What is OpenPSYC?

OpenPSYC is a free online resource for students in Introduction to Psychology courses. Use the links on the right to learn more about the site, visit a course module or search by keyword.

The Science of Sex

There are many stereotypes about sex and one of them is that people who have lots of casual sex (meaning that they have sexual partners who are not their significant others) are mentally unhealthy. But is there truth to this idea? The scientific evidence suggests not.

Watch: Is Casual Sex Unhealthy?



Yet another common belief is that we are currently living in an era of the "hookup culture," where people are significantly less likely to prefer relationships (and instead prefer lots of casual sex). But is there truth to this idea? Again, the science suggests not.

Read: Why Are So Many Millennials Having Zero Sex? (http://nymag.com/scienceofus/2016/08/why-are-so-many-millennials-having-zero-sex.html)

Watch: Is "Hook-Up Culture" Real? (https://youtu.be/PtQx-rhsnJU)



What about when we examine sex drive in general? How often do people have sex, both uncommitted people and people in relationships?

Read: The Ins and Outs of Sexual Frequency 
(http://www.scienceofrelationships.com/home/2012/4/6/the-ins-and-outs-of-sexual-frequency.html)

Read: Is More Sex Always Better?
(http://www.scienceofrelationships.com/home/2015/11/24/is-more-sex-always-better.html)

Watch: Your Sex Drive Is Normal (https://www.youtube.com/watch?v=At8yuIOQcaU)

The Importance of Replication in Science

The following are excerpts from Diener & Biswas-Dienerm's (2016) article in NOBA reproduced with permission under their creative commons license.

In science, replication is the process of repeating research to determine the extent to which findings generalize across time and across situations. Recently, the science of psychology has come under criticism because a number of research findings do not replicate. In this module we discuss reasons for non-replication, the impact this phenomenon has on the field, and suggest solutions to the problem.

The Disturbing Problem

The replication of findings is one of the defining hallmarks of science. Scientists must be able to replicate the results of studies or their findings do not become part of scientific knowledge. Replication protects against false positives (seeing a result that is not really there) and also increases confidence that the result actually exists. If you collect satisfaction data among homeless people living in Kolkata, India, for example, it might seem strange that they would report fairly high satisfaction with their food (which is exactly what we found in Biswas-Diener & Dienerm, 2001). If you find the exact same result, but at a different time, and with a different sample of homeless people living in Kolkata, however, you can feel more confident that this result is true (as we did in Biswas-Diener & Diener, 2006).

It turns out that many studies in psychology—including many highly cited studies—do not replicate. In an era where news is instantaneous, the failure to replicate research raises important questions about the scientific process in general and psychology specifically. People have the right to know if they can trust research evidence. For our part, psychologists also have a vested interest in ensuring that our methods and findings are as trustworthy as possible.

Psychology is not alone in coming up short on replication. There have been notable failures to replicate findings in other scientific fields as well. For instance, in 1989 scientists reported that they had produced “cold fusion,” achieving nuclear fusion at room temperatures. This could have been an enormous breakthrough in the advancement of clean energy. However, other scientists were unable to replicate the findings. Thus, the potentially important results did not become part of the scientific canon, and a new energy source did not materialize. In medical science as well, a number of findings have been found not to replicate—which is of vital concern to all of society. The non-reproducibility of medical findings suggests that some treatments for illness could be ineffective. One example of non-replication has emerged in the study of genetics and diseases: when replications were attempted to determine whether certain gene-disease findings held up, only about 4% of the findings consistently did so.

What is Replication?

Psychological science is coming under criticism because many studies do not replicate.  There are different types of replication. First, there is a type called “exact replication” (also called "direct replication"). In this form, a scientist attempts to exactly recreate the scientific methods used in conditions of an earlier study to determine whether the results come out the same. If, for instance, you wanted to exactly replicate Asch’s (1956) classic findings on conformity, you would follow the original methodology: you would use only male participants, you would use groups of 8, and you would present the same stimuli (lines of differing lengths) in the same order. The second type of replication is called “conceptual replication.” This occurs when—instead of an exact replication, which reproduces the methods of the earlier study as closely as possible—a scientist tries to confirm the previous findings using a different set of specific methods that test the same idea. The same hypothesis is tested, but using a different set of methods and measures. A conceptual replication of Asch’s research might involve both male and female confederates purposefully misidentifying types of fruit to investigate conformity—rather than only males misidentifying line lengths.

Both exact and conceptual replications are important because they each tell us something new. Exact replications tell us whether the original findings are true, at least under the exact conditions tested. Conceptual replications help confirm whether the theoretical idea behind the findings is true, and under what conditions these findings will occur. In other words, conceptual replication offers insights into how generalizable the findings are.

Reasons for Non-replication

When findings do not replicate, the original scientists sometimes become indignant and defensive, offering reasons or excuses for non-replication of their findings—including, at times, attacking those attempting the replication. They sometimes claim that the scientists attempting the replication are unskilled or unsophisticated, or do not have sufficient experience to replicate the findings. This, of course, might be true, and it is one possible reason for non-replication.

One reason for defensive responses is the unspoken implication that the original results might have been falsified. Faked results are only one reason studies may not replicate, but it is the most disturbing reason. We hope faking is rare, but in the past decade a number of shocking cases have turned up. Perhaps the most well-known come from social psychology. Diederik Stapel, a renowned social psychologist in the Netherlands, admitted to faking the results of a number of studies. Marc Hauser, a popular professor at Harvard, apparently faked results on morality and cognition. Karen Ruggiero at the University of Texas was also found to have falsified a number of her results (proving that bad behavior doesn’t have a gender bias). Each of these psychologists—and there are quite a few more examples—was believed to have faked data. Subsequently, they all were disgraced and lost their jobs.

