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Studies with the retro-cue paradigm have shown that validly cueing objects in visual working memory long after encoding can still benefit performance on subsequent change detection tasks. With regard to the effects of invalid cues, the literature is less clear. Some studies reported costs, others did not. We here revisit two recent studies that made interesting suggestions concerning invalid retro-cues: One study suggested that costs only occur for larger set sizes, and another study suggested that inclusion of invalid retro-cues diminishes the retro-cue benefit. New data from one experiment and a reanalysis of published data are provided to address these conclusions. The new data clearly show costs (and benefits) that were independent of set size, and the reanalysis suggests no influence of the inclusion of invalid retro-cues on the retro-cue benefit. Thus, previous interpretations may be taken with some caution at present.
Embodiment (i.e., the involvement of a bodily representation) is thought to be relevant in emotional experiences. Virtual reality (VR) is a capable means of activating phobic fear in patients. The representation of the patient’s body (e.g., the right hand) in VR enhances immersion and increases presence, but its effect on phobic fear is still unknown. We analyzed the influence of the presentation of the participant’s hand in VR on presence and fear responses in 32 women with spider phobia and 32 matched controls. Participants sat in front of a table with an acrylic glass container within reaching distance. During the experiment this setup was concealed by a head-mounted display (HMD). The VR scenario presented via HMD showed the same setup, i.e., a table with an acrylic glass container. Participants were randomly assigned to one of two experimental groups. In one group, fear responses were triggered by fear-relevant visual input in VR (virtual spider in the virtual acrylic glass container), while information about a real but unseen neutral control animal (living snake in the acrylic glass container) was given. The second group received fear-relevant information of the real but unseen situation (living spider in the acrylic glass container), but visual input was kept neutral VR (virtual snake in the virtual acrylic glass container). Participants were instructed to touch the acrylic glass container with their right hand in 20 consecutive trials. Visibility of the hand was varied randomly in a within-subjects design. We found for all participants that visibility of the participant’s hand increased presence independently of the fear trigger. However, in patients, the influence of the virtual hand on fear depended on the fear trigger. When fear was triggered perceptually, i.e., by a virtual spider, the virtual hand increased fear. When fear was triggered by information about a real spider, the virtual hand had no effect on fear. Our results shed light on the significance of different fear triggers (visual, conceptual) in interaction with body representations.
The affective dimensions of emotional valence and emotional arousal affect processing of verbal and pictorial stimuli. Traditional emotional theories assume a linear relationship between these dimensions, with valence determining the direction of a behavior (approach vs. withdrawal) and arousal its intensity or strength. In contrast, according to the valence-arousal conflict theory, both dimensions are interactively related: positive valence and low arousal (PL) are associated with an implicit tendency to approach a stimulus, whereas negative valence and high arousal (NH) are associated with withdrawal. Hence, positive, high-arousal (PH) and negative, low-arousal (NL) stimuli elicit conflicting action tendencies. By extending previous research that used several tasks and methods, the present study investigated whether and how emotional valence and arousal affect subjective approach vs. withdrawal tendencies toward emotional words during two novel tasks. In Study 1, participants had to decide whether they would approach or withdraw from concepts expressed by written words. In Studies 2 and 3 participants had to respond to each word by pressing one of two keys labeled with an arrow pointing upward or downward. Across experiments, positive and negative words, high or low in arousal, were presented. In Study 1 (explicit task), in line with the valence-arousal conflict theory, PH and NL words were responded to more slowly than PL and NH words. In addition, participants decided to approach positive words more often than negative words. In Studies 2 and 3, participants responded faster to positive than negative words, irrespective of their level of arousal. Furthermore, positive words were significantly more often associated with “up” responses than negative words, thus supporting the existence of implicit associations between stimulus valence and response coding (positive is up and negative is down). Hence, in contexts in which participants' spontaneous responses are based on implicit associations between stimulus valence and response, there is no influence of arousal. In line with the valence-arousal conflict theory, arousal seems to affect participants' approach-withdrawal tendencies only when such tendencies are made explicit by the task, and a minimal degree of processing depth is required.
Cognitive Processing in Non-Communicative Patients: What Can Event-Related Potentials Tell Us?
