cautious about treating such conditions as universal. Under normal conditions, the
human mind/brain receives simultaneous information from a range of sense organs
that simultaneously monitor the external and internal environment and this
information needs to be related to information in long-term memory, and assessed for
importance in the light of ongoing needs and goals. In short, there are many things
going on at once. But we cannot give everything our full, undivided attention. As
Donald Broadbent pointed out in 1958, there is a “bottleneck” in human information
processing. The human effector system is also limited—we only have two eyes,
hands, legs etc., and effective action in the world requires precise co-ordination of
eye-movements, limbs and body posture. As a result, the mind/brain needs to select
the most important information, to decide on best strategy and to co-ordinate its
activity sufficiently well to interact with the world in a coherent, integrated way.
To achieve this, it is as important to stop things happening in the brain as it is to make
them happen. As William Uttal observed
“There is an a priori requirement that some substantial portion, perhaps a majority, of
the synapses that occur at the terminals of the myriad synaptic contacts of the three-
dimensional ... (neural) ... lattice must be inhibitory. Otherwise the system would be
in a constant state of universal excitement after the very first input signal, and no
coherent adaptive response to complex stimuli would be possible" (Uttal, 1978,
p192).
This opens up the possibility that selective attention doesn’t so much add something
special to neural representational states at the focus of attention to give them
associated consciousness. Consciousness might be a “natural” accompaniment of
neural representation (see for example Zeki, 2007). If so, it may just be that for
attended to representational states, inhibitory processes don’t prevent it. To prevent
information overload, not to mention utter confusion, information and awareness of
information outside the focus of attention might be inhibited. Conversely,
information that is integrated into a representation of the current, “psychological
present” might be released from inhibition (Arbuthnott, 1995).
If so, the mechanisms required to select, co-ordinate, integrate and disseminate
conscious information in the human brain may not be required for simpler creatures,
with simpler brains. If consciousness is a natural accompaniment of neurally encoded
information, such creatures might have a simple form of consciousness.
The visual system of the frog, for example, appears to be structured to respond to just
four stimulus features: a sustained contrast in brightness between two portions of the
visual field, the presence of moving edges, the presence of small moving spots and an
overall dimming of the visual field. This is a far cry from the variety and detail
provided by the human visual system. But there seems little reason to jump to the
conclusion that the frog sees nothing. Rather, as Lettvin, et. al. (1959) proposed, the
frog may see just four things relating to its survival. A sudden dimming of the light or
a moving edge may indicate the presence of a predator and is likely to initiate an
escape response. Sustained differences in brightness may allow the frog to separate
water from land and lily pad. And moving spot detectors may allow the frog to see
(and catch) a moving fly at tongue's length.