Chapter 3: What is consciousness good for? Flashcards
How would Darwin describe natural selection? How does it relate to consciousness?
undirected force blindly shaping the biosphere
- spontaneous pattern generation - Alan Turing → chemical reactions leading to emergence of organized features (like zebra stripes)
- allometric relations - increase in organism size leading to proportional change in its organs
- we cannot assume that consciousness necessarily plays a positive functional role in species’ success
What does functionalist view of consciousness state?
That consciousness is useful!
- conscious perception transforms incoming information into internal code - unique processing
- consciousness offers only a glimpse from all of the processes happening → sample from unconscious distribution
- brain needs to perform reverse inference → sensations are ambiguous (Bayesian inference - infer from based on the outcomes what are the origins)
How does consciousness resolve ambiguities?
In the region of the cortex that is sensitive to motion, neurons suffer from ‘‘aperture problem’’.
Each of them receives inputs from only limited receptive fields and thus cannot figure out what is the motion direction.
To resolve this issue, neurons in area MT initially encode each local motion, but then converge signal to global interpretation = to what we consciously perceive! This convergence seems to occur only when the observer is conscious.
In summary -> unconsciousness evaluates all possibilites, but consciousness presents only the final version of this evaluation
What happens when we present participants with ambigous gratings display?
Our conscious vision alternates between the two percepts -> we don’t blend two gratings!
so brain seems to be pondering probabilities ready to change its mind at any moment
What are evolutionary advantages of transient memories?
remembering about predators, ability to synthezise information over time, space and modalities of knowledge is crucial for conscious mind
What is possible evolutionary role of consciousness relating to working memory?
learning over time, rather than simply living in the instant
What brain areas is related to working memory?
dorsolateral prefrontal cortex → often light up when we “hold” piece of information such as phone number, color etc
What brain areas are related to active memory?
prefrontal neurons → active memory! → even after picture is gone, they continue to fire during short-term memory task
What happens to somebody with lesions in prefrontal cortex?
They experience memory problems, issues planning for the future → unable to think outside present time!
Is eye- closing due to voice previously paired with puff of air conscious or unconscious? What are the two types of conditioning?
It depends on temporal gap!
”delayed conditioning” → tone lasts until puff arrives → coincidence detection = UNCONSCIOUS! → does not require cortex!
”trace conditioning” → tone is seperated from puff → memory-trace conditioning (requires keeping active memory trace) = CONSCIOUS! → requires hippocampus + connected structures (including prefrontal cortex)
What is the relation of human brain to Turing machine?
- algorithms → complex strategies formed by strining together several elementary steps → consciousness’s uniquely evolved functions
- consciousness → collect information from various processors, synthesize it and then broadcast the result (=conscious symbol)
- it resembles “production system” → type of program introduced in the 1960s to implement artificial intelligence tasks
- production system = database (”working memory”) + “if-then” production rules - at each step, system examines whether a rule matches current state of its working memory
- winning rule ‘’ignites’’ → changes contents of working memory (before entire process resumes)
- production system is able to implement thinkable computation → biological Turing machine
What is the major difference between Turing machine and human brain?
Turing machine accessess only conscious fraction of mathematician mental process
Humans can successfully solve many operations unconsciously
What types of operations can occur unconsciously? What types of operations must be performed consciously?
idea is that easy one-step operations like 3+2 can occur unconsciously (one-step calculations), BUT operations like (3 + 2) - 1 require consciousness
How does consciousness work as social sharing device?
One of key criterions for conscious perception is verbal reportability!
We usually don’t conclude that sb is aware of information unless they formulate it with language
What happens if you pair participants and present them with near-threshold target images?
- Bahrami experiment: subjects were paired and asked to perform simple perceptual task → they were shown 2 displayes → they needed to decide whether the 1st or 2nd contained near-threshold target image → in the end, pairs behaved like single participant → they always provided single answer
- as long as the two participants’ abilities were reasonably similar, pairing them yielded a significant improvement in accuracy
- most participants came up with ways to communicate levels of certainty (even on a scale) suggesting that people focus on categorical answers, not nuances
