{"id":436,"date":"2023-03-02T20:16:51","date_gmt":"2023-03-02T20:16:51","guid":{"rendered":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/psych-in-real-life-illusions\/"},"modified":"2025-11-14T01:06:47","modified_gmt":"2025-11-14T01:06:47","slug":"psych-in-real-life-illusions","status":"publish","type":"chapter","link":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/psych-in-real-life-illusions\/","title":{"raw":"Perceptions and Illusions: Learn It 5\u2014Illusions in Real Life","rendered":"Perceptions and Illusions: Learn It 5\u2014Illusions in Real Life"},"content":{"raw":"<h2>Ebbinghaus in the Real World<\/h2>\r\n<p>Remember the Ebbinghaus illusion (shown again below)? How do you think a psychologist might use this\u00a0illusion to learn about mental processes or behavior? Read on to see an actual example from a psychologist at Colorado State University.<\/p>\r\n<section class=\"textbox interact\">Try to match the size of the center orange circle on the left to the size of the center orange circle on the right. Use the slide bar with the label \u201cSize of left circle\u201d to make your adjustments. When you are satisfied with your adjustment, check your accuracy by clicking on the \u201cVerify Diameter\u201d button. Click \u201cReset\u201d to try again.<center><iframe src=\"https:\/\/s3-us-west-2.amazonaws.com\/oerfiles\/Psychology\/interactives\/circles1.html\" width=\"530\" height=\"430\" data-mce-fragment=\"1\"><\/iframe><\/center><\/section>\r\n<h2>\u00a0<\/h2>\r\n<h3>Ebbinghaus on the Golf Course<\/h3>\r\n<p>Imagine that you are in a golf competition in which you are putting against someone with the same experience and skill that you have. There is one problem: Your opponent gets to putt into a hole that is 10% larger than the hole you have to use. You\u2019d probably think that the competition was unfairly biased against you.<\/p>\r\n\r\n[caption id=\"attachment_3719\" align=\"alignright\" width=\"453\"]<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/14025440\/ball-1842170_1920.jpg\"><img class=\"wp-image-3719\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/14025440\/ball-1842170_1920.jpg\" alt=\"aerial view of a golf hole and golf ball\" width=\"453\" height=\"291\" \/><\/a> <strong>Figure 1<\/strong>. Do you suspect that the <em>perceived<\/em> size of a golf hole will affect putting performance?[\/caption]\r\n\r\n<p>Now imagine a somewhat different situation. You and your opponent are about equal in ability and the holes you are using are the same size, but the hole that your opponent is using <em>looks<\/em>\u00a010% larger than the one you are using. Would your opponent have an unfair advantage now?<\/p>\r\n<p>If you read the earlier section on the Ebbinghaus effect, you have an idea how psychologists could exploit your perceptual system (and your opponent\u2019s) to test this very question.<\/p>\r\n<p>Psychologist Jessica Witt and her colleagues Sally Linkenauger and Dennis Proffitt recruited research participants with no unusual golf experience to participate in a putting task. They competed against themselves rather than against another person. This is what they did:<\/p>\r\n<ul>\r\n\t<li>The experimenters made the task challenging by using a hole with a 2-inch diameter, which is about half the diameter of the hole you will find on a golf course.<\/li>\r\n\t<li>An overhead projector mounted on the ceiling of their lab allowed them to project Ebbinghaus\u2019s circles around the putting hole.<\/li>\r\n\t<li>Some participants saw the putting hole surrounded by circles that were smaller than the hole in the center; the other half saw surrounding black circles that were larger.<\/li>\r\n\t<li>Participants putted from about 11\u00bd feet away. They took 10 putts in one condition, and then 10 in the other condition.<\/li>\r\n\t<li>Half of the participants putted with the large surrounding circles first and half saw the small surrounding circles first.\r\n\r\n<ul>\r\n\t<li>This procedure is called <strong style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">counterbalancing<\/strong><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">. If there is any advantage (e.g., getting better over time with practice) or disadvantage (e.g., getting tired of putting), counterbalancing assures that both conditions are equally exposed to the positive or negative effects of which task goes first or second. Failure to take account of this type of problem means that you may have a <\/span><strong style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">confounding variable<\/strong><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">\u2014practice or fatigue\u2014that influences performance. <\/span>\r\n<ul>\r\n\t<li><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">A confounding variable is something that <\/span><em