The Love Hormone and Memory for Faces

When you see an attractive face, a warm glow may ensue. When you see an ugly or threatening face, just the opposite occurs. Studies in animals have made it clear that a hormone from the pituitary gland, oxytocin, modulates such responses. In animals, oxytocin helps them decide whether to shun another animal or to approach for such purposes as socialization and mating. Oxytocin promotes approach behavior and suppresses avoidance.

If the same processes occur in humans (we use oxytocin too), then it should be reflected in how we react emotionally to others. Well, it does, and that is why it is sometimes called the “love hormone.” The best documentation for such action is that oxytocin is released in great amounts when a mother gives birth and increases the mother-infant bond. How robust this effect is in people is not clear.

Oxytocin could be important for remembering other people. In an experiment in Switzerland, men received a single nasal-spray dose of oxytocin and tested for their ability to recognize previously seen faces. The hormone improved recall of faces seen the day before, but had no effect on remembering non-social objects such as houses, landscapes, or sculptures. The study involved 44 male volunteers who were given three puffs of spray in each nostril of either oxytocin or a placebo. After a 40-minute delay to let the drug reach the brain, subjects were shown photos of 84 faces (half male, half female; 1/3 emotionally positive, 1/3 emotionally negative, and 1/3 neutral) and 84 images of inanimate objects for 3.5 seconds each. One day later, they were shown the same 84 pictures mixed randomly with other pictures they had not seen and asked to identify which photos they remembered and which were new from the previous day.

During the initial exposure (encoding) no differences were found in ratings for approachability (likeability) of either the faces or inanimate objects. Likewise, no oxytocin-related differences were seen for the emotional subcategories of positive, negative, or neutral, although everyone had more difficulty in remembering emotionally neutral faces. Gender of the faces did not seem to make much difference. Maybe this lack of effect was due to insufficient dosage (a single spray of three puffs may not be enough).

Where the drug effect was evident was in recognition memory of the faces. Oxytocin also increased the ability to realize that a new face had not been in the initial encoding group on the learning day.

Other studies have shown that oxytocin has a general pro-social effect, such as trust, for example.Take home message? One thought is the next time you want to attract someone, you might make yourself more memorable if you offered them some nasal spray laced with oxytocin. Of course that is too socially awkward. But one thing that is more practical is to take a few snorts of spray before going to a meeting or conference where you need to remember the new people you meet. Novartis already makes such a spray (Syntocinon). However, the drug’s medical use is to induce labor in pregnant women.

My second thought is there may something to the old saying about “love at first sight.” Certain faces may, for unknown reasons, cause a surge in endogenous secretion of oxytocin in the brain of the viewer and thus give that face a greater impact. Women knew all along the importance of having a memorable face; that’s why they wear makeup and fuss over their hair.

Source:

Rimmele, U. et al. 2009. Oxytocin makes a face in memory familiar. J. Neuroscience. 29 (1): 38-42.

Talking Makes It Memorable

Students learn better when they can discuss test items with their peers. A group of professors at University of Colorado, Boulder, reported a study in which they tested the value of allowing peer discussion of questions during lecture. To break up the monotony of traditional lecture in a genetics course, the lecture was periodically interrupted with a paired set of similar multiple-choice questions (Q1 and Q2) for any given concept was asked back to back. For each question, each student voted for the correct answer with a "clicker," and tallies of votes were automatically posted on the instructors podium computer. After the vote on Q1, students were allowed to discuss possible answers (without being told what the right answer was) and then allowed to vote again. Then, they were asked a second question on the same concept (Q2) and voted without discussion.

Performance results were markedly enhanced on the second vote on Q1. For example, pooled over 16 sets of questions, the average correct response to Q1 without discussion was 52%. But 92% got the question right after they were allowed to discuss it with peers (usually 3-4 classmates). Of this same group, 90% then got Q2 right.

Gains were also seen in the group the gave the wrong vote the first time they saw Q1 (48%). Of these, 42% got the answer correct after they discussed it with peers and 77% got Q2 right. Of those who missed Q1, even after discussion, 44% got Q2 right. This indicates that the understanding gained from discussing Q1 helped them with Q2.

The advantage seen here of discussion is primarily one of improved understanding, not necessarily improved memory. But memory should also be improved because peer discussion engages students in thinking, and thinking promotes consolidation. The sound feedback from talking also reinforces memory. Students recognized a memory benefit, as exemplified in the comment "the answer almost sticks better (italics mine) because we talked through it instead of just hearing the answer." What I would like to have seen is a controlled study of two classes, one that got their lecture interrupted with questions in this way and another class that did not, with a final exam given to both groups in which half the questions were the same as those used in class and half that were new but related.

Source:

Smith, M. K. et al. 2009. Why peer discussion improves student performance on in-class concept questions. Science. 323: 122-124.

Caffeine or Nap: Which Helps Memory?

