Darwin, Design and Dawkins’ Dilemma

Richard Dawkins has a dilemma when it comes to design arguments. On the one hand, he maintains that it was Darwin who killed off design and so implies that his rejection of design depends upon the findings of modern science. On the other hand, he follows Hume when he claims that appealing to a designer does not explain anything and so implies that rejection of design need not be based on the findings of modern science. These contrasting approaches lead to the following dilemma: if he claims that Darwinism is necessary for rejecting design, he has no satisfactory response to design arguments based on the order in the laws of physics or the fine-tuning of the physical constants; alternatively, if Humean arguments are doing most of the work, this would undermine one of his main contentions, that atheism is justified by science and especially by evolution. In any case, his Humean arguments do not provide a more secure basis for his atheism because they are seriously flawed. A particular problem is that his argument for the improbability of theism rests on a highly questionable application of probability theory since, even if it were sound, it would only establish that the prior probability of God’s existence is low, a conclusion which is compatible with the posterior probability of God’s existence being high.     

Why do humans reason? Arguments for an argumentative theory

Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given the exceptional dependence of humans on communication and their vulnerability to misinformation. A wide range of evidence in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis. Poor performance in standard reasoning tasks is explained by the lack of argumentative context. When the same problems are placed in a proper argumentative setting, people turn out to be skilled arguers. Skilled arguers, however, are not after the truth but after arguments supporting their views. This explains the notorious confirmation bias. This bias is apparent not only when people are actually arguing, but also when they are reasoning proactively from the perspective of having to defend their opinions. Reasoning so motivated can distort evaluations and attitudes and allow erroneous beliefs to persist. Proactively used reasoning also favors decisions that are easy to justify but not necessarily better. In all these instances traditionally described as failures or flaws, reasoning does exactly what can be expected of an argumentative device: Look for arguments that support a given conclusion, and, ceteris paribus, favor conclusions for which arguments can be found.     

Social Psychology and Virtue Ethics

Several philosophers have recently claimed to have discovered a new and rather significant problem with virtue ethics. According to them, virtue ethics generates certain expectations about the behavior of human beings which are subject to empirical testing. But when the relevant experimental work is done in social psychology, the results fall remarkably short of meeting those expectations. So, these philosophers think, despite its recent success, virtue ethics has far less to offer to contemporary ethical theory than might have been initially thought. I argue that there are plausible ways in which virtue ethicists can resist arguments based on empirical work in social psychology. In the first three sections of the paper, I reconstruct the line of reasoning being used against virtue ethics by looking at the recent work of Gilbert Harman and John Doris. The remainder of the paper is then devoted both to responding to their challenge as well as to briefly sketching a positive account of character trait possession.     

Scientists’ Argumentative Reasoning

Reasoning, defined as the production and evaluation of reasons, is a central process in science. The dominant view of reasoning, both in the psychology of reasoning and in the psychology of science, is of a mechanism with an asocial function: bettering the beliefs of the lone reasoner. Many observations, however, are difficult to reconcile with this view of reasoning; in particular, reasoning systematically searches for reasons that support the reasoner’s initial beliefs, and it only evaluates these reasons cursorily. By contrast, reasoners are well able to evaluate others’ reasons: accepting strong arguments and rejecting weak ones. The argumentative theory of reasoning accounts for these traits of reasoning by postulating that the evolved function of reasoning is to argue: to find arguments to convince others and to change one’s mind when confronted with good arguments. Scientific reasoning, however, is often described as being at odds with such an argumentative mechanisms: scientists are supposed to reason objectively on their own, and to be pigheaded when their theories are challenged, even by good arguments. In this article, we review evidence showing that scientists, when reasoning, are subject to the same biases as are lay people while being able to change their mind when confronted with good arguments. We conclude that the argumentative theory of reasoning explains well key features of scientists’ reasoning and that differences in the way scientists and laypeople reason result from the institutional framework of science.     

HOW TO CONFUSE ORGANISMS WITH MOUSETRAPS: MACHINE METAPHORS AND INTELLIGENT DESIGN

Why do design arguments—particularly those emphasizing machine metaphors such as “Organisms and/or their parts are machines”—continue to be so convincing to so many people after they have been repeatedly refuted? In this essay I review various interpretations and refutations of design arguments and make a distinction between rationally refuting such arguments (Refuting_R) and rendering them psychologically unconvincing (Refuting_P). Expanding on this distinction, I provide support from recent work on the cognitive power of metaphors and developmental psychological work indicating a basic human propensity toward attributing agency to natural events, to show that design arguments “make sense”unless one is cued to look more closely. As with visual illusions, such as the Müller‐Lyer arrow illusion, there is nothing wrong with a believer's cognitive apparatus any more than with their visual apparatus when they judge the lines in the illusion to be of unequal length. It takes training or a dissonance between design beliefs and other beliefs or experiences to play the role that a ruler does in the visual case. Unless people are cued to “look again” at what initially makes perfect sense, they are not inclined to apply more sophisticated evaluative procedures.     

