Biological Approach (Canli et al.)

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HUMANITIES & SOCIAL SCIENCES

Psychology 9990

Notes

Biological Approach (Canli et al.)

Biological Approach (Canli et al.)

Biological Approach 


Introduction To The Biological Approach: 

All that is psychological is first physiological – that is because the mind appears to reside in the brain, all feelings, thoughts, and behaviours ultimately have a biological/physical causation. All things ultimately are controlled by our biological aspects. Such as running, laughing, crying and pretty much everything else. That is because even if we were physically doing nothing, our brain was active, and the biological process of chemical and electric signalling was active between the nerve cells.

Various parts of our brain are designated to perform different functions and actions. Physical movement, memory, hormonal responses and emotions are controlled by assigned parts of our brain. For instance, a hormone called ‘adrenalin’ would be released during the excitement of a race and would help you to run faster.

Brain Scanning Used For Psychological Research: 

Psychological research now employs brain study and research of living people though brain scans and thus they can now draw objective conclusions about the relationship between behaviour and brain structure/activity. 

The two types of medical scans are: 

•   Structural Scans: These take detailed pictures of the brain, the nervous system and helps in diagnosing physical injuries such as concussions and large-scale intracranial disease such as tumours. 

•   Functional Scans: These are able to show different activity levels in different parts of the brain. Functional Magnetic resonance imagining (fMRI) is a neuroimaging procedure using MRI technology that measures brain activity and blood flow by detecting changes that are associated with it. 

In the simplest fMRI study a participant would alternate between periods of completing a specific task and a control or test state to measure baseline activity. The fMRI data is then analysed to identify brain areas in which the signal changed between the activity and the rest state and it is inferred that these areas were activated by the task. 

The data from an fMRI scan be used to generate images illustrating how the brain is working during different tasks. Such a scan allows for a living brain to be portrayed and seen without primarily resorting to surgical procedures. 

The standard procedure goes with the patients placed in a scanner which sends strong magnetic fields through their head. The magnetic field provides a clause for the nuclei in the hydrogen molecules to spin in a certain way, which the scanner picks up. Because hydrogen concentrations vary in different parts of the brain the scanner is able to construct a detailed picture of the brain. 

Areas that have been shown to have significant association with emotion and memory are the sub cortical areas of the brain, including the amygdala

Canli Et Al. (2000)

This study deals with event-related activation in the brain’s area known as amygdala with later memory for individual emotional experience. The functions of the amygdala are explored in this study quite a lot. 

Amygdala is essentially an almond shaped set of neurons, which plays a key role in the processing of emotions such as pleasure, anger and fear. It is also responsible for determining where memories are stored in the brain and which ones are kept. 

In 1998, LaBar and Phelps suggested that emotional experiences are often better recalled than non-emotional ones and emotional arousal appears to increase the likelihood of memory consolidation during the storage stage of memory. Brain imaging studies have shown that amygdala activation correlates with emotional memory in the brain. 

Some correlations were hypothesized, these were:

-   During scanning, some people are probably in a more emotionally enhanced state. 

-   The amygdala responds in a dynamic way to moment to moment subjective emotional experiences. 

-   Some participants might simply just be more responsive to emotional experiences. 

Aim: 

He wanted to show that emotive images will be remembered better than those that have little emotional valence for an individual. 

The two main aims were:

•   Testing if the amygdala is sensitive to varying degrees of emotional intensity

•   If the varying degrees of emotional intensity affects the role in memory enhancement, if an emotional stimuli is involved. 

Method:


-   Experimental Design: Repeated Measures Design (Participants contributed to each condition) 

-   Setting: Laboratory Experiment

-   Independent Variable: Intensity of emotional arousal to each of the 96 scenes.

-   Dependant Variable:

  •    Level of activation of the amygdala measured by the fMRI, during the first stages of the experiment when the participants were exposed to 96 scenes.

  • The measure of memory of the scenes, 3 weeks later during the recognition of the images. 
-   Measurement of Data: It was via a 4-point Likert scale that ranged from 0-3 with 0 (not emotionally intense at all) and 3 (extremely emotionally intense). 

Sample: 


-   10, right-handed (specific), healthy female (gynocentric) volunteers. 

-   They were chosen primarily due to the assumption that females are more likely to report intense, detailed emotional experiences and more reactivity. (Generalized assumption). 

-   All participants had given informed consent, aware of the nature of the experiment. (Ethical consideration)

Procedure: 


-   During the scanning, participants viewed 96 scenes that were presented by an overhead projector and mirror that allowed them to see what was going on in the fMRI scanner. 

-   These 96 scenes were chosen from the International Affective Picture System Stimuli set. 

-   These had a normative valence of ‘Emotional Value’ ranging from 1.17 (highly negative to 5.44 (neutral). 

-   The normative ‘Arousal Rating’ was between 1.97 (tranquil) to 7.63 (highly arousing). 

-   The order of these 96 scenes was randomised across all participants (so as to limit exposure to demand characteristics). 

