Probabilistic models in human sensorimotor control

Sensory and motor uncertainty form a fundamental constraint on human sensorimotor control. Bayesian decision theory (BDT) has emerged as a unifying framework to understand how the central nervous system performs optimal estimation and control in the face of such uncertainty. BDT has two components: Bayesian statistics and decision theory. Here we review Bayesian statistics and show how it applies to estimating the state of the world and our own body. Recent results suggest that when learning novel tasks we are able to learn the statistical properties of both the world and our own sensory apparatus so as to perform estimation using Bayesian statistics. We review studies which suggest that humans can combine multiple sources of information to form maximum likelihood estimates, can incorporate prior beliefs about possible states of the world so as to generate maximum a posteriori estimates and can use Kalman filter-based processes to estimate time-varying states. Finally, we review Bayesian decision theory in motor control and how the central nervous system processes errors to determine loss functions and select optimal actions. We review results that suggest we plan movements based on statistics of our actions that result from signal-dependent noise on our motor outputs. Taken together these studies provide a statistical framework for how the motor system performs in the presence of uncertainty.     

The emotional feeling as a combination of two qualia: A neurophilosophical-based emotion theory

It is argued that the emotional feeling comprises the following two emotional qualia. (1) A nucleus feeling or primary emotional quale, which is the phenomenological counterpart of the end product of appraisal by the central nervous system. (2) The experience of being urged to emotion-related reflection or secondary emotional quale, which is the phenomenological counterpart of the brain's decision to inhibit pre-programmed emotional behaviour, and to initiate emotion-related reflections. Different brain modules regulate these two qualia, and thus each can be experienced independently of the other. The primary emotional quale is related to activation of the amygdala, it is emotion specific, and neutral with respect to affect. The secondary emotional quale is related to activation of the orbito-prefrontal cortex (O-PFC), and includes affective aspects.

It is argued that emotional behaviour is regulated by the following three neural mechanisms, two of which two are directly related to the two qualia. (1) An evolutionary ancient system (amygdala-system), which comprises the amygdalae and subcortical nuclei, and which activates pre-programmed emotional behaviour. (2) An evolutionary recent system (PFC-system), comprising the prefrontal cortex, which inhibits pre-programmed emotional behaviour, activates emotional reflection, generates and evaluates behavioural alternatives. In contrast to the pre-programmed behaviour, the behavioural alternatives are more likely to serve long-term goals. (3) A default mechanism, which gives rise to default (i.e., “just do something”) behaviour. The first two systems are mutually competitive, while the third mechanism takes over if either the competition between the first two mechanisms, or the decision process of the PFC-system, takes too long. This default mechanism involves the function of the medial-prefrontal cortex (M-PFC).     

Dealing with missed opportunities: Action vs. state orientation moderates inaction inertia

Inaction inertia refers to the effect that missing a more attractive opportunity decreases the likelihood to act on an attractive current opportunity in the same domain. We studied the influence of how people cope with negative decision outcomes (i.e., action vs. state orientation) on this inaction inertia effect. Experiment 1 used an experimental induction of action vs. state orientation and confirmed our prediction that state oriented people showed more inaction inertia than action oriented people. Experiment 2 replicated these results with a measure of chronic action orientation and showed a mediating effect of valuation of the current opportunity. Experiment 3 showed that temporal segregation of the current from the missed opportunity decreased inaction inertia effects for state oriented, but not for action oriented people. We discuss the implications of these results for the inaction inertia and action vs. state orientation literatures.     

Contrasting roles for cingulate and orbitofrontal cortex in decisions and social behaviour

There is general acknowledgement that both the anterior cingulate and orbitofrontal cortex are implicated in reinforcement-guided decision making, and emotion and social behaviour. Despite the interest that these areas generate in both the cognitive neuroscience laboratory and the psychiatric clinic, ideas about the distinctive contributions made by each have only recently begun to emerge. This reflects an increasing understanding of the component processes that underlie reinforcement-guided decision making, such as the representation of reinforcement expectations, the exploration, updating and representation of action values, and the appreciation that choices are guided not just by the prospect of reward but also by the costs that action entails. Evidence is emerging to suggest that the anterior cingulate and orbitofrontal cortex make distinct contributions to each of these aspects of decision making.     

