Neural Correlates of Emotional Judgements

EEG

At the outset of this journey
into the emotions, I considered the philosophical work of Robert Solomon.
Recall that Solomon argues that emotions are judgements and strategies rather
than experiences that well up unbidden from the deep. This post asks whether it
is possible to find any empirical evidence for this attractive idea.
Using EEG recording, Hajcak,
Moser & Simons (2006) investigated the way people’s physiological responses
varied with the type of judgement they made to emotionally arousing stimuli.
Participants were shown pictures from the International Affective Picture
System three times with different instructions each time:

  • First time (or block):
    Participants just looked at the pictures naturally – or as naturally as you can
    with a load of wires attached to your scalp.
  • Second block: participants
    were asked to make judgements about the emotional content of the pictures
  • Third block: participants were
    simply asked to indicate how many people were in the image.
The recording being made in
this study were via EEG and, more specifically, focussed on a particular
response called the ‘late positive potential’ (LPP). To interpret their results
we need to understand something about what this LPP is. Here is how Hajcak et
al. (2006) describe it:
“…the enhanced LPP may relate
to augmented attention to arousing stimuli […] the LPP might, like increased
blood flow in visual cortex, index the facilitated perceptual processing that
results from the activation of structures such as the amygdala…” (Hajcak et
al., 2006:517)
So, the theory goes that the
LPP is related in some close way to emotional processing. What this study
found, then, was that the LPP was greater when participants were attending to
the emotional content of the images, rather than when they were attending to a
non-emotional aspect. This seems to provide some nice evidence that appraisals
impinge on the processing of emotions.
The use of EEG is not as sexy
as fMRI but in this paradigm it has one major advantage, it is ‘temporally
sensitive’. fMRI has a lag of a few seconds between activity in the brain and
its measurement. EEG, on the other hand, only lags in the order of milliseconds
so it is much better at telling when something has happened in the brain.
I’d like to be able to
convincing connect this study with Solomon’s ideas about emotions as judgements
but the two levels of discussion are just too far removed. The most we can say
from this study is that it shows that appraisals (judgements) appear to play
some role in emotional processes. Crucially, using EEG also tells us that these
processes happen fast, suggesting they are unconscious.
About the author


Psychologist, Jeremy Dean, PhD
is the founder and author of PsyBlog. He holds a doctorate in psychology from
University College London and two other advanced degrees in psychology.
He has been writing about
scientific research on PsyBlog since 2004. He is also the author of the book
“Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks.


SOURCE: PSYBLOG
Kayode Ojo
Kayode Emmanuel Ojo is the Co-Founder and Managing Director at SHEFFA Limited. He is presently studying Computer Science at the National Open University, Victoria Island, Lagos.