-   For a time period of: 2-3 seconds, precisely 2.88 seconds. 

-   For a time interval of: 12-13 seconds on a fixation cross. (This may have cause fatigue effects.)

-   They were asked to rate their reaction on the 4-point Likert scale. 

-   The individuals operating the scanner were fully trained and competent staff, following safety protocol as should be in a medical scan. 

-   Participants were asked to view each picture for the entirety of the time that it was displayed. 

-   The participants lied in a 1.5 tesla fMRI scanner, which was used to measure the blood-oxygen level dependant contrast present. 

-   Contrast imaging is used to observe the different, varying functionalities and results from the active parts. 

-   For the Functional Image, 11 frames were captured per trial, per participant. Each frame was assigned either as an activation image or baseline image. 

-   After 3 weeks (which was the testing period) after the first stage, participants were tested in an ‘unexpected recognition’ test. 

-   This test now included 48 new foil scenes to the previous 96 scenes. These foils were selected to match the previously presented scenes in their valence and arousal characteristics. 

-   During the recognition test, participants were asked if they had/had not seen the slide before (of previously seen images). If the answer was “yes”, they were asked whether they remember the scene with certainty (remember), or were certain but less familiar (familiar). If the answer was no it was deemed (forgotten.)

Results:


-   Participants’ ratings of emotional intensity reflected the valence and arousal ratings of the scenes. 

-   There was found to be an appropriate and significant correlation with higher ratings of ‘experienced’ emotional intensity. This provides evidence that amygdala activation is related to the subjective sense of emotional intensity and the participants’ perceived arousal is associated with the activation of the brain’s amygdala. 

-   For measuring the arousal, a similar 4-point scale was used with a 0-3 rating scale to the scenes: 

-   29% of the participants rated 0 on the scale

-   22% of the participants rated 1 on the scale

-   24% of the participants rated 2 on the scale

-   25% of the participants rated 3 on the scale 

-   It was also found that memory recall was proportionately better for those scenes rated as ‘emotionally intense’, rated 3 rather than lower (0-2). 

-   The scenes rated as 0-2 had similar distribution percentages of ‘forgotten’, ‘familiar’ or ‘remembered’.

-   It is also important to mention how the activation of the left amygdala predicted how am individual scene would either be ‘remembered’, ‘familiar’ and ‘forgotten’. 

-   If there was little activation to a scene that was rated as ‘emotionally intense’ was linked with ‘forgetting’ that scene. 

-   If there was intermediate activation to a scene that was rated as ‘emotionally intense’ it was linked with being ‘familiar’ with it. 

-   If there was high activation to a scene that was rated as ‘emotionally intense’ it was linked to the scene being ‘remembered’. 

-   When a more detailed analysis of the left amygdala was carried out, there was found to be a significant correlation between its activation and the emotional intensity of the memory. The correlation thus became stronger the more emotional intensity was experienced – for those participants who rated 3 on the Likert scale. 

Conclusions: 


-   According to the findings of the study, Canli et al. Found that an association between individual, subjective incidents of perceived emotional intensity for stimuli with amygdala activation and thus the subsequent memory for these stimuli. 

-   This suggests that the more emotionally intense an image would be, it is naturally more likely to be remembered – this might help to explain why people tend to remember emotionally intense experiences well enough. 

-   The level of arousal a person is under could also impact and affect the strength of a memory trace. 

-   It was also observed and analysed that, when participants were granted exposure to an event like this (causing the arousal), such as witnessing a crime, the trace of memory would be more powerful. 

-   It was also found that the amygdala is sensitive to individuals witnessed and experienced emotional intensity of visual stimuli with activity in the left amygdala during encoding being predictive of subsequent memory. 

-   Canli Et Al. Also comments that some of their findings are correlational, which shows a significant correlation between the emotional impact on the individual participating and the subsequent memory for the item. 

Strengths And Weaknesses: 

Strengths
Weaknesses
-   The experiment was conducted in a laboratory, as all the participants were tested via fMRI machines and thus it was highly standardized.                                                                                                            

-   The research has high internal validity, as all variables such as time intervals for example, were operationalized.


 -   This controls the influence to confounding variables that may distort results.                                                                                                        

-   The use of a scientific apparatus such as an fMRI machine produced highly objective, quantitative data which is high in validity.                                                                                                 

-   This enables a comprehensive statistical analysis to be conducted which leads to better and more efficient interpretation of data.                                                                           

-   No demand characteristics were projected off participants.                          

-   The task has low ecological validity due to the fact that it was conducted in a laboratory environment.

 

-   We also need to take into account the difference in levels of emotional intensity experienced in a lab setting and that in the real world. Some participants may already be emotionally aroused. And thus, the baseline itself maybe flawed.


-   The researchers also need to be considering the fact that there are certain biological, cerebral anomalies that a mere fMRI scanner can never fully represent all behaviours exhibited by different and specific parts of the brain.


-   This was a gynocentric study (based on only female participants). This may make it difficult to be representative and thus, generalized. 




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