(2016)
Event-related potentials (ERP) have been proposed to improve the differential diagnosis of non-responsive patients. We investigated the potential of the P300 as a reliable marker of conscious processing in patients with locked-in syndrome (LIS). Eleven chronic LIS patients and 10 healthy subjects (HS) listened to a complex-tone auditory oddball paradigm, first in a passive condition (listen to the sounds) and then in an active condition (counting the deviant tones). Seven out of nine HS displayed a P300 waveform in the passive condition and all in the active condition. HS showed statistically significant changes in peak and area amplitude between conditions. Three out of seven LIS patients showed the P3 waveform in the passive condition and five of seven in the active condition. No changes in peak amplitude and only a significant difference at one electrode in area amplitude were observed in this group between conditions. We conclude that, in spite of keeping full consciousness and intact or nearly intact cortical functions, compared to HS, LIS patients present less reliable results when testing with ERP, specifically in the passive condition. We thus strongly recommend applying ERP paradigms in an active condition when evaluating consciousness in non-responsive patients.
Effects of Background Music on Objective and Subjective Performance Measures in an Auditory BCI
(2016)
Several studies have explored brain computer interface (BCI) systems based on auditory stimuli, which could help patients with visual impairments. Usability and user satisfaction are important considerations in any BCI. Although background music can influence emotion and performance in other task environments, and many users may wish to listen to music while using a BCI, auditory, and other BCIs are typically studied without background music. Some work has explored the possibility of using polyphonic music in auditory BCI systems. However, this approach requires users with good musical skills, and has not been explored in online experiments. Our hypothesis was that an auditory BCI with background music would be preferred by subjects over a similar BCI without background music, without any difference in BCI performance. We introduce a simple paradigm (which does not require musical skill) using percussion instrument sound stimuli and background music, and evaluated it in both offline and online experiments. The result showed that subjects preferred the auditory BCI with background music. Different performance measures did not reveal any significant performance effect when comparing background music vs. no background. Since the addition of background music does not impair BCI performance but is preferred by users, auditory (and perhaps other) BCIs should consider including it. Our study also indicates that auditory BCIs can be effective even if the auditory channel is simultaneously otherwise engaged.
The present study investigates how different emotions can alter social bargaining behavior. An important paradigm to study social bargaining is the Ultimatum Game. There, a proposer gets a pot of money and has to offer part of it to a responder. If the responder accepts, both players get the money as proposed by the proposer. If he rejects, none of the players gets anything. Rational choice models would predict that responders accept all offers above 0. However, evidence shows that responders typically reject a large proportion of all unfair offers. We analyzed participants’ behavior when they played the Ultimatum Game as responders and simultaneously collected electroencephalogram data in order to quantify the feedback-related negativity and P3b components. We induced state affect (momentarily emotions unrelated to the task) via short movie clips and measured trait affect (longer-lasting emotional dispositions) via questionnaires. State happiness led to increased acceptance rates of very unfair offers. Regarding neurophysiology, we found that unfair offers elicited larger feedback-related negativity amplitudes than fair offers. Additionally, an interaction of state and trait affect occurred: high trait negative affect (subsuming a variety of aversive mood states) led to increased feedback-related negativity amplitudes when participants were in an angry mood, but not if they currently experienced fear or happiness. We discuss that increased rumination might be responsible for this result, which might not occur, however, when people experience happiness or fear. Apart from that, we found that fair offers elicited larger P3b components than unfair offers, which might reflect increased pleasure in response to fair offers. Moreover, high trait negative affect was associated with decreased P3b amplitudes, potentially reflecting decreased motivation to engage in activities. We discuss implications of our results in the light of theories and research on depression and anxiety.
Theta oscillations in the EEG have been shown to reflect ongoing cognitive processes related to mental effort. Here, we show that the pattern of theta oscillation in response to varying cognitive demands reflects stable individual differences in the personality trait epistemic motivation: Individuals with high levels of epistemic motivation recruit relatively more cognitive resources in response to situations possessing high, compared to low, cognitive demand; individuals with low levels do not show such a specific response. Our results provide direct evidence for the theory of the construct need for cognition and add to our understanding of the neural processes underlying theta oscillations. More generally, we provide an explanation how individual differences in personality traits might be represented on a neural level.
„Perspective-taking“ is the ability to put yourself into the place of somebody else. Psychological research distinguishes three kinds of perspective-taking, namely, perceptual (visuo-spatial), affective (empathy), and cognitive (theory of mind) perspective-taking. The last two kinds of perspective-taking are often summarized as “psychological perspective-taking”. This dissertation tackles the question of whether these three kinds of perspective-taking should be conceptualized as independent constructs or as facets of one and the same construct.