Mental imagery: in search of a theory

It is generally accepted that there is something special about reasoning by using mental images. The question of how it is special, however, has never been satisfactorily spelled out, despite more than thirty years of research in the post-behaviorist tradition. This article considers some of the general motivation for the assumption that entertaining mental images involves inspecting a picture-like object. It sets out a distinction between phenomena attributable to the nature of mind to what is called the cognitive architecture, and ones that are attributable to tacit knowledge used to simulate what would happen in a visual situation. With this distinction in mind, the paper then considers in detail the widely held assumption that in some important sense images are spatially displayed or are depictive, and that examining images uses the same mechanisms that are deployed in visual perception. I argue that the assumption of the spatial or depictive nature of images is only explanatory if taken literally, as a claim about how images are physically instantiated in the brain, and that the literal view fails for a number of empirical reasons--for example, because of the cognitive penetrability of the phenomena cited in its favor. Similarly, while it is arguably the case that imagery and vision involve some of the same mechanisms, this tells us very little about the nature of mental imagery and does not support claims about the pictorial nature of mental images. Finally, I consider whether recent neuroscience evidence clarifies the debate over the nature of mental images. I claim that when such questions as whether images are depictive or spatial are formulated more clearly, the evidence does not provide support for the picture-theory over a symbol-structure theory of mental imagery. Even if all the empirical claims were true, they do not warrant the conclusion that many people have drawn from them: that mental images are depictive or are displayed in some (possibly cortical) space. Such a conclusion is incompatible with what is known about how images function in thought. We are then left with the provisional counterintuitive conclusion that the available evidence does not support rejection of what I call the "null hypothesis"; namely, that reasoning with mental images involves the same form of representation and the same processes as that of reasoning in general, except that the content or subject matter of thoughts experienced as images includes information about how things would look.     

The effect of iconicity of visual displays on statistical reasoning: evidence in favor of the null hypothesis

Knowing which properties of visual displays facilitate statistical reasoning bears practical and theoretical implications. Therefore, we studied the effect of one property of visual diplays?– iconicity (i.e., the resemblance of a visual sign to its referent)?– on Bayesian reasoning. Two main accounts of statistical reasoning predict different effect of iconicity on Bayesian reasoning. The ecological-rationality account predicts a positive iconicity effect, because more highly iconic signs resemble more individuated objects, which tap better into an evolutionary-designed frequency-coding mechanism that, in turn, facilitates Bayesian reasoning. The nested-sets account predicts a null iconicity effect, because iconicity does not affect the salience of a nested-sets structure—the factor facilitating Bayesian reasoning processed by a general reasoning mechanism. In two well-powered experiments (N = 577), we found no support for a positive iconicity effect across different iconicity levels that were manipulated in different visual displays (meta-analytical overall effect: log OR = ?0.13, 95 % CI [?0.53, 0.28]). A Bayes factor analysis provided strong evidence in favor of the null hypothesis—the null iconicity effect. Thus, these findings corroborate the nested-sets rather than the ecological-rationality account of statistical reasoning.     

The Selective Laziness of Reasoning

Reasoning research suggests that people use more stringent criteria when they evaluate others' arguments than when they produce arguments themselves. To demonstrate this “selective laziness,” we used a choice blindness manipulation. In two experiments, participants had to produce a series of arguments in response to reasoning problems, and they were then asked to evaluate other people's arguments about the same problems. Unknown to the participants, in one of the trials, they were presented with their own argument as if it was someone else's. Among those participants who accepted the manipulation and thus thought they were evaluating someone else's argument, more than half (56% and 58%) rejected the arguments that were in fact their own. Moreover, participants were more likely to reject their own arguments for invalid than for valid answers. This demonstrates that people are more critical of other people's arguments than of their own, without being overly critical: They are better able to tell valid from invalid arguments when the arguments are someone else's rather than their own.     

The “who designed the designer?” objection to design arguments

One of the most commonly-raised objections to the design argument is the so-called “who designed the designer?” objection, which charges that any designer invoked to explain complexity in the universe will feature complexity of its own, and thus require explanation in terms of design. There are two distinct versions of this objection in the contemporary literature, with it being couched in terms of: (1) Complexity of designer: a designer exhibits complexity, which calls for explanation in terms of design; (2) Complexity of ideas: a designer’s ideas exhibit complexity, which calls for explanation in terms of design. To each of these versions of the objection there corresponds various responses from proponents of design. These proponents adopt a very particular strategy when crafting their responses: they argue that the objection can be neutralised simply by appealing to one or more of God’s attributes. In this paper I argue that this strategy is inapt, and unable to yield a successful response to either version of the objection. I also argue that a more promising way of tackling the objections is to identify their own peculiar weaknesses, for once these are exposed the objections cease to be a credible threat to the design hypothesis.     

