Response randomization of one- and two-person rock-paper-scissors games in individuals with schizophrenia

Repeated rock, paper, scissors play reveals limits in adaptive sequential behavior

How do people adapt to others in adversarial settings? Prior work has shown that people often violate rational models of adversarial decision-making in repeated interactions. In particular, in mixed strategy equilibrium (MSE) games, where optimal action selection entails choosing moves randomly, people often do not play randomly, but instead try to outwit their opponents. However, little is known about the adaptive reasoning that underlies these deviations from random behavior. Here, we examine strategic decision-making across repeated rounds of rock, paper, scissors, a well-known MSE game. In experiment 1, participants were paired with bot opponents that exhibited distinct stable move patterns, allowing us to identify the bounds of the complexity of opponent behavior that people can detect and adapt to. In experiment 2, bot opponents instead exploited stable patterns in the human participants' moves, providing a symmetrical bound on the complexity of patterns people can revise in their own behavior. Across both experiments, people exhibited a robust and flexible attention to transition patterns from one move to the next, exploiting these patterns in opponents and modifying them strategically in their own moves. However, their adaptive reasoning showed strong limitations with respect to more sophisticated patterns. Together, results provide a precise and consistent account of the surprisingly limited scope of people's adaptive decision-making in this setting.

Differences in learning retention and experience of augmented reality notes compared to traditional paper notes in a chiropractic technique course: A randomized trial

OBJECTIVE

To investigate if a written guide or augmented reality (AR) guide improves free recall of diversified chiropractic adjusting technique and to capture participants' impressions of the study in a poststudy questionnaire.

METHODS

Thirty-eight chiropractic students were evaluated for diversified listing (a nomenclature denoting vertebral malposition and correction) recall, pre-AR and post-AR, or written guide review. The vertebral segments used were C7 and T6. Two randomized groups reviewed an original course written guide (n = 18) or a new AR guide (n = 20). A Wilcoxon-Mann-Whitney (C7) and t test (T6) compared group differences in reevaluation scores. A poststudy questionnaire was given to capture participants' impressions of the study.

RESULTS

Both groups showed no significant differences in free recall scores after reviewing the guides for C7 or T6. The poststudy questionnaire suggested a number of strategies could be used to improve current teaching material such as more detail in the written guides and organizing content into smaller blocks.

CONCLUSION

Use of an AR or written guide does not seem to change participants' free recall ability when used to review diversified technique listings. The poststudy questionnaire was useful to identify strategies to improve currently used teaching material.

Assessing behavioural profiles following neutral, positive and negative feedback

Previous data suggest zero-value, neutral outcomes (draw) are subjectively assigned negative rather than positive valence. The combined observations of faster rather than slower reaction times, subsequent actions defined by shift rather than stay behaviour, reduced flexibility, and, larger rather than smaller deviations from optimal performance following draws all align with the consequences of explicitly negative outcomes such as losses. We further tested the relationships between neutral, positive and negative outcomes by manipulating value salience and observing their behavioural profiles. Despite speeded reaction times and a non-significant bias towards shift behaviour similar to losses when draws were assigned the value of 0 (Experiment 1), the degree of shift behaviour approached an approximation of optimal performance when the draw value was explicitly positive (+1). This was in contrast to when the draw value was explicitly negative (-1), which led to a significant increase in the degree of shift behaviour (Experiment 2). Similar modifications were absent when the same value manipulations were applied to win or lose trials (Experiment 3). Rather than viewing draws as neutral and valence-free outcomes, the processing cascade generated by draws produces a complex behavioural profile containing elements found in response to both explicitly positive and explicitly negative results.

Transferring cognitive talent across domains to reduce the disposition effect in investment

We consider Theory of Mind (ToM), the ability to correctly predict the intentions of others. To an important degree, good ToM function requires abstraction from one’s own particular circumstances. Here, we posit that such abstraction can be transferred successfully to other, non-social contexts. We consider the disposition effect, which is a pervasive cognitive bias whereby investors, including professionals, improperly take their personal trading history into account when deciding on investments. We design an intervention policy whereby we attempt to transfer good ToM function, subconsciously, to personal investment decisions. In a within-subject repeated-intervention laboratory experiment, we record how the disposition effect is reduced by a very significant 85%, but only for those with high scores on the social-cognitive dimension of ToM function. No such transfer is observed in subjects who score well only on the social-perceptual dimension of ToM function. Our findings open up a promising way to exploit cognitive talent in one domain in order to alleviate cognitive deficiencies elsewhere.

