Babies understand dogs

Gibson, an obviously happy dog

Have you seen the media response to the July 2009 article in Developmental Psychology on babies & dogs? "Infants’ intermodal perception of canine (Canis familairis) facial expressions and vocalizations" by authors Flom, Whipple & Hyde is taking the world by storm, with coverage in DiscoveryNews, LiveScience®, Physorg.com, and more.

The researchers describe how they showed babies (ages 6-24 months) unfamiliar with dogs two pictures: one dog with an aggressive expression and a second photo of the same dog with a non-aggressive posture. Before hearing the barks, the babies showed no preference for either photo and stared around the room at other things in addition to looking at the pictures. But after hearing the barks, babies as young as six months understood the connection between the pictures and the sounds. In older babies, their first look went toward the correct dog picture upon hearing the bark. The study showed that babies responded to the information differently as they got older. Younger babies spent more time staring at the pictures, apparently trying to figure out what was going on.

Jeanna Bryner, Senior Writer for LiveScience®, recently covered the study and interviewed one of the authors. You can see examples of the pictures the babies were shown (the aggressive dog pictures are scary!) and the researcher's (sometimes humorous) thoughts about the study in her article, Babies Grasp Dogs' Emotions.

As our baby approaches the six month mark, I often wonder what she is thinking. She responds to our smiles with smiles of her own. Clearly, understanding emotion is a priority for the little ones. "[These] new findings come on the heels of a study from the same Brigham Young University lab showing that infants can detect mood swings in Beethoven's music," reports Physorg.com. I wonder if babies ever smile at dogs?

Our Princess often startles from loud noise, but our dog's bark has never bothered her. She even sleeps through our dog's (sometimes protracted) barking jags. Somehow, knowing that Princess senses our dog's mood makes me feel better about them sharing her Boppy® pillow.


Photo credit of happy dog Gibson: Mike McCune, through a Creative Commons Attribution 2.0 Generic License.

Cricket ears are amazing

A department store recently used this fact -- Crickets have ears on their knees! -- to peak interest in an email ad. I thought the claim sounded bogus (can you just picture a little cricket with tiny ears sticking out of its legs?), so I took to the Internet to investigate.

It turns out the ad is correct (my apologies to Kohl's). The University of Arizona Center for Insect Science Education Outreach states in their Cricket Information sheet that when the male chirps, "the resulting chirping sound is picked up by the female's ears on her front legs."

Still, I figured that these "ears" would be simple structures, nothing that would even come close to rivaling the complexity of the human ear. But again, I was mistaken. The book Artificial Neural Networks: Biological Inspirations – ICANN 2005 includes a paper entitled "New Ears for a Robot Cricket". The authors, Torben-Nielsen, Webb & Reeve, state that a cricket has "at least four body openings" used in hearing and describes the cricket's auditory system in this way:

[It] consists of two ear drums ... located on the forelegs and connected through a system of tracheal tubes. One extra sound opening on each side of the cricket body ... is also connected to the tracheal tubes.

In short, the cricket's auditory system is nothing less than amazing. The female cricket uses all of this auditory information to track down the location of the chirping male to mate with him.

Male crickets have an equally complex system for "singing", the noise they generate when rubbing their wings together. As scientist Axel Michelsen explains in the fascinating paper "The Tuned Cricket" (News Physiol Sci 13: 32-38, 1998), "a scraper on one wing hits a series of cuticular teeth on the other". (That's the male cricket's instrument!) The male cricket's wing then acts as a "loudspeaker" to amplify the sound so that the female can hear it. The song is optimized to account for the fact that crickets are low to the ground and the resulting frequency of the vibration ensures that the noise can be picked up and heard by the female.

According to Professor L. C. Miall in House, Garden and Field: A Collection of Short Nature Studies, both male and female crickets can hear:

The male cricket hears the sound which he produces, and the female hears the call of the male.

But only male crickets can sing, a fact I learned from the Minnesota Pollution Control Agency. They have a nice page about crickets that includes a coloring sheet, the formula for predicting the temperature based upon the number of cricket chirps in a given amount of time, and a recipe for (eeew!) chocolate-covered crickets.

If bugs are your thing, be sure you drop by The Center for Insect Science Education Outreach. Their website has advice for Using Live Insects in Elementary Classrooms for Early Lessons in Life, with lesson plans, information sheets about various insects (including crickets), and tips for caring and raising the little critters.


