The somatic hypothetical marker , formulated by Antonio Damasio, proposes that behavioral processes emotional (or biased) behavior, especially decision-making.
"Somatic marker" is a feeling in the body that deals with emotions, such as a rapid heartbeat relationship with anxiety or nausea with disgust. According to the hypothesis, somatic markers greatly influence subsequent decision making. In the brain, somatic markers are considered to be processed in the ventromedial prefrontal cortex (VMPFC) and the amygdala. The hypothesis has been tested in experiments using Iowa gambling tasks.
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In economic theory, human decision making is often modeled as having no emotion, involving only logical reasoning based on cost-benefit calculations. In contrast, the somatic hypothesis proposes that emotions play an important role in the ability to make quick rational decisions in complex and uncertain situations.
Patients with frontal lobe damage, such as Phineas Gage, provide the first evidence that the frontal lobe is associated with decision making. Frontal lobe damage, especially in the ventromedial prefrontal cortex (vmPFC), results in impaired ability to organize and plan behavior and learn from previous mistakes, without affecting the intellect in terms of working memory, attention, and understanding of language and expression.
VmPFC patients also have difficulty expressing and experiencing appropriate emotions. This led Antonio Damasio to hypothesize that the decision-making deficit follows the result of vmPFC's damage from the inability to use emotions to help guide future behavior based on past experiences. Consequently, vmPFC damage forces those who suffer to rely on a slow and exhausting cost-benefit analysis for each given option situation.
Maps Somatic marker hypothesis
Hypothesis
When individuals make decisions, they must assess the incentive value of the choices available to them, using cognitive and emotional processes. When individuals face complex and contradictory choices, they may not be able to decide just using cognitive processes, which may become overloaded. Emotions, consequently, are hypothesized to guide decision-making.
Emotions, as defined by Damasio, are changes in both body and brain state in response to stimuli. Physiological changes (such as muscle tone, heart rate, endocrine activity, posture, facial expression, etc.) occur in the body and are transmitted to the brain where they are transformed into emotions that inform individuals about the stimuli they have encountered. Over time, appropriate emotions and body changes, called "somatic markers," become related to a particular situation and the outcome of the past.
When making the next decision, these somatic and emotionally generated markers are consciously or unconsciously related to their past results, and influence decision-making that supports some behaviors rather than others. For example, when a somatic marker associated with a positive outcome is felt, the person may feel happy and motivated to pursue the behavior. When somatic markers associated with negative outcomes are felt, people may feel sad, which acts as an internal alarm to warn individuals to avoid that action. The specific somatic situation of the situation is based, and reinforced by, past experiences that help guide behavior that supports a more favorable choice, and is therefore adaptive.
According to the hypothesis, two distinct pathways reactivate the somatic marker response. In the first path, emotions can be generated by changes in the body that are projected onto the brain - the so-called "body loops". For example, confronting a dreaded object like a snake can trigger a fight-or-flight response and cause fear. In the second line, the cognitive representation of emotion (imagining an unpleasant situation "as if" you are in a certain situation) can be activated in the brain without being directly generated by sensory stimuli - the so-called "as-if body loop". Thus, the brain can anticipate the expected body changes, allowing individuals to respond more quickly to external stimuli without waiting for events to actually occur. The amygdala and VMPFC (subsections of the orbitomedial prefrontal cortex or OMPFC) are important components of this hypothesized mechanism, and therefore damage to both structures will interfere with decision making.
Experimental evidence
In an effort to produce a simple neuropsychological tool that will assess deficits in emotional processing, decision-making, and social skills of OMPFC-lesion individuals, Bechara and collaborators create Iowa gambling duties. The task of measuring the form of emotion-based learning. Studies using gambling tasks have found deficits in various neurologists (such as amygdala lesions and OMPFC) and psychiatric populations (such as schizophrenia, mania, and drug abusers).
The Iowa gambling task is a computerized test in which participants are presented with four deck cards from which they repeatedly vote. Each deck contains various prize amounts of between $ 50 or $ 100, and sometimes greater losses on the deck with higher rewards. The participants did not know where the punishment cards were, and were told to choose a card that would maximize their winnings. The most lucrative strategy turns out to be choosing a card only from a small reward/small penalty deck, because although the rewards are smaller, the penalty is proportionately smaller than in high reward/high deck penalties. During the session, most healthy participants came to adopt a favorable low-deck penalty strategy. Participants with brain damage, however, can not determine which deck is better to choose from, and continue to choose from high reward/high penalty decks.
Because Iowa gambling tasks measure participants' speed in "developing anticipatory emotional responses to guide favorable choices", it is helpful in testing somatic marker hypotheses. According to the hypothesis, the somatic marker raises the anticipation of the emotional consequences of the decisions made. As a result, the people who do the job well are considered aware of the penalty cards and the negative emotions associated with the withdrawal of such cards, and to realize which deck is less likely to result in a penalty.
This experiment has been used to analyze disorders suffered by people with damage to the ventromedial prefrontal cortex, which has been known to affect neural signaling from prospective rewards or punishments. Such people do not do a good job. Functional magnetic resonance imaging (fMRI) has been used to analyze the brain during gambling tasks in Iowa. Parts of the brain activated during the Iowa gambling task are also hypothesized to be triggered by somatic markers during decision making.
