Seance Sunday: A Mechanical model of human learning and memory Part 1

This week’s Séance Sunday will be on a paper by D. E. Broadbent.

The paper begins with the proposition that people hate model building. The paper’s purpose is to describe a very basic model of the human perceptual system.


The above figure is the simple model for attention. Needed are a Y-shaped tubes and some small balls. Each ball is numbered individually. The Y-shaped tube has a narrow mouth that takes only one ball at a time. At the junction of the stem and the branches is a flap that typically hangs downward, though it can also be pivoted to close off one branch or the other. The pivoting is done by a handle on the outside of the tube. When no human turns the pivot, the ball is free to move into a branch, knocking the flap freely.

This model is supposed to represent human attention, with the balls representing incoming stimuli. The branches represent different sensory modalities. The stem represents a response. Dr. Broadbent says that the behavior of the model represents human in these ways:


In other words, having several senses being paid attention to at once will cause distraction, and nothing will be properly processed by the brain. However, choosing to focus on one sensory modality at a time means that attention can be focused and information, therefore processed.


In other words, the first sensory modality to be incoming will take precedence in being processed over the next sensory modality coming right after it.


In other words, we are more attuned to certain aspects of a sensory modality than other aspects. For example, we may be able to see this or that color better than another, or hear this or that tone better than another. We are evolutionarily wired to be amore attentive to certain stimuli. For example, mothers’ brains are wired to be attentive to a baby’s cries, whether that baby is hers or not. Hearing any baby cry, a mother’s brain will perk up and pay attention, even if all her babies have grown up.


A stimuli that is more forceful will take precedence in our attention. For example, we pay more attention to a bright flashing light than to a nearby low dull tone. Or we may pay more attention to that loud roaring saber tooth tiger than to the pretty butterfly hovering near a flower just to our side.

Capture Capture

In other words, our senses can become acclimated. Think of a perfume–you smell it at first once you spray it on, but shortly thereafter, you no longer smell if on yourself. Your olfactory system has become acclimated.

Capture Capture2

In other words, it is not so much the speed at which a signal is oncoming, but more, how many signals are incoming in a given time interval, that affects processing of stimuli.

This article will continue in a part 2 with the remaining scenarios the Broadbent paper describes.


Findings Friday: Lucid Dreamers

Who wouldn’t want to lucid dream,–be aware of oneself when dreaming, and able to control the dream? I sure would. I experienced it once, and needless to say, the experience left me craving more.

There are techniques to enable yourself to lucid dream. They will be discussed in a future article.

This article, however, will focus on the lucid dreamers themselves.

Lucid dreamers may be more self-reflective than the general population, a new study conducted at the Max Planck Institute of Psychiatry at Munich has indicated.

It was found that the anterior prefrontal cortex, which is involved in controlling conscious cognitive processes and plays a role in self-reflection, is larger in lucid dreamers than in non-lucid dreamers. This suggests that metacognition and lucid dreaming are closely connected.

Brain scans taken of subjects solving metacognitive tests while awake indicated that brain activity in the prefrontal cortex was higher in lucid dreamers than non-lucid dreamers. The researchers thus concluded that those who can lucid dream are more self-reflective in daily life.

The researchers want to go further and determine whether metacognitive skills can be trained.

Now, of course, correlation does not mean causation. And just because a brain region shows activity does not necessarily mean that brain area is involved in a particular process being studied. It may very well be that the brain region being activated during an activity is actually shutting down other processes. So, this study is a good preliminary one, but as is always said, more research needs to be done.

Techniques Thursday: Memory Sleuth: How to tell a memory is false

In light of an earlier article I wrote on the vulnerability of memories, and how false memories can be planted in our minds, I decided to write an article on how to tell a memory is false.

Consider Madrigal (yes, it’s the name of a book character, from Dreams of Gods and Monsters if you must know. I’m reading it now and rather enjoying it. No, I’m not linking it because I get a commission from the publisher if you buy the book. I wish, though. No pun intended. And yes, if you read the trilogy, you would get the pun.)

