Seeing what you believe: recognition memory for evolutionary tree structure is affected by students' misconceptions.

Peoples' recognition memory for pictorial stimuli is extremely good. Even complex scientific visualisations are recognised with a high degree of accuracy. The present research examined recognition memory for the branching structure of evolutionary trees. This is an educationally consequential topic due to the potential for contamination from students' misconceptions. The authors created six pairs of scientifically accurate and structurally identical evolutionary trees that differed in whether they included a taxon that cued a misconception in memory. As predicted, Experiment 1 found that (a) college students (N = 90) had better memory for each of the six tree structures when a neutral taxon (M = 0.73) rather than a misconception-cuing taxon (M = 0.64) was included in the tree, and (b) recognition memory was significantly above chance for both sets of trees. Experiment 2 ruled out an alternative hypothesis based on the possibility that 8-12 sec was not enough time for students to encode the relationships depicted in the trees. The authors consider implications of these results for using evolutionary trees to better communicate scientific information. This is important because these trees provide information that is relevant for everyday life.

Perceptual grouping affects students' propensity to make inferences consistent with their misconceptions.

People have many incorrect beliefs about evolutionary relationships among living things, in part due to the prominence people place on observable similarities as indicators of such. Consider: People think that porpoises and whales are more closely related to manatees than to bison based on their shared aquatic habitat. Our research asked whether it is possible to combat misconceptions using compelling visual representations. Previous research found that the Gestalt principles of perceptual grouping affect reasoning with evolutionary trees. We explored the potential of designing such trees as a "myth buster" tool to target biological misconceptions. More specifically, we tested the hypothesis that students would be less likely to make misconception-based inferences when the perceptual grouping of the tree branches strongly, as opposed to weakly, contradicts the misconception. The results of Experiment 1 showed that it is possible to manipulate perceptual grouping such that the tree structures are viewed as more versus less contradictory to a targeted misconception. Experiments 2 and 3 found that grouping manipulations reduced students' propensity to make inferences consistent with their misconceptions for six misconceptions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Perception and conception in understanding evolutionary trees.

Relationships depicted in evolutionary trees depend solely on levels of most recent common ancestry. Integrating discipline-based education research in biology with perceptual/cognitive psychology, the authors predicted, however, that the Gestalt principles of perceptual grouping would affect how students interpret these relationships. Experiment 1 (N = 93) found that students segment 6-9 branch trees in accordance with the Gestalt principle of connectedness. Experiment 2 (N = 310) found that students in introductory through advanced biology classes predominantly believed, incorrectly, that the evolutionary relationships among a set of target taxa differed in two trees because the grouping of those taxa differed. Experiment 3 (N = 99) found that students from these same classes were more likely to make inferences consistent with the depicted evolutionary relationships when Gestalt grouping supported those inferences. The authors discuss implications for improving students' understanding of cladograms.

Fostering 21st-Century Evolutionary Reasoning: Teaching Tree Thinking to Introductory Biology Students.

The ability to interpret and reason from Tree of Life (ToL) diagrams has become a vital component of science literacy in the 21st century. This article reports on the effectiveness of a research-based curriculum, including an instructional booklet, laboratory, and lectures, to teach the fundamentals of such tree thinking in an introductory biology class for science majors. We present the results of a study involving 117 undergraduates who received either our new research-based tree-thinking curriculum or business-as-usual instruction. We found greater gains in tree-thinking abilities for the experimental instruction group than for the business-as-usual group, as measured by performance on our novel assessment instrument. This was a medium size effect. These gains were observed on an unannounced test that was administered ∼5-6 weeks after the primary instruction in tree thinking. The nature of students' postinstruction difficulties with tree thinking suggests that the critical underlying concept for acquiring expert-level competence in this area is understanding that any specific phylogenetic tree is a subset of the complete, unimaginably large ToL.

Inference is bliss: using evolutionary relationship to guide categorical inferences.

Three experiments, adopting an evolutionary biology perspective, investigated subjects' inferences about living things. Subjects were told that different enzymes help regulate cell function in two taxa and asked which enzyme a third taxon most likely uses. Experiment 1 and its follow-up, with college students, used triads involving amphibians, reptiles, and mammals (reptiles and mammals are most closely related evolutionarily) and plants, fungi, and animals (fungi are more closely related to animals than to plants). Experiment 2, with 10th graders, also included triads involving mammals, birds, and snakes/crocodilians (birds and snakes/crocodilians are most closely related). Some subjects received cladograms (hierarchical diagrams) depicting the evolutionary relationships among the taxa. The effect of providing cladograms depended on students' background in biology. The results illuminate students' misconceptions concerning common taxa and constraints on their willingness to override faulty knowledge when given appropriate evolutionary evidence. Implications for introducing tree thinking into biology curricula are discussed.

