Science Sunday: Gut Reaction

I recently read a 2006 paper titled "Visceral Influences on Risk-Taking Behavior." In spite of it's problems this paper uses some great language. Take for example this opening paragraph from the introduction:

"People often do things that they almost immediately regret. Would-be dieters succumb to the lure of forsworn foods, only to curse their weak wills once their hunger (or the food) is gone. Unfaithful spouses live wracked with guilt after an impulsive sexual dalliance, only to repeat the cycle again and again, each time as bewildered as the last by the inconsistency between the strength of their resolve in the company of their families and the crumbling of this resolve in the presence of a willing lover." (Ditto, et al., 2006)

Forsworn. Dalliance. These aren't words that get bandied about normally. The paper also sports a comprehensive literature review of "failures of will" dating back to the 4th century BCE and the Aristotelian akrasia, where a person knowingly does something wrong. Economists have also been baffled about our ability to act against our own self-interest, and folks like Larry Winget make a career telling us about it. But why do people behave this way?

The authors of this paper attribute it to Visceral Factors. According to Loewenstein (1996) Visceral Factors are motivational states such as hunger, thirst, pain, and sexual desire. In this paper the authors looked at hunger and sexual desire and how exposure to them led participants to make irrational or impulsive decisions. (Surprised yet?)

Chocolate chiopcookie

In the first experiment participants wagered spending more time in the lab doing experiments  vs. chocolate chip cookies. One group had the cookies described to them, but the other got to see and smell the cookies. The smellers were the fellers ones more likely to wager time, even when told they didn't have good odds. The idea being that the visceral hunger response led to the impulsive, riskier decision. Side note: Imagine how awesome it would be to be the researcher; tempting hapless volunteers with delicious cookies but forcing them to wager time just in the hopes of getting a taste.

French Kiss

The second experiment involved a vignette where a young couple begins to make out and prepare to have sex, and then realize they have no condom. In the visceral condition this was presented as a video, in the non-visceral condition this was presented in a passage that participants would read. Then participants were asked to respond as if they were in that situation how likely they would be to have sex even without a condom. Again the idea is that the stronger visceral response to viewing the soft-core video was the reason that group was more likely to choose to engage in risky sexual behavior.

All of this is great, and as I said I thought the paper has great use of language in science writing. But I'm not so sure that it is just viscera, and not just stronger stimuli. In general Bigger Stimuli = Bigger Response. The response here being desire for the stimuli. What I'm saying is, you want the cookies you smell more because the smell is more stimulating in general, not just because it made your tummy rumble. So in order to control for the impact of the stimuli, you would have to find a way to use the same stimuli but have it effect the viscera of only some participants. I think you could do this with a group of quadriplegic participants, right? I mean they have viscera but they can't sense them. Or maybe easier you could have a hungry and full groups when presented with cookies, but that I think would still be looking at motivation, not viscera exclusively. But hey, I don't have to have the solution, just identify the problem.

Ditto, P., Pizarro, D., Epstein, E., Jacobson, J., & MacDonald, T. (2006). Visceral influences on risk-taking behavior Journal of Behavioral Decision Making, 19 (2), 99-113 DOI: 10.1002/bdm.520

Science Sunday: The ontogeny of behaviour in the albino rat

Every Sunday, I'd like to post a review of an interesting peer-reviewed science article. To kick things off I'm picking an old favorite, originally posted in 1964! It is certainly well cited, Google Scholar lists the citation count at 452! Indeed this paper was a "Citation Classic" in Current Contents in 1981. At the time the lead author  Robert Bolles, was still living and stated:

"I have always believed in the idea that experimenters should look at their animals...the human eyeball is the instrument of choice if you want to observe a new phenomenon, and particularly if you want to gain a new understanding of it."

Sprague-Dawley Rat

If you have ever wondered why science uses rats the answer is that we know everything there is to know about rats. We know how they age, how they metabolize ... anything, how the respond to stress, how they develop over time, even how they laugh when tickled. Well, our understanding of rat behavior begins in antiquity but is greatly expanded by this 1964 article originally published in the journal Animal Behaviour.

In fact this article describes qualitatively the behaviors of infant rats from birth to about 24 days (rats are weened at day 21). In the first experiment, Bolles and Woods observed 13 litters with an average of 9 pups (117 pups) in their "natural" laboratory environment (cages). The animals were of the Sprague-Dawley line, which is still used today. They did use several different methods of observation and schedules of observation to arrive at a comprehensive guide to the ontogeny of lab rats.

They begin with postural observations, describing three postures that develop over time: lying, sitting and standing. Lying being the default resting position of the rat, often using other bodies for support. Sitting began on day 4 when subjects first began to lift their heads, and was fully developed by day 17 when subjects could sit and perform activities such as grooming. Also beginning on day 4 are the first attempts to support weight on the legs, and by day 10 the animals can support themselves. By day 13 they can run, by day 15 they can stand on three legs and scratch with the fourth. They can rear up on two legs with support for the front legs on day 16 and can rear independent of support (for the purpose of play-fighting with siblings) by day 18.

In similiar fashion reflexes are described. Without relating the specific timeline the reflexes are: twitiching, head waving, stretching and yawning, body flexion, righting reaction, freezing, sniffing, auditory orientation, and visual orientation. When describing startle response int he auditory orientation section there is a great footnote on the word "click:"

*The sound used was relatively well-controlled and constant, but, unfortunately rather poorly defined; it was the sound of a Parker T-Ball Jotter pen being retracted at a distance of approximately 1 foot.

Psychologists are hilarious. Also found it interesting that the animals did not freeze in fear until day 26 and they froze for approximately 15 seconds. I've never seen any rats hold still for that long unless they were sleeping. Following this functional activities are described. Here is the list: sleeping, consumatory behavior, locomotor activity, climbing, grooming, exploration  manipulation, digging, and defecation  Here the theme of development was similar as above, with rudimentary non-functional behaviors appearing first (such as scratching motion without making contact with the skin), that later developed into full-fledged adult-like behavior.

Ultimately we get a description of the social behaviors in the observed rats. Social behavior in young rats is evidenced by chasing and fighting. Bolles, and Woods observed rats begin this social play-fighting on day 14 when their eyes began to open.The activity peaks between day 20 and 30 when the whole litter engages in a high level of activity.

Table 1

In a second experiment Bolles and Woods attempt to quantify the behaviors they observed in the first experiment. Using experimental methods the authors observed 12 rats (2 each from 6 litters) and summarized their behaviors as percentages. To the right is table 1 from the paper. There are many more graphs showing the time course of the development of behaviors and it really is a fascinating reference, but I won't reproduce all of that here.

The first point of discussion and perhaps the most salient is that from these findings we can view rats as a far more social animal than might otherwise be considered. Early social interactions are to wrangle for nursing or comfort, and later become play fighting and chasing. As the authors noted this social behavior likely leads to long lasting changes in the adult organism and "offers interesting possibilities for research in this area." (See the next 50 years of rat studies for more on these possibilities)

Bolles, R., & Woods, P. (1964). The ontogeny of behaviour in the albino rat Animal Behaviour, 12 (4), 427-441 DOI: 10.1016/0003-3472(64)90062-4