Second-level thinking occurs in two forms, subconscious and conscious. It is defined to be occurring when the mind discovers meaningful associations between stored memories (i.e., earlier-formed, data-storing, neural networks) and incoming information, between two or more sets of incoming data, or between stored memories. Second-level thinking happens continuously at the subconscious level and intermittently at the conscious level. (This implies that subconscious thought precedes conscious thought, a phenomenon that brain-scanning has verified. We will refer to this again, in Revelations And Conversions.)
Scanning incoming data for relevancy and significance is second-level thinking’s most important function. A living entity’s most relevant and important concern is almost always survival (resulting in a constant search for active threats or potential danger, and for food and water). Its second most relevant and important concern is the possible opportunity to reproduce. The nature of this kind of thinking means that information is almost always stored in conjunction with emotional overtones.
Almost all subconscious second-level thinking is immediately discarded (as most habitat environments are benign and otherwise not of much significance). When meaningful relationships between incoming data and stored memories are found, they may trigger body reactions (such as danger-avoiding activity) and may break through from the subconscious into the conscious mind, where they are further considered.
Again, animals make these associations and comparisons (continually at the subconscious level, and periodically, with varying degrees of ability, at the conscious level). Animals generally ignore non-threatening events but react to potential danger situations, demonstrating that they know from past experience or instinct (remembering the gosling experiment) how to distinguish one from the other.
(Animals can do more than simply react to situations; they can plan ahead, using a knowledge of prevailing circumstances—social as well as situational. Dunbar [after describing how an old, ousted, male chimpanzee used rewards and punishments to manipulate an alliance with a weak young chimpanzee and so regain and retain control of a harem from its new, stronger leader] concluded that the behaviour of monkeys and apes showed that they can predict the outcome of their actions.)
Associating memories and/or stimuli in meaningful ways forms the basis of second-level thinking; language is certainly not needed to make such neural network linkages. Infants demonstrate that they can make associations and comparisons long before they can speak; for example, they react with surprise if some aspect of a frequently observed image has been changed.
The critical aspects that distinguish second-level thinking from first-level thinking are that, during second-level thinking, two or more sets of information are compared, differences are noted, and the relevance of any found variance is sought. The degree to which any detected difference is understood depends upon the sophistication of the animal—its evolutionary level, past experiences, education and intelligence. Simple animals may understand little about any discovered differences; humans may understand much.
The discovered relationship may, as previously noted, be immediately discounted and forgotten. However, those deemed to be significant may become stored as part of a new neural network if one or more links are forged between pre-existing patterns. The simple example that follows might clarify this important process.
Imagine that I want to drill a hole through a block of wood, and that I have the required drill but the drill bits are too short. What would I do? Well, I would look around to see what I had that might be long enough. When this first happened to me, it took a little while to think of cutting the head from a long nail then using the nail. However, the second time this occurred, I quickly remembered my previous solution.
The first situation above entailed second-level thought, the second occurrence did not. In the first situation, my mind had to mentally list the properties a useful bit must possess (strength, hardness, rigidity, length and so on) then cause me to seek something that possessed such properties. The two data sets (the neural network patterns that stored information about what was required, and the streams of data coming from my eyes as I looked over my workshop) were compared, and matches that denoted relevance to the problem induced temporary ion-flow loops between corresponding aspects. Once a solution was found, once I had spotted a nail and realized that it would serve my purpose, the temporary links that were significant were retained long enough to be made permanent through the growth of synaptic knobs, thus becoming available for future use as part of my neural network complex. Linking and learning turn out to be the same thing.
Simply remembering something done, heard, seen or read about is not second-level thinking, it is merely reactivating previously formed neural paths. No new links are made, and nothing new is learned during simple recall. In other words, recalling memories to mind is similar to looking at a picture or running a movie in one’s head, whereas second-level thinking is more akin to looking at two pictures or running two movies side-by-side, while constantly comparing and contrasting the two.
