Artificial life: organization, adaptation and complexity from the bottom up

Artificial life attempts to understand the essential general properties of living systems by synthesizing life-like behavior in software, hardware and biochemicals. As many of the essential abstract properties of living systems (e.g. autonomous adaptive and intelligent behavior) are also studied by cognitive science, artificial life and cognitive science have an essential overlap. This review highlights the state of the art in artificial life with respect to dynamical hierarchies, molecular self-organization, evolutionary robotics, the evolution of complexity and language, and other practical applications. It also speculates about future connections between artificial life and cognitive science.     

Mental representation of logical connectives

Logical connectives, such as “AND”, “OR”, “IF . . . THEN”, and “IF AND ONLY IF” are ubiquitous in both language and cognition; however, reasoning with logical connectives is error-prone. We argue that some of these errors may stem from people's tendency to minimize the number of possibilities compatible with logical connectives and to construct a “minimalist” one-possibility representation. As a result, connectives denoting a single possibility (e.g., conjunctions) are likely to be represented correctly, whereas connectives denoting multiple possibilities (e.g., disjunctions or conditionals) are likely to be erroneously represented as conjunctions. These predictions were tested and confirmed in three experiments using different paradigms. In Experiment 1, participants were presented with a multiple-choice task and asked to select all and only those possibilities that would indicate that compound verbal propositions were true versus false. In Experiment 2, a somewhat similar task was used, except that participants were asked later to perform a cued recall of verbal propositions. Finally, Experiment 3 used an old/new recognition paradigm to examine participants' ability to accurately recognize different logical connectives. The results of the three experiments are discussed in relation to theories of representation of possibilities and theories of reasoning.     

Mental representation of prepositional compounds: evidence from Italian agrammatic patients

The processing of Prepositional compounds (typical Neo-latin noun--noun modifications where a head noun is modified by a prepositional phrase, e.g., mulino a vento, windmill) was preliminarily studied with a group of six agrammatic aphasic patients, and, in more detail, with a further agrammatic patient (MB). Omission was the most frequent error type in naming, whereas in the other tasks (repetition, reading, writing, and completion) errors were mostly substitutions of the target preposition. This happened even with fully lexicalized compound forms, i.e., those forms where the linking preposition is syntactically and semantically opaque. These findings are interpreted in terms of a dual-route theory of lexical access to morphologically complex words.     

Mental representation and two kinds of eliminativism

The battle over the proper place of mental representation in cognitive science is often portrayed as a clash between realism and eliminativism. But this simple dichotomy belies the variety of different ontological positions available. This article investigates the various stances that one can adopt toward the ontology of mental representation, and in so doing, shows that eliminativism is in fact best understood as two distinct positions: a posteriori eliminativism and a priori eliminativism. Furthermore, I show that a priori eliminativism faces two crippling challenges. I argue that once we put a priori eliminativism aside, determining the ultimate ontological status of representation can be postponed while we assess its utility across different domains of cognitive science—something all remaining positions can agree on.     

Mental representation in visual/haptic crossmodal memory: evidence from interference effects

Two experiments used visual-, verbal-, and haptic-interference tasks during encoding (Experiment 1) and retrieval (Experiment 2) to examine mental representation of familiar and unfamiliar objects in visual/haptic crossmodal memory. Three competing theories are discussed, which variously suggest that these representations are: (a) visual; (b) dual-code—visual for unfamiliar objects but visual and verbal for familiar objects; or (c) amodal. The results suggest that representations of unfamiliar objects are primarily visual but that crossmodal memory for familiar objects may rely on a network of different representations. The pattern of verbal-interference effects suggests that verbal strategies facilitate encoding of unfamiliar objects regardless of modality, but only haptic recognition regardless of familiarity. The results raise further research questions about all three theoretical approaches.     

