Evaluating the effectiveness of different perceptual training methods in a difficult visual discrimination task with ultrasound images.

Recent work has shown that perceptual training can be used to improve the performance of novices in real-world visual classification tasks with medical images, but it is unclear which perceptual training methods are the most effective, especially for difficult medical image discrimination tasks. We investigated several different perceptual training methods with medically naïve participants in a difficult radiology task: identifying the degree of hepatic steatosis (fatty infiltration of the liver) in liver ultrasound images. In Experiment 1a (N = 90), participants completed four sessions of standard perceptual training, and participants in Experiment 1b (N = 71) completed four sessions of comparison training. There was a significant post-training improvement for both types of training, although performance was better when the trained task aligned with the task participants were tested on. In both experiments, performance initially improves rapidly, with learning becoming more gradual after the first training session. In Experiment 2 (N = 200), we explored the hypothesis that performance could be improved by combining perceptual training with explicit annotated feedback presented in a stepwise fashion. Although participants improved in all training conditions, performance was similar regardless of whether participants were given annotations, or underwent training in a stepwise fashion, both, or neither. Overall, we found that perceptual training can rapidly improve performance on a difficult radiology task, albeit not to a comparable level as expert performance, and that similar levels of performance were achieved across the perceptual training paradigms we compared.

Characterizing the time course of decision-making in change detection.

We propose a novel modeling framework for characterizing the time course of change detection based on information held in visual short-term memory (VSTM). Specifically, we seek to answer whether change detection is better captured by a first-order integration model, in which information is pooled from each location, or a second-order integration model, in which each location is processed independently. We diagnose whether change detection across locations proceeds in serial or parallel and how processing is affected by the stopping rule (i.e., detecting any change vs. detecting all changes; Experiment 1) and how the efficiency of detection is affected by the number of changes in the display (Experiment 2). We find that although capacity is generally limited in both tasks, the architecture varies from parallel self-terminating in the OR task to serial self-terminating in the AND task. Our novel framework allows model comparisons across a large set of models ruling out several competing explanations of change detection. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Explainable models for forecasting the emergence of political instability.

Building on previous research on the use of macroeconomic factors for conflict prediction and using data on political instability provided by the Political Instability Task Force, this article proposes two minimal forecasting models of political instability optimised to have the greatest possible predictive power for one-year and two-year event horizons, while still making predictions that are fully explainable. Both models employ logistic regression and use just three predictors: polity code (a measure of government type), infant mortality, and years of stability (i.e., years since the last instability event). These models make predictions for 176 countries on a country-year basis and achieve AUPRC's of 0.108 and 0.115 for the one-year and two-year models respectively. They use public data with ongoing availability so are readily reproducible. They use Monte Carlo simulations to construct confidence intervals for their predictions and are validated by testing their predictions for a set of reference years separate from the set of reference years used to train them. This validation shows that the models are not overfitted but suggests that some of the previous models in the literature may have been. The models developed in this article are able to explain their predictions by showing, for a given prediction, which predictors were the most influential and by using counterfactuals to show how the predictions would have been altered had these predictors taken different values. These models are compared to models created by lasso regression and it is shown that they have at least as good predictive power but that their predictions can be more readily explained. Because policy makers are more likely to be influenced by models whose predictions can explained, the more interpretable a model is the more likely it is to influence policy.

Using meta-predictions to identify experts in the crowd when past performance is unknown.

A common approach to improving probabilistic forecasts is to identify and leverage the forecasts from experts in the crowd based on forecasters' performance on prior questions with known outcomes. However, such information is often unavailable to decision-makers on many forecasting problems, and thus it can be difficult to identify and leverage expertise. In the current paper, we propose a novel algorithm for aggregating probabilistic forecasts using forecasters' meta-predictions about what other forecasters will predict. We test the performance of an extremised version of our algorithm against current forecasting approaches in the literature and show that our algorithm significantly outperforms all other approaches on a large collection of 500 binary decision problems varying in five levels of difficulty. The success of our algorithm demonstrates the potential of using meta-predictions to leverage latent expertise in environments where forecasters' expertise cannot otherwise be easily identified.

Evidence that within-dimension features are generally processed coactively.

In this paper, we examine whether information about an item's category, provided by the same dimension type presented across multiple spatial locations (which we term within-dimension features), is processed independently or pooled into a common representation. We use Systems Factorial Technology (SFT; Townsend & Nozawa, Journal of Mathematical Psychology, 39, 321-340, 1995) and fit parametric logical rule-based models to diagnose whether information processing is serial, parallel, or coactive. The present work focuses on expanding the scope of categorization response time (RT) models by synthesizing recent work in perceptual categorization with theories of visual attention. Our results show that for the majority of participants, processing occurs coactively (i.e., is pooled into a single decision process). For the remainder, other processing strategies were found (e.g., parallel processing). This finding provides new insight into decision-making using within-dimension features presented in multiple locations. It also highlights the importance of both featural information and spatial attention in categorization decision-making.