Moving on.

Consider Madrigal. She claims to have been raped by the White Wolf when she was younger. She repressed the memory, but after undergoing therapy with a psychologist, the memory was unearthed, like old pottery from a deserted cave. Her explanation of the situation and her memories are detailed, emotional and provocative. Can she be trusted? Or more aptly stated, can her memory be trusted?

An examiner an focus on groups of memories or on the individual remembering to determine whether a particular memory is a false one.

one way to potentially do this is via criteria-based content analysis. The idea behind this analysis is that false statement have inherent differences, in relation to veritable statements. 19 criteria are scored, such as logic unusual details, spontaneous corrections, etc.

True memory reports, though, tend to contain more detail than dishonest or false ones. The details are also more sensory.

The best approach to determining false memories are to combine various approaches:

  • focus on groups of memories
  • focus on the individual reporting the memory
  • focus on the details of the memory

 Working to determine how sensory-detailed a memory is, on how this makes sense, and how the structure of the memory is organized, can help determine if a memory is a true or false one. However, more research needs to be done in this arena, to develop not only personal strategies for determining the veracity of a memory, but also for developing laboratory-oriented techniques, such as better neuroimaging, etc. to determine the structure of memories.

Manic Monday: Loftus lost in the Mall

We’ve heard about how false memories can be “planted” in someone’s mind. For example, people can be convinced they committed a crime they never did commit–in just a few hours! Others have been convinced they were raped, or molested as children.

In 1999, Dr. Elizabeth F. Loftus conducted a study that greatly impacted our understanding of human memory, and its superb vulnerability.

Dr. Loftus begins her notes by stating that the idea to plant ideas in people’s minds was just that–an idea. She thought it was safe to do: getting someone to create a memory of being lost most likely won’t be traumatic. Dr. Loftus had been at a birthday party and she had casually told a friend about her idea. He then brought his daughter over and asked her “Do you remember that time you were lost…”

Dr. Loftus chimed in after and asked the daughter if she had been scared when she was lost.

It would be months, however, before any sort of research design had been done.

In 1991, Dr. Loftus taught her cognitive psychology course about memory distortion as she had been doing for 20 years. She had an extra credit assignment that she always had: go out and try to distort someone’s memory or “create” a new memory in their minds. Her hope with this sort of assignment is to indicate to students that it is rather easy to plan a memory in someone’s mind, and once planted, it becomes as real to the person as their “real” memories. (Sounds sorta like Inception to me. Awesome!)

Students go over and try to convince their roommates they had chicken instead of burgers the night before, and safe things like that.

In 1991, however, Dr. Loftus created a twist in her assignment: is there a difference between changing the detail of a memory, and planting an entirely new one?


Dr. Loftus got back the assignment papers, and several students had tried to convince their relatives they’d been lost. One student even involved both his mother and brother. The brother was subsequently convinced that he’d been lost in the University City shopping mall in Spokane, Washington.

Another student involved her daughter, who, at the prodding of her mother, came to believe that she had once been lost at a ranch.

A study was eventually born. It involved three phases:

Subjects first completed booklet with four stories about childhood events provided by a relative of theirs. Later on, they were debriefed and told that 4/6 of their memories were false, and then they were asked to identify which of the memories they thought were indeed false.

According to Dr. Loftus:


She further noted:


She also interestingly reports a little about past-lives and how memories can be created regarding them:


So all in all, Dr. Loftus, as well as a host of other researchers, have studied the phenomenon of false memories being planted in another person’s mind. One does wonder, then, how this knowledge can be used, such as during interrogations, trials, and more. Seems rather interesting, but also, it creates a responsibility in others to not plant false memories in another’s mind to implicate them in crimes or events they have not committed, nor took any part in. Further, it behooves individuals to understand memories to ensure that they are never “tricked” into believing something that never happened.