Prior research findings concerning this are equivocal. While some authors consider correlations between the different kinds of perspective-taking as too low for a unitary construct, others interpret correlations of the same magnitude as evidence for this. A less arbitrary way of deciding this would be to identify common mechanisms that underlie all kinds of perspective-taking and to examine whether manipulating these mechanisms in psychological experiments affects measures of perceptual, affective, and cognitive perspective-taking in parallel.
In accordance with this reasoning, the present dissertation assumes that the mental self-rotation of the body schema into the physical location of another person, the main mechanism of perceptual perspective-taking, is a common mechanism of all kinds of perspective-taking. Thus, contrary to previous research a unitary construct is not only justified on the grounds of a common central functionality of all kinds of perspective-taking, that is, overcoming one’s egocentrism in favor of an alternative (perceptual, affective or cognitive) point of view, but additionally on the grounds of a common psychological mechanism. From this, the simple hypothesis that inducing visuo-spatial perspective-taking also leads to psychological consequences is derived. This hypothesis was tested in 6 experiments.
In these experiments, participants first had to adopt the visual perspective of another person. To this end, they saw a person sitting at a table with two objects. During every trial, participants had to decide which hand the person would have to use in order to grab one of the two objects. Furthermore, the angular disparity between the participant and the target was manipulated in such a way that during half of the trials the target person was within the same visuo-spatial reference frame as the participant and thus no perspective-taking was necessary to solve the task correctly. During the remaining trials, the target person was sitting in another visuo-spatial reference frame so that the participants had to engage in perspective-taking to solve the task correctly. After every such trial, the target person was imbued with a mental state. This was done using an adapted paradigm for the investigation of the anchoring heuristic. Specifically, participants were asked to answer a trivia question and also saw what the target person from the visuo-spatial perspective-taking task was guessing.
In line with the hypothesis that visuo-spatial perspective-taking leads to psychological outcomes, too, it was found that participants adopted the thoughts of the target person more strongly after visuo-spatial perspective-taking. This was evident in the absolute size of the anchoring effect, as well as the differences between participant and target estimations. Further experiments ruled out sample and stimulus characteristics and task difficulty as alternative explanations for these effects. The last two experiments furthermore established that the effects were specific to constellations where an embodied self-rotation into the target’s perspective was necessary and that the adoption of the target’s thoughts was associated with feelings of similarity.
Taken together, these findings support the theoretically elaborated unitary view of perspective-taking and furthermore distinguish this construct from other related phenomena. In the general discussion, the significance of these findings for research on empathy, theory of mind, and perspective-taking, as well as practical implications are discussed.
Frontal asymmetry, a construct invented by Richard Davidson, linking positive and negative valence as well as approach and withdrawal motivation to lateralized frontal brain activation has been investigated for over thirty years. The frontal activation patterns described as relevant were measured via alpha-band frequency activity (8-13 Hz) as a measurement of deactivation in electroencephalography (EEG) for homologous electrode pairs, especially for the electrode position F4/ F3 to account for the frontal relative lateralized brain activation.
Three different theories about frontal activation patterns linked to motivational states were investigated in two studies. The valence theory of Davidson (1984; 1998a; 1998b) and its extension to the motivational direction theory by Harmon-Jones and Allen (1998) refers to the approach motivation with relative left frontal brain activity (indicated by relative right frontal alpha activity) and to withdrawal motivation with relative right frontal brain activation (indicated by relative left frontal alpha activity). The second theory proposed by Hewig and colleagues (2004; 2005; 2006) integrates the findings of Davidson and Harmon – Jones and Allen with the reinforcement sensitivity theory of Jeffrey A. Gray (1982, 1991). Hewig sees the lateralized frontal approach system and withdrawal system proposed by Davidson as subsystems of the behavioral activation system proposed by Gray and bilateral frontal activation as a biological marker for the behavioral activation system. The third theory investigated in the present studies is the theory from Wacker and colleagues (2003; 2008; 2010) where the frontal asymmetrical brain activation patterns are linked to the revised reinforcement sensitivity theory of Gray and McNaughton (2000). Here, right frontal brain activity (indicated by lower relative right frontal alpha activity) accounts for conflict, behavioral inhibition and activity of the revised behavioral inhibition system, while left frontal brain activation (indicated by lower relative left frontal alpha activity) stands for active behavior and the activity of the revised behavioral activation system as well as the activation of the revised flight fight freezing system. In order to investigate these three theories, a virtual reality T-maze paradigm was introduced to evoke motivational states in the participants, offering the opportunity to measure frontal brain activation patterns via EEG and behavior simultaneously in the first study. In the second study the virtual reality paradigm was additionally compared to mental imagery and a movie paradigm, two well-known state inducing paradigms in the research field of frontal asymmetry.
