January 8, 2017 Explain the psychophysiological process and function of the area youwish to explore. Distill and discuss the research that has been carried out onthis element and what implications this has on emotion, cognition andevaluating truthfulness and credibility. Critically analyze and look at futuredevelopments/uses within a sector of your choice. FEDERICA URSO Word Count: 1997 IntroductionAs Electro Dermal Activity (EDA) hasfor long played a crucial part in the OrientingReflex approach to Polygraph testing, the discussion will engage in thefunctional aspects of the Electro Dermal System (EDS) to explore the mind-bodylink shaping modern Psychophysiology, followed by a second section examiningthe far-reaching implications of cognitive processes on emotion and cognition. Theconnections between Psychophysiology and credibility assessment will be drawnin the third section, by embarking into a critical debate over the use of theGuilty Knowledge Test (GKT). Finally, some suggestions for future developmentsof EDA applicability to lies detection will be presented accordingly.
1. EDA: From Physiology to PsychophysiologyAs the EDS consists of eccrine sweat glands, locatedon the skin’s surface and concentrated in the hands’ palms and digits, EDA occurswhen sweat glands fill with sweat, so to provide less resistance for thepassage of current. Hence, either an increase in conductance1or decrease in skin resistance causes a change in EDA, measured as an endosomatic or exosomatic activity.
With endosomaticbeing the activity of the sympathetic nerves measured in terms of uniphasic or biphasic action potential (Edelberg 1968), and exosomatic being the uniphasicskin-conductance responses recorded from the skin’s surface. EDAMEASURESEDA’s recordings may register tonic – i.e. one’s person baseline activity reflecting continued attention- or phasic changes – i.e. theunexpected impact of a discrete stimulus – occurring few seconds after the stimuluspresentation. Both of them represent skin-conductance responses.
However,phasic changes occur also in absence of a stimulus. And these are called spontaneous fluctuations, susceptible toarousal and anxiety. Another measure is the recovery rate (Edelberg 1970), that is the time that it takes forthe Skin Conductance Level (SCL) to go back to its pre-stimulus level. Edelberg,in the same year, argued that emotionality relates to slower recovery rate,whereas attention involves a higher rate. As it will be discussed later, timeplays a key role not only for EDA measurement but also for lie detection. EDA measures are suggestive of how the EDS isregulated both at central and peripheral level. EDS EDS is innervated by the sympathetic branch of theAutonomic Nervous System (ANS) responding to perceived stress or attacks and,thus, affected by the adrenergic effect of acetylcholine neurotransmitter.
However, as the myoepithelial cells on the outer skin’s layer are affected by bothadrenal norepinephrine, the main post-ganglionic neurotransmitter of thesympathetic system, which acts as hormone in the ANS, and epinephrine, dermalactivity is influenced by hormone secretion and provides information on theANS’ sympathetic activity. Additionally, eccrine glands are controlled by highercentres in Central Nervous Systems (CNS): the frontal cortex viahypothalamic-limbic (Luria and Homskaya, 1970) and basal ganglia corticalcontrol systems (see tab.1).Tab.1 Emotion Brain: interaction between cortical and subcorticalstructures. Amygdala & Hippocampus Cingulate Gyrus Insula VTA and PFC Basal Ganglia Stress Responses Key Functions Hippocampus Medial to the temporal lobe.
Responsible for the consolidation of the working memory into long-term memory. Amygdala Located on the lower part of the Hippocampus. – React with “aggression” when stimulated; – linked to fear and sexual responses. Located above the Corpus Collosum.
-Focusing on emotionally significant events; -Associating sensory inputs to specific memories. Part of the cerebrum placed behind the Temporal lobe. The anterior portion is part of the Limbic System. – Associated to disgust and empathy; – Providing the emotional setting for sensory information; – Interpreting and mapping emotional body states; – Possible links to self-awareness and deity. Ventral Tegmental Area Part of the Basal Ganglia which consists of dopamine pathways. It plays a major “pleasure” role in the brain and it is associated with: gabling, recreational drugs and reward. Prefrontal Cortex – Responsible for future planning and decision making; – Also has links to pleasure and addiction.