Formalizing Opponent Modeling with the Rock, Paper, Scissors Game

In simple dyadic games such as rock, paper, scissors (RPS), people exhibit peculiar sequential dependencies across repeated interactions with a stable opponent. These regularities seem to arise from a mutually adversarial process of trying to outwit their opponent. What underlies this process, and what are its limits? Here, we offer a novel framework for formally describing and quantifying human adversarial reasoning in the rock, paper, scissors game. We first show that this framework enables a precise characterization of the complexity of patterned behaviors that people exhibit themselves, and appear to exploit in others. This combination allows for a quantitative understanding of human opponent modeling abilities. We apply these tools to an experiment in which people played 300 rounds of RPS in stable dyads. We find that although people exhibit very complex move dependencies, they cannot exploit these dependencies in their opponents, indicating a fundamental limitation in people’s capacity for adversarial reasoning. Taken together, the results presented here show how the rock, paper, scissors game allows for precise formalization of human adaptive reasoning abilities.

Variability in competitive decision-making speed and quality against exploiting and exploitative opponents

A presumption in previous work has been that sub-optimality in competitive performance following loss is the result of a reduction in decision-making time (i.e., post-error speeding). The main goal of this paper is to test the relationship between decision-making speed and quality, with the hypothesis that slowing down decision-making should increase the likelihood of successful performance in cases where a model of opponent domination can be implemented. Across Experiments 1–3, the speed and quality of competitive decision-making was examined in a zero-sum game as a function of the nature of the opponent (unexploitable, exploiting, exploitable). Performance was also examined against the nature of a credit (or token) system used as a within-experimental manipulation (no credit, fixed credit, variable credit). To compliment reaction time variation as a function of outcome, both the fixed credit and variable credit conditions were designed to slow down decision-making, relative to a no credit condition where the game could be played in quick succession and without interruption. The data confirmed that (a) self-imposed reductions in processing time following losses (post-error speeding) were causal factors in determining poorer-quality behaviour, (b) the expression of lose-shift was less flexible than the expression of win-stay, and, (c) the use of a variable credit system may enhance the perceived control participants have against exploitable opponents. Future work should seek to disentangle temporal delay and response interruption as determinants of decision-making quality against numerous styles of opponency.

Switching Competitors Reduces Win-Stay but Not Lose-Shift Behaviour: The Role of Outcome-Action Association Strength on Reinforcement Learning

Predictability is a hallmark of poor-quality decision-making during competition. One source of predictability is the strong association between current outcome and future action, as dictated by the reinforcement learning principles of win–stay and lose–shift. We tested the idea that predictability could be reduced during competition by weakening the associations between outcome and action. To do this, participants completed a competitive zero-sum game in which the opponent from the current trial was either replayed (opponent repeat) thereby strengthening the association, or, replaced (opponent change) by a different competitor thereby weakening the association. We observed that win–stay behavior was reduced during opponent change trials but lose–shiftbehavior remained reliably predictable. Consistent with the group data, the number of individuals who exhibited predictable behavior following wins decreased for opponent change relative to opponent repeat trials. Our data show that future actions are more under internal control following positive relative to negative outcomes, and that externally breaking the bonds between outcome and action via opponent association also allows us to become less prone to exploitation.

