Once and for all—How people change strategy to ignore irrelevant information in visual tasks

Abrupt and spontaneous strategy switches emerge in simple regularised neural networks

Humans sometimes have an insight that leads to a sudden and drastic performance improvement on the task they are working on. Sudden strategy adaptations are often linked to insights, considered to be a unique aspect of human cognition tied to complex processes such as creativity or meta-cognitive reasoning. Here, we take a learning perspective and ask whether insight-like behaviour can occur in simple artificial neural networks, even when the models only learn to form input-output associations through gradual gradient descent. We compared learning dynamics in humans and regularised neural networks in a perceptual decision task that included a hidden regularity to solve the task more efficiently. Our results show that only some humans discover this regularity, and that behaviour is marked by a sudden and abrupt strategy switch that reflects an aha-moment. Notably, we find that simple neural networks with a gradual learning rule and a constant learning rate closely mimicked behavioural characteristics of human insight-like switches, exhibiting delay of insight, suddenness and selective occurrence in only some networks. Analyses of network architectures and learning dynamics revealed that insight-like behaviour crucially depended on a regularised gating mechanism and noise added to gradient updates, which allowed the networks to accumulate "silent knowledge" that is initially suppressed by regularised gating. This suggests that insight-like behaviour can arise from gradual learning in simple neural networks, where it reflects the combined influences of noise, gating and regularisation. These results have potential implications for more complex systems, such as the brain, and guide the way for future insight research.

Using position rather than color at the traffic light - Covariation learning-based deviation from instructions in attention deficit/hyperactivity disorder

Based on instructions people can form task representations that shield relevant from seemingly irrelevant information. It has been documented that instructions can tie people to a particular way of performing a task despite that in principle a more efficient way could be learned and used. Since task shielding can lead to persistence of inefficient variants of task performance, it is relevant to test whether individuals with attention deficit/hyperactivity disorder (ADHD) - characterized by less task shielding - are more likely and quicker to escape a suboptimal instructed variant of performing a task. The paradigm used in this online study builds on the observation that in many environments different covarying features could be used to determine the appropriate response. For instance, as they approach a traffic light, drivers and pedestrians monitor the color (instructed stimulus feature) and/or the position of the signal (covarying stimulus feature, more efficient in case of reduced color sight). Similarly, we instructed participants to respond to the color of a stimulus without mentioning that color covaried with the position of the stimulus. In order to assess whether with practice participants would use the non-instructed feature position to an increasing extent, we compared reaction times and error rates for standard trials to trials in which color was either ambiguous or did not match the usual covariation. Results showed that the covariation learning task can be administered online to adult participants with and without ADHD. Performance differences suggested that with practice ADHD participants (n = 43 out of a total N = 245) might increase attention to non-instructed stimulus features. Yet, they used the non-instructed covarying stimulus feature to a similar extent as other participants. Together the results suggest that participants with ADHD do not lag behind in abandoning instructed task processing in favor of a learned alternative strategy.

Visual gaze patterns in trainee endoscopists - a novel assessment tool

BACKGROUND

Colonoscopy proficiency is significantly influenced by skills achieved during training. Although assessment scores exist, they do not evaluate the impact of visual search strategies and their use is time and labour intensive. Eye-tracking has shown significant differences in visual gaze patterns (VGPs) between expert endoscopists with varying polyp detection rates, so may provide a means of automated assessment and guidance for trainees. This study aimed to assess the feasibility of eye-tracking as a novel assessment method for trainee endoscopists.

METHODS

Eye-tracking glasses were used to record 26 colonoscopies from 12 endoscopy trainees who were assessed with directly observed procedural scores (DOPS), devised by the Joint Advisory Group (JAG) on GI endoscopy, and a visual analogue score of overall competence. A 'total weighted procedure score' (TWPS) was calculated from 1 to 20. Primary outcomes of fixation duration (FixD) and fixation frequency (FixF) were analysed according to areas of interest (AOIs) with the bowel surface and lumen represented by three concentric rings. Correlation was assessed using Pearson's coefficient. Significance was set at p<.050.

RESULTS

Trainees displayed a significant positive correlation between TWPS and FixD (R = 0.943, p<.0001) and FixF (R = 0.936, p<.0001) in the anatomical bowel mucosa peripheries. Conversely, they had significant negative correlations between TWPS and the anatomical bowel lumen (FixD: R= -0.546, p=.004; FixF: R= -0.568, p=.002).

