This article might have some more useful results, and there’s a nice summary in Table 1.
There’s also an ongoing debate about the necessity of attention for consciousness.
At the level of theories, Global Workspace Theory, or more narrowly the Global Neuronal Workspace Model, one of the leading theories of consciousness, requires it forconsciousness, and I think Dennett’s views are similar (see his discussions here and more recently here). Basically, it requires attention and for the attended states to be accessible in some “global workspace”, which might include things like working memory and executive functions. Attended Intermediate-level Representation Theory requires attention but not for the state to be passed into any global workspace. Recurrent Processing Theory only requires recurrent connections, i.e. directed loops. It also seems like if you try to abstract away the details of GWT (global to what?), the necessary conditions for consciousness might reduce to Recurrent Processing Theory. See the discussions here and here.
As for evidence, attention (or specific kinds of attention, e.g. “top-down”) may not be necessary for consciousness, based on iconic memory, gist, animal and gender detection in dual tasks, and partial reportability, according to this article (see a summary in Table 5.1). It’s also argued unnecessary in this (and insufficient for consciousness, too), this and this, and some recent experiments here and here. EDIT: I should add that I think recurrent processes reduce to feedforward ones when you draw them out as causal diagrams over time.
Attention is argued necessary here. Some experimental results here (consistent with being necessary, since we still “attend” to things we don’t focus on), on iconic memory here and here, ensemble perception (gist?) here, and more discussion here (leans towards attention being necessary).
Finally, “no-report paradigms” could be useful. They can be used to address the problem that subjective reports may involve capacities and structures that are only necessary for reporting, not the conscious experiences themselves, and so cause us to falsely label these capacities and structures as necessary for consciousness. No-report paradigms do this by measuring “reflexive behaviors correlated with conscious states to provide a window on the phenomenal that is independent of access” (SEP article section, which also discusses some limitations: you can’t know for sure the reflexive behaviours still indicate consciousness in the absence of report). There’s some recent discussion here, and here’s the abstract, which I hope further illustrates its usefulness and subtleties:
Cognitive approaches to consciousness dictate that consciousness involves frontal and parietal circuits that are devoted to thinking, reasoning, evaluating, reporting, deciding, and memory. By contrast, sensory approaches allow for consciousness in creatures that have little or no ability to think and reason.
To decide between cognitive and sensory accounts, we must distinguish between the neural basis of consciousness and the neural basis of reports.
The no-report paradigm purports to solve this problem by using the reports of some subjects to calibrate indicators of consciousness, allowing experimental subjects to make no report.
The problem with the no-report paradigm is that you cannot keep subjects from thinking, and their thought processes may be stimulated by and reflect the contents of perception.
The solution is a ‘no-post-perceptual cognition’ paradigm, one version of which is illustrated here.
This article might have some more useful results, and there’s a nice summary in Table 1.
There’s also an ongoing debate about the necessity of attention for consciousness.
At the level of theories, Global Workspace Theory, or more narrowly the Global Neuronal Workspace Model, one of the leading theories of consciousness, requires it for consciousness, and I think Dennett’s views are similar (see his discussions here and more recently here). Basically, it requires attention and for the attended states to be accessible in some “global workspace”, which might include things like working memory and executive functions. Attended Intermediate-level Representation Theory requires attention but not for the state to be passed into any global workspace. Recurrent Processing Theory only requires recurrent connections, i.e. directed loops. It also seems like if you try to abstract away the details of GWT (global to what?), the necessary conditions for consciousness might reduce to Recurrent Processing Theory. See the discussions here and here.
As for evidence, attention (or specific kinds of attention, e.g. “top-down”) may not be necessary for consciousness, based on iconic memory, gist, animal and gender detection in dual tasks, and partial reportability, according to this article (see a summary in Table 5.1). It’s also argued unnecessary in this (and insufficient for consciousness, too), this and this, and some recent experiments here and here. EDIT: I should add that I think recurrent processes reduce to feedforward ones when you draw them out as causal diagrams over time.
Attention is argued necessary here. Some experimental results here (consistent with being necessary, since we still “attend” to things we don’t focus on), on iconic memory here and here, ensemble perception (gist?) here, and more discussion here (leans towards attention being necessary).
Finally, “no-report paradigms” could be useful. They can be used to address the problem that subjective reports may involve capacities and structures that are only necessary for reporting, not the conscious experiences themselves, and so cause us to falsely label these capacities and structures as necessary for consciousness. No-report paradigms do this by measuring “reflexive behaviors correlated with conscious states to provide a window on the phenomenal that is independent of access” (SEP article section, which also discusses some limitations: you can’t know for sure the reflexive behaviours still indicate consciousness in the absence of report). There’s some recent discussion here, and here’s the abstract, which I hope further illustrates its usefulness and subtleties: