Letting the Cat Out of the Bag

I’ve talked a lot on this blog about canine social cognition, but what about feline social cognition? That may sound a bit oxymoronic to some, but cats, like other domesticated species, live closely alongside humans, so it makes sense that they could have social cognitive abilities.

However, an important difference between cats and other domesticated species lies in the domestication process itself: whereas most domesticated species were actively domesticated by humans through artificial selection, researchers hypothesize that cats were domesticated through natural selection. Unlike dogs, which could be trained to aid humans with hunting, herding, etc., cats had little usefulness to humans (except maybe killing rodents, which could also be accomplished by dogs). Cats were actually probably first attracted not to humans, but to the mice and rats that infested their fields and grain stores. The cats that were least averse to humans were more likely to hang around humans in order to have greater access to rodents. These less-averse cats then bred with each other, causing successive generations of cats to be less and less averse to humans. Cats essentially selectively bred themselves the same way Dmitri Belyaev selectively bred silver foxes.

The upshot of this difference in domestication between cats and other species is that cats weren’t bred to work with humans; rather, they were bred to be less averse to humans. This is basically the difference between cooperating and tolerating. And although both characteristics allow cohabitation with humans, being tolerant doesn’t entail the possession of any social cognitive abilities.

Fortunately for us, some researchers have investigated the influence of the differential domestication in cats and dogs by directly comparing their performance on social cognition tasks. Miklosi et al. (2005) first tested cats and dogs on the hidden food task, where a human indicates the location of food by pointing at it. Cats, like dogs, were able to understand the human social cue of pointing to find the food.

CatMiklosi et al. then observed cats’ and dogs’ behavior in a task where the food was impossible to access (very similar to this study). While dogs looked to humans for help, cats rarely did so.  Taken together, these results suggest that cats can understand human social cues, but are unable to communicate with humans.

 

A more recent study investigated whether cats could recognize the voice of their owner. Saito & Shinozuka (2013) played recordings of people saying a cat’s name and examined the cat’s response. In order to gauge recognition, the researchers used what’s called a habituation task. The basic principle behind a habituation task is that if you experience a stimulus enough (many times or over a prolonged period), your response to that stimulus will decrease. For example, when you first hear a fire alarm, you instantly become alert, adrenaline rushes through your body, etc. However, if the alarm goes on long enough and nothing else happens, your body will return to normal. Similarly, when you first put on clothes in the morning, you’re probably aware of how they feel against your skin for a minute or two, but then you stop noticing. Habituation is the brain’s way of filtering out unimportant stimuli so you can focus on the important stuff. In a habituation task, experimenters habituate a subject to a stimulus, then change the stimulus in some way and see how the subject responds. If the subject perceives the stimulus as different, then her response will be comparable to the first time she heard the habituation stimulus. If she doesn’t perceive the stimulus as different, then she will have little or no response.

For each cat, Saito & Shinozuka played three recordings of different strangers saying the cat’s name, followed by a recording of the owner saying the cat’s name. They were interested in comparing the cat’s habituated reaction to the third recording (a stranger) and the potentially different fourth recording (the owner). If the cat has a greater response to the owner’s recording than the third stranger’s recording, then he probably recognizes his owner’s voice.

The researchers found that overall, the cats had a greater response to their owners’ recordings than to the third strangers’ recordings, demonstrating that they recognized their owners’ voices. Interestingly, the responses were limited mostly to ear and head movements – no cats actually stood up and moved toward the sound. (The media have had some fun with this result – here’s an informative but slightly biased video about the study and its results.)

So it seems that although cats are domesticated and can understand some human social cues, they may not have all the social cognitive abilities of dogs, and this is likely due to their domestication through natural selection.

I’ll leave you with a video about an interesting study comparing the relationships between humans and cats, dogs, and babies. Do the results fit with our hypotheses about dog and cat domestication?

Sources Cited:

Miklósi, Áam, et al. “A comparative study of the use of visual communicative signals in interactions between dogs (Canis familiaris) and humans and cats (Felis catus) and humans.” Journal of Comparative Psychology 119.2 (2005): 179.