CONCLUSIONS

Higher objective performance scores were associated with VGPs focussing on bowel mucosa. This is consistent with prior analysis showing peripheral VGPs correspond with higher polyp detection rates. Analysis of VGPs, therefore, has potential for training and assessment in colonoscopy.

No matter how you mark the points on the fever curve – threatening shapes do not add to threat of climate change

Graphs have become an increasingly important means of representing data, for instance, when communicating data on climate change. However, graph characteristics might significantly affect graph comprehension. The goal of the present work was to test whether the marking forms usually depicted on line-graphs, can have an impact on graph evaluation. As past work suggests that triangular forms might be related to threat, we compared the effect of triangular marking forms with other symbols (triangles, circles, squares, rhombi, and asterisks) on subjective assessments. Participants in Study 1 (N = 314) received 5 different line-graphs about climate change, each of them using one out of 5 marking forms. In Study 1, the threat and arousal ratings of the graphs with triangular marking shapes were not higher than those with the other marking symbols. Participants in Study 2 (N = 279) received the same graphs, yet without labels and indeed rated the graphs with triangle point markers as more threatening. Testing whether local rather than global spatial attention would lead to an impact of marker shape in climate graphs, Study 3 (N = 307) documented that a task demanding to process a specific data-point on the graph (rather than just the line graph as a whole) did not lead to an effect either. These results suggest that marking symbols can principally affect threat and arousal ratings but not in the context of climate change. Hence, in graphs on climate change, choice of point markers does not have to take potential side-effects on threat and arousal into account. These seem to be restricted to the processing of graphs where form aspects face less competition from the content domain on judgments.

Incidental covariation learning leading to strategy change

As they approach a traffic light, drivers and pedestrians monitor the color (instructed stimulus feature) and/or the position of the signal (covarying stimulus feature) for response selection. Many studies have pointed out that instructions can effectively determine the stimulus features used for response selection in a task. This leaves open whether and how practice with a correlating alternative stimulus feature can lead to a strategy change from an instructed to a learned variant of performing the task. To address this question, we instructed participants to respond to the position of a stimulus within a reference frame, at the same time, during task performance, an unmentioned second stimulus feature, the color, covaried with stimulus position and allowed the use of an alternative response strategy. To assess the impact of the non-instructed stimulus feature of color on response selection throughout practice, the spatial position of the stimulus was ambiguous on some trials. Group average increases in color usage were based on a mixture of (1) participants who, despite extended practice on the covariation, exclusively relied on the instructed stimulus feature and (2) those who abruptly started to rely heavily on stimulus color to select responses in ambiguous trials. When the instructed and uninstructed feature predicted different actions, choices were still biased by the uninstructed color feature, albeit more weakly. A second experiment showed that the influence of color generalized across frequently and infrequently presented combinations of position and color. Strategy changes were accompanied by awareness in both experiments. The results suggest that incidental covariation learning can trigger spontaneous voluntary strategy change involving a re-configuration of the instructed task set.

Are longer advertising slogans more dangerous? The influence of the length of ad slogans on drivers’ attention and motor behavior

The purpose of this project was to verify whether slogans displayed on roadside advertisements created a distraction for drivers. In order to explain the mechanisms underlying this phenomenon, Study 1 examined the impact of slogan length on attentional processing efficiency. Study 2 investigated the relationship between the length of the slogan and the motor behavior of respondents driving a car simulator. We assumed that slogan length would decrease the drivers’ task performance in both studies. Study 1 was conducted on a group of 70 participants, who completed a modified version of the Attention Network Test (ANT; Fan et al. Journal of Cognitive Neuroscience, 14(3), 340–347, 2002). The task consisted of visual ads intended to distract respondents from the primary task. Reaction times were significantly longer when ads had longer slogans compared to shorter slogans. Study 2, involving a car simulator, was conducted on a group of 53 drivers performing a task of driving in a convoy. Participants were shown billboards with ads at the roadside in random order (two pairs of corresponding ads with short and long text on it). Participants’ driving performance decreased when longer slogans were presented in comparison to the short-slogan condition. In conclusion, we interpret the results of Study 1 to indicate that longer slogan leads to a greater load of attentional processing. This subsequently leads to a reduction of the processing efficiency within attentional systems and further increases the amount of time to resist the irrelevant stimulus. A consequence of this, as shown in Study 2 using a car simulator, is a decrease in cognitive resources necessary for safe driving and therefore worse performance on a driving task.

