categorization

We've all done it: used the wrong name when we know the right one perfectly well. And we all know when it's most likely to happen. But here's a study come to reassure us that it's okay, this is just how we roll.

The study, based on five separate surveys of more than 1,700 respondents, finds that these naming errors (when you call someone you know very well by the wrong name) follow a particular pattern that tells us something about how our memory is organized.

In the study, 18 children (aged 7-8), 20 adolescents (13-14), and 20 young adults (20-29) were shown pictures and asked to decide whether it was a new picture or one they had seen earlier. Some of the pictures were of known objects and others were fanciful figures (this was in order to measure the effects of novelty in general). After a 10-minute break, they resumed the task — with the twist that any pictures that had appeared in the first session should be judged “new” if that was the first appearance in the second session.

One survey of nearly 200 undergraduate college students who were not living with a parent or legal guardian found that 55% reported getting less than seven hours sleep. This is consistent with other surveys. The latest study confirms such a result, but also finds that students tend to think their sleep quality is better than it is (70% of students surveyed described their sleep as "fairly good" or better).

Memory begins with perception. We can’t remember what we don’t perceive, and our memory of things is influenced by how we perceive them.

Our ability to process visual scenes has been the subject of considerable research. How do we process so many objects? Some animals do it by severely limiting what they perceive, but humans can perceive a vast array of features. We need some other way of filtering the information. Moreover, it’s greatly to our advantage that we can process the environment extremely quickly. So that’s two questions: how do we process so much, and so fast?

‘Face-blindness’ — prosopagnosia — is a condition I find fascinating, perhaps because I myself have a touch of it (it’s now recognized that this condition represents the end of a continuum rather than being an either/or proposition). The intriguing thing about this inability to recognize faces is that, in its extreme form, it can nevertheless exist side-by-side with quite normal recognition of other objects.

Previous research has found that individual neurons can become tuned to specific concepts or categories. We can have "cat" neurons, and "car" neurons, and even an “Angelina Jolie” neuron. A new monkey study, however, reveals that although some neurons were more attuned to car images and others to animal images, many neurons were active in both categories. More importantly, these "multitasking" neurons were in fact the best at making correct identifications when the monkey alternated between two category problems.

Like human faces, infants are predisposed to pay attention to words. Now a new study shows that they learn concepts from them from a very early age. In the study, in which 46 three-month-old infants were shown a series of pictures of fish that were paired either with words (e.g., "Look at the toma!") or beeps (carefully matched to the words for tone and duration), those who heard the words subsequently showed signs of having formed the category “fish”, while those who heard the tones did not.