new bits from tomorrow's presentation handout

Evolutionary Psychology and its critics:
Samuels: Massive modular minds: evolutionary psychology and cognitive architecture

EP says modules are domain-specific and innate.
Massive Modularity Hypothesis: like Fodor’s modules, except everything is modular, even the executive control mechanisms that he said were not modular.
unclear if informational-encapsulation is required. maybe taken as part of domain-specificity? unclear whether EP modules must be implemented by physiologically discrete neural structures, but how could they be domain-specific otherwise? can global characteristics or distributed structures implement modules?

do autistic kids demonstrate that there is a Theory of Mind module, or are they missing domain knowledge about other people’s minds?

evidence against innate domain-specific microcircuitry as a viable account of cortical development. do cortical plasticity and transplant studies in developmental biology undermine the idea of innate, domain-specific modules? (Quartz, Elman et al.)

Samuels says this criticism depends on a false assumption, Principle of Invariance: the innately specified properties of a piece of cortical tissue are invariant under alterations of location in the brain and the afferent inputs to it

what does innate mean?
Tissue Nativism: specific tissues have innate computational properties FALSE
Organism Nativism: it’s innately specified that organisms possess certain domain-specific cognitive structures TRUE?
But who would seriously propose tissue nativism?
and how would/could organism nativism happen? neural nets?


Additions to bibliography

Churchland, Sejnowski (1992) The Computational Brain. Cambridge, MA: MIT Press

Elman et al. (1996) Rethinking Innateness: A Connectionist Perspective on Development. Cambridge, MA: MIT Press

Gazzaniga (1989) “Organization of the Human Brain” Science. Vol. 245, No. 4921, pp.947-952

Segal (1996) “The Modularity of Theory of Mind” in Carruthers and Smith eds. Theories of Theories of Mind. pp.141-157. Cambridge: Cambridge University Press

more on the quartz paper

Section 3:
- present a behavioral systems model that regards the brain as a hierarchical control structure, where this hierarchical
organization is evident both developmentally and evolutionarily. This behavioral systems model places a premium on the complex interaction between developmental mechanisms and a structured environment
- highly conserved nervous system developmental mechanisms suggests that nervous systems, despite their apparent diversity, share a deep structure, or common design principles, just as the fact that two million distinct species share only 35 major body plans suggest that body plans share many common design principles
- At virtually all levels of the human nervous system, for example, reward systems can be found that play a central role in
goal-directed behavior (Schultz, 2000)
- Rather than simply carrying information regarding reward, it appears that octopamine signals information regarding prediction errors. (bumblebee)
- A system that learns through prediction learning need not have the path from goal to reward specified, in contrast to fixed behavioral patterns, such as stimulus-response learning. Instead, the path from goals to rewards may be left open and discoverable via learning, resulting in flexible action.
- in monkeys, Schultz also found dopamine reward signals that code prediction errors

midbrain dopamine system (old) projects to (new) dorsolateral prefrontal, premotor, and parietal cortex, ... structures implicated in crucial components of human cognition, particularly social cognition and theory of mind (Stone et al., 1998), symbolic learning (Deacon, 1997), representations of self (Craik et al., 1999), and executive function and behavioral inhibition ... these structures constitute a hierarchically organized control structure, where additional layers of control have been added to the evolutionarily conserved dopamine system and where this hierarchical organization is evident developmentally as well.

dopamine connected to all kinds of abilities involving the frontal cortex, and into adolescence, behaviour becomes increasingly mediated by frontal regions... the brain keeps developing until quite late.

Although there is strong evidence that an intact dopamine system is necessary for the developmental emergence of prefrontal functions, a largely unresolved question concerns the specific nature of this developmental link. One particularly intriguing possibility is that the dopamine signal serves as a learning signal that guides the construction of prefrontal structures during development.

The developmental link between the midbrain dopamine system and prefrontal structures suggests that an explicit account of the developmental trajectory of cognitive skills is necessary; an account based on innately-specified modules is inadequate.

neural constructivism whereby the functional properties of cortex are built from the dynamic interaction between neural growth mechanisms and environmentally-derived neural activity, acting hierarchically at the regional level and with high specificity at the cellular level (Quartz & Sejnowski, 1997; Quartz, 1999)

neural development during the acquisition of major cognitive skills is best characterized as a progressive construction of neural structures, in which environmentally-derived activity plays a role in the construction of neural circuits.

There is now good evidence to indicate that one component of social competence, theory of mind, depends at least in part on the appropriate social exposure for its development, as many deaf children show delays on theory of mind tasks

LOP = eeeek

I picked up a couple of the books that the Samuels paper pointed me to, but still haven't grabbed the Elman paper. The books are in various locations around campus, hidden in buildings I've never heard of, some of them at the top of annoyingly steep hills. and then the day i was doing all this, it started raining, so i fled home before making it to all the libraries. i have no good excuse for why i still haven't made it there. nor why i still haven't transferred my notes on the samuels paper in here.

nevertheless, i've got a book on brain development and connectionism, and another one on autism.

I've also finally looked at one of the papers from the Modularity book Sandy reviewed.
this paper critiques domain-specificity. I think the developmental cognitive neuroscience people are more into critiquing innateness, whatever that means, but maybe also informational encapsulation. all of these things seem to be quite related anyway...

Velichkovsky
Modularity and Cognitive Organization: Why It Is So Appealing and Why It Is So Wrong
the title seems somewhat misleading, but i just skimmed most of the article, so maybe i missed some parts. seemed like it was mostly about a few kinds of levels of processing (LOP) experiments and a bit about brain imaging of subjects doing the same sorts of tasks. When I took a class with Fergus Craik in undergrad, I thought the LOP idea was wishy-washy to the point of saying almost nothing useful, became indignant, and stopped going to class. we also had to read a bunch of ancient crap about working memory. maybe it was just that i was in 4th year and taking a 2nd year course, so it was a bit too dumbed down. i think i also participated in a study exactly like the ones discussed in the paper. Craik's voice was on the tape they played to me while i did the distracting task, listing words, but his strong Scottish accent made it difficult to tell what he was saying. The student running the experiment knew exactly when he was impossible to understand and automatically repeated some of the words without the accent. One of the formative experiences leading me to believe that the results of psychology experiments should be considered as highly dubious. but i digress...

LOP effects on saccades:
with visual, auditory, or "relevant" stimuli, the time lag before the next saccade is the same? or maybe different? i didn't read it that closely. oops. does this mean that there are cross-modal effects? i wasn't sure.

LOP effects on word memory:
with word memory tasks given after the encoding happened at different levels, differences in how much was remembered. deeper encoding means better memory, as far as i could tell/remember. not sure what the significance of this is supposed to be for domain-specificity either.

EEG results for the same sort of word memory tasks:
the deeper the level of processing (perceptual encoding, semantic emcoding, self-referential encoding), activation was seen farther towards the anterior regions of the brain.
this one does seem kind of relevant to modularity. recalling words seems like a specific task, but it doesn't happen in a well-defined region. several types of processes affect it, from perceptual to self-referential, whatever that means. they say something in the results about "neuroanatomical change". I'm not sure what they mean by that. but they think it's significant that the direction it happens in is in the main direction of evolutionary growth of the cortex. they had a bit near the beginning about what the older vs. newer regions of the brain are responsible for. laid out a hierarchy of levels of processing, basically that correspond to the brain regions and when they emerged in our evolution.

I still don't think it's all that clear what these results say about modularity or domain-specificity. memory isn't the sort of thing that most people call a module, for just these sorts of reasons. But maybe I missed the point because i only skimmed most of it. but i can't bring myself to carefully read a paper about LOP.