Basal Ganglia Covering each side of the Limbic system and in close contact with the surrounding cerebral cortex. – Focussed attention; – Linked to repetitive behaviour and reward experiences. (See VTA). . Thalamus Located lower into the mesencephalon and Medial to the Basal Ganglia. Receiving input from visual, auditory and somatosensory systems.
Hypothalamus Placed lower to the Thalamus. -Controlling the body’s homeostatic function: thirst, sex, temperature and hunger; -Linking CNS and endocrine system. Through the Hypohalamus, the Sympathetic branch of ANS regulates 2 major stress responses: Hypothalamic_Pittuitary Adranal system (HPA) and the Sympathetic-Adrenal-Medulla System (SAM). HPA: Chronic stress response via the secretion of Chorticotropine releasing factor acting on the pituitary gland so to release Adenochoricotropine hormone causing the adrenal cortex to release cortisol among other corticosteroids to: -Increase production of glucose; -Increase blood pressure; -Weaken immune system; -Raise attentiveness and memory. SAM: acute stress response acting through noradrenaline neurotransmitters to: -Increase heart rate; -Increase palmar sweat; -Pupil Dilatation; -Decrease Digestion. Boucsein (1992) proposed that the CNS controls the EDAboth ipsilaterally – throughhypothalamus, anterior thalamus and cingulate gyrus, linked to emotion – and contralaterally– through the lateral frontal cortex, (i.
e. premotor cortex and parts of basal ganglia)linked to orienting cognition and locomotion. Specifically, the CNS of the EDS can be divided inthree systems: the locomotor system,to facilitate the fiction against the ground, the orienting-activating system, involving the lateral cortex, reticularformation and limbic structures in the eliciting of the orienting-arousalresponse, and the thermoregulatorysystem, associated with the anterior hypothalamus.
The psychologicalcontrol over the peripheral system and outcomes finds evidences in the study ofRaine, Reynolds and Sheard (1991), who via fMRI found a strong correlationbetween the amplitude of EDA and some areas in the frontal cortex.Structural and functional findings in the field of EDAare clear-cut evidences of the evolution of psychophysiology.PSYCHOPHYSIOLOGYIn psychophysiology, the major challenge is “to understand how brain modulatemind-body link, in the sense of peripheral changes in the autonomic orendocrine systems not only analysed in terms of psychological processes butalso in terms of brain control of the peripheral outflow”(Stern 1964).In 1972, drawing from an evolutionary model ofindividual’s adaptation to threat, Edelberg argued that skin may be regarded asthe “first psychological defence”.
Increased sweating in the palms of the handsor soles of the feet would provide an individual fleeing from an attack with strongerhold and coordination, thus throwing the basis of modern psychophysiology.As opposed to physiological psychology, concerningwith the manipulation of physiological states and measurement of the effects onbehaviour, psychophysiology points at the mind-body interface, providing anapproach to assess and interpret how behavioural, cognitive, emotional andsocial events are represented in psycophysiological processes including health (Hugdahl1995)According to the traditional focus of psychophysiologyon arousal and emotion, having its origin in the ANS controlling involuntary musclesand glands, emotional responses are seen as a series of physiological systemsfunctioning in parallel as the consequence of the experiencing of an emotion. Withreference to the EDS, the latter approach also known as Parallelist approach (Colesand Gale, 1978) finds its raison d’êtrein the common referral to EDA as a galvanic skin reflex (GSR). The majorimplication is that the skin is considered as a galvanic element, whose physiologicalchanges are regarded as a reflex, hence elicited automatically. According to a Jamesion approach, physiologicalsystems interact with each other so to cause the eliciting of an emotion, driftingthe focus from the correlates ofbehaviour to the causal links. Edelberg (1972) showed how sweat-gland activity inpsychological relevant contexts, (e.g.
changes in cognitive and emotionalefficiency) may have somatic effects. Later in 1994, Ekman and Davidson showedthat not all emotions have an increase in general arousal psychologicallyinterpreted. Following these studies, psychophysiology extended its traditionalfield of emotions to the cognitive process involved in associative learning,establishing the two-way relationship between brain and body, psychology andphysiology.
