and the SRT got longer in the order of the simultaneous task, and the overlap task, and the anti-SM task. Some subjects easily showed an express saccade in the gap task, but others did not.

Cerebellar flocculus and ventral paraflocculus Purkinje cell activity during predictive and visually driven pursuit in monkey.

Purkinje cells in the flocculus and ventral paraflocculus were studied in tasks designed to distinguish predictive versus visually guided mechanisms of smooth pursuit. A sum-of-sines task allowed studies of complex predictive pursuit. A perturbation task examined visually driven pursuit during unpredictable right-angle changes in target direction. A gap task examined pursuit that was maintained when the target was turned off. Neural activity patterns were quantified using multi-linear models with sensitivities to the position, velocity, and acceleration of both motor output (eye motion) and visual input (retinal slip). During the sum-of-sines task, neural responses led eye motion by an average of 12 ms, a value larger than the 9-ms transmission delay between flocculus stimulation and eye motion. This suggests that flocculus/paraflocculus neurons drove pursuit along predictable sum-of-sines trajectories. In contrast, neural responses led eye motion by an average of only 2 ms during the perturbation task and by 6 ms during the gap task. These values suggest a follow-up role during tasks more heavily dependent on visual processing. Activity in all three tasks was explained primarily by sensitivities to eye position and velocity. Eye acceleration played a minor role during ongoing pursuit, although its influence on firing rate increased during the high accelerations following unexpected changes in target motion. Retinal slip had a relatively small influence on responses during pursuit. This was particularly true for the sum-of-sines and gap tasks where predictive control eliminated any consistent retinal-slip signals that might have been used to drive the eye. Surprisingly, the influence of retinal slip did not increase appreciably during unpredictable perturbations in target direction that generated large amounts of retinal slip. Thus although visual control signals are needed in varying amounts during the three pursuit tasks, they have been converted to motor control signals by the time they leave the flocculus/paraflocculus system. Individual neurons showed a remarkable constancy in eye-sensitivity direction across tasks that indicated direct links to oculomotor neurons. However, some neurons showed changes in sensitivity magnitude that suggested changes in control strategy for different tasks. Magnitude differences were largest for the perturbation task. We conclude that the flocculus/paraflocculus system plays a major role in driving predictive pursuit. It also processes visually driven control signals that originate in other brain regions after a slight delay.

The role of the superior colliculus in saccade initiation: a study of express saccades and the gap effect

Neural mechanisms underlying the initiation of saccadic eye movements were studied by recording the activity of neurons in the superior colliculus of rhesus monkeys that had extensive experience on the gap task using targets restricted to one visual field. The superposition of visual activation upon the increased excitability occurring on gap trials facilitates the occurrence of a motor burst with extremely short latency; the motor burst is tightly coupled to saccade onset for the full range of saccadic reactions times, both regular and express. We found no evidence that express saccades are a special class of saccades triggered directly by visual responses. The low frequency activity, necessary for the occurrence of express saccades, neither initiates express saccades nor serves as an accurate predictor of the direction or latency of saccades. Based upon these findings, the hypothesis that the motor burst of collicular neurons serves as a signal for triggering saccade onset can now be extended to express saccades.