Commitments increase preparedness for floods.

The current study investigated whether we could encourage Australian residents to become better prepared for floods by inviting them to make a specific commitment to do so. We sampled 374 residents of the state of Victoria (56% male, 81% metropolitan) and 400 residents of the state of New South Wales (45% male, 59% metropolitan) who lived in locations that were potentially at risk of floods. They residents were sampled so that their distributions of ages, genders and living locations were as representative as possible of the population of those two states. These residents completed two surveys that ascertained their preparedness for floods at two points in time, separate by a two-week period. At the end of the first survey all residents received information about how they could better prepare for floods. In addition, approximately half the residents were randomly selected to be invited to commit to becoming better prepared for floods. We found that 74% of residents who were invited to commit to becoming better prepared for floods, were willing to make this commitment. We found that the group that was invited to commit to become better prepared for floods increased their preparedness for floods over the two-week period that separated the two surveys more than the group that was not invited to make this commitment, F(1, 772) = 4.53, p = .034, η2 = .006. We conclude that when emergency services inform residents of flood-prone areas how to better prepare for floods, they should also attempt to elicit from the residents a commitment to become better prepared for floods.

Conformity to the descriptive norms of people with opposing political or social beliefs.

The descriptive norm effect refers to findings that individuals will tend to prefer behaving certain ways when they know that other people behave similarly. An open question is whether individuals will still conform to other people's behaviour when they do not identify with these other people, such as a Democrat being biased towards following a popular behaviour amongst Republicans. Self-categorization theory makes the intuitive prediction that people will actively avoid conforming to the norms of groups with which they do not identify. We tested this by informing participants that a particular action was more popular amongst people they identified with and additionally informed some participants that this action was unpopular amongst people they did not identify with. Specifically, we presented descriptive norms of people who supported different political parties or had opposing stances on important social issues. Counter to self-categorization theory's prediction, we found that informing participants that an action was unpopular amongst people they did not identify with led participants' preferences to shift away from that action. These results suggest that a general desire to conform with others may outpower the common ingroup vs outgroup mentality.

Even arbitrary norms influence moral decision-making.

It is well known that individuals tend to copy behaviours that are common among other people-a phenomenon known as the descriptive norm effect1-3. This effect has been successfully used to encourage a range of real-world prosocial decisions4-7, such as increasing organ donor registrations8. However, it is still unclear why it occurs. Here, we show that people conform to social norms, even when they understand that the norms in question are arbitrary and do not reflect the actual preferences of other people. These results hold across multiple contexts and when controlling for confounds such as anchoring or mere-exposure effects. Moreover, we demonstrate that the degree to which participants conform to an arbitrary norm is determined by the degree to which they self-identify with the group that exhibits the norm. Two prominent explanations of norm adherence-the informational and social sanction accounts2,9-11-cannot explain these results, suggesting that these theories need to be supplemented by an additional mechanism that takes into account self-identity.

Predictors of gambling and problem gambling in Victoria, Australia.

In 2016, the gambling habits of a sample of 3361 adults in the state of Victoria, Australia, were surveyed. It was found that a number of factors that were highly correlated with self-reported gambling frequency and gambling problems were not significant predictors of gambling frequency and problem gambling. The major predictors of gambling frequency were the degree to which family members and peers were perceived to gamble, self-reported approval of gambling, the frequency of discussing gambling offline, and the participant's Canadian Problem Gambling Severity Index (PGSI) score. Age was a significant predictor of gambling frequency for certain types of gambling (e.g. buying lottery tickets). Approximately 91% of the explainable variance in the participant's PGSI score could be explained by just five predictors: Positive Urgency; Frequency of playing poker machines at pubs, hotels or sporting clubs; Participation in online discussions of betting on gaming tables at casinos; Frequency of gambling on the internet, and Overestimating the chances of winning. Based on these findings, suggestions are made as to how gambling-related harm can be reduced.

An argument for how (and why) to incentivise replication.

Although Zwaan et al. (2018) have made a compelling case as to why direct replications should occur more frequently than they do, they do not address how such replications attempts can best be encouraged. We propose a novel method for incentivising replication attempts and discuss some issues surrounding its implementation.

Perceptual training to improve hip fracture identification in conventional radiographs.