“Psychophysiologyenriches cognitive theory providing a bridge between reaction time and responseaccuracy (cognitive measures) and precise timing of brain events to thepresentation of the stimuli”, argued Jennings and Coles (1991).Psychophysiology has enabled to investigate individuals’temporary as well as physiological adaptations to changing environments troughOrienting and Conditioning.2. Orientingand Conditioning: EDA ImplicationsAs Psychophysiology started focussing on theinteraction between cognitive and emotional processes, Stormark et al. (1995) claimedthat people tend to shift their focus of attention towards emotional relevantstimuli. The underlying idea was that the time following a cue with emotionalmeaning was higher than that following one with no emotional attachment.
The attention shift from an emotional significant cue to target triggers an Orienting Response (OR) – a generalisedresponse to an unexpected stimuli. According to recent OR theories, called information-processing theories, the mechanismresponsible for the elicitation of the OR is a limited resource-centralprocessing mechanism (Ohman 1973) based on the so-called “matching principle”. Theunderlying hypothesis is that the response time following a cue with emotional relevanceis higher than a meaningless one. Indeed, an incoming stimulus is “matched”against a memory template, so that at every presentation of the signal thetemplate is updated. An OR is elicited in case a mismatch between the input andthe template occurs.
After repeated presentations, the OR amplitude slowly decreasesuntil it fades and habituation takesplace.This process is an example of behavioural plasticityin so far the stimulus association allows for the build-up of memory, shapingthe information processing mechanism.Thereby, OR is a many-sided response involving somatic,sensory, autonomic and EEG changes (Graham 1973), boosting sensorial perception,by bringing attention to a new stimuli.
Indeed, EDA is seen as suggestive ofOR. How is explained via three models (see tab.2)Tab.2 Ohman’s model Cognitive-neuroscience approach Classical conditioning The major assumption is that OR is elicited when pre-attentive processing identifying the stimulus fails to match it in the short-term memory, thus causing a shift from automatic to controlled processing. Then the limited-central channel is the one appointed to search for a match in the long-term memory. If the matching occurs, EDA takes place as a consequence of the activation of the retrieved memory in the short-term template.
A stimulus is matched against the template in associative memory. If the stimulus has some emotional valence (i.e. surprise – related to an environment change – or arousal – an emotional-attached information) the amplification system, consisting of limbic structures, boosts the signal and sends it to two cortical control systems involved in attention gating: the interruption system, inhibiting one’s action to allow the new plan to be executed and a run subsystem. The latter kicks-in during habituation, when OR amplitude decreases until the signal is too weak to interrupt the ongoing activity in the control system, which continues functioning in the run mode. Also, arousal amplification is associated with the so-called Defense Respone (DR), a planned action interruption due arousal in the limbic structures and reticular formation.
In this framework, the matching process signals qualities, which turn a weak input in a Conditioned Stimulus (CS). This elicits a response similar to that of a stronger stimulus (Unconditioned Stimulus, UCS) and triggers a change in behaviour called Unconditioned Response (UR) and a temporary response tied-up with the pairing of CS and UCS, called Conditionend Response (CR). These studies revealed that conditioning is not mere habit learning, it involves complex interactions between cognitive processes and both acquisition and elicitation of conditioned responses can manifest themselves unconsciously (Ohman, 1992). Pavlov (1927) argued that classical conditioningprovides the theoretical turf for explaining cortical hemispheres’ functioning.Indeed, he considered the CR as a stimulus-stimulusassociation instead as a stimulus-responseand he called this phenomenon “association of associations”. The so-called”second signal system” is a version of it, according to which a CR is notconditioned to the stimulus but to its meaning. Following this rational,classical conditioning explains brain’s associations through CS-UCS mediation.In so doing, it also provides the basis for the use of the Orienting Reflex inpolygraph tests.