Infants, with brains containing well over 100 billion neurons, make neural links continuously as they attempt to join sensory stimuli with information that is stored in memory. Infants and young children learn quickly and easily, because stimuli are being stored and linked on a more-or-less “tabula rasa” (a term meaning “blank slate,” first used by John Locke in 1690 in his Essay Concerning Human Understanding to describe the mind of a newborn). That many of these associations will turn out to be incorrect and unusable is inconsequential; the links that matter are the ones that are subsequently reinforced through use. Billions of early made connections remain unused throughout all our lives, slowly atrophying. Christian de Duve pointed out that neurons initially make many loose connections; these are strengthened only if useful, and are discarded if not. The associations that are used, of course, are those connecting memories that, by being linked, provide useful understandings: the name of a toy, object or a sibling; the idea that certain results always follow certain activities (things fall to the ground when released, for instance); how to call for food, etc. Adults learn more slowly, because their minds first attempt to fit new stimuli into previously existing networks, and only when this can’t be done do they progress to looking for, then forming, completely new links. In other words, adults do not immediately think when reacting to a stimulus; they first search, very rapidly and almost entirely subconsciously, for past associations and use them, whenever the fit seems close enough.
Realizing that second-level thinking is little more than electrochemically comparing memories with incoming data (or comparing memories already in storage), recognizing relationships of significance between them, then making new neural links, tells us again that this kind of thinking cannot be unique to humankind. The brains of many animals do this. In fact, we should expect linkages to form between memories and incoming sensory stimulations in all animate entities, because sense receptor cells and neurons exist to provide information so that similarities and differences between incoming and stored memories can be detected. Animals and humans learn what these variations may imply and use this knowledge to survive and to mate. In short, humans are not the only life forms that think—animals do too.
However, thinking did not become what we generally understand it to be today until early humans discovered the use of words and languages. The next section shows how this ability led to a more comprehensive level of thought, one that we will be calling third-level thinking. Third-level thinking is, primarily, a human activity.
- It also occurs as a stress-relieving activity, as will be discussed later.
- This is why information from the eyes is first routed to pass through networks that check for changes—see The Brain, footnote 9.
- Penfield, more than seventy years ago, noted that electrically stimulating tiny areas of the temporal lobes of a patient produced sensations of different smells, accompanied by associated memories and feelings.
- Stimuli propagate in two ways: as electrically charged ions, which flow along and between neurons; and as chemical discharges (e.g., the release of adrenaline or endorphin) which move about in body fluids. Neural transmissions are relatively fast, and some of them may give rise to feelings (e.g., pain). Chemical transmissions are relatively slow to act and take longer to fade; they may give rise to the longer-lasting emotions (e.g., happiness). Emotional responses are considered to be inherited from ancient learned responses. Animals employing such devices have inherited them from ancestors who first developed these as solutions to survival or reproductive threats. Thus human males react emotionally (particularly in early adulthood) to other males entering their territory or attempting to usurp females. Overt emotional displays act as warnings, and may obviate the need to use potentially self-harmful force.
For a well-organized and informative discussion of the mind’s psychological development and functioning, see David M. Buss, Evolutionary Psychology: The New Science of the Mind (Boston: Allyn and Bacon, 1999).
- Robin Dunbar, Grooming, Gossip, and the Evolution of Language (Cambridge, Massachusetts: Harvard University Press, 1996), 25.
- Temporary ion-flow loop formation is similar to storing data in random access memory (RAM) in computers; this information is retained only as long as its supporting medium is energized. Permanent link storage, on the other hand, is similar to storing data on a computer’s hard disk, where it remains even after the power is switched off. (This suggests that it may be possible, one day, to retrieve the long term memories stored in a “dead” brain.)
- However, additional synaptic knobs may form, lessening the neural pathway’s resistance to future ion flows and thus somewhat increasing the probability that this path will be chosen above neighbouring others.