style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">could<\/em><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">\u00a0influence performance, but is not part of the study. We try to <\/span><em style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">control<\/em><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">\u00a0(that is, neutralize) potentially confounding variables so they cannot be the cause of performance differences. So, for instance, if everyone did the large surrounding circles condition first and then the small surrounding circles, then differences in performance could be due to order of conditions (leading to practice or fatigue effects) rather than the size of the surrounding circles. <\/span><\/li>\r\n\t<li><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">By counterbalancing, they don\u2019t get rid of the effects of practice or fatigue for any particular person, but\u2014across all the participants\u2014practice or fatigue should affect both conditions (both types of Ebbinghaus circles) equally.<\/span><\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<p>The experimenters wanted to know two things.<\/p>\r\n<ul>\r\n\t<li>First, did they actually produce the Ebbinghaus illusion?\r\n\r\n<ul>\r\n\t<li>Remember: there is no guarantee that people see or think the way your theory says they should. So just before the participant started putting in a particular condition, they drew a circle using a computerized drawing tool, attempting to match the exact size of the putting hole. This is better than simply asking, \u201cdo you see the illusion?\u201d The drawing task attempts to directly measure what they perceive.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li>Second, the experimenters wanted to see if the perceived size of the hole influenced putting accuracy. They recorded the success or failure of each putt. Each participant could get a score of 0 to 10 successful putts in each condition.<\/li>\r\n<\/ul>\r\n<h3>Methods Summary<\/h3>\r\n<p>Recap the steps you've read about thus far:<\/p>\r\n<ol>\r\n\t<li>The participant practices putting to get used to the task.<\/li>\r\n\t<li>The participant completes\u00a0the first condition (large surrounding circles for half of the participants and small surrounding circles for the other half).\r\n\r\n<ul>\r\n\t<li>The participant draws a circle corresponding to their estimation of the actual size of the putting hole. This allows\u00a0the experimenters to determine if the Ebbinghaus effect actually occurred.<\/li>\r\n\t<li>The participant putts 10 times in this condition.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li>Participant completes\u00a0the second condition (whichever condition they have not yet done).\r\n\r\n<ul>\r\n\t<li>The participant draws a circle corresponding to their estimation of the actual size of the putting hole.<\/li>\r\n\t<li>The participant putts 10 times in this condition.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ol>\r\n<section class=\"textbox tryIt\">\r\n<div>[ohm2_question height=\"675\"]4061[\/ohm2_question]<\/div>\r\n<\/section>\r\n<p>Now see if you can guess the results of this study.<\/p>\r\n<section class=\"textbox tryIt\">\r\n<h3><strong>How did the participants perceive the holes?\u00a0<\/strong><\/h3>\r\n\r\nResize\u00a0the bars below by clicking and dragging them to show your predicted results when the subjects were asked to draw the circles.\u00a0Make a general prediction based on your understanding of the experiment.\r\n\r\n<p>[reveal-answer q=\"566454\"]Show Answer[\/reveal-answer]<br \/>\r\n[hidden-answer a=\"566454\"]This question tested whether or not the Ebbinghaus effect was produced in this experiment. If there is no difference between the bars, that would mean that participants didn\u2019t experience the Ebbinghaus illusion. The exact height of the bars is not important here, but the relative heights should look something like this:<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070233\/bars11.png\"><img class=\"aligncenter wp-image-3793\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070233\/bars11.png\" alt=\"Bar graph showing that participants drew larger circles to represent the putting hole when the hole was surrounded by the smaller circles. Participants perceived the putting hole was larger when surrounded by smaller circles.\" width=\"341\" height=\"268\" \/><\/a>The taller bar on the right means that the center putting hole looks larger when it is surrounded by smaller circles than when the same hole is surrounded by large circles (the Ebbinghaus illusion!). This result was important because the reasoning behind the experiment was dependent on successfully producing the Ebbinghaus illusion. There is a technical term for a dependent variable that is used to determine if your independent variable is actually working: a <strong>manipulation check<\/strong>. Good experimenters use manipulation checks to be sure they aren\u2019t fooling themselves into believing that they have done something that really didn\u2019t work.