The tension between interpreting the brain as a collection of specialized areas and as a distributed network is as old as brain research itself. Rejecting the medieval idea that the brain was unitary because the soul was indivisible, nineteenth-century phrenologists emphasized modularity. Although these phrenologists got the details wrong because of inadequate methods, they introduced the idea of different functions being handled by distinct cortical areas. The idea was made concrete by neurologists such as Fritsch and Hitzig (Reference Fritsch, Hitzig and Pribram1870/1960) (sensory and motor areas), Broca (Reference Broca1861) and Wernicke (Reference Wernicke1874) (language areas), and many others. Distributed coding and the neurological evidence for it came from Karl Lashley's (Reference Lashley1929) mass action, through his student Karl Pribram's (Reference Pribram1971) distributed coding, to present-day parallel distributed processing.
The contrast between the “concept empiricists” and the rational or amodal concept also has a long history, far more than “the last twenty years or so” (as Anderson writes in sect. 4, para. 3) and unknown to most philosophers. The idea that “the vehicles of thought are re-activated perceptual representations” (Weiskopf Reference Weiskopf2007, p. 156) – which Anderson refers to in this section (same paragraph) – was championed at Cornell by Titchner, a student of Wilhelm Wundt. He fought a long battle with the followers of Külpe at Würzburg, who saw mental life as built of a great hierarchy of ideas. The controversy was defined as an evaluation of the role of imageless thought. Külpe insisted that some ideas had no associated images, and that Titchner just hadn't found those ideas yet. Titchner, in turn, held that all ideas included images, and that Külpe hadn't found the images yet. Each founded a school to press his introspection, and the battle raged around the turn of the twentieth century. Eventually, the whole controversy blew up in their faces, as it became clear that the introspective method could not resolve the issue. Objective data, not private opinions, were necessary for psychology to become scientific. Tragically, philosophers of mind continue to use the discredited method, disguised in phrases such as “it is obvious that” or “a moment's thought will reveal that.” Introspection is a good starting point for an investigation, but it can never be an ending point.
The essential features of the “action-sentence compatibility effect” are also older than Glenberg and Kaschak (Reference Glenberg and Kaschak2002) (referred to in section 4.1, para. 2, of the target article). An obvious example is the Stroop effect (Stroop Reference Stroop1935), well known to cognitive psychologists. Color naming is easy when a printed color name is in the corresponding color, but difficult when the color and name are incompatible, such as the word “blue” printed in red ink.
There are really two parts to the reuse hypothesis: First, a given brain area can be involved in processing functions of more than one kind; and second, a brain area that evolves to perform one function can later be pressed into service to participate in performing other related functions as well.
Models like Hurley's (Reference Hurley2008, p. 41) may be too specific in assigning hardwired logic to each problem. It is like tracing the functions of my word processor, or my spreadsheet, through the hardware of my computer. Reuse implies that the hardware can be more flexible, like the general-purpose hardware in my computer that supports a variety of software in the same array of logic elements.
In this light, can cognitive functions be independent when they have overlapping neural implementations? Of course. For example, numbers in a computer's register do not gain their meaning from any particular bit. Rather, it is the combination of bits, 16 or 32 at a time, that determines what is represented. With 16 bits operating as independent detectors, a brain could store 16 different events. But when combined as a binary number, the same 16 bits can code more than 64,000 distinct states. As the number of elements available increases, the combinatoric advantage of this distributed coding becomes overwhelming. Given the large swaths of brain involved in almost any mental operation, neural reuse becomes inevitable.
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The tension between interpreting the brain as a collection of specialized areas and as a distributed network is as old as brain research itself. Rejecting the medieval idea that the brain was unitary because the soul was indivisible, nineteenth-century phrenologists emphasized modularity. Although these phrenologists got the details wrong because of inadequate methods, they introduced the idea of different functions being handled by distinct cortical areas. The idea was made concrete by neurologists such as Fritsch and Hitzig (Reference Fritsch, Hitzig and Pribram1870/1960) (sensory and motor areas), Broca (Reference Broca1861) and Wernicke (Reference Wernicke1874) (language areas), and many others. Distributed coding and the neurological evidence for it came from Karl Lashley's (Reference Lashley1929) mass action, through his student Karl Pribram's (Reference Pribram1971) distributed coding, to present-day parallel distributed processing.
The contrast between the “concept empiricists” and the rational or amodal concept also has a long history, far more than “the last twenty years or so” (as Anderson writes in sect. 4, para. 3) and unknown to most philosophers. The idea that “the vehicles of thought are re-activated perceptual representations” (Weiskopf Reference Weiskopf2007, p. 156) – which Anderson refers to in this section (same paragraph) – was championed at Cornell by Titchner, a student of Wilhelm Wundt. He fought a long battle with the followers of Külpe at Würzburg, who saw mental life as built of a great hierarchy of ideas. The controversy was defined as an evaluation of the role of imageless thought. Külpe insisted that some ideas had no associated images, and that Titchner just hadn't found those ideas yet. Titchner, in turn, held that all ideas included images, and that Külpe hadn't found the images yet. Each founded a school to press his introspection, and the battle raged around the turn of the twentieth century. Eventually, the whole controversy blew up in their faces, as it became clear that the introspective method could not resolve the issue. Objective data, not private opinions, were necessary for psychology to become scientific. Tragically, philosophers of mind continue to use the discredited method, disguised in phrases such as “it is obvious that” or “a moment's thought will reveal that.” Introspection is a good starting point for an investigation, but it can never be an ending point.
The essential features of the “action-sentence compatibility effect” are also older than Glenberg and Kaschak (Reference Glenberg and Kaschak2002) (referred to in section 4.1, para. 2, of the target article). An obvious example is the Stroop effect (Stroop Reference Stroop1935), well known to cognitive psychologists. Color naming is easy when a printed color name is in the corresponding color, but difficult when the color and name are incompatible, such as the word “blue” printed in red ink.
There are really two parts to the reuse hypothesis: First, a given brain area can be involved in processing functions of more than one kind; and second, a brain area that evolves to perform one function can later be pressed into service to participate in performing other related functions as well.
Models like Hurley's (Reference Hurley2008, p. 41) may be too specific in assigning hardwired logic to each problem. It is like tracing the functions of my word processor, or my spreadsheet, through the hardware of my computer. Reuse implies that the hardware can be more flexible, like the general-purpose hardware in my computer that supports a variety of software in the same array of logic elements.
In this light, can cognitive functions be independent when they have overlapping neural implementations? Of course. For example, numbers in a computer's register do not gain their meaning from any particular bit. Rather, it is the combination of bits, 16 or 32 at a time, that determines what is represented. With 16 bits operating as independent detectors, a brain could store 16 different events. But when combined as a binary number, the same 16 bits can code more than 64,000 distinct states. As the number of elements available increases, the combinatoric advantage of this distributed coding becomes overwhelming. Given the large swaths of brain involved in almost any mental operation, neural reuse becomes inevitable.