Read here about attention, a critical idea to the study of scale, since our awareness of other scales is due to our ability to pay attention to those scales.


We follow Dehaene's definition.

Definition by Dehaene

Attention is the cognitive process of marshalling global, cross-modality mental resources to selectively concentrate on one relevant aspect of the environment while dismissing other irrelevant things. Attention has also been referred to as the allocation of processing resources.

We view attention as selective attention, attention orienting. We follow Dahaene and define attention as "capable of access to conscious report."

Assocation: An important aspect of attention and access to conscious report, whether the person paying attention associates with the phenomenon.

One way of avoiding the awkward "paying" adverb is to use the awkward phrasing, "there is attentional activity."

Distinction between subliminal, preconscious, and conscious processing

Proposed distinction between subliminal, preconscious, and conscious processing. by Dehaene.

Image above:
Three types of brain states are schematically shown, jointly defined by bottomup stimulus strength (on the vertical axis at left) and top-down attention (on the horizontal axis). Shades of color illustrate the amount of activation in local areas, and small arrows the interactions among them. Large arrows schematically illustrate the orientation of top-down attention to the stimulus, or away from it (‘task-unrelated attention’). Dashed curves indicate a continuum of states, and thick lines with separators indicate a sharp transition between states.
During subliminal processing, activation propagates but remains weak and quickly dissipating (decaying to zero after 1–2 seconds). A continuum of subliminal states can exist, depending on masking strength, top-down attention, and instructions (see Box 1).
During preconscious processing, activation can be strong, durable, and can spread to multiple specialized sensori-motor areas (e.g. frontal eye fields). However, when attention is oriented away from the stimulus (large black arrows), activation is blocked from accessing higher parieto-frontal areas and establishing long-distance synchrony.
During conscious processing, activation invades a parieto-frontal system, can be maintained ad libidum in working memory, and becomes capable of guiding intentional actions including verbal reports. The transition between preconscious and conscious is sharp, as expected from the dynamics of a self-amplified non-linear system [4].

Top-down attention
Bottom-up stimulus strength
Subliminal (unattended)
Subliminal (attended)
Weak or interrupted
Very little activation
Strong feedforward activation
Activation is already weak in early extrastriate areas
Activation decreases with depth
Little or no priming
Depth of processing depends on attention and task set
No reportability
Activation can reach semantic level
Short-lived priming
No durable frontoparietal activity
No reportability
Sufficiently strong
Intense activation, yet confined to sensori-motor processors
Orientation of top-down attention
Occipito-temporal loops and local synchrony
Amplification of sensori-motor activity
Priming at multiple levels
Intense activation spreading to parietofrontal network
No reportability while attention is occupied elsewhere
Long-distance loops and global synchrony
Durable activation, maintained at will
Conscious reportability

Why attention and consciousness are different

Why attention and consciousness are different: topdown influences on subliminal processing
Subliminal processing is frequently thought to be automatic and independent of attention. However, the present framework implies that top-down attention and task set can have an effect on subliminal processing (see Figure 1 in main text, top row). This prediction has been verified in several recent reports.
Modulation of subliminal priming by temporal attention In a numerical masked priming paradigm, Naccache et al. [43] first showed that subliminal priming was present when subjects could allocate attention to the prime-target pair, but vanished when stimuli could not be temporally attended. Kiefer and Brendel [44] observed a similar effect in an experiment investigating the N400 potential elicited by masked words. Unseen masked words elicited a much larger N400 when they were temporally attended than when they were not.
Modulation by spatial attention
Kentridge et al. [45,46] first reported that blindsight patient GY could use consciously perceived cues to enhance unconscious processing of visual targets. When a target was presented in his blind visual field, GY responded faster and more accurately when it was validly cued by a consciously perceptible arrow pointing to it, than when it was invalidly cued. In both cases, he still claimed that he could not see the target. Modulation of subliminal priming by spatial attention was also observed in normal subjects [47].
Modulation by strategies
Task instructions also alter the fate of subliminal stimuli. For instance, masked primes can elicit instruction-dependent activation in motor cortex [48,49], suggesting that arbitrary stimulus–response mappings conveyed by conscious instructions can also apply to nonconscious stimuli. The influence is always unidirectional: once a strategy or response mapping is consciously adopted, it extends to non-conscious primes [50,51]. Kunde et al. [51] studied the ‘Gratton effect’, a strategic increase in executive control that follows Stroop interference trials. They observed this effect following conscious conflict trials, but not following subliminal conflict trials. Once established, however, the increase in control applied to both subliminal and supraliminal trials – another instance of a top-down effect on subliminal processing.

Attention as Defined By Other Researchers

William James

In 1890, William James, in his textbook Principles of Psychology, remarked:
Everyone knows what attention is. It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness are of its essence. It implies withdrawal from some things in order to deal effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrained state which in French is called distraction, and Zerstreutheit in German.


Dormashev reviewed the literature and summarized that attention is considered either as a process in-and-of-itself, or a manifestation or properties of other mental and physiological processes. Viewed as a range from independent to dependent, it is discussed variously as
  • a separate process or human ability
  • a specific or a total attuning of an organism,
  • a set of certain mechanisms and resources
  • a characteristic of information processing,
  • a characteristic of other processes of consciousness,
  • a manifestation of other abilities,
  • an aspect of any activity.


Fuller called it "dismissing irrelevancies." See his macro/micro diagram.

Effort And Attention

We distinguish between effortless attention and vigilant attention.


Effort applies to both physical and mental activities. For example, in a ballet, the physical enactment of the choreography always requires the same physical energy to propel the dancer’s body, but the mental effort required decreases in proportion to the amount of repetition. Both are amenable to repeatable measurement, though it is easier (and often thought to be more objective) to measure the former in units of joules than the latter as reports of feelings of effortlessness. But the latter is shown to follow broad objective characteristics, as Bruya summarizes in the following curves (Bruya p.1).

Figure 1 Effort versus demand in effective action, normal experience by Bruya

Figure 2 Effort versus demand in effective action, flow experience by Bruya


Flow is the experience of full engagement in an activity, with ongoing mutually-reinforcing streams of attention and action causing a satisfying, engaged experience of being where no time seems to elapse.
Flow was codified by Mihaly Csikszentmihalyi in the 1970’s. He called it “autotelic experience” and described it in rigorous terms, including “the manner of its occurrence, its duration, its depth, its phenomenal characteristics, its variability, its breadth across populations, its parameters of occurrence, and its psychological value.” (Bruya p.1).

Links and Citations

Citation: Effortless Attention edited by Brian Bruya, MIT Press, 2010

Other pages on attention: