Chapter 1: Introduction to social neuroscience
- The fact that different patterns of thought should result in different patterns of
brain activity is perhaps not surprising. The fact that we now have methods that
can attempt to measure this is certainly noteworthy. What is most interesting
about studies such as these is the fact that activity in regions of one person’s
brain can reliably elicit activity in other regions of another person’s brain during
this social interaction
- Cognition in an individual brain is characterized by a network of flowing signals
between different regions of the brain. However, social interactions between
different individuals can be characterized by the same principle: a kind of ‘mega-
brain’ in which different regions in different brains can have mutual influence
over each other. This is not caused by a physical flow of activity between brains
(as happens between different regions in the same brain) but by our ability to
perceive, interpret and act on the social behaviour of others
- The technique of hyper-MRI (functional magnetic resonance imaging) records
from two different MRI scanners simultaneously: for example, whilst participants
in the scanners engage in a social activity
- What is of interest is that neural activity in different regions correlates not only
within the same brain (due to physical connections) but also across brains (due
to mutual understanding)
THE EMERGENCE OF SOCIAL NEUROSCIENCE
- Social psychology An attempt to understand and explain how the thoughts,
feelings, and behaviours of individuals are influenced by the actual, imagined or
implied presence of others
- Based on this definition, one could regard social neuroscience as being a sub
discipline within social psychology that is distinguished only by its adherence to
particular methods and/or theories. Whilst this may be perfectly true, most
researchers working within the field of social neuroscience do not have
backgrounds within social psychology but tend to be drawn from the fields of
cognitive psychology and neuroscience
- Cognitive psychology The study of mental processes such as thinking,
perceiving, speaking, acting, and planning
- Social neuroscience links together all these disciplines: linking cognitive and
social psychology, and linking ‘mind’ (psychology) with brain (biology,
neuroscience).
THE SOCIAL BRAIN?
- One overarching issue within social neuroscience is the extent to which the so-
called ‘social brain’ can be considered distinct from all the other functions that
the brain carries out – talking, walking, planning, etc.
- One possibility is that there are particular neural substrates in the brain that are
involved in social cognition but not in other types of cognitive processing. This
relates to the notions of modularity and domain specificity
,- Modularity The notion that certain cognitive processes (or regions of the
brain) are restricted in the type of information they process and the type of
processing carried out
- Domain specificity The idea that a cognitive process (or brain region) is
specialized for processing only one particular kind of information
- A module is the term given to a computational routine that responds to
particular inputs and performs a particular computation on them, that is, a
routine that is highly specialized in terms of what it does to what. One core
property that has been attributed to modules is domain specificity, namely that
the module processes only one kind of input (only faces, only emotions)
- In this modular view, the social brain is special by virtue of brain mechanisms
that are specifically dedicated to social processes. Moreover, it is claimed that
these mechanisms evolved to tackle specific challenges within the social
environment (the need to recognize others, the need to detect when you are
being exploited).
- The alternative, diametrically opposite, approach (non-modular view) is to
argue that the ‘social brain’ is not, in fact, specialized uniquely for social
behaviour but is also involved in non-social aspects of cognition (reasoning,
visual perception, threat detection)
- Evolving general neural and cognitive mechanisms that increase intellect, such as
having bigger brains, may make us socially smarter too
- Of course, it is also possible that the reverse is true – namely that the
evolutionary need to be socially smarter leads to general cognitive advances in
other domains
- There are other positions that lie in-between these two extremes. Mitchell notes
that there are certain regions of the brain that are activated in fMRI studies by a
wide range of social phenomena such as evaluating attitudes, interpreting other’s
behaviour, and emotional experience. Rather than arguing for a narrowly defined
module in this region, he suggests that social psychology is a ‘natural kind’ that
distinguishes itself from other aspects of cognition because it relates to concepts
that are less stable and less definite than those involved in, say, perception and
action. In this account, the ‘social brain’ is special because of the nature of the
information that is processed (more fuzzy) rather than because it is social
- Mirror neurons respond both when an animal sees an action performed by
someone else and when they perform the same action themselves. The key
insight, with regard to social neuroscience, is that there may be a simple
mechanism – implemented at the level of single neurons – that enables a
correspondence between self and other. Mirror neurons have been implicated in
imitation, empathy, and ‘mind-reading’. Although they were originally discovered
for actions, it is possible that mirroring is a general property of many neurons
and they may not be tightly localized to one region. Whether they are specifically
social or derive from general cognitive demands (linking perception and action)
is hard to say
- The phrenologist’s head is an extreme form of a modularity view
,IS NEUROSCIENCE AN APPROPRIATE LEVEL OF EXPLANATION FOR STUDYING SOCIAL
BEHAVIOR?
