Download Answers to Test Your Knowledge questions for

Answers to Test Your Knowledge questions for
Chapter 22 Brains, minds and consciousness
Question 22.1
This is bound to be highly speculative. It raises the issue of exactly what we mean by
consciousness (a topic discussed shortly). Is it some kind of sentience with a capacity to
experience emotional states? Is it possession of a sense of existential awareness of one's
self? It might be that we want to use the term to cover a range of phenomena and hence
would use different criteria in different species.
Let us speculate and consider the suggestions 1-9 on the role of conscious processing, i.e.
what the processes underlying consciousness (as opposed to those underlying
unconscious processing) do. Let us then consider how different animals might exploit
such information processing. 1 and 3-8 would appear to be widely represented in those
species that are more than a collection of reflexes, modal action patterns and rhythms, i.e.
species exhibiting motivation and emotion. The first part of 2 might be widely
represented. That is, as a general feature, predator and prey species survive by being able
to predict the behaviour of others. The second part of 2, on shared assumptions regarding
conscious intention, might be confined to only social primates but we don't know. 9
might appear to a peculiar feature of primates, especially humans. If all of 1-9 need to be
present, we might want to confine consciousness to very few species. If it is sufficient
that a number of them be present, the range might increase enormously.
Question 22.2
According to Crick's (1994) metaphor, the 'spotlight of attention' brings into conscious
awareness only a fraction of the available information, e.g. a small sub-set of the
information extracted by our sense organs.
Of relevance to this would appear to be a study on non-human primates described in
Chapter 21, 'Cognition'. Researchers looked at the electrical activity of particular neurons
in the inferior temporal cortex (IT). A neuron's receptive field was mapped in terms of
area on the screen. IT neurons have large receptive fields and are triggered by complex
patterns. With eyes still fixed, the animal was trained to shift covert orientation to one of
two locations within the receptive field as directed by a cue.
An IT neuron that was sensitive to red stimuli but insensitive to green within its receptive
field was found. When attention was drawn to the location of the red stimulus, activity in
this IT neuron was high. When it was drawn to the location of the green stimulus, activity
in the neuron was low. This is in spite of the fact that the (green) stimulus present at the
target of attention was ineffective in triggering the IT neuron under investigation (though,
of course, effective in triggering some other IT neurons).
Since the eyes did not move and the same red and green stimuli were present in both
cases, stimulation at the retina was the same. However, the effect of the red stimulus
depended upon the target of covert orientation. In other words, attention modulated the
activity of neurons according to its locus.
That much information over a wide area of visual field can be computed by the same IT
neuron illustrates the functional rationale for attentional processes that bias in favour of
some inputs. The neuron would otherwise be inundated and computation impossible.
Such biasing of attention in favour of part of the visual input would seem to be a
necessary condition for consciousness to be associated with a spotlight function.
Question 22.3
I guess that a lot hangs on the word 'reasonable'! Again, this is very much a question of
intelligent speculation and we could use various sources of information. We could go
back to an earlier section and look at the list (1-9) of the kind of information processing
attributed to conscious processes. Does this suggest that these information processing
tasks are ones that build on unconscious processes? In particular, 1, 2, 3, 6, 7 and 9
suggest that conscious processes appear in evolution at a stage when the information
processing demands of the animal are such that they cannot be met by purely unconscious
processes. As noted in the answer to Question 22.1, 2 raises the possibility that only
rather few species (e.g. social primates) possess conscious awareness. This might be felt
to reinforce the case that conscious awareness emerged at a stage in evolution from the
unconscious processes of precursor forms.
Question 22.4
Whether goats possess conscious awareness is open to speculation. The kind of complex
information processing performed by goats would meet many of the criteria (1-9) listed
earlier. The goat's brain has the kind of structures such as the nucleus accumbens and
cortex that we often associate with consciousness.
Suppose that we credit the goat with a capacity for conscious awareness. We would
surely want to attribute the capacity to feel pain to the goat (it is in possession of
nociceptive neurons and the brain systems underlying emotion). Try to think of the lifestyle of a goat in an evolutionary context. It would have been vulnerable to predation and
so we might postulate an emotional experience of fear. It is a social animal and so one
might speculate about such things as negative emotion experienced when an individual is
isolated from the rest of the herd. You might feel that all of this is not very scientific and
you would be right. However, it is informed by science and precisely such questions are
posed by researchers in advising on animal welfare legislation. Such considerations have
had considerable influence on national farming policy, especially in Sweden.
Question 22.5
Have you ever tried your hand at fiction! The identity theorist might suggest that this is a
metaphorical way of speaking (in this case, accompanied by some irony) and that any
such pang of guilt might, in principle, be equally well described as a pattern of activity
within the nervous system. The dualist might react that this remains an act of faith. The
dualist, if sharing his or her mentor's (Descartes or Eccles) religious faith might suggest
that there is something God-given about the feeling and that processes outside the
nervous system can be engaged by such sentiments. The identity theorist might react that
this is an unparsimonious way of trying to understand the world and that the job of
psychology and neuroscience is to attempt to understand behaviour without appeal to
supernatural notions of God and soul.