The Mystery of the Vanished Citations

James McConnell’s Forgotten 1960s Quest for Planarian Learning,
a Biochemical Engram, & Celebrity
by Mark Rilling

The controversy about planarian learning highlights the constructive role of the scientific critic. McConnell, an innovator, raced from one exciting phenomenon to the next without comprehensive experimental analysis or adequate controls. McConnell’s controls were often developed as a response to his critics. McConnell’s students and other scientists were left the task of cleaning up after McConnell by adding the control groups that he omitted. After his arrival at the University of Michigan, Donald Jensen
Donald Jensen is an American hepatitis C researcher and clinician, and Richard B. Capps Chair Emeritus, Rush University Medical Center.
 
 
 
 
  became McConnell’s nemesis over invertebrate learning—Jensen’s position was

that no invertebrate, no matter how complex is capable of showing ‘true [associative] learning.’

(McConnell & Shelby, 1970, p. 75)

Jensen (1965) attributed the results of planarian learning to sensitization and called for better control groups. McConnell met Jensen’s objections by upgrading the quality of the control groups. As he put it,

There is probably no other group of scientists as enamored of the use of ‘control groups’ as are psychologists; indeed the entire history of scientific psychology may be viewed as a continuing search for better controls

(McConnell, 1967a, pp. 25-26).

The planarian learning controversy brought passion to the discussion of control groups for classical conditioning because a Nobel prize
Nobel prize are five separate prizes that, according to Alfred Nobel’s will of 1895, are awarded to those who, during the preceding year, have conferred the greatest benefit to humankind.
 
 
 
  was thought to await the discovery of a biochemical engram.

Controlling for Experimenter Bias

Experimenter bias was one of the simplest criticisms. Cordaro and Ison (1963) manipulated the expectancy of students in a course in introductory psychology who were running an experiment in classical conditioning on planaria. Sure enough, the students who were led to expect contractions reported more responses than students who were led to believe that conditioning would not occur. McConnell (1967a) quickly instituted a blind control procedure in which the experimenter did not know the group to which the planarian was assigned, so experimenter bias failed to explain the data.

Controlling for Pseudoconditioning & Sensitization

Baxter and Kimmel (1963) repeated the original Thompson and McConnell (1955) study with the addition of an unpaired control group. The unpaired group equated experimental and control groups for the amount of exposure to the CS and US. For the classical-paired group, the number of trials with a CR increased to 50%, whereas the unpaired group showed a steady decrease in responding during conditioning. To distinguish between pseudoconditioning—the enhanced responding to a CS that is not dependent on a forward, temporal CS-US relationship—Jacobson, Horowitz, and Fried (1967) added a backward conditioning control group. There was no learning with the backward conditioning group. Ultimately, by giving the animals only a few trials per day, lengthening the intertrial interval, and not running the animals each day, McConnell (1964) was able to obtain a CR on 90% of the trials. Thus, the controversy about planarian learning produced a steady improvement in the quality of the data as the researchers identified optimal parameters.
Today, a common control procedure in invertebrate learning is a discrimination in which a CS+ is paired with the US, and a CS- is presented alone. This procedure controls for sensitization, an increase in responding to a CS that does not depend on the forward pairing of the CS with the US. This control was introduced to invertebrate learning with planaria by Block and McConnell (1967) to address concerns raised by Jensen (1965) about sensitization as an alternative explanation to associative learning. Block and McConnell established exactly the kind of discrimination called for by Jensen by implementing an elegant A-B-A-B reversal design withinsubjects. One CS was vibration produced by a speaker mounted below the trough, and the other CS was the traditional illumination from lights mounted above the trough. Paired presentations in Phase A increased responding to CS+ but not CS-, whereas extinction in Phase B reduced responding. As Block and McConnell concluded in their study,

The findings of the present study .., should go a long way towards answering in the affirmative the question, ‘Can planarians be conditioned reliably?’ (p. 1466). Amen.