[\/hidden-answer]<\/p>\r\n<p>[ohm2_question height=\"400\"]4065[\/ohm2_question]<\/p>\r\n<\/section>\r\n<section class=\"textbox tryIt\" aria-label=\"Try It\">\r\n<h3>How well did the participants putt?<\/h3>\r\n<p>Resize the bars below by clicking and dragging them to show your predicted results when the subjects putted.<\/p>\r\n<center><\/center><center>\r\n<p><iframe src=\"https:\/\/s3-us-west-2.amazonaws.com\/oerfiles\/Psychology\/interactives\/bargraph5.html\" width=\"530\" height=\"450\" data-mce-fragment=\"1\"><\/iframe><\/p>\r\n<\/center>\r\n<p>[reveal-answer q=\"751987\"]Show Answer[\/reveal-answer][hidden-answer a=\"751987\"]This question lets you check out your skills as a psychologist. The description of the experiment did not include the researchers\u2019 hypothesis, so you have to decide for yourself what you think is going to happen. The three possible patterns of results are shown below. <a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070056\/bars21.png\"><img class=\"aligncenter wp-image-3791\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070056\/bars21.png\" alt=\"Three possible results: better putting when the hole looks small, the perceived size of the hole doesn\u2019t matter, or better putting when the hole looks large.\" width=\"591\" height=\"265\" \/><\/a>[\/hidden-answer]<\/p>\r\n<\/section>\r\n<section class=\"textbox tryIt\">Before we show you the actual results of the study, do you think the illusion affected putting performance? Why or why not?\r\n\r\n<p>[reveal-answer q=\"277954\"]Show Answer[\/reveal-answer]<br \/>\r\n[hidden-answer a=\"277954\"]If you think that they putted worse, then you are right! Putting accuracy was better when participants perceived a larger hole.[\/hidden-answer]<\/p>\r\n<p>[reveal-answer q=\"396752\"]See the actual results here[\/reveal-answer]<br \/>\r\n[hidden-answer a=\"396752\"]Until now, we haven\u2019t told you exactly how the Ebbinghaus illusion was predicted to influence putting\u2014only that the experimenters thought it would have some sort of influence. So here is what they said. <br \/>\r\n<br \/>\r\nThe experimenters thought that the perceived size of the hole would affect the SELF-CONFIDENCE of the person as they putted. If you are putting into a larger hole (or what is PERCEIVED as a larger hole) you should be more confident that you will sink your putt. Remember, this is just a prediction based on the experimenters\u2019 reasoning. Their ideas came from interviewing skilled athletes who claimed that objects seemed larger and time seemed to slow down as they gained skill. If the ball you have to catch is bigger or the person blocking you is slower, you can perform at a higher level.<br \/>\r\n<br \/>\r\nThe experimenters could be right or they could be wrong. Your own reasoning might be different than that of the experimenters. For instance, perhaps you thought that people would be MORE CAREFUL if they thought the hole was smaller. That would be a perfectly fine hypothesis. Interestingly, it makes the opposite prediction from the experimenters\u2019 self-confidence hypothesis. This \u201ccareful putting with smaller holes\u201d theory predicts that people should putt better when they perceive the hole as smaller (i.e., when the surrounding circles are large). The experimenters\u2019 \u201cmore confidence with larger holes\u201d hypothesis predicts that people should putt better when they perceive the hole as larger.<\/p>\r\n<p>Here are the actual results. First, the hole was perceived as larger when it was surrounded by smaller holes, so there is evidence that they successfully produced the Ebbinghaus illusion. Second, the experimenters predicted that participants would be more successful when the hole seemed larger (i.e., surrounded by smaller circles). Consistent with these predictions, the results looked like this:<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070152\/bars3.png\"><img class=\"aligncenter wp-image-3792\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070152\/bars3.png\" alt=\"Bar graph showing better putting when participants perceived the hole to look larger (when it was surrounded by the smaller circles).\" width=\"365\" height=\"322\" \/><\/a><\/p>\r\n<p>[\/hidden-answer]<\/p>\r\n<\/section>\r\n<h3>Illusions Impact Performance<\/h3>\r\n<p>This is not the only experiment that has used a sports context to study the effects of illusions. Other experiments have shown that people hit softballs better when the balls are perceived as larger. People score higher in darts when the board appears larger. Athletes kick field goals and return tennis balls more successfully when the goal posts or tennis balls appear larger. In all of these studies, the balls or boards or goalposts were not actually larger, but they were perceived as larger because the experimenters created illusions. Skilled athletes often report that targets appear larger or time slows down when they are \u201cin the zone\u201d, as if practice and skill create their own perceptual illusions that increase confidence and make difficult challenges feel easier.