Behavioural and neural interactions between objective and subjective performance in a Matching Pennies game

To examine the behavioural and neural interactions between objective and subjective performance during competitive decision-making, participants completed a Matching Pennies game where win-rates were fixed within three conditions (win > lose, win = lose, win < lose) and outcomes were predicted at each trial. Using random behaviour as the hallmark of optimal performance, we observed item (heads), contingency (win-stay, lose-shift) and combinatorial (HH, HT, TH, TT) biases across all conditions. Higher-quality behaviour represented by a reduction in combinatorial bias was observed during high win-rate exposure. In contrast, over-optimism biases were observed only in conditions where win rates were equal to, or less than, loss rates. At a group level, a neural measure of outcome evaluation (feedback-related negativity; FRN) indexed the binary distinction between positive and negative outcome. At an individual level, increased belief in successful performance accentuated FRN amplitude differences between wins and losses. Taken together, the data suggest that objective experiences of, or, subjective beliefs in, the predominance of positive outcomes may be mutual attempts to self-regulate performance during competition. In this way, increased exposure to positive outcomes (real or imagined) may help to weight the output of the more diligent and analytic System 2, relative to the impulsive and intuitive System 1.

A novel fMRI paradigm to dissociate the behavioral and neural components of mixed-strategy decision making from non-strategic decisions in humans

During competitive interactions, such as predator-prey or team sports, the outcome of one's actions is dependent on both their own choices and those of their opponents. Success in these rivalries requires that individuals choose dynamically and unpredictably, often adopting a mixed strategy. Understanding the neural basis of strategic decision making is complicated by the fact that it recruits various cognitive processes that are often shared with non-strategic forms of decision making, such as value estimation, working memory, response inhibition, response selection, and reward processes. Although researchers have explored neural activity within key brain regions during mixed-strategy games, how brain activity differs in the context of strategic interactions versus non-strategic choices is not well understood. We developed a novel behavioral paradigm to dissociate choice behavior during mixed-strategy interactions from non-strategic choices, and we used task-based functional magnetic resonance imaging (fMRI) to contrast brain activation. In a block design, participants competed in the classic mixed-strategy game, "matching pennies," against a dynamic computer opponent designed to exploit predictability in players' response patterns. Results were contrasted with a non-strategic task that had comparable sensory input, motor output, and reward rate; thus, differences in behavior and brain activation reflect strategic processes. The mixed-strategy game was associated with activation of a distributed cortico-striatal network compared to the non-strategic task. We propose that choosing in mixed-strategy contexts requires additional cognitive demands present to a lesser degree during the control task, illustrating the strength of this design in probing function of cognitive systems beyond core sensory, motor, and reward processes.

Behavioural and neural limits in competitive decision making: The roles of outcome, opponency and observation

To understand the boundaries we set for ourselves in terms of environmental responsibility during competition, we examined a neural index of outcome valence (feedback-related negativity; FRN) in relation to an early index of visual attention (N1), a later index of motivational significance (P3), and, eventual behaviour. In Experiment 1 (n = 36), participants either were (play) or were not (observe) responsible for action selection. In Experiment 2 (n = 36), opponents additionally either could (exploitable) or could not (unexploitable) be beaten. Various failures in reinforcement learning expression were revealed including large-scale approximations of random behaviour. Against unexploitable opponents, N1 determined the extent to which negative and positive outcomes were perceived as distinct categories by FRN. Against exploitable opponents, FRN determined the extent to which P3 generated neural gain for future events. Differential activation of the N1 - FRN - P3 processing chain provides a framework for understanding the behavioural dynamism observed during competitive decision making.

Behavioural Isomorphism, Cognitive Economy and Recursive Thought in Non-Transitive Game Strategy

Game spaces in which an organism must repeatedly compete with an opponent for mutually exclusive outcomes are critical methodologies for understanding decision-making under pressure. In the non-transitive game rock, paper, scissors (RPS), the only technique that guarantees the lack of exploitation is to perform randomly in accordance with mixed-strategy. However, such behavior is thought to be outside bounded rationality and so decision-making can become deterministic, predictable, and ultimately exploitable. This review identifies similarities across economics, neuroscience, nonlinear dynamics, human, and animal cognition literatures, and provides a taxonomy of RPS strategy. RPS strategies are discussed in terms of (a) whether the relevant computations require sensitivity to item frequency, the cyclic relationships between responses, or the outcome of the previous trial, and (b) whether the strategy is framed around the self or other. The negative implication of this taxonomy is that despite the differences in cognitive economy and recursive thought, many of the identified strategies are behaviorally isomorphic. This makes it difficult to infer strategy from behavior. The positive implication is that this isomorphism can be used as a novel design feature in furthering our understanding of the attribution, agency, and acquisition of strategy in RPS and other game spaces.