In the two studies, there was confirming evidence for the theory of Hewig and colleages (2004; 2005; 2006), showing higher bilateral frontal activation for active behavior and lateralized frontal activation patterns for approach (left frontal brain activation) and avoidance (right frontal brain activation) behavior. Additionally a limitation for the capability model of anterior brain asymmetry proposed by Coan and colleagues (2006), where the frontal asymmetry should be dependent on the relevant traits driving the frontal asymmetry pattern if a relevant situation occurs, could be found. As the very intense virtual reality paradigm did not lead to a difference of frontal brain activation patterns compared to the mental imagery paradigm or the movie paradigm for the traits of the participants, the trait dependency of the frontal asymmetry in a relevant situation might not be given, if the intensity of the situation exceeds a certain level. Nevertheless there was an influence of the traits in the virtual reality T-maze paradigm, because the shown behavior in the maze was trait-dependent.
The implications of the findings are multifarious, leading from possible objective personality testing via diversification of the virtual reality paradigm to even clinical implications for depression treatments based on changes in the lateralized frontal brain activation patterns for changes in the motivational aspects, but also for changes in bilateral frontal brain activation when it comes to the drive and preparedness for action in patients. Finally, with the limitation of the capability model, additional variance in the different findings about frontal asymmetry can be explained by taking the intensity of a state manipulation into account.
Cross-Modal Action Control
(2016)
Nowadays, multitasking is ubiquitously discussed within many different scientific disciplines. The present work addressed multitasking from the perspective of cognitive behavioural sciences by investigating the role of conflict resolution processes that arise during the requirements of multiple-action control. More specifically, the present work focuses on cognitive mechanisms in the case of cross-modal action control, which involves the performance of two actions in different effector systems. One aim was to broaden the scope of action modalities typically considered in the literature by studying oculomotor responses (i.e. saccades) – an action modality that has been largely neglected in previous research – in combination with responses in other effector systems (i.e. manual and vocal responses). A further aim was to specify the mechanisms of crosstalk as an explanatory concept referring to the action content, which is particularly relevant since cross-modal actions usually differ regarding their response characteristics. The present work comprises four studies (each involving two or three experiments).
In Study A, cross-modal response compounds based on a single stimulus were studied with respect to the interplay of the presence of response alternatives and between-response compatibility (i.e. crosstalk potential). In three experiments, this study showed that crosstalk can be dissociated into a component that determines the amount of current conflict (i.e. online crosstalk) and a memory-based component that originates either from residual activation of previous action demands (retrospective crosstalk) or from preparation for future demands (prospective crosstalk).
Study B provided first evidence that oculomotor responses are subject to interference based on both structural and content-based origins. In three experiments, an overlapping tasks paradigm was employed in which the onsets between two stimuli that triggered oculomotor and manual responses were varied. Evidence for both serial and parallel processing of the two tasks was found. The results further indicated that based on the between-task compatibility participants shifted between these processing modes, i.e. to more parallel processing during compatible task demands and to more serial processing during incompatible task demands.
Study C examined processing priorities among effector systems and demonstrated in two experiments that the previously reported prioritisation scheme, in which the oculomotor system is prioritised over the vocal and manual effector system, can be replicated, but is also adjusted in its strength by the presence of response conflict. Specifically, processing priorities were shifted towards the response that already is involved in conflict resolution (in terms of stimulus-response compatibility), suggesting that processing priorities can be flexibly adapted to particular task demands.
Study D addressed response order control in dual tasks, an issue that has been widely neglected in previous research. In a comprehensive study of three experiments including several factors that are known to be relevant for dual-task interference mechanisms, it was shown that the final response order in a given trial is the result of a continuous adjustment process based on the interplay of several top-down factors, such as the anticipation of response characteristics, and bottom-up factors, such as stimulus order and between-task compatibility.
In summary, the present work advances the theoretical understanding of complex action control by providing a cross-modal action perspective, by proposing mechanisms for effector-system prioritisation and response order control, and by proposing a novel taxonomy of crosstalk as an overarching framework for interference mechanisms in multiple-response control.