- The brain enlarges rapidly in volume, from about 350 cc (cubic centimetres) at birth to double that at six months, doubling again to approximately adult size (some 1400 cc) at four years old. (See Susan Greenfield, The Human Brain: A Guided Tour [New York: Basic Books, 1997].) Dendrites form most rapidly after this neuronal growth has occurred—from four to ten years of age. The majority of association-forming neural connections are made during these early years.
Newborns and very young infants initially experience stimuli devoid of context. Stimuli produce feelings and emotions—pleasure, pain, satisfaction, rejection, joy, anger, and so on—with initially no understanding that a link between stimuli and emotion, or between past cause and future effect, exists. Understanding only begins to arrive after experiences have become stored as memories, when neural links between them, or between them and new stimuli, can be made.
(Although the retrieval and use of some of the information already held in the mind is often under rational control, the storage of information coming to our brains from our body’s sensors is usually not. However, when we want to sure we will remember something of importance, we can consciously direct our minds in the way it stores thoughts. Thus, for example, as a reminder to telephone Bill early tomorrow, we can picture ourselves drinking a breakfast mug of coffee, then picking up the phone. The next morning this task comes to mind while coffee drinking, just as desired. We remember to call because we have associated or linked it to another action, an action that needs no reminder to occur. Mnemonics, used in memory training, employ the same trick.)
- Christian de Duve, Vital Dust: Life as a Cosmic Imperative (New York: Basic Books, 1995), 241.
- Memory-building in infants must progress from knowing nothing, to becoming vaguely aware of a shape, noise, or other sensation, then on to storing this as an unrecognized neural pattern that seems to have some significance. Subsequent detection of similar stimuli, because it is of a comparable nature, follows the now-existing neural pathway and thus reaches the first neural patterns stored. Any extra information brought in by the new stimuli may then be stored as additional neural patterns linked to (i.e., associated with) the earlier stored patterns. In this way, memories slowly build in complexity and data completeness, until they become what adolescents and adults experience—full-blown mental representations of objects and events that have existed (or exist) in the outside world.
(It is because many repetitions of an event must occur before it can be meaningfully linked to create an understanding, that fully one-third of all blind-from-birth adults, whose ability to see has abruptly been restored, revert initially to closing their eyes to navigate and generally make sense of the world.)
- We must again differentiate between simply recalling memories and second-level thought. The example of European blue tits all over England opening tinfoil caps on milk bottles to obtain the cream is widely known. But only the first bird to discover this was “thinking”; the others simply copied what they saw another bird do. (The first bird associated or linked memories of cream at the top of bottles and memories of pecking to make holes; it was “thinking.” Birds copying this behaviour were simply demonstrating “learned” behaviour, or memory recall, not original thinking.)
A related observation involves Imo, a macaque monkey, who discovered the benefits of washing sweet potatoes in the sea before eating them. This could have been due to second-level thinking (for instance, if Imo had associated memories of eating sweet potatoes found in the sea and sensory perceptions that these potatoes lacked grit or were saltier, etc., and were more enjoyable to eat). The many other macaques who later adopted this practice did so because they had seen and memorized, then recalled and imitated, what Imo did. Thinking was not involved in these subsequent behaviours. (Similarly, much of what any animal does, including humans, does not require conscious thought.)
(Note that each of these behaviours have come into common use, and thus might be considered to have become part of the animal’s culture, to be passed through repetition from generation to generation, and to die out when their practice is recognized as being no longer beneficial. Human cultures build in exactly the same way.)
- Plants, also, react to changes in their environment. For example, stomata close in dry weather, rootlets grow toward nourishment, flowers typically open in sunlight, etc. Although no one would claim that plants are thinking when they respond to changes in the environment, this kind of behaviour is genetically encoded, and was probably passed on to animals when they later evolved. Thus, plant reaction to environmental variations may be regarded as being a precursor to animal responsiveness and even to human thinking.