A purely temporal transparency mechanism in the visual system.

I report evidence for a purely temporal perceptual transparency mechanism. Rapid alternation of two images in the same location can result in the simultaneous experience of both, accompanied by a sense of transparency. This is true even when the sum of the two images does not appear transparent, which suggests that the percept is not mediated by the static transparency processes. At slow rates, alternating gratings were experienced as successive. As the rate was increased, by 8 Hz observers experienced the gratings as simultaneous. The rapidly alternating gratings are apparently processed separately before being combined for awareness by a process that integrates over about 120 ms. A final experiment tested whether the common presentation time of different parts of an image in alternation with another would cause the parts to perceptually bind. Observers did not distinguish between a rapidly alternating intact grating display and one in which halves of the display were exchanged in time. In other words, temporal binding across space did not occur. The temporal transparency phenomenon, in addition to informing theories of transparency and the dynamics of visual processing, may also be useful for the creation of transparent displays for electronic devices.     

The effect of contextual factors on the judgement of informal reasoning fallacies

Informal reasoning fallacies are arguments that are psychologically persuasive but not valid. In order to judge the validity of these arguments one has to be sensitive to the context in which they appear. However, there is no empirical study that examines students' sensitivity to contextual factors and whether contextual factors actually influence their ability to identify informal reasoning fallacies. We hypothesized that when explicitly presented with different argumentative contexts, students' performance would reflect their sensitivity to the contextual nature of informal reasoning fallacies. The two experiments that we conducted support this hypothesis and emphasize the mediating role of perspective taking in students' ability to identify fallacious arguments.     

The effect of contextual factors on the judgement of informal reasoning fallacies

Informal reasoning fallacies are arguments that are psychologically persuasive but not valid. In order to judge the validity of these arguments one has to be sensitive to the context in which they appear. However, there is no empirical study that examines students' sensitivity to contextual factors and whether contextual factors actually influence their ability to identify informal reasoning fallacies. We hypothesized that when explicitly presented with different argumentative contexts, students' performance would reflect their sensitivity to the contextual nature of informal reasoning fallacies. The two experiments that we conducted support this hypothesis and emphasize the mediating role of perspective taking in students' ability to identify fallacious arguments.     

Interhemispheric categorization of pictures and words

Earlier studies suggest that interhemispheric processing increases the processing power of the brain in cognitively complex tasks as it allows the brain to divide the processing load between the hemispheres. We report two experiments suggesting that this finding does not generalize to word-picture pairs: they are processed at least as efficiently when processed by a single hemisphere as compared to processing occurring between the two hemispheres. We examined whether dividing the stimuli between the visual fields/hemispheres would be more advantageous than unilateral stimulus displays in the semantic categorization of simultaneously presented pictures, words, and word-picture pairs. The results revealed that within-domain stimuli (semantically related picture pairs or word pairs) were categorized faster in bilateral than in unilateral displays, whereas cross-domain stimuli (word-picture pairs) were not categorized faster in bilateral than in unilateral displays. It is suggested that interhemispheric sharing of word-picture stimuli is not advantageous as compared to unilateral processing conditions because words and pictures use different access routes, and therefore, it may be possible to process in parallel simultaneously displayed word-picture stimuli within a single hemisphere.     

Associations between myside bias on an informal reasoning task and amount of post‐secondary education

One hundred and twelve undergraduate university students completed an informal reasoning task in which they were asked to generate arguments both for and against the position they endorsed on three separate issues. Performance on this task was evaluated by comparing the number of arguments they generated which endorsed (myside arguments) and which refuted (otherside arguments) their own position on that issue. Participants generated more myside arguments than otherside arguments on all three issues, thus consistently showing a myside bias effect on each issue. Differences in cognitive ability were not associated with individual differences in myside bias. However, year in university was a significant predictor of myside bias. The degree of myside bias decreased systematically with year in university. Year in university remained a significant predictor of myside bias even when both cognitive ability and age were statistically partialled out. Copyright © 2003 John Wiley & Sons, Ltd.     