<\/p>\r\n<section class=\"textbox watchIt\">Watch this interview with Psychologist Jessica Witt to see her talk about how her research utilizing the Ebbinghaus illusion impacts a golfer's perception and performance. You can also <a href=\"http:\/\/www.apa.org\/science\/about\/psa\/2016\/12\/action-visual-perception.aspx\" target=\"_blank\" rel=\"noopener\">read about more about similar variations of Witt's research here<\/a>.<br \/>\r\n<iframe src=\"\/\/plugin.3playmedia.com\/show?mf=4322719&amp;p3sdk_version=1.10.1&amp;p=20361&amp;pt=573&amp;video_id=XDNfTUOSjFw&amp;video_target=tpm-plugin-had2c60a-XDNfTUOSjFw\" width=\"800px\" height=\"500px\" frameborder=\"0\" marginwidth=\"0px\" marginheight=\"0px\" data-mce-fragment=\"1\"><\/iframe><br \/>\r\nYou can <a href=\"https:\/\/oerfiles.s3-us-west-2.amazonaws.com\/Psychology\/Transcriptions\/AHoleInTheHeadGolfAndPerception.txt\" target=\"_blank\" rel=\"noopener\">view the transcript for \"A hole in the head: Golf and Perception\" here (opens in new window)<\/a>.<\/section>\r\n<h2>A Final Note: Science Doesn't Always Produce Simple Results<\/h2>\r\n<p>Professor Witt\u2019s study had interesting results; however, they weren\u2019t quite as simple as we have made them seem. The researchers actually had two different hole sizes: 2 inches and 4 inches. The Ebbinghaus circles were adjusted to be relatively larger or smaller than the putting hole.<\/p>\r\n<p>The Ebbinghaus illusion worked for the smaller (2-inch) putting holes, but not for the larger (4-inch) putting holes. In other words, when people drew the circles as they perceived them (the \u201cmanipulation check\u201d dependent variable), they drew different-sized circles for the 2-inch holes (the Ebbinghaus illusion), but the same size circles for the 4-inch holes (no Ebbinghaus illusion).<\/p>\r\n<p>For the larger (4-inch) putting holes, putting accuracy was the same for the two different conditions. This didn\u2019t bother the experimenters, because\u2014as we have already noted\u2014the participants did not experience the Ebbinghaus illusion with the larger holes. If the holes were perceived as the same, then self-confidence should not have been affected, and, in turn, putting should not have been better in one condition than the other.<\/p>\r\n<p>In the research paper, the experimenters suggest a few technical reasons that the larger hole might not have produced the Ebbinghaus illusion, but they admit that they have no definitive explanation. That\u2019s okay. Science often yields messy results\u2014and these can be the basis for new experiments and sometimes for really interesting discoveries. The world is not as simple as our theories try to make it seem. Happily, in science, as in many aspects of life, you learn more from your failures than your successes, so good scientists don\u2019t try to hide from results they don\u2019t expect.<\/p>","rendered":"<h2>Ebbinghaus in the Real World<\/h2>\n<p>Remember the Ebbinghaus illusion (shown again below)? How do you think a psychologist might use this\u00a0illusion to learn about mental processes or behavior? Read on to see an actual example from a psychologist at Colorado State University.<\/p>\n<section class=\"textbox interact\">Try to match the size of the center orange circle on the left to the size of the center orange circle on the right. Use the slide bar with the label \u201cSize of left circle\u201d to make your adjustments. When you are satisfied with your adjustment, check your accuracy by clicking on the \u201cVerify Diameter\u201d button. Click \u201cReset\u201d to try again.<\/p>\n<div style=\"text-align: center;\"><iframe loading=\"lazy\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/oerfiles\/Psychology\/interactives\/circles1.html\" width=\"530\" height=\"430\" data-mce-fragment=\"1\"><\/iframe><\/div>\n<\/section>\n<h2>\u00a0<\/h2>\n<h3>Ebbinghaus on the Golf Course<\/h3>\n<p>Imagine that you are in a golf competition in which you are putting against someone with the same experience and skill that you have. There is one problem: Your opponent gets to putt into a hole that is 10% larger than the hole you have to use. You\u2019d probably think that the competition was unfairly biased against you.<\/p>\n<figure id=\"attachment_3719\" aria-describedby=\"caption-attachment-3719\" style=\"width: 453px\" class=\"wp-caption alignright\"><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/14025440\/ball-1842170_1920.