Saito, Atsuko, and Kazutaka Shinozuka. “Vocal recognition of owners by domestic cats (Felis catus).” Animal cognition (2013): 1-6.

If you’re interested in reading more about domestication, here’s an interesting paper:

Driscoll, Carlos A., David W. Macdonald, and Stephen J. O’Brien. “From wild animals to domestic pets, an evolutionary view of domestication.” Proceedings of the National Academy of Sciences 106.Supplement 1 (2009): 9971-9978.

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Same Difference

Last week I talked about the case of Clever Hans and the importance of verifying abilities in animals. This week I’m going to expand on that by discussing how different training procedures can cause animals to use different cognitive strategies in a task.

In order to test whether an animal has a particular cognitive ability, we usually have to use tasks that animals don’t immediately understand how to do. We could easily explain such tasks to humans, but since animals don’t understand language, we have to “train” them to do tasks before assessing their performance. Depending on the task and the particular animal being studied, this can take anywhere from a few trials to a few months or more. Sometimes the animal never learns the task, which tells us something important, too.

1013114081_dcf5ec1ba4_nTo illustrate the importance of task training, we’re going to look at a recent study investigating whether a harbor seal could understand the concept of same/different. It would be easy to study this concept in humans because we could just tell them to indicate whether two pictures are the same or different. Not only can we not do the same with animals, but also the concept of same/different is especially complicated because it’s abstract. Understanding same/different involves more than just making a simple association; it requires making a particular cognitive judgment about the relationship between two stimuli, including stimuli never encountered before.

Scholtyssek et al. (2013) investigated whether a harbor seal could indicate whether two pictures were the same or different. The seal began each trial with his head on a “stationing target” in front of a monitor. One picture would appear on the left side of the monitor, followed by another picture on the right side of the monitor. If the pictures were the same, the seal was to keep his head on the stationing target. If the pictures were different, he had to touch his nose to the monitor.

In Stage 1, the researchers trained the seal on one image pair at a time (each image pair formed four problems: two same and two different). The seal worked on these same four problems until his accuracy was at least 80% (to give you an idea of how slow this training can be, it took almost 2000 trials for the seal to reach 80% accuracy!). Then the researchers trained him using a new image pair, either until he reached 80% accuracy or 360 trials.

9221462544_e9e549c21f_mThey found that the seal reached 80% accuracy for five different image pairs, but was unable to do so for a sixth image pair within 360 trial limit. This indicates that, rather than learning the concept of same/different, the seal was actually just memorizing the correct response for every single problem (i.e. Image A & Image A: don’t move nose; Image A & Image B: touch monitor with nose; Image B & Image B: don’t move nose; Image B & Image A: touch monitor with nose). When he couldn’t store any more problems in his memory, he couldn’t accurately do the task.

In Stage 2, the seal only saw 5 trials of each problem (20 total trials) for each image pair, before moving on to the next pair. It took the seal fewer than 18 image pairs (about 350 trials) to reach the 80% accuracy criterion. He was 80% correct even though he had seen fewer than 20 trials of an image pair, and even though he had already seen more than five other image pairs. This suggests that he may have learned the same/difference concept, rather than memorizing the correct response for each problem. However, he could also have just gotten quicker and better at making associations between the specific problems shown and the correct responses.

To rule out this possibility, Scholtyssek et al. went a step further and tested whether the seal could do the same/different task with completely new images on every trial (rather than every 20 trials). For Stage 3, they trained the seal using sets of 15 images to create 30 problems (15 same and 15 different), where each image only appeared in three trials (one same trial and two different trials) and no pair of images was shown twice. Once he reached 80% accuracy, they tested him using completely new images on every trial.

The seal reached 80% accuracy in the fifth image set during training. More importantly, his overall accuracy on the test trials was above 80%, confirming that he had learned the same/different concept.