Reasoning serves argumentation in children

The argumentative theory of reasoning (Mercier & Sperber, in press-c) claims that reasoning evolved for argumentation: to find and evaluate arguments in dialogic contexts. The theory has drawn most of its supportive evidence from work with adults, leaving open the possibility that argumentive features of reasoning are in fact entirely learned. Evidence is reviewed here suggesting that the special relation between reasoning and argumentation holds at all ages. More specifically, it is argued that (a) children possess at least rudimentary argument skills, (b) they are able to reap the benefits of social reasoning from very early on, (c) confirmation bias is present as soon as they start to argue, and (d) children can be victims of the same biases that affect adults when they use reasoning in the wrong contexts. These claims strengthen the argumentative theory of reasoning and support a call for more research on the interactive features of reasoning in both adults and children.     

Specific-token effects in screening tasks: possible implications for aviation security

Screeners at airport security checkpoints perform an important categorization task in which they search for threat items in complex x-ray images. But little is known about how the processes of categorization stand up to visual complexity. The authors filled this research gap with screening tasks in which participants searched for members of target categories in visual displays. The authors found that when targets were sampled with replacement and repetition, participant screeners relied on recognizing familiar targets and had great difficulty using category-general knowledge. The authors observed a "heartbeat" in detection performance--it improved while test images repeated but dropped sharply when unfamiliar targets from the same categories appeared. This reliance on familiarity illuminates the processes of categorization under conditions of visual complexity and suggests limits on those processes. This reliance also has implications for the training and evaluation of screeners in the field.     

Can there be reasoning with degrees of belief?

In this paper I am concerned with the question of whether degrees of belief can figure in reasoning processes that are executed by humans. It is generally accepted that outright beliefs and intentions can be part of reasoning processes, but the role of degrees of belief remains unclear. The literature on subjective Bayesianism, which seems to be the natural place to look for discussions of the role of degrees of belief in reasoning, does not address the question of whether degrees of belief play a role in real agents’ reasoning processes. On the other hand, the philosophical literature on reasoning, which relies much less heavily on idealizing assumptions about reasoners than Bayesianism, is almost exclusively concerned with outright belief. One possible explanation for why no philosopher has yet developed an account of reasoning with degrees of belief is that reasoning with degrees of belief is not possible for humans. In this paper, I will consider three arguments for this claim. I will show why these arguments are flawed, and conclude that, at least as far as these arguments are concerned, it seems like there is no good reason why the topic of reasoning with degrees of belief has received so little attention.     

Visual representation in analogical problem solving

Analogical reasoning has been shown to be effective in the process of solving Dunker’s radiation problem. The spatial nature of the solution to this problem suggests that a visually represented analogue should be particularly effective. However, recent work seems to indicate that a visual analogue does not assist in solving the radiation problem. This paper reports a detailed experimental analysis of the effectiveness of visually represented analogues to the radiation problem. The results show that visual analogues can be effective ff they represent the appropriate features of the problem-solution relationship. The paper also reports on the use of an appropriate visual representation within the problem as a facilitator of analogical reasoning. The results indicate that a visual representation within the problem can act as a facilitator of analogical reasoning, possibly by acting as a retrieval cue.     

Consequences of aggressive threats by Betta splendens

Male Siamese fighting fish continued to approach visual stimuli associated with conspecifics in the absence of opportunities to perform threat displays or to attack. Dominant fish performed more operant responses than subordinates when such responses led to the appearance of their own mirror images, and all fish learned to delay their threat displays if these resulted in disappearance of the mirror image. In a second experiment, subjects overwhelmingly preferred to view conspecifics (to whom they frequently displayed) compared to no stimulus or members of other species (to whom they did not display). The functions of threat displays in aggressive encounters is discussed.     

Precuing benefits for color and location in a visual search task

Selection in multiple-item displays has been shown to benefit immensely from advance knowledge of target location (e.g., Henderson, 1991), leading to the suggestion that location is completely dominant in visual selective attention (e.g., Tsal & Lavie, 1993). Recently, direct selection by color has been reported in displays in which location does not vary (Vierck & Miller, 2005). The present experiment investigated the possibility of independent selection by color in a task with multiple-item displays and location precues in order to see whether color is also used for selection even when target location does vary and supposedly dominant location precues can be used. Precues provided independent information about the location and color of a target, and each type of precue could be either valid or invalid. The precues were followed by brief displays of six letters in six different colors, and participants had to discriminate the case of a prespecified target letter (e.g., R vs. r). Performance was much better when location cues were valid than when they were invalid, confirming the large advantage associated with valid advance location information. Performance was also better with valid advance color information, however, both when location cues were valid and when they were invalid. But these color benefits were dependent on the closeness of the colored letter to the cued location. Our results thus suggest that selection by color in a multiple-item display, where location and color information are independent from each other and equalized, is mediated by location information.