Intentional Action and the Post-Coma Patient

Detecting conscious awareness in a patient emerging from a coma state is problematic, because our standard attributions of conscious awareness rely on interpreting bodily movement as intentional action. Where there is an absence of intentional bodily action, as in the vegetative state, can we reliably assume that there is an absence of conscious awareness? Recent neuroimaging work suggests that we can attribute conscious awareness to some patients in a vegetative state by interpreting their brain activity as intentional mental action. I suggest that this change of focus, from the interpretation of motor behaviour as intentional bodily action to the interpretation of neural activity as intentional mental action, raises philosophical issues that affect the interpretation of the neuroimaging data.     

Individual Differences in Decision Making Depend on Cognitive Abilities,Monitoring and Control

Decision making is the process by which actions are constructed and initiated. Across many research streams, this can be explained in terms of three broad cognitive processes: cognitive abilities that construct judgements and potential courses of action, and interacting monitoring and control processes that determine when to initiate them as behaviour. The aim of this research was to investigate the generality of individual differences in these processes, and their power to predict patterns of decision behaviour identified in our previous research. Undergraduate participants (N = 364) completed nine tests assessing cognitive abilities, monitoring confidence, control thresholds and various patterns of decision behaviour. The tests differed in their cognitive ability requirements and the nature of the payoffs associated with decisions. Cognitive abilities were a strong predictor of individuals' decision competence and optimality, while monitoring confidence and control thresholds were strong and unique predictors of their overall decisiveness, and reckless and hesitant errors. These results were strongest when the measures of cognitive abilities and monitoring confidence were derived from tests with the same cognitive requirements as the tests used to derive the decision behaviours and when the control threshold measure was derived from tests with the same decision payoffs as the test used to derive the decision behaviours. This effect was particularly pronounced for control thresholds, highlighting the domain‐specific nature of cognitive control processes. These findings demonstrate how cognitive abilities, monitoring output and control thresholds interact with cognitive requirements and context‐specific payoffs to drive individual differences in decision‐making behaviour. Copyright © 2016 John Wiley & Sons, Ltd.     

Visual prediction: psychophysics and neurophysiology of compensation for time delays

A necessary consequence of the nature of neural transmission systems is that as change in the physical state of a time-varying event takes place, delays produce error between the instantaneous registered state and the external state. Another source of delay is the transmission of internal motor commands to muscles and the inertia of the musculoskeletal system. How does the central nervous system compensate for these pervasive delays? Although it has been argued that delay compensation occurs late in the motor planning stages, even the earliest visual processes, such as phototransduction, contribute significantly to delays. I argue that compensation is not an exclusive property of the motor system, but rather, is a pervasive feature of the central nervous system (CNS) organization. Although the motor planning system may contain a highly flexible compensation mechanism, accounting not just for delays but also variability in delays (e.g., those resulting from variations in luminance contrast, internal body temperature, muscle fatigue, etc.), visual mechanisms also contribute to compensation. Previous suggestions of this notion of "visual prediction" led to a lively debate producing re-examination of previous arguments, new analyses, and review of the experiments presented here. Understanding visual prediction will inform our theories of sensory processes and visual perception, and will impact our notion of visual awareness.     

Risky visuomotor choices during rapid reaching in childhood

Many everyday actions are implicit gambles because imprecisions in our visuomotor systems place probabilities on our success or failure. Choosing optimal action strategies involves weighting the costs and gains of potential outcomes by their corresponding probabilities, and requires stable representations of one's own imprecisions. How this ability is acquired during development in childhood when visuomotor skills change drastically is unknown. In a rewarded rapid reaching task, 6‐ to 11‐year‐old children followed ‘risk‐seeking’ strategies leading to overly high point‐loss. Adults' performance, in contrast, was close to optimal. Children's errors were not explained by distorted estimates of value or probability, but may reflect different action selection criteria or immature integration of value and probability information while planning movements. These findings provide a starting point for understanding children's risk‐taking in everyday visuomotor situations when suboptimal choices can be dangerous. Moreover, children's risky visuomotor decisions mirror those reported for non‐motor gambles, raising the possibility that common processes underlie development across decision‐making domains.     

