Unconscious Processing of Semantic Information: A Study

Dehaene provides many studies within the book to explain how the unconscious is capable of processing semantic information. In the 1970s Anthony Marcel produced a study in which participants were flashed the word red or blue under the threshold of consciousness, then asked to pick a corresponding color, even though the participant stated that he/she was not able to perceive any word being shown. The study showed that participants were able to choose a corresponding color one-twentieth of a second faster when the word flashed ahead of time was red or blue, instead of an unrelated word. Since the participant was better able to pick the color patch based on the congruent primed word, it can be suggested that the brain is able to unconsciously process

semantic meaning of words that aren’t consciously perceived. Dehaene then goes over the pushback put forth by skeptics. Marcel’s study did not yield large results, but rather a small effect, that could be explained if a subject had in fact seen the flashed word. Marcel’s test needed to be more objective in order to prove that the brain is able to process semantic information unconsciously. Instead of asking participants at the end of the study whether they saw the flashed words, rather do so after every word and have participants attempt to name the hidden word. Though there are many tests that study the ability of the brain to unconsciously process semantic meaning, there is no overwhelming evidence that the brain is able to do so with words.
The metaphor of spreading activation is used in order to describe unconscious processing in how a wave is brought on by sensory stimulus and this wave then travels throughout our brain. Dehaene is able to use this metaphor when going over the use of bottom-up processing and early models of attention. Bottom-up processing is stimulus driven, which means that perception is based upon incoming stimulus. Top-down mechanisms can be unconscious as well, which is shown through the penny or pound sterling coin experiment. In this study participants are shown a picture of the penny or pound, and they must squeeze a handle with a certain amount of excess force to earn the money. Now some of the images were flashed too fast for participants to consciously perceive, but they were still able to exert more force for the image of the pound, rather than the penny, even if both were presented below the conscious threshold. Participants also had sweaty palms, due to the unconscious reward from the pound. Top-down processing was used for the participants brain to emphasis the want of the pound, over the penny even though the images weren’t consciously perceived. Top -down processing is knowledge driven, therefore perception is based on knowledge applied to stimulus. Top-down processing is used to sort out what incoming sensory information will be presented in conscious awareness through the use of attention. Attention will only be given to stimulus that has some sort of value, and if the stimulus has value then it will be given access to consciousness.
Out of all the examples the Dehaene provided, the one that I find most interesting and easiest to explain would be the gorilla experiment.

He did not go over this in depth within the text, but we did watch and discuss the experiment in class. In this experiment the subject is to watch a video where there are six people playing basketball. Three players are wearing white shirts and the other three are wearing black shirts. The subject must count the number of passes made between the players in black shirts. While the subject is paying close attention to the number of passes being made, a person in a gorilla suit enters the video, which is usually unnoticeable to the watcher. At the end of the video the subject is asked whether they saw the gorilla, in which the typical response is no, because he/she was too busy keeping up with the basketball passes being made. This experiment explains inattentional blindness, which a person does not recognize a certain object, due to their attention being placed upon another task. A person is only able to point out the gorilla, once he/she has been told that a gorilla is expected to enter the scene at some point during the video. Attention is required in order to be consciously

aware.
I come from a family of musicians, so my parents and I spend a lot of time going to different places to play music and sing. Playing instruments becomes second nature, due to the learned motor capabilities that come with all the practice and repetition. There are often many times in which I zone out while playing or singing, yet still make it through the whole song. Now once the song is over and I no longer have to play, it is like a snap back to reality. I had never really thought of this as my unconscious taking over, but it is clear to me that I was not consciously aware during a song. We usually play from the same list, so I have become very accustomed to the songs we play, which makes sense to why I would zone out and no longer need to consciously aware of what I am doing.