Thursday, June 17, 2021

Neuroscientists Keep Using Misleading Coloring in Brain Visuals

In my July 2018 post "The Brain Shows No Sign of Working Harder During Thinking or Recall," I looked at quite a few brain scan studies looking for neural correlates of thinking or recall, and showed how such studies show no evidence that brains work harder when you are thinking or remembering anything. Below I will discuss some other studies not listed in that post, studies looking for signs of increased activity when a person is engaging in some kind of recall, recognition or heavy thinking. 

  • A study published in November 2018 was entitled "BOLD Activity During Correct-Answer Feedback in Cued Recall Predicts Subsequent Retrieval Performance: An fMRI Investigation Using a Partial Trial Design." Some fMRI scans were made of dozens of subjects during a verbal recall task. Figure 4 of the paper shows a graph displaying signal changes of no greater than about .3 percent. This is about 1 part in 1000, no greater than we would expect to see by chance. The results are quite consistent with the claim that memories are not stored in brains.  No significant sign has been found that brains act differently during recall. 
  • An August 2020 paper was entitled "Aging alters neural activity at event boundaries in the hippocampus and Posterior Medial network."  Hundreds of subjects were shown a movie and had their brain scanned. Ignoring Figure 1, which doesn't deal with recall, and looking at Figure 2, which does deal with recall, we see that the average signal change was only about 1 part in 1000, and that the greatest reported signal change (in the highest outliers) was only about 1 part in 300. No significant sign has been found that brains act differently during recall. 
  • A 2010 study not mentioned in my July 2018 post is the study "Age-related effects on the neural correlates of autobiographical memory retrieval."  The study did brain scans of 14 young and 14 old people during recall of things that had happened in their lives. None of the results reported in the paper's graphs (such as Figure 1) show a percent signal change greater than 1 part in 1000. The results are quite consistent with the claim that memories are not stored in brains.  No significant sign has been found that brains act differently during autobiographical recall. 
  • A January 2021 study was entitled "Neural correlates of recursive thinking during interpersonal strategic interactions." Figure 3 of the study shows no percent signal change greater than about 1 part in 300.  The results are consistent with the idea that thinking is not produced by the brain, and no significant sign has been found that brains act differently during thinking. 
  • A 2018 study not mentioned in my July 2018 post is the study "Neural correlates of free recall of 'famous events' in a 'hypermnestic' individual as compared to an age- and education-matched reference group."  The study scanned the brains of 11 people while recalling famous events. Figure 3 shows that the percent signal change was no greater than about 1 part in 500. The results are consistent with the claim that memories are not stored in brains.  No significant sign has been found that brains act differently during recall of famous events. 
  • A 2015 study not mentioned in my July 2018 post is the study "Amygdala Activity During Autobiographical Memory Recall in Depressed and Vulnerable Individuals: Association With Symptom Severity and Autobiographical Overgenerality."  We are told, "Sixty healthy control subjects, 45 unmedicated currently depressed individuals, 25 unmedicated remitted depressed individuals, and 30 individuals at high familial risk of developing depression underwent functional MRI while recalling autobiographical memories in response to emotionally valenced cue words."  Figure 1 of the paper has a graph showing that the percent signal change was less than .2 percent, less than 1 part in 500. The results are consistent with the claim that memories are not stored in brains.  No significant sign has been found that brains act differently during recall.
  • A 2014 study not mentioned in my July 2018 post is the study "Mean signal and response time influences on multivoxel signals of contextual retrieval in the medial temporal lobe." Brain scans were done "while participants retrieved pair, spatial, and temporal source memories." 17 subjects had their brains scanned during such recall.  Figure 3 shows that the percent signal change was less than .1 percent, less than 1 part in 1000. The results are consistent with the claim that memories are not stored in brains.  No significant sign has been found that brains act differently during recall.
  • A 2019 study not mentioned in my July 2018 post is the study "Common and Distinct Functional Brain Networks for Intuitive and Deliberate Decision Making." The study is unable to show brain imaging evidence for brains causing thinking, because its graphs (Figures 4, 5  and 6) show no percent signal change greater than 1 part in 300. 
As we can see from examples like the ones above and the more numerous examples ones in my earlier post, brains look the same when you are doing nothing as they do when people are thinking hard, learning and remembering. So how is it that neuroscientists manage to create the impression that particular parts of the brain are more active during particular mental activities? They use two main tricks:

(1) The trick of wrongly using the words "activated" or "activation" when referring to differences in activity that are only about 1 part in 1000, the kind of difference you would expect to occur by chance. Such language is profoundly misleading.  All parts of the brain are active at all times, and there is no appreciable effect of certain brain regions "turning on" during particular mental activities. 
(2) The trick of visuals that depict brain activity differences of only about 1 part in 1000 in bright red, thereby suggesting a very big difference when there is only an extremely slight difference.  You can read here about how such a trick is performed. 

We can imagine a racist using similar coloring tactics to mislead us. Getting data showing negligible temperature differences between races of only 1 part in 1000, the racist might show us a diagram of different races, depicting some particular race with bright red heads, in an attempt to persuade us that the members of that race are "hot-headed" and prone to get angry.  

Eye pupils vary by 500% under different light conditions, and heart rate differs by as much as 300% between resting and heavy exercise. That shows you that eye pupils are really involved in vision, and that hearts are really involved in supplying the body with blood.  The thousand-times weaker variation in brain activity between mind resting and heavy mind activity does nothing to establish claims that brains produce thinking or that brains store memories. 

The tricks and fallacies of those trying to prove that brains make minds are similar to the tricks and fallacies of the people who called themselves phrenologists in the nineteenth century. In that century, a system called phrenology was very popular.  It was all based on the idea that particular mind functions and personality traits were concentrated in particular areas of the brain, and that you could tell something about a person's mind or personality by feeling little bumps on his head. If you click on the link here, you can find many long works attempting to prove this extremely erroneous idea. In fact, following that link will show that in its vast archives of old books www.archive.org has more than 500 books devoted to teaching the bunk that is phrenology. Most of the writers of such books  thought they were teaching the "latest and greatest" neuroscience when they taught phrenology nonsense.   A wiser future age will look back on the main papers of today's self-described "cognitive neuroscientists" the way we look back now on the phrenology volumes of the nineteenth century. 

phrenology
 

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