Differences in learning retention when teaching a manual motor skill with a visual vs written instructional aide

OBJECTIVE:

This study aimed to determine if a written or visual teaching aid influenced learning retention when teaching a manual motor skill.

METHODS:

Seventy chiropractic students who had completed an upper cervical specific chiropractic technique course were evaluated for technique-specific recall before and after a review using either a visual teaching aid or a written guide. Two randomized groups reviewed original course-written guides ( n = 33) or new visual teaching aids ( n = 37). Repeated-measures analysis of variance and post hoc t tests compared group differences in reevaluation scores.

RESULTS:

Performance of both groups improved postintervention ( F[1, 68] = 182.56, p < .001). However, the visual teaching aid group improved more than the written guide group ( F[1, 68] = 4.66, p = .03). The visual teaching aid group percentage score improved by 24.4% (SD ± 12.3%, p < .01); the written guide group improved by 17.7% (SD ± 13.7%; p < .01).

CONCLUSION:

The mean learning retention improved in both the visual and the written teaching guide groups, but there was greater improvement in the visual aid group. This study suggests that visual teaching aids may be more useful than written guides when students attempt to recall information related to learning a manual motor skill.

Behavioural and neural modulation of win-stay but not lose-shift strategies as a function of outcome value in Rock, Paper, Scissors

Competitive environments in which individuals compete for mutually-exclusive outcomes require rational decision making in order to maximize gains but often result in poor quality heuristics. Reasons for the greater reliance on lose-shift relative to win-stay behaviour shown in previous studies were explored using the game of Rock, Paper, Scissors and by manipulating the value of winning and losing. Decision-making following a loss was characterized as relatively fast and relatively inflexible both in terms of the failure to modulate the magnitude of lose-shift strategy and the lack of significant neural modulation. In contrast, decision-making following a win was characterized as relatively slow and relatively flexible both in terms of a behavioural increase in the magnitude of win-stay strategy and a neural modulation of feedback-related negativity (FRN) and stimulus-preceding negativity (SPN) following outcome value modulation. The win-stay/lose-shift heuristic appears not to be a unified mechanism, with the former relying on System 2 processes and the latter relying on System 1 processes. Our ability to play rationally appears more likely when the outcome is positive and when the value of wins are low, highlighting how vulnerable we can be when trying to succeed during competition.

Negative outcomes evoke cyclic irrational decisions in Rock, Paper, Scissors

Rock, Paper, Scissors (RPS) represents a unique gaming space in which the predictions of human rational decision-making can be compared with actual performance. Playing a computerized opponent adopting a mixed-strategy equilibrium, participants revealed a non-significant tendency to over-select Rock. Further violations of rational decision-making were observed using an inter-trial analysis where participants were more likely to switch their item selection at trial n + 1 following a loss or draw at trial n, revealing the strategic vulnerability of individuals following the experience of negative rather than positive outcome. Unique switch strategies related to each of these trial n outcomes were also identified: after losing participants were more likely to 'downgrade' their item (e.g., Rock followed by Scissors) but after drawing participants were more likely to 'upgrade' their item (e.g., Rock followed by Paper). Further repetition analysis revealed that participants were more likely to continue their specific cyclic item change strategy into trial n + 2. The data reveal the strategic vulnerability of individuals following the experience of negative rather than positive outcome, the tensions between behavioural and cognitive influences on decision making, and underline the dangers of increased behavioural predictability in other recursive, non-cooperative environments such as economics and politics.