Mental representation in visual/haptic crossmodal memory: evidence from interference effects

Two experiments used visual-, verbal-, and haptic-interference tasks during encoding (Experiment 1) and retrieval (Experiment 2) to examine mental representation of familiar and unfamiliar objects in visual/haptic crossmodal memory. Three competing theories are discussed, which variously suggest that these representations are: (a) visual; (b) dual-code—visual for unfamiliar objects but visual and verbal for familiar objects; or (c) amodal. The results suggest that representations of unfamiliar objects are primarily visual but that crossmodal memory for familiar objects may rely on a network of different representations. The pattern of verbal-interference effects suggests that verbal strategies facilitate encoding of unfamiliar objects regardless of modality, but only haptic recognition regardless of familiarity. The results raise further research questions about all three theoretical approaches.     

Naming the parents of the THOG: Mental representation and reasoning

It was hypothesized that subjects misrepresent the THOG problem by confusing data and hypotheses. An abstract version of the problem in which the given exemplars and the hypothetical ones were designated by two different labels was used in three experiments. Experiment 1 showed that this version elicits a better performance than the standard version of the problem. Experiments 2 and 3 confirmed these results, by ruling out a possible alternative account of the facilitatory effect obtained in Experiment 1. The present results are discussed in relationship to the general issues of content effects and non-consequentialism in reasoning.     

Mental representations of arithmetic facts: evidence from eye movement recordings supports the preferred operand-order-specific representation hypothesis

There are three main hypotheses about mental representations of arithmetic facts: the independent representation hypothesis, the operand-order-free single-representation hypothesis, and the operand-order-specific single-representation hypothesis. The current study used electrical recordings of eye movements to examine the organization of arithmetic facts in long-term memory. Subjects were presented single-digit addition and multiplication problems and were asked to report the solutions. Analyses of the horizontal electrooculograph (HEOG) showed an operand order effect for multiplication in the time windows 150-300?ms (larger negative potentials for smaller operand first problems than for larger operand first ones). The operand order effect was reversed in the time windows from 400 to 1,000?ms (i.e., larger operand first problems had larger negative potentials than smaller operand first problems). For addition, larger operand first problems had larger negative potentials than smaller operand first in the series of time windows from 300 to 1,000?ms, but the effect was smaller than that for multiplication. These results confirmed the dissociated representation of addition and multiplication facts and were consistent with the prediction of the preferred operand-order-specific representation hypothesis.     

Mental representations of arithmetic facts: Evidence from eye movement recordings supports the preferred operand-order-specific representation hypothesis

There are three main hypotheses about mental representations of arithmetic facts: the independent representation hypothesis, the operand-order-free single-representation hypothesis, and the operand-order-specific single-representation hypothesis. The current study used electrical recordings of eye movements to examine the organization of arithmetic facts in long-term memory. Subjects were presented single-digit addition and multiplication problems and were asked to report the solutions. Analyses of the horizontal electrooculograph (HEOG) showed an operand order effect for multiplication in the time windows 150–300 ms (larger negative potentials for smaller operand first problems than for larger operand first ones). The operand order effect was reversed in the time windows from 400 to 1,000 ms (i.e., larger operand first problems had larger negative potentials than smaller operand first problems). For addition, larger operand first problems had larger negative potentials than smaller operand first in the series of time windows from 300 to 1,000 ms, but the effect was smaller than that for multiplication. These results confirmed the dissociated representation of addition and multiplication facts and were consistent with the prediction of the preferred operand-order-specific representation hypothesis.     

Mental representation and hypothetico-deductive reasoning: The case of the THOG problem

Summary This article reports three experiments that deal with the source of the difficulty of Wason's (1977) THOG problem. The solution of this problem demands both the postulation of hypotheses and a combinatorial analysis of their consequences. Experiment 1 showed that the generation of the hypotheses is not in itself sufficient to solve the problem. Experiment 2 showed that a version presenting a plausible context for separating the level of data from that of hypotheses produced a better performance than both the original abstract version and a thematic version lacking the plausible context separating the levels. Experiment 3 gave evidence that this context can produce facilitation even with the geometric material of the classic version. This experiment also showed that a pictorial presentation of data and a verbal presentation of hypotheses affect performance negatively. The results demonstrate the role of problem representation in problem solving, and, in particular, the role of homogeneity in representing data and hypotheses in hypothetico-deductive reasoning.     