Photo credit: Larry Page, through a Creative Commons Attribution 2.0 Generic license.

The intelligence of bees: Meet a beekeeper! Part 2

Michele working the bees
Today, we continue our interview with Michele Bennett Decoteau, beekeeper and author of Blue Hive Journals. (You can read part 1 of the interview here). Our topic today is bee intelligence.

Welcome back, Michele! I've heard that honeybees are intelligent creatures. Earlier this year, Allie Wilkinson at Oh, For the Love Of Science linked to this article, "Honey bees can count to four", describing research from the head of visual neuroscience at University of Queensland. What do you think? Are bees smart?

Bees are really good at being honeybees. Each bee does her job in response to her environment. When a bee [is born and] emerges from her cell, she will begin cleaning out dirty cells within few hours. She will have lots of jobs inside the hive like caring for the young, grooming the queen, and guarding the hive. When she’s reached a certain age, she becomes a forager. This is a really hard job. She needs to find flowers, gather nectar and pollen, and fly home. Then she has to tell her sisters how many flowers [she has located] and how to find them. Sounds simple, but bees are only about an inch long and can find flowers as far away as two miles! That is a tremendously long way to go for such a tiny bug.

Bees use both visual clues (using their eyes) and olfactory cues (smells) to find both flowers and then find home. I have three hives right next to each other and bees don’t go in the wrong one. They know that their home has its own smell that they can follow.

It doesn’t surprise me that bees can count. They use all sorts of clues to find home and to find food. They use the orientation of the sun, they can tell elapsed time (how long they’ve been gone), and they can even use the Earth’s magnetic fields to navigate. Pretty amazing for a creature smaller than my thumb!

Humans have been using bees for a long time. We love their honey and their wax has special properties as well as a great smell!

I just read an article where bees are being employed in a new way: finding landmines! Just as in the University of Queensland study, scientists have trained bees to associate food (in both cases, sugar water) with other cues. In the Queensland study, they used landmarks. In the military case, they used chemical smells found in land mines. So bees can fly over a field and will hover over areas where a land mine is located.

Michele, that is just fascinating! Honeybees are truly amazing.


Join us next week as we continue our celebration of National Pollinator Week with a discussion with Michele about honeybees and colony collapse disorder (read the next part of this interview here).

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If you liked this post, check out:

Meet a beekeeper! Part 1

Meet a beekeeper! Part 3: Colony Collapse Disorder

Meet a beekeeper! Part 4: Learning to keep bees

National Pollinator Week 2009



Photo credits: Michele Bennett Decoteau (top two photographs); bottom photograph: cygnus921, through a Creative Commons Attribution 2.0 Generic license

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[10/2/09: Updated to include links to complete interview.]

Home remedies

In the early 90's, a friend of mine went to South America to perform community service. As part of her stay, she lived with a host family. One day, I received a letter from her in which she told me that she had been ill. I don't remember what was wrong with her (she recovered, thankfully), but I do remember the prescribed cure: she was supposed to drink her own urine.

Which brings to mind an important tip: try home remedies at your own risk!

How popular are home remedies? If you conduct an internet search on the topic, you can unearth over one million pages devoted to these "sure-fire" cures. Barefoot Lass has compiled a list of unusual (although slightly more palatable than my example above!) home remedies, including wet tobacco compresses for bee stings, banana peels for bruises, and rubbing 1/2 of a lime on your head to cure a headache.

Do these cures work? I'm not sure. Overall, I suspect that a small number of home remedies are truly effective, a large percentage do nothing, and a few are downright dangerous.

But some home remedies have actually undergone scientific testing to gauge their effectiveness. For example, Dr. Stephen Rennard of the University of Nebraska Medical Center conducted a 1993 study that showed that chicken soup has anti-inflammatory properties that help you recover from a cold.

More specifically, chicken soup with vegetables was shown to inhibit the activity of neutrophils (white blood cells that fight infection), which in turn was thought to retard the spread of the cold through the upper respiratory tract. Interestingly, the broth alone did not have this property, and the researchers couldn't isolate exactly which ingredient or combination of ingredients in the soup caused this effect. (Dr. Rennard also shares his wife's chicken soup recipe, but notes that other chicken soups have similar properties, although they do vary in their effectiveness.)

So, should you try a home remedy the next time you are sick? Always remember to use common sense and be careful out there!