Kinematic cues in perceptual weight judgement and their origins in box lifting

When accepting a parcel from another person, we are able to use information about that person’s movement to estimate in advance the weight of the parcel, that is, to judge its weight from observed action. Perceptual weight judgment provides a powerful method to study our interpretation of other people’s actions, but it is not known what sources of information are used in judging weight. We have manipulated full form videos to obtain precise control of the perceived kinematics of a box lifting action, and use this technique to explore the kinematic cues that affect weight judgment. We find that observers rely most on the duration of the lifting movement to judge weight, and make less use of the durations of the grasp phase, when the box is first gripped, or the place phase, when the box is put down. These findings can be compared to the kinematics of natural box lifting behaviour, where we find that the duration of the grasp component is the best predictor of true box weight. The lack of accord between the optimal cues predicted by the natural behaviour and the cues actually used in the perceptual task has implications for our understanding of action observation in terms of a motor simulation. The differences between perceptual and motor behaviour are evidence against a strong version of the motor simulation hypothesis. A. F. de C. Hamilton and D. W. Joyce have contributed equally to this work.     

Not only in the brain: Cabanis and the Montpellierian tradition of localization

Antonio Damasio (1995) has recently presented evidence to the effect that we are perhaps wrong in thinking that it is only the brain that thinks. Rational decision making involves emotional reactions as a necessary condition and background. And since emotions involve bodily reactions which are not limited to the brain but which embrace the autonomous nervous system and the viscera, one could say that we actually think with our bodies and not merely with our brains. According to Damasio the incapacity of patients with frontal lobe pathology in decision making could be explained by a disturbance in emotional reactions involving the whole organism. Philosophical discussions concerning brains in a vat have completely forgotten these aspects of our mental life. Despite the fact that the idea that we think exclusively with our brains has during the modern age been a rather widely held "received view," there is a physiological and philosophical tradition which regarded mental functions as the result of the interaction of several organs, instead of seeing them as the result of the activity of the brain alone.     

An empirical study of the decision to use condoms among Norwegian adolescents using the theory of reasoned action

The decision whether or not to use condoms was studied among Norwegian adolescents using the theory of reasoned action (TRA). The empirical data stem from a survey of a random sample of 3000 adolescents aged 17–19 (response rate 60.9 per cent). A total of 1172 persons had made their sexual debuts, and thus constituted the material of this paper. TRA is an expectancy-value model of attitude for understanding and changing a behaviour, and views condom behaviour as a decision based upon consideration of the expected consequences of using or not using condoms. The decision whether or not to use a condom was primarily under normative control, and immediate consequences were more important than long-term consequences, indicating that persuasive communications should pay more attention to social pressure and psychological costs. Most of the effect of prior behaviour upon intention was not mediated by attitudes and subjective norm, and by far exceeded the effects of attitudes and subjective norm, raising doubts of the generality of the model. The possible inclusion of a measure of perceived behavioural control is discussed.     

Eliciting salient beliefs in research on the theory of planned behaviour: The effect of question wording