Linear versus branching depictions of evolutionary history: implications for diagram design.

This article reports the results of an experiment involving 108 college students with varying backgrounds in biology. Subjects answered questions about the evolutionary history of sets of hominid and equine taxa. Each set of taxa was presented in one of three diagrammatic formats: a noncladogenic diagram found in a contemporary biology textbook or a cladogram in either the ladder or tree format. As predicted, the textbook diagrams, which contained linear components, were more likely than the cladogram formats to yield explanations of speciation as an anagenic process, a common misconception among students. In contrast, the branching cladogram formats yielded more appropriate explanations concerning levels of ancestry than did the textbook diagrams. Although students with stronger backgrounds in biology did better than those with weaker biology backgrounds, they generally showed the same effects of diagrammatic format. Implications of these results for evolution education and for diagram design more generally are discussed.

Solving problems using matrix, network, and hierarchy diagrams: the consequences of violating construction conventions.

In order for a diagram to be useful for solving a problem, it must be constructed so that its perceptual features facilitate inferences relevant to that problem. In Experiment 1, we established the construction conventions, which relate to how information is assigned to different parts of the diagram, for three spatial representations-networks, hierarchies, and matrices. In Experiment 2, participants solved problems using diagrams that either followed or violated these conventions. As hypothesized, participants took longer to draw inferences from convention-violating matrix and network diagrams than from their convention-following counterparts, and these inferences were less accurate. Convention adherence did not affect reasoning time or accuracy for hierarchy diagrams. The authors concluded that the construction conventions are related to perceptual features that facilitate certain types of inferences for matrix and network diagrams, and they discussed why this might not have been the case for the hierarchy.

The effects of superficial and structural information on online problem solving for good versus poor anagram solvers.

The two experiments reported here tested two predictions concerning the sensitivity of good and poor problem solvers to superficial and structural information during online problem solving: (a) Superficial features have a greater effect on solution difficulty for poor problem solvers, whereas (b) structural features have a greater effect on solution difficulty for good problem solvers. The tests were conducted in the domain of anagram solution by manipulating or measuring several superficial and structural characteristics in this domain. The results supported both predictions. They also indicated that better problem solvers have access to structural information from the earliest stages of processing (within the first 2 s). The authors discuss the implications of their results for the types of solution strategies used by more and less competent anagram solvers.

Understanding phylogenies in biology: the influence of a Gestalt Perceptual Principle.

Cladograms, hierarchical diagrams depicting evolutionary histories among (groups of) species, are commonly drawn in 2 informationally equivalent formats--tree and ladder. The authors hypothesize that these formats are not computationally equivalent because the Gestalt principle of good continuation obscures the hierarchical structure of ladders. Experimental results confirmed that university students (N = 44) prefer to subdivide ladders in accordance with good continuation rather than with the underlying hierarchical structure. Two subsequent experiments (N = 164) investigated cladogram understanding by examining students' ability to translate between formats (e.g., from tree to ladder). As predicted, students had greater difficulty understanding ladders than trees. This effect was larger for students with weaker backgrounds in biology. These results have important implications for evolution education reform.

Understanding spatial diagram structure: an analysis of hierarchies, matrices, and networks.

Abstract diagrams are powerful tools for comprehension and problem solving in diverse contexts. Two studies examined the structural properties of (i.e., applicability conditions for) three interrelated spatial diagrams--hierarchies, matrices, and networks. College students from two groups with distinct educational backgrounds and learning histories--advanced computer science students and representative undergraduates--rated the diagnosticity of the hypothesized applicability conditions for each of the 3 diagrams. The results validated 24-26 of the 30 hypothesized applicability conditions and provided evidence regarding the relative importance, or diagnosticity, of the validated properties for each type of diagram. A different set of properties was identified as most highly diagnostic for each type of diagram, indicating that the three spatial diagrams are optimized to serve different representational functions: The matrix stores static information about the kind of relation that exists between pairs of items in different sets, the network conveys dynamic information by showing the local connections and global routes connecting the items being represented, and the hierarchy depicts a rigid structure of power or precedence relations among items. The quantitative and qualitative differences in representational knowledge due to educational background are discussed.