Orienting to see what's important: Learn to ignore the irrelevant

The current study used a triad judgment task to assess whether blocking by comparison type in a triad judgment task could lead people to pay less attention to surface-level (irrelevant) features and pay more attention to deep (structural) features of information. A sample of 313 participants recruited through Mechanical Turk participated in this study. On each triad, participants were asked to evaluate which of two source scenarios went best with the target scenario. Three types of triads were constructed with materials related to the ability to perceive ethical issues within the practice of psychology. One type of triad contrasted a scenario that was similar to the target in terms of surface-level features and a scenario that was similar in terms of deep features (similar surface-similar deep, SS/SD). A second triad type contrasted a scenario that was similar in terms of deep features with an unrelated scenario (similar deep-unrelated, SD/U). The third contrasted a scenario that was similar in terms of surface features with an unrelated scenario (similar surface-unrelated, SS/U). There were 10 triads of each type. We found that with all the blocking orders except two, participants reliably chose the SS scenario over the SD scenario for the SS/SD triads. However, participants who started out with the SD/U triads did not. The results provide evidence that people often have the ability to perceive the deep, but they are distracted by the surface-level features. The results also show that people can be oriented away from being distracted by the surface-level features so that they can see the deep.

Comparison of gaze behaviour of trainee and experienced surgeons during laparoscopic gastric bypass

Background

Eye tracking presents a novel tool that could be used to profile skill levels in surgery objectively. The primary aim of this study was to identify differences in gaze behaviour between expert and junior surgeons performing a laparoscopic Roux-en-Y gastric bypass (LRYGB) for obesity.

Methods

This prospective observational study used a lightweight eye-tracking apparatus to determine the difference in gaze behaviours between expert (more than 75 procedures) and junior (75 or fewer procedures) surgeons at defined stages of LRYGB. Primary endpoints were normalized dwell time and fixation frequency. Secondary endpoints were blink rate, maximum pupil size and rate of pupil change.

Results

A total of 20 procedures (12 junior, 8 expert) were analysed. Compared with juniors, experts showed a prolonged dwell time on the screen during angle of His dissection (median (range) 91·20 (83·40–94·40) versus 68·95 (59·80–87·60) per cent; P = 0·001), formation of the retrogastric tunnel (91·50 (85·80–95·50) versus 73·60 (34·60–90·50) per cent; P = 0·001) and gastric pouch formation (86·95 (83·60–90·20) versus 67·60 (37·10–80·00) per cent P &lt; 0·001). Juniors had a greater blink frequency throughout all recorded segments (P &lt; 0·010) and had a larger maximum pupil size during all recorded operative segments (P &lt; 0·010). Rate of pupil change was greater in juniors in all analysed segments (P &lt; 0·010).

Conclusion

These results suggest that experts display more focused attention on significant stimuli, alongside experiencing a reduced mental workload and having increased concentration. This has the potential for future use in validation of surgical skill in high-stakes assessment.

Task-Irrelevant Expectation Violations in Sequential Manual Actions: Evidence for a "Check-after-Surprise" Mode of Visual Attention and Eye-Hand Decoupling

When performing sequential manual actions (e.g., cooking), visual information is prioritized according to the task determining where and when to attend, look, and act. In well-practiced sequential actions, long-term memory (LTM)-based expectations specify which action targets might be found where and when. We have previously demonstrated (Foerster and Schneider, 2015b) that violations of such expectations that are task-relevant (e.g., target location change) cause a regression from a memory-based mode of attentional selection to visual search. How might task-irrelevant expectation violations in such well-practiced sequential manual actions modify attentional selection? This question was investigated by a computerized version of the number-connection test. Participants clicked on nine spatially distributed numbered target circles in ascending order while eye movements were recorded as proxy for covert attention. Target’s visual features and locations stayed constant for 65 prechange-trials, allowing practicing the manual action sequence. Consecutively, a task-irrelevant expectation violation occurred and stayed for 20 change-trials. Specifically, action target number 4 appeared in a different font. In 15 reversion-trials, number 4 returned to the original font. During the first task-irrelevant change trial, manual clicking was slower and eye scanpaths were larger and contained more fixations. The additional fixations were mainly checking fixations on the changed target while acting on later targets. Whereas the eyes repeatedly revisited the task-irrelevant change, cursor-paths remained completely unaffected. Effects lasted for 2–3 change trials and did not reappear during reversion. In conclusion, an unexpected task-irrelevant change on a task-defining feature of a well-practiced manual sequence leads to eye-hand decoupling and a “check-after-surprise” mode of attentional selection.