The Anterior Insula Tracks Behavioral Entropy during an Interpersonal Competitive Game

In competitive situations, individuals need to adjust their behavioral strategy dynamically in response to their opponent’s behavior. In the present study, we investigated the neural basis of how individuals adjust their strategy during a simple, competitive game of matching pennies. We used entropy as a behavioral index of randomness in decision-making, because maximizing randomness is thought to be an optimal strategy in the game, according to game theory. While undergoing functional magnetic resonance imaging (fMRI), subjects played matching pennies with either a human or computer opponent in each block, although in reality they played the game with the same computer algorithm under both conditions. The winning rate of each block was also manipulated. Both the opponent (human or computer), and the winning rate, independently affected subjects’ block-wise entropy during the game. The fMRI results revealed that activity in the bilateral anterior insula was positively correlated with subjects’ (not opponent’s) behavioral entropy during the game, which indicates that during an interpersonal competitive game, the anterior insula tracked how uncertain subjects’ behavior was, rather than how uncertain subjects felt their opponent's behavior was. Our results suggest that intuitive or automatic processes based on somatic markers may be a key to optimally adjusting behavioral strategies in competitive situations.

Neural and sympathetic activity associated with exploration in decision-making: further evidence for involvement of insula

We previously reported that sympathetic activity was associated with exploration in decision-making indexed by entropy, which is a concept in information theory and indexes randomness of choices or the degree of deviation from sticking to recent experiences of gains and losses, and that activation of the anterior insula mediated this association. The current study aims to replicate and to expand these findings in a situation where contingency between options and outcomes is manipulated. Sixteen participants performed a stochastic decision-making task in which we manipulated a condition with low uncertainty of gain/loss (contingent-reward condition) and a condition with high uncertainty of gain/loss (random-reward condition). Regional cerebral blood flow was measured by (15)O-water positron emission tomography (PET), and cardiovascular parameters and catecholamine in the peripheral blood were measured, during the task. In the contingent-reward condition, norepinephrine as an index of sympathetic activity was positively correlated with entropy indicating exploration in decision-making. Norepinephrine was negatively correlated with neural activity in the right posterior insula, rostral anterior cingulate cortex, and dorsal pons, suggesting neural bases for detecting changes of bodily states. Furthermore, right anterior insular activity was negatively correlated with entropy, suggesting influences on exploration in decision-making. By contrast, in the random-reward condition, entropy correlated with activity in the dorsolateral prefrontal and parietal cortices but not with sympathetic activity. These findings suggest that influences of sympathetic activity on exploration in decision-making and its underlying neural mechanisms might be dependent on the degree of uncertainty of situations.

Neural substrates underlying effort computation in schizophrenia

The lack of initiative, drive or effort in patients with schizophrenia is linked to marked functional impairments. However, our assessment of effort and motivation is crude, relying on clinical rating scales based largely on patient recall. In order to better understand the neurobiology of effort in schizophrenia, we need more rigorous measurements of this construct. In the behavioural neuroscience literature, decades of work has been carried out developing various paradigms to examine the neural underpinnings of an animal's willingness to expend effort for a reward. Here, we shall review this literature on the nature of paradigms used in rodents to assess effort, as well as those used in humans. Next, the neurobiology of these effort-based decisions will be discussed. We shall then review what is known about effort in schizophrenia, and what might be inferred from experiments done in other human populations. Lastly, we shall discuss future directions of research that may assist in shedding light on the neurobiology of effort cost computations in schizophrenia.

Neural mechanisms mediating association of sympathetic activity and exploration in decision-making

The somatic marker hypothesis asserts that decision-making can be guided by feedback of bodily states to the brain. In line with this hypothesis, the present study tested whether sympathetic activity shows an association with a tonic dimension of decision-making, exploratory tendency represented by entropy in information theory, and further examined the neural mechanisms of the association. Twenty participants performed a stochastic reversal learning task that required decision-making in an unstable and uncertain situation. Regional cerebral blood flow was evaluated using (15)O-water positron emission tomography (PET), and cardiovascular indices and concentrations of catecholamine in peripheral blood were also measured, during the task. In reversal learning, increased epinephrine during the task positively correlated with larger entropy, indicating a greater tendency for exploration in decision-making. The increase of epinephrine also correlated with brain activity revealed by PET in the somatosensory cortices, anterior insula, dorsal anterior cingulate cortex, and the dorsal pons. This result is consistent with previously reported brain matrixes of representation of bodily states and interoception. In addition, activity of the anterior insula specifically correlated with entropy, suggesting possible mediation of this brain region between peripheral sympathetic arousal and exploration in decision-making. These findings shed a new light about a role of bodily states in decision-making and underlying neural mechanisms.