Caffeine gets our brain pumped up. We are more alert and perhaps should remember things better. Naps have recently been found to help the memory consolidation process. Until now, nobody has made a direct comparison of these two factors in the same people under identical conditions. But Sara Mednick and her colleagues at the University of California, San Diego, now report some helpful findings.
They tested caffeine in a single dose of 200 mg (roughly equivalent to 2-3 cups of coffee) and compared with an episode of napping (60-90 min) or placebo on the effects on performance on three types of memory tasks. For verbal memory, they tested recall and recognition memory of word lists 7 hours after learning, with an intervening nap, caffeine dose, or placebo. In addition, they conducted memory tests for a finger tap and texture discrimination task.They also conducted short-term memory on a different set of words after the first experiment.
Compared with either caffeine or placebo, naps were more effective in the word recall test, both in the consolidation test and in the short-term memory condition. Caffeine actually impaired word recall in the short-term memory task, even though the caffeine had been given some seven hours earlier. Naps also improved recognition memory in the consolidation test and recall of the texture discrimination learning. For the finger-tap learning, naps were ineffective and caffeine markedly impaired performance. The caffeine group did feel less sleepy in the late afternoon immediately prior to the memory testing, but that did not help their memory performance.
What I take from this is that the morning coffee may help you awaken, but don’t count on it to improve your memory. Other research does show that caffeine enhances mood and alertness, reaction times and speed, but don’t count on it to help your memory for things you learn that day. Note to students: all-night study sessions are a bad idea for lots of reasons and probably made much worse by drinking lots of coffee. Note to bosses: letting workers take an afternoon snooze might be a good idea.

Source:
Mednick, S. C. et al. 2008. Comparing the benefits of caffeine, naps, and placebo on verb al, motor and perceptual memory. Behavioural Brain Research. 193: 79-86.

Make Them Learn: With Carrot or Stick?

Feedback is essential for learning. Not only does the feedback need to ensure that learning was achieved (as in testing), but feedback also needs to reinforce the motivation to learn. The age-old questions arises: do we use the carrot or the stick? Which works best, negative or positive reinforcement? Most people have an opinion, but now we have scientific studies of the question. And the answer is, it depends.

For example, three studies showed that adults correct their behavior better in response to negative feedback rather than positive feedback, whereas 8- to 11-year old children respond just the opposite. A follow-up study by Anna van Duijvenvoorde and colleagues in the Netherlands used MRI scans to examine how the brain changes with age and how that relates to feedback-based learning. The subjects were divided into three age groups, 8-9, 11-13, and 18-25. Each subject performed the same learning task and were given positive and negative feedback to improve their performance. After each trial, subjects were shown on a screen an “X” or a “+” to tell them they were wrong or right.

Regardless of the nature of the feedback, young adults learned bdetter than the children. For all three age groups, learning was more effective with positive feedback. Moreover, the decreased learning from negative feedback was conspicuously greater in the youngest age group, while in the young adults, the effect of feedback type was negligible.

Not surprisingly, there were brain scan indicators of differing response to type of feedback. With age, both types of feedback produced a shift toward recruiting more activity in the dorsolateral prefrontal cortex. This part of the cortex was more active after negative feed back in adults but after positive feedback in the 8-9 year-old children. The prefrontal cortex activity was about the same for negative and positive feedback in the 11-13 year olds, suggesting that this is a transition stage in development of learning style and capability.

Take home message? Positive feedback usually works best in young children (that is, after all, how they train seals). Negative feedback works just about as well as positive feedback in young adults. One more point: with the exception of language acquisition, young children are not the superior learners that many people believe.

Source: van Duijvenvoorde, A. C. K. 2008. Evaluating the negative or valuing the positive? Neural mechanisms supporting feedback-based learning across development. J. Neuroscience. 28 (38) 9495-9503.

Negative Emotions and Memory

I have a big section in my memory book on the interference with memory formation caused by negative emotions. I have seen first hand how emotional crises cause the grades of college students to plummet. Whenever a good student suddenly starts making poor grades, I know this student has recently had an emotional trauma. Common problems for college students include trouble making friends, boy/girl problems, parent divorce, homesickness, financial worries―grades invariably suffer.

Recently, I had a reader of this blog challenge my position, pointing out that the most severe form of negative emotions, post-traumatic stress (PTSD), has as its main problem the inability to forget the events that triggered the PTSD. My reader is of course correct. But so also is all the evidence that negative emotions interfere with memory. How do I reconcile these incompatible views?

What is so well-remembered in PTSD are the traumatic events that caused the negative emotions. That is not the same as saying that PTSD patients have exceptional ability to remember other things or learn new things. I contend that their memory for new learning is impaired because of their distressed emotional state. The reason they remember the PTSD events so well is because they rehearse them so often.

All intense situations, even happy ones, tend to be well-remembered because of the intensity of the stimuli and the fact that such situations are repeatedly rehearsed. Rehearsal usually occurs immediately, because of the intensity of stimulation, and is repeated frequently, because the situation had such a big emotional impact. It is not so much the positive or negative aspect of the situation that matters for memory formation, but rather the timing and frequency of rehearsal.