Another reason for non-replication is that, in studies with small sample sizes, statistically-significant results may often be the result of chance. For example, if you ask five people if they believe that aliens from other planets visit Earth and regularly abduct humans, you may get three people who agree with this notion—simply by chance. Their answers may, in fact, not be at all representative of the larger population. On the other hand, if you survey one thousand people, there is a higher probability that their belief in alien abductions reflects the actual attitudes of society. Now consider this scenario in the context of replication: if you try to replicate the first study—the one in which you interviewed only five people—there is only a small chance that you will randomly draw five new people with exactly the same (or similar) attitudes. It’s far more likely that you will be able to replicate the findings using another large sample, because it is simply more likely that the findings are accurate.

Another reason for non-replication is that, while the findings in an original study may be true, they may only be true for some people in some circumstances and not necessarily universal or enduring. Imagine that a survey in the 1950s found a strong majority of respondents to have trust in government officials. Now imagine the same survey administered today, with vastly different results. This example of non-replication does not invalidate the original results. Rather, it suggests that attitudes have shifted over time.

A final reason for non-replication relates to the quality of the replication rather than the quality of the original study. Non-replication might be the product of scientist-error, with the newer investigation not following the original procedures closely enough. Similarly, the attempted replication study might, itself, have too small a sample size or insufficient statistical power to find significant results. 

In Defense of Replication Attempts

Failures in replication are not all bad and, in fact, some non-replication should be expected in science. Original studies are conducted when an answer to a question is uncertain. That is to say, scientists are venturing into new territory. In such cases we should expect some answers to be uncovered that will not pan out in the long run. Furthermore, we hope that scientists take on challenging new topics that come with some amount of risk. After all, if scientists were only to publish safe results that were easy to replicate, we might have very boring studies that do not advance our knowledge very quickly. But, with such risks, some non-replication of results is to be expected.


The reward structure in academia has served to discourage replication. Many psychologists—especially those who work full time at universities—are often rewarded at work—with promotions, pay raises, tenure, and prestige—through their research. Replications of one’s own earlier work, or the work of others, is typically discouraged because it does not represent original thinking. Instead, academics are rewarded for high numbers of publications, and flashy studies are often given prominence in media reports of published studies.

Psychological scientists need to carefully pursue programmatic research. Findings from a single study are rarely adequate, and should be followed up by additional studies using varying methodologies. Thinking about research this way—as if it were a program rather than a single study—can help. We would recommend that laboratories conduct careful sets of interlocking studies, where important findings are followed up using various methods. It is not sufficient to find some surprising outcome, report it, and then move on. When findings are important enough to be published, they are often important enough to prompt further, more conclusive research. In this way scientists will discover whether their findings are replicable, and how broadly generalizable they are. If the findings do not always replicate, but do sometimes, we will learn the conditions in which the pattern does or doesn’t hold. This is an important part of science—to discover how generalizable the findings are.

Extinction

Extinction is the process of unlearning a behavior when reinforcement is no longer associated with it. For example, imagine that a dog scratches at the door to signal that it wants to go outside.  The behavior of scratching has been positively reinforced in the past -- every time the dog scratches at the door the owner takes it outside (which the dog likes).  Of course, as the dog's owner, you're not as thrilled about the damage being done to your door.  To put that behavior through extinction you would need to break the link between the behavior and the reinforcement.  So, you make sure to take the dog out frequently throughout the day and if it ever scratches at the door you ignore it.  If scratching at the door no longer leads to a fun walk, the behavior will eventually go extinct.

There are two issues you will run into.  First, you are likely to observe a sudden increase in the behavior, or what is know as an extinction burst.  Think of it from the dog's perspective... this has worked in the past, so keep trying and it will eventually work again.  We might expect this sudden increase in scratching for a while, and then the rate of scratching should gradually decrease until it is extinct.

We are especially likely to see an extinction burst if the behavior was previously reinforced on a variable schedule and if reinforcement is suddenly removed.  In the dog's experience, sometimes it scratched for two seconds, sometimes ten, and sometimes for two minutes before the door opened.  Since a variable schedule is unpredictable, the animal is already accustomed to persisting until the reward arrives.  Therefore, it will take longer for the animal to learn that the reward is never coming and give up on the behavior as a way to get what it wants.

One important point to stress is that is we want an behavior to go away, we have to be very consistent about not reinforcing it.  If we accidentally give in at times and allow the behavior to be reinforced, we end up introducing an even more variable schedule, which will make the behavior even more resistant to extinction.

The final issue you may run into is known as spontaneous recovery.  A some point after a behavior has gone through extinction and stopped, it may suddenly reappear for a bit and then go away again.  That unexpected (spontaneous) reoccurrence (recovery) of the behavior is perhaps best thought of as a mechanism by which intelligent animals test out the environment in case the problem was only temporary and things are back to the way they used to be.  As long as you ignore it, a spontaneously recovered behavior should go extinct again in short time.

In cases like this, we can facilitate extinction if we replace the behavior with something else that we want the animal to do.  So, for example, we might reinforce the dog for sitting calmly by the door, or for ringing a bell by the door with its nose.  Thus, rather than scratching because the dog doesn't know what else to do, it will learn to abandon one behavior in favor of a more desirable one.