Mental representation and learning: The influence of practice on the development of mental representation structure in complex action

ObjectivesRecent research has elicited distinct differences in mental representations between athletes of different skill levels. Such differences suggest that the structure of mental representations changes as a function of skill level. However, research examining how such mental representation structures develop over the course of learning is lacking. In the present study, we examine the effects of practice on the development of one's mental representation of a complex action during early skill acquisition.DesignFor this purpose, we created a controllable learning situation, using a repeated-measures design with a control group. More specifically, novice golfers were randomly assigned to either a practice group (n = 12) or a control group (n = 12). Both groups were tested before and after an acquisition phase of three days as well as after a three day retention interval.MethodsMental representation structures of the putt were recorded, employing the structural dimensional analysis of mental representation (SDA-M), which provides psychometric data on the structure and grouping of action concepts in long-term memory. In addition, outcome performance of the practice group was measured, using two-dimensional error scores of the putt.ResultsFindings revealed a significant improvement in task performance, as well as functional changes in the structure of the practice group's mental representation. In contrast, no functional adaptations were evident in the mental representation of the control group.ConclusionOur findings suggest that motor skill acquisition is associated with functional adaptations of action-related knowledge in long-term memory.     

Mental representation of three-dimensional objects in visual problem solving and recognition

Subjects inspected sets of flat, separated orthographic projections of surfaces of potential three-dimensional objects. After solving problems based on these orthographic views, subjects discriminated between isometric views of the same objects and drawings of distractor structures. Recognition of the isometrics, which had never been shown during the problem solving phase of the experiment, was excellent. In addition, recognition of isometrics corresponding to problems that had been solved correctly when presented in orthographic form was significantly superior to recognition of isometrics based on problems solved incorrectly. In Experiment 2, conditions were included in which either orthographic or isometric views functioned as problem solving or recognition displays. Only in the case of orthographic problem solving followed by isometric recognition (Experiment 1) was the superiority of recognition for correctly-solved problems over incorrectly-solved problems obtained. The pattern of results suggests that viewers construct mental representations embodying structural information about integrated, three-dimensional objects when asked to reason about flat, disconnected projections.     

Linda问题的表象-命题双表征解释视角探究

本文首先提出了Linda问题的表象-命题双表征这一新的解释视角。该视角认为,Linda问题基于表象表征和命题表征可以有两种不同的解读与表征方式;而不同的被试在Linda问题上可能分别采取了上述表征方式之一;但由于Linda问题的特殊性,大多数被试采用了表象表征;大多数被试的这一表征取向则可能是所谓谬误判断出现的原因。本文通过4项研究,让被试在基于表象表征设计的转述版本与基于命题表征设计的转述版间选择接近自身理解的版本;并考察了将Linda问题修改成更符合命题表征的数学化表达形式能否降低所谓谬误水平;还考察了增加促使被试运用命题表征的排序项"Linda是全人类中的一员"能否降低所谓谬误水平。结果显示,在转述版本选择上,大多数被试选择了基于表象表征设计的版本;而上文所指的两个修正版Linda问题则都降低了被试的所谓谬误水平。这些结果支持了本文所提的视角。     

Mental representation of length and weight series and transitive inferences in young children

Forty-eight second graders (8 years of age) were trained on length or weight relationships between adjacent members of a five-term series of colored objects. Feedback was visual and of either minimal or strong salience. Differences in weight were assessed by either a balance scale or a spring scale. Results showed that more salient visual feedback reduced the learning effort for length but not for weight comparisons. After training children were tested on all possible object pairs. Children's comparisons of items by length were very accurate in contrast to their comparisons by weight. An explanation for these findings is suggested by the data from a group of 6-year-olds who were trained on two independent pairs of a four-term series. Test results showed that subjects spontaneously encoded absolute lengths but tended to ignore information about the absolute weight of objects. It is suggested that high test accuracy depends on stimulus material for which the absolute values of the relevant dimension are encoded. The implications for taking test performance as an indicator of “transitive reasoning” ability are discussed.