Mental Organs

Phrenology An important part of popular culture in Victorian England and in Europe during the 19th century.

Four Assumptions Behind Phrenology 1) The Mind was made up of “organs” – Each organ is localized in distinct parts of the brain Include basic domains such as language, and colour Also includes other, separate domains such as “self-esteem” “secretiveness”, and “cautiousness”

Four Assumptions Behind Phrenology 2) Mental faculties were innate propensities or predispositions – i.e. individuals were born with these abilities, however this did not mean they were static “(A human being)...has, apart from animal-like properties, the ability to speak and the more extensive capacity for education: two sources of inexhaustible knowledge and motivation..... he is gifted with a sense of morality and with evidence of consciousness, and so forth. With these weapons, man battles his propensities.”

Four Assumptions Behind Phrenology 3) Each faculty is determined by the content of the information on which it relies, not by the way this information is used to carry out different tasks – i.e. each faculty contains/comprises all aspects pertaining to it, including manipulation or cognitive functions Faculties are “domain-specific”

Phrenology Knowledge (i.e. faculties) that are domain- specific are thus “self containing” – In science, we would call this modular i.e. a particular kind of knowledge that is not reliant on other knowledge Abilities (i.e. manipulations) are domain- general in that all faculties make use of them – In science, we call this the mode of operation

Domains & Modes of Operations Pay attention: “faculty” is used to denote both Knowledge and Abilities! What differentiates between them is whether they are domain-specific, or domain-general!

Domains & Modes of Operations

Four Assumptions Behind Phrenology 4) An especially well developed faculty (i.e. mental organ) requires a correspondingly well developed cortical (i.e. physical) organ. – Because the bones of an infant are soft and pliable, a highly developed cortical organ will create a protrusion of the adjoining skull that is measurable.

Phrenology Without (domain) general constructs like Intelligence, Reason, Memory, and Imagination, it is possible to be gifted in one domain, and be congenitally predisposed (predisposed from birth) to be well below average ability in other faculties – E.g. Autistic Savants

Phrenology It is important to remember that Gall was interested in measuring differences in the talents or natural propensities between individuals – Therefore, he looked for exceptional (extreme) cases that he considered very gifted or seriously deficient in a particular faculty Once again, this is an attempt at modularity

Gall vs. Aristotle Aristotle – Mental faculties responded to information from sense organs Sensation was followed by Perception, that could be manipulated by Imagination. Memory and Reasoning were both distinct as well. Sensation Perception Imagination Memory Reasoning Aristotle: “The Common Sense” Cross-Modal

Gall vs. Aristotle Gall – No specific organ for any of Aristotle’s faculties Including memory! – No specific organ for “Intellect” Therefore not biologically possible  Each organ had it’s own mode of functioning

Gall vs. Aristotle Gall – Sensory information was transformed into a perceptual code that was unique to that sense Perceptual codes could access other codes, but were still modular Stimulus Colour percep AttentionMemory Shape percep MemoryAttention

Gall and Modern Thinking Modern (neuro)psychology has not found evidence for a specific biological organ responsible for Memory – Semantic Memory Memory for facts – Episodic Memory Memory for particular events – Auditory short-term Memory “bee, sup, vale, goop”

Gall and Modern Thinking Dissociation research has also demonstrated this modularity – Semantic dementia patients have lost knowledge of the meaning of words but in early stages of the disease, have intact episodic memory – Anterograde Amnesia patients lose the ability to retain episodic information but retain memory for facts about the world. In addition, patients with this kind of memory loss can learn motor tasks quite normally. – Auditory short-term memory deficits patients cannot repeat a short list of words in their order of occurrence, but retain semantic memory and episodic memory.

Gall and Modern Thinking Modern Psychology – The goal to understand the details of mental computations in a particular domain, so we need to go well beyond Gall’s notion of mental organs In non-modular systems, a small change to improve one part (whether by natural selection in the case of the brain or by a human designer in the case of a machine) would have consequences (often undesirable) in many other places.

Gall and Modern Thinking Modern Psychology – Modularity, refers to the idea that complex neural systems responsible for some task (e.g. understanding a sentence) are organized into subcomponents -- modules -- which are functionally independent of one another This principle of modularity makes very good sense when processing tasks are very complicated (like sentence comprehension).