Oswald Huber

The Anterior Frontomedian Cortex and Evaluative Judgment: An fMRI Study

This study investigated the neuronal basis of evaluative judgment. Judgments can be defined as the assessment of an external or internal stimulus on an internal scale and they are fundamental for decision-making and other cognitive processes. Evaluative judgments (I like George W. Bush: yes/no) are a special type of judgment, in which the internal scale is related to the persons value system (preferences, norms, aesthetic values, etc.). We used functional magnetic resonance imaging to examine brain activation during the performance of evaluative judgments as opposed to episodic and semantic memory retrieval. Evaluative judgment produced significant activation in the anterior frontomedian cortex (BA 10/9), the inferior precuneus (BA 23/31), and the left inferior prefrontal cortex (BA 45/47). The results show a functional dissociation between the activations in the anterior frontomedian cortex and in the inferior precuneus. The latter was mainly activated by episodic retrieval processes, supporting its function as a multimodal association area that integrates the different aspects of retrieved and newly presented information. In contrast, the anterior frontomedian cortex was mainly involved in evaluative judgments, supporting its role in self-referential processes and in the self-initiation of cognitive processes.

Active information search and complete information presentation in naturalistic risky decision tasks

Most experimental results in research on risky decisions have been obtained with lotteries. Choices between lotteries differ in many respects from natural risky decision tasks. Furthermore, the mode of information presentation in gambling experiments is very different from natural situations. In our experiment, 32 non-students made choices in two naturalistic risky decision tasks. The mode of information presentation was varied: Complete information presentation (as common in gambling experiments) vs. Method of Active Information Search (the subject gets a basic description of the task, and has to ask questions to receive additional information). In naturalistic tasks, probability was used less often than expected from classical decision theory, whereas the search for new alternatives, worst-case plans and control considerations were more relevant. The type of information presentation had a distinct effect. With Active Information Search, only a minority of subjects was interested in probabilities. Precise probabilities were used solely in the condition with Complete information presentation.

Functional specialization within the anterior medial prefrontal cortex: a functional magnetic resonance imaging study with human subjects

This study investigated the functional neuroanatomy of the anterior medial prefrontal cortex (aMPFC). Previous studies have shown that the aMPFC is involved in evaluative judgment and self-referential processes. Specifically, different sections of the aMPFC are differentially influenced by attention demanding processes. Whereas the dorsal section is supposed to be involved in self-referential processes, the ventral section is assumed to be attenuated during attention demanding processes. The present study investigates the involvement of the dorsal and ventral aMPFC in evaluative judgment by using functional magnetic resonance imaging with spin-echo echo-planar-imaging. Processes involved in evaluative judgment are attention-demanding, self-referential and activate regions in the dorsal and ventral section of the aMPFC. Attention demanding tasks do not necessarily lead to an attenuation of the ventral section of the aMPFC, a region mainly involved in emotional and affective processing.

Neural substrates of incongruity-resolution and nonsense humor.

By means of functional magnetic resonance imaging the present paper analyzes the neural correlates of processing and appreciating incongruity-resolution and nonsense cartoons. Furthermore, the relation between experience seeking and these neural substrates was investigated as this personality characteristic is known to influence humor appreciation. In the processing of incongruity-resolution stimuli the incongruity of the joke is largely resolvable, whereas in nonsense stimuli it is only partially resolvable and more incongruity remains. The anterior medial prefrontal cortex, bilateral superior frontal gyri and temporo-parietal junctions (TPJ) show more activation during processing of incongruity-resolution than of nonsense cartoons. These differences indicate that processing of incongruity-resolution cartoons requires more integration of multi-sensory information and coherence building, as well as more mental manipulation and organization of information. In addition, less self-reference might be established in nonsense cartoons as it is more absurd and more often deals with impossible situations. Higher experience-seeking scores correlate with increased activation in prefrontal, posterior temporal regions and the hippocampus. This might be due to a more intense exploration of the humorous stimuli as experience seekers tend to search novel mental stimulation. Furthermore, experience seeking was positively associated with brain reactivity towards processing nonsense in contrast to incongruity-resolution stimuli, which is in line with behavioral studies that showed a preference for nonsense humor by experience seekers.

The neural implementation of multi-attribute decision making: a parametric fMRI study with human subjects.

Decision making is not a unitary entity but involves rather a series of interdependent processes. Decisions entail a choice between two or more alternatives. Within the complex series of decisional processes, at least two levels can be differentiated: a first level of information integration (process level) and a second level of information interpretation (control level), leading to a subsequent motor response or cognitive process. The aim of this study was to investigate the neural network of these decisional processes. In a single trial fMRI study, we implemented a simple decision-making task, where subjects had to decide between two alternatives represented on five attributes. The similarity between the two alternatives was varied systematically in order to achieve a parametric variation of decisional effort. For easy trials, the two alternatives differed significantly in several attributes, whereas for difficult trials, the two alternatives differed only in small details. The results show a distributed neural network related to decisional effort. By means of time course analysis different subprocesses within this network could be differentiated: regions subserving the integration of the presented information (premotor areas and superior parietal lobe) and regions subserving the interpretation of this information (frontolateral and frontomedial cortex, anterior insula, and caudate) as well as a region in the inferior frontal junction updating task rules.