Significant Inter-Test Reliability across Approximate Number System Assessments

The approximate number system (ANS) is the hypothesized cognitive mechanism that allows adults, infants, and animals to enumerate large sets of items approximately. Researchers usually assess the ANS by having subjects compare two sets and indicate which is larger. Accuracy or Weber fraction is taken as an index of the acuity of the system. However, as Clayton et al. (2015) have highlighted, the stimulus parameters used when assessing the ANS vary widely. In particular, the numerical ratio between the pairs, and the way in which non-numerical features are varied often differ radically between studies. Recently, Clayton et al. (2015) found that accuracy measures derived from two commonly used stimulus sets are not significantly correlated. They argue that a lack of inter-test reliability threatens the validity of the ANS construct. Here we apply a recently developed modeling technique to the same data set. The model, by explicitly accounting for the effect of numerical ratio and non-numerical features, produces dependent measures that are less perturbed by stimulus protocol. Contrary to their conclusion we find a significant correlation in Weber fraction across the two stimulus sets. Nevertheless, in agreement with Clayton et al. (2015) we find that different protocols do indeed induce differences in numerical acuity and the degree of influence of non-numerical stimulus features. These findings highlight the need for a systematic investigation of how protocol idiosyncrasies affect ANS assessments.

Learning to explore the structure of kinematic objects in a virtual environment

The current study tested the quantity and quality of human exploration learning in a virtual environment. Given the everyday experience of humans with physical object exploration, we document substantial practice gains in the time, force, and number of actions needed to classify the structure of virtual chains, marking the joints as revolute, prismatic, or rigid. In line with current work on skill acquisition, participants could generalize the new and efficient psychomotor patterns of object exploration to novel objects. On the one hand, practice gains in exploration performance could be captured by a negative exponential practice function. On the other hand, they could be linked to strategies and strategy change. After quantifying how much was learned in object exploration and identifying the time course of practice-related gains in exploration efficiency (speed), we identified what was learned. First, we identified strategy components that were associated with efficient (fast) exploration performance: sequential processing, simultaneous use of both hands, low use of pulling rather than pushing, and low use of force. Only the latter was beneficial irrespective of the characteristics of the other strategy components. Second, we therefore characterized efficient exploration behavior by strategies that simultaneously take into account the abovementioned strategy components. We observed that participants maintained a high level of flexibility, sampling from a pool of exploration strategies trading the level of psycho-motoric challenges with exploration speed. We discuss the findings pursuing the aim of advancing intelligent object exploration by combining analytic (object exploration in humans) and synthetic work (object exploration in robots) in the same virtual environment.

Transferring control demands across incidental learning tasks - stronger sequence usage in serial reaction task after shortcut option in letter string checking

After incidentally learning about a hidden regularity, participants can either continue to solve the task as instructed or, alternatively, apply a shortcut. Past research suggests that the amount of conflict implied by adopting a shortcut seems to bias the decision for vs. against continuing instruction-coherent task processing. We explored whether this decision might transfer from one incidental learning task to the next. Theories that conceptualize strategy change in incidental learning as a learning-plus-decision phenomenon suggest that high demands to adhere to instruction-coherent task processing in Task 1 will impede shortcut usage in Task 2, whereas low control demands will foster it. We sequentially applied two established incidental learning tasks differing in stimuli, responses and hidden regularity (the alphabet verification task followed by the serial reaction task, SRT). While some participants experienced a complete redundancy in the task material of the alphabet verification task (low demands to adhere to instructions), for others the redundancy was only partial. Thus, shortcut application would have led to errors (high demands to follow instructions). The low control demand condition showed the strongest usage of the fixed and repeating sequence of responses in the SRT. The transfer results are in line with the learning-plus-decision view of strategy change in incidental learning, rather than with resource theories of self-control.