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-3719\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/14025440\/ball-1842170_1920.jpg\" alt=\"aerial view of a golf hole and golf ball\" width=\"453\" height=\"291\" \/><\/a><figcaption id=\"caption-attachment-3719\" class=\"wp-caption-text\"><strong>Figure 1<\/strong>. Do you suspect that the <em>perceived<\/em> size of a golf hole will affect putting performance?<\/figcaption><\/figure>\n<p>Now imagine a somewhat different situation. You and your opponent are about equal in ability and the holes you are using are the same size, but the hole that your opponent is using <em>looks<\/em>\u00a010% larger than the one you are using. Would your opponent have an unfair advantage now?<\/p>\n<p>If you read the earlier section on the Ebbinghaus effect, you have an idea how psychologists could exploit your perceptual system (and your opponent\u2019s) to test this very question.<\/p>\n<p>Psychologist Jessica Witt and her colleagues Sally Linkenauger and Dennis Proffitt recruited research participants with no unusual golf experience to participate in a putting task. They competed against themselves rather than against another person. This is what they did:<\/p>\n<ul>\n<li>The experimenters made the task challenging by using a hole with a 2-inch diameter, which is about half the diameter of the hole you will find on a golf course.<\/li>\n<li>An overhead projector mounted on the ceiling of their lab allowed them to project Ebbinghaus\u2019s circles around the putting hole.<\/li>\n<li>Some participants saw the putting hole surrounded by circles that were smaller than the hole in the center; the other half saw surrounding black circles that were larger.<\/li>\n<li>Participants putted from about 11\u00bd feet away. They took 10 putts in one condition, and then 10 in the other condition.<\/li>\n<li>Half of the participants putted with the large surrounding circles first and half saw the small surrounding circles first.\n<ul>\n<li>This procedure is called <strong style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">counterbalancing<\/strong><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">. If there is any advantage (e.g., getting better over time with practice) or disadvantage (e.g., getting tired of putting), counterbalancing assures that both conditions are equally exposed to the positive or negative effects of which task goes first or second. Failure to take account of this type of problem means that you may have a <\/span><strong style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">confounding variable<\/strong><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">\u2014practice or fatigue\u2014that influences performance. <\/span>\n<ul>\n<li><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">A confounding variable is something that <\/span><em style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">could<\/em><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">\u00a0influence performance, but is not part of the study. We try to <\/span><em style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">control<\/em><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">\u00a0(that is, neutralize) potentially confounding variables so they cannot be the cause of performance differences. So, for instance, if everyone did the large surrounding circles condition first and then the small surrounding circles, then differences in performance could be due to order of conditions (leading to practice or fatigue effects) rather than the size of the surrounding circles. <\/span><\/li>\n<li><span style=\"font-family: 'Public Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;\">By counterbalancing, they don\u2019t get rid of the effects of practice or fatigue for any particular person, but\u2014across all the participants\u2014practice or fatigue should affect both conditions (both types of Ebbinghaus circles) equally.<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>The experimenters wanted to know two things.<\/p>\n<ul>\n<li>First, did they actually produce the Ebbinghaus illusion?\n<ul>\n<li>Remember: there is no guarantee that people see or think the way your theory says they should. So just before the participant started putting in a particular condition, they drew a circle using a computerized drawing tool, attempting to match the exact size of the putting hole. This is better than simply asking, \u201cdo you see the illusion?\u201d The drawing task attempts to directly measure what they perceive.<\/li>\n<\/ul>\n<\/li>\n<li>Second, the experimenters wanted to see if the perceived size of the hole influenced putting accuracy. They recorded the success or failure of each putt. Each participant could get a score of 0 to 10 successful putts in each condition.<\/li>\n<\/ul>\n<h3>Methods Summary<\/h3>\n<p>Recap the steps you&#8217;ve read about thus far:<\/p>\n<ol>\n<li>The participant practices putting to get used to the task.