- Perhaps the most general criticism that could be levelled at social neuroscience is
that the brain is not the most appropriate level of explanation for understanding
social processes. Surely social processes need to be studied and understood at
the social level – that is, at the level of interactions between people, groups of
people, and societies
- Reductionism One type of explanation will become replaced with another,
more basic, type of explanation over time
- In a reductionist framework the language of social psychology will be replaced by
the concepts of neuroscience. However, most researchers in social neuroscience
are attempting to create bridges between different levels of explanation rather
than replace one kind of explanation with another
- Another common way in which neuroscience data are used to bridge levels of
explanation has been termed the reverse inference approach
- Reverse inference An attempt to infer the nature of cognitive processes from
neuroscience (notably neuroimaging data)
- Is reverse inference necessarily good practice? It goes without saying that the
reliability of this inference depends on what is known about the functions of
given regions. If these regions turned out to have very different functions then
the inference would be flawed. Also the function of regions is not resolutely fixed
but depends on the context in which they are employed
- There is one scenario in which brain-based data could have no significant impact
on our understanding of social processes – and that is the blank slate scenario
- Blank slate The idea that the brain learns environmental contingencies
without imposing any biases, constraints, or pre-existing knowledge on that
learning
- According to the blank slate, the brain is not completely redundant (it still
implements social behaviour) but the nature of social interactions themselves is
entirely attributed to culture, society, and the environment. According to the
blank slate, the structure of our social environment is created entirely within the
environment itself, reflecting arbitrary but perpetuated historical precedents:
culture, society, and the nature of social interactions invent and shape themselves
- Social processes are all in the brain, but some of them are created by
environmental constraints and historical accidents (and learned by the brain)
whereas others may be caused by the inherent organization, biases, and
limitations of the brain itself
- Variability in the levels of aggression need not reflect randomness in the
situations that tend to trigger aggressive acts (to gain access to resources, to
maintain social order by punishing those perceived to violate it). These triggers
are likely to have been shaped by evolution rather than reflecting an arbitrary
cultural trend
- The existence of a cultural variant such as slavery may require particular kinds of
neurocognitive mechanisms: for instance, the switching off of empathic processes
towards the slave group and particular kinds of thoughts that drive this switching
off. An impossible culture could therefore be a system of slavery associated with
high levels of empathy and humane cognitions towards the slave group. The
, impossibility is created by the nature of brain-based mechanisms, even though it
manifests itself in terms of the nature of social processes
- It is worthwhile pointing out that variability is not always attributable to the
social or environmental level. For example, different genetic variants and
different hormone levels across individuals do contribute to variability in social
behaviour. In some cases the different levels of explanation cannot be separated
from each other
Chapter 2: The methods of social neuroscience
- Psychological methods performance measures (response times),
observational studies and questionnaires
- Methods linked to cognitive neuroscience psychophysiological responses
(skin conductance responses) and electrophysiological responses,
functional imaging, effects of brain lesions and transcranial magnetic
stimulation (TMS)
- TMS the application of a strong magnetic field over a region of the scalp that
causes temporary and localized interference in neural activity
- Temporal resolution the accuracy with which one can measure when an
event is occurring
- The effects of brain damage are permanent and so this has no temporal
resolution as such. Methods such as electroencephalography/event-related
potential (EEG/ERP), magnetoencephalography (MEG), TMS, and single-cell
recording have millisecond resolution. Positron emission tomography (PET)
and functional magnetic resonance imaging (fMRI) have temporal resolutions
of minutes and seconds, respectively, that reflect the slower hemodynamic
response
- Spatial resolution the accuracy with which one can measure where an event
is occurring
- Lesion and functional imaging methods have comparable resolution at the
millimeter level, whereas single-cell recordings have spatial resolution at the
level of the neuron
- Invasiveness PET is invasive because it requires an injection of a
radiolabelled isotope. Single-cell recordings are performed on the brain itself and
are normally only carried out in non-human animals. Methods such as TMS are
not strictly invasive (because the coil is located entirely outside the body) even
though it leads to stimulation of the brain
MEASURING BEHAVIOR AND COGNITION: PSYCHOLOGICAL METHODS
- Almost all experiments in social neuroscience measure behaviour in some way,
given that it is social behaviour that they are trying to explain. In functional
imaging experiments, the participant is given a set of instructions on how to
respond even if the main dependent measure is brain activity rather than
behaviour per se. In social neuroscience, it is also common to correlate
neurophysiological responses (during functional imaging) when performing a
task with individual differences on a psychological measure such as empathy or
personality (assessed outside the scanner using a questionnaire)