5961318915_59ef5547ce_nOverall, this experiment demonstrates the importance of training animals to do a task using the cognitive ability you’re testing for – in this case, learning the concept of same/different. For small numbers of images, it requires less cognitive effort to just memorize each problem than it does to create a concept or rule about them. For the training in Stage 1, which only focused on one image pair at a time, it was actually more cognitively efficient for the seal to memorize the correct responses to individual problems (at least at first). In Stage 2 and especially Stage 3, new images were shown much more frequently, causing the seal to learn a rule (i.e. same/different concept) to generalize to new images, which was much more efficient for those types of training.

Since we can’t give animals instructions for how to do a task (or which type of mental strategy to use when doing a task) we have to be very careful about how we train them – just another factor to keep in mind when studying animal cognition!

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(Note: Scholtyssek et al. also had a fourth stage in their experiment, where the “different” problems had two of the same image, but in different shades of gray or with different patterns. As the title of their paper indicates, the seal was able to use his concept of same/different to respond significantly more accurately than chance!)

Source Cited:

Scholtyssek, Christine, et al. “A harbor seal can transfer the same/different concept to new stimulus dimensions.” Animal cognition (2013): 1-11.

Clever Hans

One of the most difficult things about doing animal cognition research is that it’s impossible to get reflective feedback from animals. We can’t ask them, “What strategy did you use to figure out this problem?” or “Why did you come up with this particular answer?” This kind of feedback could be useful because, in addition to investigating whether an animal possesses a particular cognitive ability, researchers must also verify that the ability that an animal appears to demonstrate actually is the ability in question.

OstenHans

von Osten and Clever Hans

Perhaps the most famous example of the importance of this is the case of Clever Hans. In the early 1900s, a teacher named Wilhelm von Osten claimed to have taught his horse, Clever Hans, to do arithmetic and tell time, among other cognitive tasks. von Osten would pose a problem to Clever Hans, who would then tap out the answer with his hoof. The pair traveled around their native Germany, exhibiting Clever Hans’s “abilities”.

Eventually a psychologist, Oskar Pfungst, decided to study Clever Hans. Pfungst found that Clever Hans didn’t possess any of his purported abilities; rather, he relied solely on the body language of von Osten and the audiences he performed for. As Clever Hans’s taps approached the correct answer, the postures of the people around him got tenser and tenser. When he reached the correct answer, the tension was released, visibly changing the peoples’ postures. Clever Hans had learned to stop tapping when he saw this change (which really is clever, just not in the way von Osten thought). Pfungst found that Clever Hans was nowhere near accurate when he couldn’t see anyone as he answered, or when the people around him didn’t know the answer to the question.

HansAddPfungst took his study a step further by investigating whether humans could respond to body language in the same way as Clever Hans. First, he asked subjects to think of a number, which he would then guess by tapping out the answer. Pfungst found that he was much more accurate than chance, even though he only relied on the body language of the subjects. Moreover, when Pfungst and the subjects switched roles, the subjects were also much more accurate than chance when guessing Pfungst’s number. Knowing what he did about body language, Pfungst attempted to remain as still as possible, but he still made involuntary movements that cued the subjects.

This phenomenon, where an experimenter’s involuntary cues influence a subject’s performance, became known as the Clever Hans Effect (or, more generally, the Observer-Expectancy Effect), and has greatly influenced how we design experiments involving both animals and humans. Some ways to prevent the Clever Hans Effect are for the experimenter to be unaware of the correct answers (a “double-blind” study), or to have the experimenter hidden out of sight of the subject. Either way, the experimenter is unable to inadvertently cue the subject to the correct answer.

HansOstenWhile the Clever Hans case warns us specifically of the possibility of experimenters cueing subjects, it also shows the general importance of confirming that subjects are actually demonstrating the ability you’re studying, rather than relying on other cues or strategies. This is especially important when working with animals, since we can’t just ask them to describe their cognitive strategies.

Thanks to Project Gutenberg, Pfungst’s original (translated) paper is available for free online. It looks long, but it’s very interesting and readable.

I’ll continue this short series on experimental design next week with a look at how different training procedures can lead to different results. Plus, our first paper about seal cognition!

Source:

Pfungst, Oskar. Clever Hans:(the horse of Mr. Von Osten.) a contribution to experimental animal and human psychology. Holt, Rinehart and Winston, 1911.