<\/li>\n<li>The participant completes\u00a0the first condition (large surrounding circles for half of the participants and small surrounding circles for the other half).\n<ul>\n<li>The participant draws a circle corresponding to their estimation of the actual size of the putting hole. This allows\u00a0the experimenters to determine if the Ebbinghaus effect actually occurred.<\/li>\n<li>The participant putts 10 times in this condition.<\/li>\n<\/ul>\n<\/li>\n<li>Participant completes\u00a0the second condition (whichever condition they have not yet done).\n<ul>\n<li>The participant draws a circle corresponding to their estimation of the actual size of the putting hole.<\/li>\n<li>The participant putts 10 times in this condition.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<section class=\"textbox tryIt\">\n<div><iframe loading=\"lazy\" id=\"ohm4061\" class=\"resizable\" src=\"https:\/\/ohm.one.lumenlearning.com\/multiembedq.php?id=4061&theme=lumen&iframe_resize_id=ohm4061&source=tnh&show_question_numbers\" width=\"100%\" height=\"675\"><\/iframe><\/div>\n<\/section>\n<p>Now see if you can guess the results of this study.<\/p>\n<section class=\"textbox tryIt\">\n<h3><strong>How did the participants perceive the holes?\u00a0<\/strong><\/h3>\n<p>Resize\u00a0the bars below by clicking and dragging them to show your predicted results when the subjects were asked to draw the circles.\u00a0Make a general prediction based on your understanding of the experiment.<\/p>\n<p><div class=\"qa-wrapper\" style=\"display: block\"><button class=\"show-answer show-answer-button collapsed\" data-target=\"q566454\">Show Answer<\/button><\/p>\n<div id=\"q566454\" class=\"hidden-answer\" style=\"display: none\">This question tested whether or not the Ebbinghaus effect was produced in this experiment. If there is no difference between the bars, that would mean that participants didn\u2019t experience the Ebbinghaus illusion. The exact height of the bars is not important here, but the relative heights should look something like this:<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070233\/bars11.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-3793\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070233\/bars11.png\" alt=\"Bar graph showing that participants drew larger circles to represent the putting hole when the hole was surrounded by the smaller circles. Participants perceived the putting hole was larger when surrounded by smaller circles.\" width=\"341\" height=\"268\" \/><\/a>The taller bar on the right means that the center putting hole looks larger when it is surrounded by smaller circles than when the same hole is surrounded by large circles (the Ebbinghaus illusion!). This result was important because the reasoning behind the experiment was dependent on successfully producing the Ebbinghaus illusion. There is a technical term for a dependent variable that is used to determine if your independent variable is actually working: a <strong>manipulation check<\/strong>. Good experimenters use manipulation checks to be sure they aren\u2019t fooling themselves into believing that they have done something that really didn\u2019t work.<\/div>\n<\/div>\n<p><iframe loading=\"lazy\" id=\"ohm4065\" class=\"resizable\" src=\"https:\/\/ohm.one.lumenlearning.com\/multiembedq.php?id=4065&theme=lumen&iframe_resize_id=ohm4065&source=tnh&show_question_numbers\" width=\"100%\" height=\"400\"><\/iframe><br \/>\n<\/section>\n<section class=\"textbox tryIt\" aria-label=\"Try It\">\n<h3>How well did the participants putt?<\/h3>\n<p>Resize the bars below by clicking and dragging them to show your predicted results when the subjects putted.<\/p>\n<div style=\"text-align: center;\"><\/div>\n<div style=\"text-align: center;\">\n<p><iframe loading=\"lazy\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/oerfiles\/Psychology\/interactives\/bargraph5.html\" width=\"530\" height=\"450\" data-mce-fragment=\"1\"><\/iframe><\/p>\n<\/div>\n<p><div class=\"qa-wrapper\" style=\"display: block\"><button class=\"show-answer show-answer-button collapsed\" data-target=\"q751987\">Show Answer<\/button><\/p>\n<div id=\"q751987\" class=\"hidden-answer\" style=\"display: none\">This question lets you check out your skills as a psychologist. The description of the experiment did not include the researchers\u2019 hypothesis, so you have to decide for yourself what you think is going to happen. The three possible patterns of results are shown below. <a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070056\/bars21.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-3791\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070056\/bars21.png\" alt=\"Three possible results: better putting when the hole looks small, the perceived size of the hole doesn\u2019t matter, or better putting when the hole looks large.