Diagnosing certain fractures in conventional radiographs can be a difficult task, usually taking years to master. Typically, students are trained ad-hoc, in a primarily-rule based fashion. Our study investigated whether students can more rapidly learn to diagnose proximal neck of femur fractures via perceptual training, without having to learn an explicit set of rules. One hundred and thirty-nine students with no prior medical or radiology training were shown a sequence of plain film X-ray images of the right hip and for each image were asked to indicate whether a fracture was present. Students were told if they were correct and the location of any fracture, if present. No other feedback was given. The more able students achieved the same level of accuracy as board certified radiologists at identifying hip fractures in less than an hour of training. Surprisingly, perceptual learning was reduced when the training set was constructed to over-represent the types of images participants found more difficult to categorise. Conversely, repeating training images did not reduce post-training performance relative to showing an equivalent number of unique images. Perceptual training is an effective way of helping novices learn to identify hip fractures in X-ray images and should supplement the current education programme for students.

Attribute amnesia is greatly reduced with novel stimuli.

Attribute amnesia is the counterintuitive phenomenon where observers are unable to report a salient aspect of a stimulus (e.g., its colour or its identity) immediately after the stimulus was presented, despite both attending to and processing the stimulus. Almost all previous attribute amnesia studies used highly familiar stimuli. Our study investigated whether attribute amnesia would also occur for unfamiliar stimuli. We conducted four experiments using stimuli that were highly familiar (colours or repeated animal images) or that were unfamiliar to the observers (unique animal images). Our results revealed that attribute amnesia was present for both sets of familiar stimuli, colour (p < .001) and repeated animals (p = .001); but was greatly attenuated, and possibly eliminated, when the stimuli were unique animals (p = .02). Our data shows that attribute amnesia is greatly reduced for novel stimuli.

Natural scenes can be identified as rapidly as individual features.

Can observers determine the gist of a natural scene in a purely feedforward manner, or does this process require deliberation and feedback? Observers can recognise images that are presented for very brief periods of time before being masked. It is unclear whether this recognition process occurs in a purely feedforward manner or whether feedback from higher cortical areas to lower cortical areas is necessary. The current study revealed that the minimum presentation time required to identify or to determine the gist of a natural scene was no different from that required to determine the orientation or colour of an isolated line. Conversely, a visual task that would be expected to necessitate feedback (determining whether an image contained exactly six lines) required a significantly greater minimum presentation time. Assuming that the orientation or colour of an isolated line can be determined in a purely feedforward manner, these results indicate that the identification and the determination of the gist of a natural scene can also be performed in a purely feedforward manner. These results challenge a number of theories of visual recognition that require feedback.

Shared processing in multiple object tracking and visual working memory in the absence of response order and task order confounds.

To understand how the visual system represents multiple moving objects and how those representations contribute to tracking, it is essential that we understand how the processes of attention and working memory interact. In the work described here we present an investigation of that interaction via a series of tracking and working memory dual-task experiments. Previously, it has been argued that tracking is resistant to disruption by a concurrent working memory task and that any apparent disruption is in fact due to observers making a response to the working memory task, rather than due to competition for shared resources. Contrary to this, in our experiments we find that when task order and response order confounds are avoided, all participants show a similar decrease in both tracking and working memory performance. However, if task and response order confounds are not adequately controlled for we find substantial individual differences, which could explain the previous conflicting reports on this topic. Our results provide clear evidence that tracking and working memory tasks share processing resources.

Global Cue Inconsistency Diminishes Learning of Cue Validity.

In daily life, we make decisions that are associated with probabilistic outcomes (e.g., the chance of rain today). People search for and utilize information that validly predicts an outcome (i.e., we look for dark clouds to indicate the possibility of rain). In the current study (N = 107), we present a two-stage learning task that examines how participants learn and utilize predictive information within a probabilistic learning environment. In the first stage, participants select one of three cues that gives predictive information about the outcome of the second stage. Participants then use this information to predict the outcome in stage two, for which they receive feedback. Critically, only one of the three cues in stage one gives valid predictive information about the outcome in stage two. Participants must differentiate the valid from non-valid cues and select this cue on subsequent trials in order to inform their prediction of the outcome in stage two. The validity of this predictive information, however, is reinforced with varying levels of probabilistic feedback (i.e., 75, 85, 95, 100%). A second manipulation involved changing the consistency of the predictive information in stage one and the outcome in stage two. The results show that participants, with higher levels of probabilistic feedback, learned to utilize the valid cue. In inconsistent task conditions, however, participants were significantly less successful in utilizing higher validity cues. We interpret this result as implying that learning in probabilistic categorization is based on developing a representation of the task that allows for goal-directed action.

Comparing Breast Screening Protocols: Inserting Catch Trials Does Not Improve Sensitivity over Double Screening.