Why do negative emotions interfere with new learning? I haven’t seen formal studies of this question, but what I know about memory allows some useful speculation. First, feelings such as worry, fear, depression, loneliness, and the like, have devastating effects on motivation. Under such conditions, nobody feels much like taking on challenges. Negative feelings also make it hard to pay attention to anything else besides what is causing the emotional distress. Attentiveness is pre-requisite for forming memories of new learning. Negative feelings lead to persistent negative thoughts, and thinking about one thing while trying to memorize another just doesn’t work. Negative feelings also erode confidence and sense of well being, both of which are essential for optimal memory ability. Why confidence and sense of well being are important is unclear, but I suspect they motivate a person to do what it takes to achieve personal goals. In the case of memory ability, it is easier for an up-beat person to take on learning challenges and to do the right things for promoting memory formation.

Internet Is Better for the Brain than Books?

A new brain imaging study showed that going online stimulated larger parts of the brain than the relatively passive activity of reading a novel or non-fiction book.

The science writer, Richard Alleyenne, of the lay article claims that this proves that Internet browsing is better for brain development than reading books. The scientists involved in the research seem to agree. Here are quotes from the article:

It was so stimulating that the authors of the study believe it could actually help people maintain healthier brains into their old age. The study results are encouraging, that emerging computerised technologies may have physiological effects and potential benefits for middle-aged and older adults," said principal investigator Dr Gary Small, a professor at the Semel Institute for Neuroscience and Human Behavior at University of California. Internet searching engages complicated brain activity, which may help exercise and improve brain function." The study, the first of its kind to assess the impact of internet searching on brain performance, is published in the American Journal of Geriatric Psychiatry.

Well, before you tell schools to throw away the textbooks and let the kids browse away, you should know this: when a brain lights up in many places, it means the brain does not know how to deal with all the stimuli. It has not mobilized or focused its neural circuitry to deal with the stimuli efficiently and effectively. In most imaging studies I have read, when a brain knows how to cope with a task, FEWER areas light up. In other words, a brain works best when it can focus its resources. If you want your kids to grow up scatterbrained, put them on the Web. If you want them to develop longer attention spans and improve critical thinking skills, have them read good books. Their brain will thank you.

Reading comprehension: role of eye movements

The capacity of working memory, for example the number of digits in a phone number you can hold long enough to dial it, determines how well you can think and the ability to form lasting memory. I have explained this in my book, Thank You Brain For All You Remember. New insight into working memory capacity has recently been reported by Paul Bays and Masud Husain in a research report in Science. They studied the capacity for visual memory, that is, the number of visual objects a person can hold in working memory. In the study, the emphasis was on the role played by eye fixation.

The design was to display four geometric shapes on a screen, each with a different color. The subjects viewed the screen without moving their eyes, and then the screen was blanked. Next, one of the items was redisplayed, but in a different location and rotation. The working memory task was to remember the original orientation and location. The objects were then withdrawn. Typically, subjects recalled well as long as the set size was no larger than four and as long as the probe object was not changed much. But precision of recall fell off drastically, even with only two or three objects, if the probe object was moved significantly.

Next, they wanted to explore the effects of moving the eyes across the stimulus field. Actually, this presents a major challenge to the brain, because more information has to be held in working memory. Even so, the results when eye movement was allowed and when it was not seemed about the same. The decline in accuracy depended mostly on the number of objects in the set. This suggests that the brain parcels out the task so that memory resources are assigned proportionately to each item. But eye movements are important. In another study, subjects made a series of eye movements to fixate on each item in a five-set display, and the screen was blanked just before the fifth item was fixated. Then subjects were tested to report the location and orientation of the objects. Accuracy was greatest for the fifth item, presumably because the brain had allocated more of its memory resources to registering the item the eyes were about to fixate. This, of course, is being done at the expense of remembering all of the previous four fixations.

These facts must have profound implications for reading comprehension. Certainly, these data seem to support the value of “whole reading” theory, which emphasizes fixing eyes on whole words, preferably where one eye fixation takes in several words.^* The point is that if brain allocates more of its memory resources to each upcoming eye fixation, then reducing the number of fixations ought to increase comprehension, as indicated by working memory of what is seen with each fixation. In other words, the brain can process the meaning of multiple words in an upcoming fixation because the brain is devoting more memory resources to the next fixation task.

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^*This is not to denigrate phonics, for there is compelling evidence that phonics is the best way to learn words in the first place. But once learned, remembering the words you read is probably best achieved by reducing the number of eye fixations.

Source:

Bays, P. M., and Husain, M. 2008. Dynamic shifts of limited working memory resources in human vision. Science. 321: 851-85

What You Can do to Improve Memory (and Why It Deteriorates in Old Age)

As a regular columnist for the newsletter, Sharp Brains - The Brain Fitness Authority, I have just posted an article that might interest those of you whose slipping memory reminds you that you are getting older. The article summarizes research that explains why memory often deteriorates with old age. But it does not have to decline, and the article suggests things you can do to delay or even prevent memory decline. "Eat your blueberries" is only a part of the answer. I present the evidence that as you get older your thinking style has to change. The article suggests ways to do that.

Click here to see the article. Searching on "Klemm" will lead you to other articles I have written for the brain fitness newsletter. And don't forget to order my book, which is pre-requisite to getting the most out of these blog and newsletter posts. The Website now sells it for less than Amazon.