\" width=\"591\" height=\"265\" \/><\/a><\/div>\n<\/div>\n<\/section>\n<section class=\"textbox tryIt\">Before we show you the actual results of the study, do you think the illusion affected putting performance? Why or why not?<\/p>\n<p><div class=\"qa-wrapper\" style=\"display: block\"><button class=\"show-answer show-answer-button collapsed\" data-target=\"q277954\">Show Answer<\/button><\/p>\n<div id=\"q277954\" class=\"hidden-answer\" style=\"display: none\">If you think that they putted worse, then you are right! Putting accuracy was better when participants perceived a larger hole.<\/div>\n<\/div>\n<p><div class=\"qa-wrapper\" style=\"display: block\"><button class=\"show-answer show-answer-button collapsed\" data-target=\"q396752\">See the actual results here<\/button><\/p>\n<div id=\"q396752\" class=\"hidden-answer\" style=\"display: none\">Until now, we haven\u2019t told you exactly how the Ebbinghaus illusion was predicted to influence putting\u2014only that the experimenters thought it would have some sort of influence. So here is what they said. <\/p>\n<p>The experimenters thought that the perceived size of the hole would affect the SELF-CONFIDENCE of the person as they putted. If you are putting into a larger hole (or what is PERCEIVED as a larger hole) you should be more confident that you will sink your putt. Remember, this is just a prediction based on the experimenters\u2019 reasoning. Their ideas came from interviewing skilled athletes who claimed that objects seemed larger and time seemed to slow down as they gained skill. If the ball you have to catch is bigger or the person blocking you is slower, you can perform at a higher level.<\/p>\n<p>The experimenters could be right or they could be wrong. Your own reasoning might be different than that of the experimenters. For instance, perhaps you thought that people would be MORE CAREFUL if they thought the hole was smaller. That would be a perfectly fine hypothesis. Interestingly, it makes the opposite prediction from the experimenters\u2019 self-confidence hypothesis. This \u201ccareful putting with smaller holes\u201d theory predicts that people should putt better when they perceive the hole as smaller (i.e., when the surrounding circles are large). The experimenters\u2019 \u201cmore confidence with larger holes\u201d hypothesis predicts that people should putt better when they perceive the hole as larger.<\/p>\n<p>Here are the actual results. First, the hole was perceived as larger when it was surrounded by smaller holes, so there is evidence that they successfully produced the Ebbinghaus illusion. Second, the experimenters predicted that participants would be more successful when the hole seemed larger (i.e., surrounded by smaller circles). Consistent with these predictions, the results looked like this:<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070152\/bars3.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-3792\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/855\/2017\/02\/23070152\/bars3.png\" alt=\"Bar graph showing better putting when participants perceived the hole to look larger (when it was surrounded by the smaller circles).\" width=\"365\" height=\"322\" \/><\/a><\/p>\n<\/div>\n<\/div>\n<\/section>\n<h3>Illusions Impact Performance<\/h3>\n<p>This is not the only experiment that has used a sports context to study the effects of illusions. Other experiments have shown that people hit softballs better when the balls are perceived as larger. People score higher in darts when the board appears larger. Athletes kick field goals and return tennis balls more successfully when the goal posts or tennis balls appear larger. In all of these studies, the balls or boards or goalposts were not actually larger, but they were perceived as larger because the experimenters created illusions. Skilled athletes often report that targets appear larger or time slows down when they are \u201cin the zone\u201d, as if practice and skill create their own perceptual illusions that increase confidence and make difficult challenges feel easier.<\/p>\n<section class=\"textbox watchIt\">Watch this interview with Psychologist Jessica Witt to see her talk about how her research utilizing the Ebbinghaus illusion impacts a golfer&#8217;s perception and performance. You can also <a href=\"http:\/\/www.apa.org\/science\/about\/psa\/2016\/12\/action-visual-perception.aspx\" target=\"_blank\" rel=\"noopener\">read about more about similar variations of Witt&#8217;s research here<\/a>.<br \/>\n<iframe loading=\"lazy\" src=\"\/\/plugin.3playmedia.com\/show?mf=4322719&amp;p3sdk_version=1.10.1&amp;p=20361&amp;pt=573&amp;video_id=XDNfTUOSjFw&amp;video_target=tpm-plugin-had2c60a-XDNfTUOSjFw\" width=\"800px\" height=\"500px\" frameborder=\"0\" marginwidth=\"0px\" marginheight=\"0px\" data-mce-fragment=\"1\"><\/iframe><br \/>\nYou can <a href=\"https:\/\/oerfiles.s3-us-west-2.amazonaws.com\/Psychology\/Transcriptions\/AHoleInTheHeadGolfAndPerception.txt\" target=\"_blank\" rel=\"noopener\">view the transcript for &#8220;A hole in the head: Golf and Perception&#8221; here (opens in new window)<\/a>.