The authors of the theory of reasoned action (TRA) and its extension, the theory of planned behaviour (TPB) recommend that researchers who use these theories to investigate the determinants of a given behaviour should first conduct an elicitation study to identify the modal salient beliefs in the target population. In spite of the importance accorded to salient beliefs by the TRA/TPB, the elicitation stage has received little research attention. This paper reports a detailed analysis of beliefs about “being more physically active in the next 12 months.” A general population sample of 213 adults completed a questionnaire while attending a research centre for a series of tests. The findings showed that the beliefs that were elicited by questions designed to prompt affective outcomes (like or enjoy, dislike or hate) differed systematically from those that were elicited by the traditional questions designed to prompt instrumental out-comes (advantages and disadvantages). Whether this resulted in different final sets of modal salient beliefs was found to depend on the particular decision rule that was employed. An alternative decision rule is proposed, based on maximizing the degree of overlap between the modal set and the full set of salient beliefs generated by the sample. The index of overlap can be used to gauge the adequacy of using a modal set of a given size to represent the salient beliefs of the whole sample. In the current dataset, the optimal modal set for “advantages and disadvantages” was associated with only 26 percent overlap with the salient beliefs of the whole sample, which was judged to be insufficient. In such cases, a better strategy may be to ask participants to generate and rate their own beliefs.     

Eliciting salient beliefs in research on the theory of planned behaviour: The effect of question wording

The authors of the theory of reasoned action (TRA) and its extension, the theory of planned behaviour (TPB) recommend that researchers who use these theories to investigate the determinants of a given behaviour should first conduct an elicitation study to identify the modal salient beliefs in the target population. In spite of the importance accorded to salient beliefs by the TRA/TPB, the elicitation stage has received little research attention. This paper reports a detailed analysis of beliefs about “being more physically active in the next 12 months.” A general population sample of 213 adults completed a questionnaire while attending a research centre for a series of tests. The findings showed that the beliefs that were elicited by questions designed to prompt affective outcomes (like or enjoy, dislike or hate) differed systematically from those that were elicited by the traditional questions designed to prompt instrumental out-comes (advantages and disadvantages). Whether this resulted in different final sets of modal salient beliefs was found to depend on the particular decision rule that was employed. An alternative decision rule is proposed, based on maximizing the degree of overlap between the modal set and the full set of salient beliefs generated by the sample. The index of overlap can be used to gauge the adequacy of using a modal set of a given size to represent the salient beliefs of the whole sample. In the current dataset, the optimal modal set for “advantages and disadvantages” was associated with only 26 percent overlap with the salient beliefs of the whole sample, which was judged to be insufficient. In such cases, a better strategy may be to ask participants to generate and rate their own beliefs.     

The Biology of Morality

Abstract. The morality of human beings, defined here as our ability to determine whether our actions are right or wrong, depends not just on following rules but also on understanding the impact of our actions on another person. How we understand the impact of our actions on another person depends on our state of consciousness, which is mediated by our brain and nervous system. We describe how we understand our morality to flow naturally from the biological state we are living in and how we see our biology and our morality as mutually interactive. A change in one changes the other. Another way of saying this is that changing either our morality or our biology changes both—changes who we are and what we do.     

Who do you trust? The impact of facial emotion and behaviour on decision making

During social interactions, we use available information to guide our decisions, including behaviour and emotional displays. In some situations, behaviour and emotional displays may be incongruent, complicating decision making. This study had two main aims: first, to investigate the independent contributions of behaviour and facial displays of emotion on decisions to trust, and, second, to examine what happens when the information being signalled by a facial display is incongruent with behaviour. Participants played a modified version of the Trust Game in which they learned simulated players’ behaviour with or without concurrent displays of facial emotion. Results indicated that displays of anger, but not happiness, influenced decisions to trust during initial encounters. Over the course of repeated interactions, however, emotional displays consistent with an established pattern of behaviour made independent contributions to decision making, strengthening decisions to trust. When facial display and behaviour were incongruent, participants used current behaviour to inform decision making.     