3. EDAand Lie Detection”Arousal-basedprotocols centre around two broad areas: physiological and behavioural cues.Central to these protocols is the assumption that when people engage indeception, there is a fear or concern that they will be discovered. Thisconcern raises arousal levels leading to a physiological or behaviouralresponse ….”(Patterson2009)It is commonly believed that arousal-based approaches lackof precision and effectiveness in assessing credibility because of their poorcapacity to distinguish anxiety symptoms from deception cues (Ekman et al.
, 1976;Vrij, 2000). A widely used example of arousal-based test is the OR-based GKT (Likken1959).Through the use of Polygraph technology – conceived tomeasure stress response – in terms of EDA (Skin Conductance Resistance, SCR, andSCL), respiration and blood pressure – the GKT is designed so to induce an OR whenthe examinee is confronted with a personally significant information, mainlymeasured in terms of reaction time compared with neutral controlimages/statements – i.e.
foils. Therefore, GKT is set to measure the differencein terms of psychophysiological response between control images and relevantones. In a typical GKT, the interviewee attached at the polygraph is shown arange of objects from the crime scene and is asked for each of them whether herecognises them. The liar will show an OR when the object recalls him ofsomething present in the crime scene or the murder weapon. Besides increasedEDA, the Polygraph, with the support of the GKT, is able to detect phasic heartrate deceleration and breathe suppression in liars. However, this method hasbeen subject to several criticisms (Vrij 2008) (see tab.
3). Tab.3 Lack of applicability Theoretical concerns Difficulty in formulating proper questions Countermeasures Leakage of Items Reaction Time GKT test can be applied only to specific events cases. Honts (2004) argues that for an OR to occur, it is fundamental that the culprit recognises all critical details when undergoing the test. -The culprit’s memory may be affected by the time separating the crime from the test, making it more likely to forget the detail of the crime scene; -Different alternatives may elicit different responses –i.e. interpersonal differences or that some evoke stronger responses because reckoned more plausible; – OR may become stronger with personally significant information and in higher-stakes situations; -A change in the interviewers’ behaviours may influence culprit’s responses. -Physical countermeasure: Tongue bite, pressing toes or any attempt to influence the polygraph outcome might falsify the verdict of the test; -Psychological countermeasures like mediation, rehearsal, conditioning; -Pharmaceutical countermeasures such as sedatives or recreational drugs.
In interviewees receive information about the items prior to testing, they too can elicit an OR. -Reaction time may trigger a false accusation when an innocent suspect show a response to critical items or a guilty one shows an OR for filler objects; -Relying on one only measure is like relying on Pinocchio’s growing nose, reaction time cannot be used with illiterate, dyslexic or blind people. From a psychophysiological perspective, however, theconcern is not about OR measurement but that it might not happen at all. Regarding deception, experts have long argued that layinginvolves an increase in cognitive load (e.g. decrease of body movements,decreased eye blinking speech hesitations, changes in voice volume, decrease inemblems when constructing a lie) (Ekman and Friesen, 1971; Vrj, 2000).
This,however, provides another source of criticism. Edelberg’s studies voice concernabout the EDA ipsilateral and contralateral attributes, to the extent that theymay produce misleading outcomes when cognitive and emotional tasks are notseparated from sensory motor ones. In light of this issue, Patterson (2009), drawing fromcognitive theory belief that additional tasks would employ and, hence, erodefurther cognitive resources, proposed to introduce a secondary task with nodeception detection purposes, during the Polygraph test, so to magnify thedifference between lie and truth tellers. As it follows, liars will struggle toanswer correctly to the questions and show behavioural disturbances due toincreased cognitive load. Outcomes are assessed using two criteria, accuracyrate and reaction time. In addition, introducing the secondary task as acognitive test will diminish the chance of using countermeasures, which willeventually amplify cognitive efforts and in so doing secondary taskeffectiveness. Although Patterson study was addressed to pre-employmentscreening, it would be interesting to extend it to policy interrogations.ConclusionsExploring the EDS from a functional and structuralperspective, has allowed to draw the filrouge linking psychophysiological responses to the assessment of credibility,by examining the cognitive implication of EDA through Orienting andConditioning.
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