Using bad science for the greater good

These days, you can't open a newspaper or magazine without bumping into bad science: poorly explained topics, unsubstantiated claims, theories touted as facts. And the web isn't helping any -- anyone can put up a website and claim whatever they choose. So, how do we separate bad science from good?

Ben Goldacre is a British doctor who writes a weekly column in the Guardian devoted to the topic of Bad Science. He also teamed up with Planet Science to develop a series of experiments to test some of the crazier claims.

I like the idea of taking bad science and using it for good. Testing crazy or unproven claims (as long as they aren't dangerous) can be fun. It's also a good opportunity to practice setting up an experiment.

For example, instead of rolling your eyes at the next television commercial -- the one that promises that this new and improved breakfast cereal is tastier than the leading brand -- why not put the claim to the test? Set up your own scientific trial at breakfast. Blindfold your family, put two bowls of cereal (one bowl of the old brand, one of the new) in front of each person, and record their responses. Do they like the new cereal? Could they taste a difference?

Or, if a new dishwashing detergent claims to make your dishes less spotty, do your mom a favor and run a load of dishes. Compare the newly washed glasses to the previously washed ones. How do they compare? Do you get a different answer if you count the spots in a new way? Do you get a different answer depending upon how many dishes you examine?

Questioning the world around you is the hallmark of a good scientist. And that applies to everything you read -- including this post!

(My thanks to CricketB for pointing out the benefits of Bad Science!)

How big are raindrops?

Photo credit: Leon Brooks, BurningWell.org

While I was taking out the trash the other night, I commented to my young son that it was misting outside.

He gave me a funny look and said, “It’s raining.”

I said, “No, it’s misting. It’s not coming down hard enough to be rain.” I started to tell him about the different ways that people might describe rain, like drizzle or light showers, but I stopped short.

How do we define rain? What are the actual meteorological classifications of liquid precipitation? I thought that this would be a simple question, but there's been some debate on the subject.

According to the National Oceanic and Atmospheric Association, drizzle consists of fine water droplets with diameters of less than 0.5 mm; rain is usually larger than 0.5 mm. Fog droplets are similar to drizzle, but they don’t hit the ground.

I found an older set of definitions from the U.S. Department of Agriculture, though the U.S. Geological Survey at The Water Cycle: Precipitation. The 1959 USDA table referenced on this site has definitions for precipitation that include fog, mist, drizzle, light rain, moderate rain, heavy rain, and cloudburst. Part of this table included the median diameters of different precipitation droplets, including 0.96 mm for drizzle and 1.24 mm on up for rain (note that these don't exactly match the NOAA definitions).

I couldn’t wrap my mind around the numbers, so I took the data about droplet sizes and made my own graph. I discovered a couple of interesting things when I sat down with the numbers.

Data taken from a USGS adaptation (The Water Cycle: Precipitation) of Lull, H.W., 1959, Soil Compaction on Forest and Range Lands, U.S. Dept. of Agriculture, Forestry Service, Misc. Publication No.768
First, none of the droplets are very big. Even the largest water droplet -- occurring during a cloudburst -- is extremely small, typically measuring less than 2/10 of an inch in diameter. (Now, I don’t know about you, but I’ve had raindrops fall in my eye and it’s hard for me to believe that they are usually so tiny.)

Second, comparing droplet sizes reveals enormous differences between the categories. Cloudburst droplets (at 2.85 mm in diameter) are over 200 times larger than fog droplets (0.01 mm in diameter).

How do scientists know these things? Here’s one way: In 1971, researcher Motoi Kumai went out into the fog armed with gelatin-coated glass slides and studied the results under an optical microscope. He measured the radii of about 20,000 fog droplets for his paper, published in the Journal of Atmospheric Sciences in 1973. (You can read Arctic Fog Droplet Size Distribution and Its Effect on Light Attenuation in the online journals at the American Meteorological Society. Interesting side note: Kumai found that long-lasting fogs have larger water droplets than short duration fogs.

So, how big are raindrops, anyway? See for yourself! The next time you see a storm brewing, take a piece of colored construction paper outside and lay it securely on the ground. Let the first few raindrops fall and then grab your paper and quickly run inside before you both get drenched. The water droplets should have made marks on your paper; you can take your own measurements. Do you think that your results will be the same or different than those found by the meteorologists? Why?