Robust interactive decision-analysis (RID): Behavioral results and implications

We have proposed a novel interactive procedure for performing decision analysis, called Robust Interactive Decision Analysis (RID), which permits a decision maker (DM) to voluntarily and interactively express strong (viz, sure) binary preferences for actions, partial decision functions, and full decision functions, and only imprecise probability and utility function assessments. These serve as INPUTS TO operators to prune the state probability space and decision space until an optimal choice strategy is obtained. The viability of the RID approach depends on a DM's ability to provide such information consistently and meaningfully. On a limited scale we experimentally investigate the behavioral implications of the RID method in order to ascertain its potential operational feasibility and viability. More specifically, we examine whether a DM can (1) express strong preferences between pairs of vectors of unconditional and conditional payoffs or utilities consistently; (2) provide imprecise (ordinal and interval) state probabilities that are individually as well as mutually consistent with the state probabilities imputed from the expressed strong preferences. The results show that a DM can provide strong individually and mutually consistent preference and ordinal probability information. Moreover, most individuals also appear to be able to provide interval probabilities that are individually and mutually consistent with their strong preference inputs. However, the several violations observed, our small sample size, and the limited scope of our investigation suggest that further experimentation is needed to determine whether and/or how such inputs should be elicited. Overall, the results indicate that the RID method is behaviorally viable.     

Decision making in a dynamic situation: The effect of false alarms and time pressure

An experiment was conducted to investigate the effect of a priori probability of false alarms and time pressure on decision-making behaviour in a dynamic task environment. In order to assess whether strategy selection in a dynamic task environment would be adaptive, we modelled the task mathematically, and compared actual decision strategies to the optimal ones. In addition to the selected strategy, we also studied decision-making behaviour at a lower operational level, reflecting the amount of effort subjects are willing to spend on the decision process. Subjects were required to monitor the fitness level of a simulated athlete, who was running a race, and had to provide treatments whenever the athlete's fitness level suggested a real physiological problem. When a decline of the athlete's fitness was caused by a false alarm, a spontaneous recovery would occur after some time, without any need for intervention. Time pressure was manipulated by the rate at which the athlete's fitness level declined. Overall, subjects did not select the most efficient strategy: they dominantly selected information before applying an action, even though it would have been more profitable, and less effortful, just to apply actions. At the operational level, subjects appeared to invest less effort when the probability of false alarms increased and to invest more effort when time pressure increased. However, in contrast to the outcomes of our mathematical model, subjects adjusted the amount of intervention to the a priori probability of false alarms and not to time pressure. Together, the results indicate that the selection of a decision strategy in a dynamic task is less adaptive then is generally concluded from studies with static tasks.     

Prolegomenon to the structure of emotion: Gleanings from neuropsychology

Abstract

This article presents a model of the structure of emotion developed primarily from a consideration of neuropsychological evidence and behavioural data which have bearing on neuropsychological theories. Valence is first considered and highlighted as a defining characteristic of emotion. Next, the use of facial behaviour and autonomic nervous system patterns as defining characteristics of discrete emotions is questioned on empirical and conceptual grounds. The regulation of emotion is considered and proposed to affect the very structure of emotion itself. If there is an invariant pattern of biological activity across different instantiations of the same emotion, it is likely to be found in higher-order associative networks of central nervous system activity, the very same networks that subserve goal-directed behaviour and other cognitive functions. Drawing upon evolutionary considerations, it is argued that what is basic about emotion are the dimensions of approach and withdrawal. The nature of the linkage between such action tendencies and emotion is discussed.     

Six Challenges for Ethical Conduct in Science

The realities of human agency and decision making pose serious challenges for research ethics. This article explores six major challenges that require more attention in the ethics education of students and scientists and in the research on ethical conduct in science. The first of them is the routinization of action, which makes the detection of ethical issues difficult. The social governance of action creates ethical problems related to power. The heuristic nature of human decision making implies the risk of ethical bias. The moral disengagement mechanisms represent a human tendency to evade personal responsibility. The greatest challenge of all might be the situational variation in people’s ethical behaviour. Even minor situational factors have a surprisingly strong influence on our actions. Furthermore, finally, the nature of ethics itself also causes problems: instead of clear answers, we receive a multitude of theories and intuitions that may sometimes be contradictory. All these features of action and ethics represent significant risks for ethical conduct in science. I claim that they have to be managed within the everyday practices of science and addressed explicitly in research ethics education. I analyse them and suggest some ways in which their risks can be alleviated.