Seance Sunday: The Snark was a Boojum

This article certainly starts off fun. The article, written by Frank A. Beach, begins with a reference to Lewis Carroll’s poem, “The Hunting of the Snark.”  In the poem, a crew goes hunting for a snark, which turns out to be a very dangerous boojum.  The article by Beach goes on to state that for anyone who has never read the Carroll poem, must now be informed that the poem contains a number of characters:


All this sets up the rest of the paper, where Beach indicates that thirty years prior, Comparative Psychologists went hunting for Animal Behavior. The albino rat was found and Comparative Psychologists disappeared. Beach then proposes that his paper traces the history of Comparative Psychology in the US, as well as explain the attitudes of psychologists towards comparative psychologists.

He explains what comparative psychology is:


He makes the rather valid point that only a small subset of extant species are studied in the lab; in particular, mammals. Therefore, comparative studies can only be deemed comparative in a very restricted sense. Research went from using mostly amphibious animals, to using mammals.

Now, today, both groups of animals are used; though rats and mice are big in neuroscience and psychology. As Beach states, there is excessive concentration on just a few animals.

Beach argues that we have mainly been narrow in our selection of animals to study.

Now, this makes sense. However, the animals chosen are chosen because their physiology is similar to humans, enough so that any results coming from animal experimentation can be applied to human studies. Also, rats are a favorite because they are easy to rear, are generally hardy unless some strain makes them immuno-susceptible, and they can generally exist well in a laboratory environment. I do understand what Beach is saying, however, and feel that he does indeed have a point. What do you think?

He further argued on the types of behaviors psychologists study, which tend to be focused on a small group of behaviors:


He further argues that he thinks that the reason psychologists rely on just a few behaviors to study is mostly due to tradition:


Now he does admit that there are advantages and disadvantages to using a small concentration of animals.

As Beach eloquently states:


However, he does add later on:


So what do you think; is Beach right?

Seance Sunday: Papez Circuit

Many of us have heard of Papez Circuit, the neural network that controls human emotion.

In 1937, James Papez wrote an article called A Proposed Mechanism of Emotion. He begins his article by citing the relevant word of Bard and Cannon, who will be discussed in a later article. But Papez cites the reason for his article was to discuss the hypothalamus, hippocampus, the gyrus cinguli (aka the cingulate gyrus), and their interconnections.

He says:


He further wrote:


In other words, emotional expression, as according to Bard’s experiments, depends on the hypothalamus rather than the thalamus or cortex. However, the subjective aspects of emotions depends more on the cortex, which then plays a role in understanding what we are feeling, and why.

Papez spends a significant amount of time explaining the neuroanatomy he thought was involved in emotion:


He uses the above diagram, going through the connection between parts, and what he thought that meant. For example, he says the mammillary bodies have a connection between the hypothalamus and the cortex:


Now, Papez circuit itself is a proposed network whereby it is the hypothalamus which bears the most significance to emotional expression. Interestingly, Papez work had involved cases of rabies, which can produce aggression in those afflicted with it. He found that there was damage to the hippocampus, which led Papez to believe then that it was the hippocampus which was responsible for emotional expression. He also further noted that the stimulation of the senses, such as taste or smell, could bring about emotional responses, thus giving him more reason to believe that it was the hippocampus that is responsible for the expression of emotion.

The Papez circuit involves a number of brain structures:

hippocampus → fornix → mammillary bodies → mammillothalamic tract → anterior thalamic nucleus → cingulum → entorhinal cortex → hippocampus

The hypothalamus and the cortex are connected in Papez circuit, and are seen to act as the emotional network of the brain. Papez stated that the cingulate cortex projects to the hippocampus, which then projects to the hypothalamus via the fornix. And though his anatomy may be correct, Papez interpretation of the circuit was not fully right.

Of course, we know today that the hippocampus is responsible for emotion. With Papez work on aggression, he thought it was the hippocampus that was responsible for aggression. However, we know today that the amygdala (which is close to the hippocampus) receives connections from the hippocampus. Considering the hippocampus is the storage of memories, (somewhat so, though things are more complicated than this, and will be explored in a future article), it makes sense then that certain emotions may be triggered by strong memories.