<\/section>\n<h2>A Final Note: Science Doesn&#8217;t Always Produce Simple Results<\/h2>\n<p>Professor Witt\u2019s study had interesting results; however, they weren\u2019t quite as simple as we have made them seem. The researchers actually had two different hole sizes: 2 inches and 4 inches. The Ebbinghaus circles were adjusted to be relatively larger or smaller than the putting hole.<\/p>\n<p>The Ebbinghaus illusion worked for the smaller (2-inch) putting holes, but not for the larger (4-inch) putting holes. In other words, when people drew the circles as they perceived them (the \u201cmanipulation check\u201d dependent variable), they drew different-sized circles for the 2-inch holes (the Ebbinghaus illusion), but the same size circles for the 4-inch holes (no Ebbinghaus illusion).<\/p>\n<p>For the larger (4-inch) putting holes, putting accuracy was the same for the two different conditions. This didn\u2019t bother the experimenters, because\u2014as we have already noted\u2014the participants did not experience the Ebbinghaus illusion with the larger holes. If the holes were perceived as the same, then self-confidence should not have been affected, and, in turn, putting should not have been better in one condition than the other.<\/p>\n<p>In the research paper, the experimenters suggest a few technical reasons that the larger hole might not have produced the Ebbinghaus illusion, but they admit that they have no definitive explanation. That\u2019s okay. Science often yields messy results\u2014and these can be the basis for new experiments and sometimes for really interesting discoveries. The world is not as simple as our theories try to make it seem. Happily, in science, as in many aspects of life, you learn more from your failures than your successes, so good scientists don\u2019t try to hide from results they don\u2019t expect.<\/p>\n","protected":false},"author":20,"menu_order":33,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Mond-Vergleich image\",\"author\":\"Fibonacci\",\"organization\":\"\",\"url\":\"https:\/\/commons.wikimedia.org\/wiki\/File:Mond-vergleich.svg\",\"project\":\"Wikimedia\",\"license\":\"cc-by-sa\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"A hole in the head: Golf and Perception\",\"author\":\"sciencentral\",\"organization\":\"\",\"url\":\"https:\/\/www.youtube.com\/watch?v=XDNfTUOSjFw\",\"project\":\"\",\"license\":\"other\",\"license_terms\":\"Standard YouTube License\"},{\"type\":\"original\",\"description\":\"Ebbinghaus Application\",\"author\":\"Patrick J Carroll\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"golf picture\",\"author\":\"coffee\",\"organization\":\"Pixabay\",\"url\":\"https:\/\/pixabay.com\/en\/ball-golf-golf-ball-golf-course-1842170\/\",\"project\":\"\",\"license\":\"cc0\",\"license_terms\":\"\"}]","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"part":402,"module-header":"- Select Header -","content_attributions":[{"type":"cc","description":"Mond-Vergleich image","author":"Fibonacci","organization":"","url":"https:\/\/commons.wikimedia.org\/wiki\/File:Mond-vergleich.svg","project":"Wikimedia","license":"cc-by-sa","license_terms":""},{"type":"cc","description":"A hole in the head: Golf and Perception","author":"sciencentral","organization":"","url":"https:\/\/www.youtube.com\/watch?v=XDNfTUOSjFw","project":"","license":"other","license_terms":"Standard YouTube License"},{"type":"original","description":"Ebbinghaus Application","author":"Patrick J Carroll","organization":"Lumen Learning","url":"","project":"","license":"cc-by","license_terms":""},{"type":"cc","description":"golf picture","author":"coffee","organization":"Pixabay","url":"https:\/\/pixabay.com\/en\/ball-golf-golf-ball-golf-course-1842170\/","project":"","license":"cc0","license_terms":""}],"internal_book_links":[],"video_content":null,"cc_video_embed_content":{"cc_scripts":"","media_targets":[]},"try_it_collection":null,"_links":{"self":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/436"}],"collection":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/users\/20"}],"version-history":[{"count":13,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/436\/revisions"}],"predecessor-version":[{"id":7190,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/436\/revisions\/7190"}],"part":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/parts\/402"}],"metadata":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/436\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/media?parent=436"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapter-type?post=436"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/contributor?post=436"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/license?post=436"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}