Evolutionary meaning
Damasio has argued that the human ability to do abstract thinking quickly and efficiently coincides with the development of the ventromedial cortex (VM) and with the use of somatic markers to guide human behavior during evolution. Patients with damage to the VM cortex are more likely to engage in behaviors that adversely affect personal relationships in the distant future, but they never engage in actions that would cause immediate damage to themselves or others. The evolution of the prefrontal cortex is associated with the ability to represent events that may occur in the future.
Apps to risky behavior
The somatic hypothesis hypothesis has been applied to try to understand risky behavior, such as risky sexual behavior and drug addiction.
According to the hypothesis, risky sexual behavior is more exciting and enjoyable, and therefore they are more likely to stimulate recurrent involvement in such behavior. When this idea was tested on HIV-infected individuals and dependent on substances, differences were found between people who scored well on Iowa gambling tests, and those who scored poorly. High value printers show a correlation between the amount of suffering they report on their HIV status, and their acceptance of risk during sexual behavior - the greater the pressure, the greater the risk these people will be. The low score, on the other hand, does not show such correlation. This result is interpreted as demonstrating that people with intact decision-making ability are more able to rely on past emotional experiences when weighing risks, than those who are deficient in that ability, and that acceptance of risk serves to improve emotional distress.
Drug users are considered to neglect the negative consequences of addiction when looking for drugs. According to the somatic hypothesis, the offender suffers disruption in his ability to remember and consider the unpleasant past experience when weigh whether to consider drug seeking behavior. Researchers analyzed the neuroendocrine response of individuals who were dependent on healthy substances and individuals after being shown a pleasant or unpleasant picture. In response to an unpleasant image, drug users show a decrease in the level of some neuroendocrine markers, including norepinephrine, cortisol, and adrenocorticotropic hormone. Addicts show a lower response to pleasant and unpleasant images, suggesting that they may have less emotional responses. Neuroimaging studies using fMRI show that drug-related stimuli have the ability to activate areas of the brain involved in emotional evaluation and prize processing. When shown a film about people smoking cocaine, cocaine users showed greater activation of the anterior cingulate cortex, the right inferior parietal lobe, and the caudateus nucleus than non-users. In contrast, cocaine users showed lower activation while watching a sex movie than non-users.
Criticism
Some researchers believe that the use of somatic markers (ie, afferent feedback) would be a very inefficient method for influencing behavior. Damasio's notion of as-if has a dependent feedback route, in which the body's response is represented by using somatosensory cortex (gyrus postcentral), also proposes inefficient methods to influence explicit behavior. Rolls (1999) states that; "It would be very inefficient and noisy to be placed on the route of execution, peripheral responses, and transducers to try to measure the peripheral response, itself is a very difficult procedure" (p.77). The strengthening of associations located in the orbitofrontal cortex and the amygdala, where incentive value of stimulation is translated, is sufficient to induce emotionally based learning and to influence behavior through, for example, orbitofrontal-striatal pathways. This process can occur through an implicit or explicit process.
The somatic hypothesis is a model of how feedback from the body can contribute to favorable and unfavorable decision making in situations of complexity and uncertainty. Most of the supporting data comes from data taken from Iowa gambling assignments. While Iowa gambling has proven to be an ecologically valid measure of decision-making, there are three assumptions that need to be held firmly.
First, claims that assess implicit learning as a reward/punishment design are inconsistent with data showing accurate knowledge of possible tasks and mechanisms such as work-memory seem to have a strong effect. Second, the claim that this knowledge occurs through a preventive marker signal is not supported by competing explanations of the profile generated by psychophysiology. Finally, the claim that this disorder is caused by 'myopia for the future' is undermined by a more plausible psychological mechanism that explains deficits in tasks such as reversal learning, risk taking, and work-memory deficits. There may also be more variability in control performance than previously thought, making it difficult to interpret the findings.
Furthermore, although the somatic hypothesis has accurately identified many areas of the brain involved in decision-making, emotion, and body-state representation, it fails to show clearly how this process interacts at the psychological and evolutionary levels. There are many experiments that can be applied to further test the hypothesis of somatic markers. One way is to develop a variant of the Iowa gambling task that controls some of the methodological problems and ambiguity of the resulting interpretation. It might be a good idea to include the elimination of learning bending, which will make the task more difficult to understand consciously. In addition, a causal test of the somatic marker hypothesis can be practiced more urgently in a larger population range with peripheral feedback being altered, as in patients with facial paralysis.
In conclusion, the somatic marker hypothesis needs to be tested in more experiments. Until a wider empirical approach is used to test somatic-marking hypotheses, it appears that the framework is merely an interesting idea that requires some better supporting evidence. Despite these problems, the somatic hypothesis of sam- ples and Iowa gambling tasks rebuild the idea that emotions have the potential to be beneficial as well as problems during the human decision-making process.
References
External links
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Bechara, A.; Damasio, H.; Damasio, A. R. (March 2000). "Emotions, decision-making and orbitofrontal cortex". Cereb. Cortex . 10 (3): 295-307. doi: 10.1093/cercor/10.3.295. PMID 10731224.
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