Constraints and Preferences in Inductive Learning: An Experimental Study of Human and Machine Performance

The paper examines constraints and preferences employed by people in learning decision rules from preclassified examples. Results from four experiments with human subjects were analyzed and compared with artificial intelligence (AI) inductive learning programs. The results showed the people's rule inductions tended to emphasize category validity (probability of some property, given a category) more than cue validity (probability that an entity is a member of a category given that it has some property) to a greater extent than did the AI programs. Although the relative proportions of different rule types (e.g., conjunctive vs. disjunctive) changed across experiments, a single process model provided a good account of the data from each study. These observations are used to argue for describing constraints in terms of processes embodied in models rather than in terms of products or outputs. Thus AI induction programs become candidate psychological process models and results from inductive learning experiments can suggest new algorithms. More generally, the results show that human inductive generalizations tend toward greater specificity than would be expected if conceptual simplicity were the key constraint on inductions. This bias toward specificity may be due to the fact that this criterion both maximizes inferences that may be drawn from category membership and protects rule induction systems from developing over-generalizations.     

Mental Models of the Day/Night Cycle

This article presents the results of an experiment which investigated elementary school children's explanations of the day/night cycle. First, third, and fifth grade children were asked to explain certain phenomena, such as the disappearance of the sun during the night, the disappearance of stars during the day, the apparent movement of the moon, and the alteration of day and night. The results showed that the majority of the children in our sample used in a consistent fashion a small number of relatively well-defined mental models of the earth, the sun, and the moon to explain the day/night cycle. These mental models of the day/night cycle were empirically accurate, logically consistent and revealed some sensitivity on the part of the children to issues of simplicity of explanation. The younger children formed Initial mental models which provided explanations of the day/night cycle based on everyday experience (e.g., the sun goes down behind mountains, clouds cover up the sun). The older children constructed synthetic mental models (e.g., the sun and the moon revolve around the stationary earth every 24 hours; the earth rotates in an up/down direction and the sun and moon are fixed on opposite sides) which represented attempts to synthesize the culturally accepted view with aspects of their Initial models. A few of the older children appeared to have constructed a mental model of the day/night cycle similar to the scientific one. A theoretical framework is outlined which explains the formation of initial, synthetic, and scientific models of the day/night cycle in terms of the reinterpretation of a hierarchy of constraints, some of which are present early in the child's life, and others which emerge later out of the structure of the acquired knowledge.     

Risk Factors for Attempting Suicide in Prisoners

We wished to examine determinants of suicidal behavior in prisoners. 903 male prisoners had a psychiatric interview which included various psychometric tests. Suicide attempters were compared with prisoners who had never attempted suicide. Significantly more of the attempters had a history of psychiatric disorder, substance abuse, a family history of suicidal behavior, convictions for violent crime, had exhibited aggressive behavior in jail, and had higher BGLHA aggression scores. A similar pattern of risk factors was found for prisoners with suicidal ideation. A lifetime history of attempting suicide, or of having suicidal ideation, is frequent in prisoners. Risk factors include family, developmental, aggression, personality, psychiatric, and substance abuse factors.     

The Validity of the Rorschach and the Minnesota Multiphasic Personality Inventory: Results from Meta-Analyses

Results from meta-analyses have been widely cited to defend the validity of the Rorschach. However, the meta-analyses have been flawed. For example, one meta-analysis included results that were obtained by calculating correlations but not results that were obtained by conducting t tests or analyses of variance. When we reanalyzed the data from the most widely cited meta-analysis (Parker, Hanson, & Hunsley, 1988), we found that for confirmatory studies (also called convergent-validity studies), the Minnesota Multiphasic Personality Inventory (MMPI) explained 23% to 30% of the variance, whereas the Rorschach explained only 8% to 13% of the variance. These results indicate that the Rorschach is not as valid as the MMPI.     

Fruitful Interchange or Polite Chitchat? The Dialogue Between Science and Theology

The demand that epistemic support be explicated as rational compulsion has consistently undermined the dialogue between theology and science. Rational compulsion entails too restrictive a form of epistemic support for most scientific theorizing, let alone interdisciplinary dialogue. This essay presents a less restrictive form of epistemic support, explicated not as rational compulsion but as explanatory power. Once this notion of epistemic support is developed, a genuinely productive interdisciplinary dialogue between theology and science becomes possible. This essay closes by sketching how the Big Bang model from cosmology and the Christian doctrine of Creation can be viewed as supporting each other.     

Cornell College: Program in Science and Religion

Cornell College in Mount Vernon, Iowa, has established a new interdisciplinary program in science and religion. One of the features of this program is an undergraduate major in science and religion that requires substantial course work in at least one of the natural sciences as well as course work in philosophy, religion, and history. As a result of a grant from the John Templeton Foundation, Cornell College will offer a special course, God and Physics: From Aquinas to Quantum Mechanics (April 1998), and will sponsor an international symposium on creation and contemporary cosmology (April 1999). Opportunities exist for interested scholars to come to Cornell as Templeton Visiting Fellows in order to participate in these activities.