Breast screening is an important tool for the early detection of breast cancers. However, tumours are typically present in less than 1% of mammograms. This low prevalence could cause radiologists to detect fewer tumours than they otherwise would, an issue known as the prevalence effect. The aim of our study was to investigate a novel breast screening protocol, designed to decrease the number of tumours missed by radiologists, without increasing their workload. We ran two laboratory-based experiments to assess the degree to which the novel protocol, called the catch trial (CT) protocol, resulted in greater sensitivity (d') than the double screener protocol (DS), currently utilised in Australia. In our first experiment we found evidence that the CT protocol resulted in a criterion shift relative to the DS protocol but the evidence that sensitivity was greater in the CT protocol relative to the DS protocol was less clear. A second experiment, using more realistic stimuli that were more representative of actual tumours, also failed to find convincing evidence that sensitivity was greater in the CT protocol than in the DS protocol. This experiment instead found that both the hit rate and the false alarm rate increased in the CT protocol relative to the DS protocol. So while there was again evidence that the CT protocol induced a criterion shift, the sensitivity appeared to be approximately the same in both protocols. Our results suggest the CT protocol is unlikely to result in an improvement in sensitivity over the DS protocol, so we cannot recommend that it be trialled in a clinical setting.

Investigating the Effect of Gaze Cues and Emotional Expressions on the Affective Evaluations of Unfamiliar Faces.

People look at what they are interested in, and their emotional expressions tend to indicate how they feel about the objects at which they look. The combination of gaze direction and emotional expression can therefore convey important information about people's evaluations of the objects in their environment, and can even influence the subsequent evaluations of those objects by a third party, a phenomenon known as the emotional gaze effect. The present study extended research into the effect of emotional gaze cues by investigating whether they affect evaluations of the most important aspect of our social environment-other people-and whether the presence of multiple gaze cues enhances this effect. Over four experiments, a factorial within-subjects design employing both null hypothesis significance testing and a Bayesian statistical analysis replicated previous work showing an emotional gaze effect for objects, but found strong evidence that emotional gaze cues do not affect evaluations of other people, and that multiple, simultaneously presented gaze cues do not enhance the emotional gaze effect for either the evaluations of objects or of people. Overall, our results suggest that emotional gaze cues have a relatively weak influence on affective evaluations, especially of those aspects of our environment that automatically elicit affectively valenced reactions, including other humans.

Failure to detect meaning in RSVP at 27 ms per picture.

The human visual system has the remarkable ability to rapidly detect meaning from visual stimuli. Potter, Wyble, Hagmann, and McCourt (Attention, Perception, & Psychophysics, 76, 270-279, 2014) tested the minimum viewing time required to obtain meaning from a stream of pictures shown in a rapid serial visual presentation (RSVP) sequence containing either six or 12 pictures. They reported that observers could detect the presence of a target picture specified by name (e.g., smiling couple) even when the pictures in the sequence were presented for just 13 ms each. Potter et al. claimed that this was insufficient time for feedback processing to occur, so feedforward processing alone must be able to generate conscious awareness of the target pictures. A potential confound in their study is that the pictures in the RSVP sequence sometime contained areas with no high-contrast edges, and so may not have adequately masked each other. Consequently, iconic memories of portions of the target pictures may have persisted in the visual system, thereby increasing the effective presentation time. Our study addressed this issue by redoing the Potter et al. study, but using four different types of masks. We found that when adequate masking was used, no evidence emerged that observers could detect the presence of a specific target picture, even when each picture in the RSVP sequence was presented for 27 ms. On the basis of these findings, we cannot rule out the possibility that feedback processing is necessary for individual pictures to be recognized.

The appropriacy of averaging in the study of context effects.

Models of human decision-making aim to simultaneously explain the similarity, attraction, and compromise effects. However, evidence that people show all three effects within the same paradigm has come from studies in which choices were averaged over participants. This averaging is only justified if those participants show qualitatively similar choice behaviors. To investigate whether this was the case, we repeated two experiments previously run by Trueblood (Psychonomic Bulletin & Review, 19(5), 962-968, 2012) and Berkowitsch, Scheibehenne, and Rieskamp (Journal of Experimental Psychology, 143(3), 1331-1348, 2014). We found that individuals displayed qualitative differences in their choice behavior. In general, people did not simultaneously display all three context effects. Instead, we found a tendency for some people to show either the similarity effect or the compromise effect but not both. More importantly, many individuals showed strong dimensional biases that were much larger than any effects of context. This research highlights the dangers of averaging indiscriminately and the necessity for accounting for individual differences and dimensional biases in decision-making.

Hallucinations and mental imagery demonstrate top-down effects on visual perception.

In this commentary, we present two examples where perception is not only influenced by, but also in fact driven by, top-down effects: hallucinations and mental imagery. Crucially, both examples avoid all six of the potential confounds that Firestone & Scholl (F&S) raised as arguments against previous studies claiming to demonstrate the influence of top-down effects on perception.