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The Science of Humor Is No Laughing Matter
by Alexandra Michel

In 1957, the BBC aired a short documentary about a mild winter leading to a bumper Swiss spaghetti crop in the town of Ticino. In a dry, distinguished tone, BBC broadcaster Richard Dimbleby narrates how even in the last few weeks of March, the spaghetti farmers worry about a late frost, which might not destroy the pasta crop but could damage the flavor and hurt prices. The narration accompanies film footage of a rural family harvesting long spaghetti noodles from trees and laying them out to dry in the warm Alpine sun.
Naturally, the hundreds of people who called the BBC asking where they could get their own spaghetti bushes hadn’t noticed the air date of the news clip: April 1st. The prank was so successful that even some BBC staff were taken in, leading to some criticism about using a serious news show for an April Fool’s Day joke.
Why April 1st became a holiday devoted to pranks and laughter remains a mystery, although some historians trace it back to the Roman holiday of Hilaria. Humans start developing a sense of humor as early as 6 weeks old, when babies begin to laugh and smile in response to stimuli. Laughter is universal across human cultures and even exists in some form in rats, chimps, and bonobos. Like other human emotions and expressions, laughter and humor provide psychological scientists with rich resources for studying human psychology, ranging from the developmental underpinnings of language to the neuroscience of social perception.

The Hidden Language of Laughter

Theories focusing on the evolution of laughter point to it as an important adaptation for social communication. Studies have shown that people are more likely to laugh in response to a video clip with canned laughter than to one without a laugh track, and that people are 30 times more likely to laugh in the presence of others than alone.

The necessary stimulus for laughter is not a joke, but another person, writes laughter expert and APS Fellow Robert R. Provine, professor emeritus at University of Maryland, Baltimore County, in an article in Current Directions in Psychological Science.

Just look at the canned laughter in TV sitcoms as an example: the laugh track has been a standard part of comedy almost from the birth of television. CBS sound engineer Charley Douglass hated dealing with the inappropriate laughter of live audiences, so in 1950 he started recording his own laugh tracks. These early laugh tracks were intended to help people sitting at home feel like they were in a more social situation, such as sitting at a crowded theater. Douglass even recorded varying types of laughter, including big laughs and small chuckles, as well as different mixtures of laughter from men, women, and children.
In doing so, Douglass picked up on one of the qualities of laughter that is now interesting researchers: a simple ha ha ha communicates an incredible amount of socially relevant information.
For example, a massive international study conducted in 2016 found that across the globe, people are able to pick up on the same subtle social cues from laughter. Samples of laughter were collected from pairs of English-speaking college students — some friends and some strangers — recorded in a lab at the University of California, Santa Cruz. An integrative team made up of more than 30 psychological scientists, anthropologists, and biologists then played audio snippets of this laughter to 966 listeners from 24 diverse societies spanning six continents, from indigenous tribes in New Guinea to urban working-class people in large cities in India and Europe. Participants then were asked whether they thought the two people laughing were friends or strangers.
On average, the results were remarkably consistent across all 24 cultures: People’s guesses about the relationship between the laughers were correct approximately 60% of the time.
Researchers also have found that different types of laughter can serve as codes to complex human social hierarchies. Across the course of two experiments, a team of psychological scientists led by Christopher Oveis of University of California, San Diego, found that high-status individuals had different laughs than low-status individuals, and that strangers’ judgments of an individual’s social status were influenced by the dominant or submissive quality of the person’s laughter.

Laughing in the presence of others indicates the interaction is safe, the researchers explain. While the norms of most social groups prevent direct, unambiguous acts of aggression and dominance, the use of laughter may free individuals to display dominance because laughter renders the act less serious.

In the first study, the researchers wanted to know whether high- and low-status individuals actually do laugh differently.
To test this, 48 male college students were randomly assigned to groups of four, with each group composed of two low-status members (pledges who had just joined a fraternity a month earlier) and two high-status members (older students who had been active in the fraternity for at least 2 years).