Assessing interactive causal influence.

The discovery of conjunctive causes--factors that act in concert to produce or prevent an effect--has been explained by purely covariational theories. Such theories assume that concomitant variations in observable events directly license causal inferences, without postulating the existence of unobservable causal relations. This article discusses problems with these theories, proposes a causal-power theory that overcomes the problems, and reports empirical evidence favoring the new theory. Unlike earlier models, the new theory derives (a). the conditions under which covariation implies conjunctive causation and (b). functions relating observable events to unobservable conjunctive causal strength. This psychological theory, which concerns simple cases involving 2 binary candidate causes and a binary effect, raises questions about normative statistics for testing causal hypotheses regarding categorical data resulting from discrete variables.

Type-based bigram frequencies for five-letter words.

Researchers often require subjects to make judgments that call upon their knowledge of the orthographic structure of English words. Such knowledge is relevant in experiments on, for example, reading, lexical decision, and anagram solution. One common measure of orthographic structure is the sum of the frequencies of consecutive bigrams in the word. Traditionally, researchers have relied on token-based norms of bigram frequencies. These norms confound bigram frequency with word frequency because each instance (i.e., token) of a particular word in a corpus of running text increments the frequencies of the bigrams that it contains. In this article, the authors report a set of type-based bigram frequencies in which each word (i.e., type) contributes only once, thereby unconfounding bigram frequency from word frequency. The authors show that type-based bigram frequency is a better predictor of the difficulty of anagram solution than is token-based frequency. These norms can be downloaded from www.psychonomic.org/archive/.

Understanding behavior makes it more normal.

Meehl (1973) has informally observed that clinicians will perceive a patient as being more normal if they can understand the patient's behaviors. In Experiment 1, undergraduate participants received descriptions of 10 people, each with three characteristics (e.g., frequently suffers from insomnia) taken from the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994). When the characteristics formed a plausible causal chain, adding a causal explanation increased perceived normality; but when a causal chain was implausible, perceived normality decreased. In Experiments 2 and 3, a negative life event (e.g., is very stressed out due to her workload) was added as an explanation for the first characteristic in a three-characteristic causal chain. Undergraduates, graduate students in clinical psychology, and expert clinicians all reliably perceived the patients as being more normal with these explanations than without them, confirming Meehl's prediction.

On the nature of insight solutions: evidence from skill differences in anagram solution.

According to the Gestalt psychologists, problem solutions that pop into mind suddenly with no awareness of the process by which they were generated are objectively as well as subjectively sudden. Thus, such pop-out solutions are qualitatively different from search solutions, which are constructed incrementally. The authors tested this claim in the domain of anagram solution. Experiment 1 documented that anagrams yield pop-out solutions, especially among highly skilled solvers. The results of Experiment 2 indicated that both pop-out and search solutions depended on the gradual accumulation of partial information, contrary to the Gestalt view of problem solving. Nevertheless, some aspects of the Experiment 2 results, as well as new analyses of an anagram study reported elsewhere, suggest that there may in fact be a qualitative difference between pop-out and search solutions. In particular, pop-out solutions may result from parallel processing of the constraints on the rearranged order of the anagram letters, whereas search solutions may result from a serial hypothesis-testing procedure. Like dynamite, the insightful solution explodes on the solver's cognitive landscape with breathtaking suddenness, but if one looks closely, a long fuse warns of the impending reorganization. (Durso, Rea, & Dayton, 1994, p. 98)

At the forefront of thought: the effect of media exposure on airplane typicality.

The terrorist attacks of September 11, 2001 provided a unique opportunity to investigate the causal status of frequency on typicality for one exemplar of a common conceptual category--namely, the typicality of airplane as a member of the category of vehicles. The extensive media coverage following the attacks included numerous references to the hijacked airplanes and to the consequences of suspending air travel to and from the United States for several days. The present study, involving 152 undergraduates, assessed airplane typicality at three time points ranging from 5 h to 1 month after the attacks and then again at 4.5 months after the attacks. Airplane was judged to be a more typical vehicle for 1 month following the attacks, relative to a baseline calculated from data collected yearly for 5 years preceding the attacks. By 4.5 months, however, typicality was back to baseline.