Accounting and convincing: the effect of two types of justification on the decision process

The effect of two types of justification pressure on the decision process was investigated. Three groups of 15 subjects each had to choose the head of a corrective home for criminal adolescents out of six candidates, who were described on 16 attributes. Two groups worked under justification pressure: subjects in the Accounting group were informed that they had to explain their decision afterwards, subjects in the Convincing group that they had to convince the other members of the executive board to vote for their selected candidate. From the third group, no justification was requested. It was found that justification pressure leads to a distinct increase in the amount of utilized information and to a more elaborate choice process, while the global decision heuristics do not seem to change. The two justification groups did not differ in the amount of information utilized, but the Convincing group employed a more elaborate process. This result shows that justification pressure is one of the task characteristics affecting the decision process, and proves that a latent justification pressure as assumed in some decision theories does not have the same effect as an explicit one. Copyright

Dissociation between overt and unconscious face processing in fusiform face area

The precise role of the fusiform face area (FFA) in face processing remains controversial. In this study, we investigated to what degree FFA activation reflects additional functions beyond face perception. Seven volunteers underwent rapid event-related functional magnetic resonance imaging while they performed a face-encoding and a face-recognition task. During face encoding, activity in the FFA for individual faces predicted whether the individual face was subsequently remembered or forgotten. However, during face recognition, no difference in FFA activity between consciously remembered and forgotten faces was observed, but the activity of FFA differentiated if a face had been seen previously or not. This demonstrated a dissociation between overt recognition and unconscious discrimination of stimuli, suggesting that physiological processes of face recognition can take place, even if not all of its operations are made available to consciousness.

Probabilistic set-up and the search for probability information in quasi- naturalistic decision tasks

The influence of the probabilistic set-up (i.e., formal aspects of the presented probability information) and of the task domain on the active search for probability information in quasi-natural risky decision tasks was investigated. In each of four tasks (domains: business, medicine, social, epidemic control) 72 subjects chose between a risky alternative and one without risk. There were three conditions in relation to the probabilistic set-up: (a) In the single condition the decision concerned a single case (e.g., one person). In the two multiple conditions (b and c) the decision was for many cases (e.g., 100 persons). In (b) the decision maker had to make an either-or decision (same alternative for all cases). In (c) the subject could assign a proportion of cases to one alternative and the rest to the other one. While the probabilistic set-up had no effect on the search for probabilistic information, the task domain had a strong impact. Risky decision making has been one of the central themes of decision research for decades. Most of the relevant experiments have used and are still using simple lotteries (gambles or bets). In these experiments, the utilities of the consequences and the probabilities of obtaining the consequences are found to be the central

Behavior in Risky Decisions: Focus on Risk Defusing

In experiments on risky decisions with gambles as alternatives the central factors determining decision behaviour are: The subjective values of the outcomes, and their subjective probability. The present paper first reports results of a number of experiments indicating that this central result cannot be generalized. In quasi-realistic risky scenarios, many decision makers are not interested in probability information and many search actively for risk-defusing operators (RDOs). An RDO is an action intended by the decision maker to be performed additionally to a specific alternative in order to decrease the risk. The paper also gives an overview about experimental research with RDOs. Topics include the factors that determine the search for RDOs and the factors affecting the acceptance of an RDO. Finding an acceptable RDO has a distinct effect on choice: If for a specific risky alternative an RDO is available, this alternative is chosen most often. The consequences of the concept of RDOs on theories about decision behaviour and on aiding decision making are discussed. Expectations to find usable probability information and to find information about the existence of an RDO are also discussed as factors explaining differences between different types of decision situations and gambles.

Information search in the laboratory and on the Web: With or without an experimenter

The focus of this study is the effect of the location (laboratory vs. Web) of experiments on active information searchin decision-making tasks. In two experiments, participants were confronted with two different search method versions (list vs. keyword) for acquiring information about a task from a database. The amount and type of information gathered and the time required for task completion were measured. In Experiment 1, significantly more information was searched for in the laboratory than on the Web when the list version was employed, whereas there was no difference between locations in the keyword version. In Experiment 2, the participants were assigned randomly to the Web or the laboratory condition. The results of Experiment 1 were replicated. Whereas location (and the presence or absence of an experimenter) had an effect on the absolute amount of information gathered in both experiments, the relative distribution and type of information items did not differ.