Monotonicity in Practical Reasoning

Classic deductive logic entails that once a conclusion is sustained by a valid argument, the argument can never be invalidated, no matter how many new premises are added. This derived property of deductive reasoning is known as monotonicity. Monotonicity is thought to conflict with the defeasibility of reasoning in natural language, where the discovery of new information often leads us to reject conclusions that we once accepted. This perceived failure of monotonic reasoning to observe the defeasibility of natural-language arguments has led some philosophers to abandon deduction itself (!), often in favor of new, non-monotonic systems of inference known as `default logics'. But these radical logics (e.g., Ray Reiter's default logic) introduce their desired defeasibility at the expense of other, equally important intuitions about natural-language reasoning. And, as a matter of fact, if we recognize that monotonicity is a property of the form of a deductive argument and not its content (i.e., the claims in the premise(s) and conclusion), we can see how the common-sense notion of defeasibility can actually be captured by a purely deductive system.     

Blood donation is an act of benevolence rather than altruism.

OBJECTIVES: Blood donation is described as an archetypal altruistic behavior, and recruitment/retention campaigns emphasize altruism. Here, a benevolence hypothesis for blood donation (both the donor and recipient benefit) rather than the altruism hypothesis (only the recipient gains) is proposed. DESIGN: Three United Kingdom-based studies contrasted benevolence and altruism: (a) a 6-month prospective study of blood donor behavior (Study 1: N = 957), (b) a cross-sectional study of blood donors' intentions (Study 2: N = 333), and (c) an experimental study examining the effect of benevolent and altruistic messages on willingness to help across high- and low-cost helping behaviors for committed and noncommitted blood donors (Study 3: N = 200). MAIN OUTCOME: Donor behavior and intentions-willingness. MEASURES: Beliefs in personal and societal benefit (Time 1) and actual donations (Time 2) were assessed in Study 1; beliefs in benevolence, altruism, hedonism, and kinship along with donation intentions were assessed in Study 2; and empathy, donor commitment, and willingness to donate blood, money, fund-raise, and staff a telephone helpline were assessed in Study 3. RESULTS: Beliefs in personal rather than societal benefit predicted actual future donation. A path model showed that only beliefs in benevolence were associated with intentions to donate. Committed blood donors were more willing to donate blood when exposed to a benevolent message rather than an altruistic one. This effect was not observed for other forms of helping. CONCLUSIONS: The benevolence hypothesis is supported, suggesting that blood donor motivation is partly selfish. Blood donation campaigns should focus on benevolent rather than purely altruistic messages.     

Predicting future blood donor returns: past behavior, intentions, and observer effects.

A prospective design was used to explore the efficacy of 6 factors (e.g., intentions) to predict the number of future blood donations in an initial sample of 630 blood donors. Differential predictions are made for the roles of past behavior and intentions with respect to occasional (4 or fewer previous blood donations) and regular (5 or more previous blood donations) blood donors. Intentions were predictive for occasional donors, and past behavior was predictive for regular donors. Furthermore, for regular donors only, an inverted U-shaped curve explained the relationship between past behavior and future behavior. Finally, it is reported that observing others fainting produces a reduction in the number of future donations for occasional donors. The theoretical and practical implications of these findings are discussed.     

The five factor model of personality: Openness a distinct but related construct

It has been argued that the Openness (O) dimension from the five factor model (FFM) of personality may in fact be an associate of the ability domain more than the personality domain. This paper explores this hypothesis using a sample of 101 managers. Participants completed the NEO-FFI and a measure of ability assessing the construct as typical performance. This measure was an occupational specific measure of typical intellectual engagement (TIE), termed the “problem solving through challenge” PSC scale. A combination of LISREL CFA and hierarchical multiple linear regression (HMLR) indicated that in fact O was a distinct but related construct to the other four dimensions of the FFM (N, E, A and C), but that O was more strongly correlated with PSC than the other dimensions. These results are taken to indicate that O, while associated with personality, assesses something to do with problem solving as a personality trait. Further the results suggest that E linked O to the other personality scales.     

The concept of parsimony in factor analysis

The concept of parsimony in factor analysis is discussed. Arguments are advanced to show that this concept bears an analogic relationship to entropy in statistical mechanics and information in communication theory. A formal explication of the term parsimony is proposed which suggests approaches to the final resolution of the rotational problem. This paper provides the rationale underlying Carroll's (2) analytical solution for approximating simple structure, and the solutions of Saunders (7) and Neuhaus and Wrigley (5).     

The effects of different component response requirements in multiple and concurrent schedules

Six pigeons were trained on multiple and concurrent schedules. The reinforcement rates were varied systematically (a) when lever pressing was required in one component and key pecking in the successive component; (b) when lever pressing was required in both multiple components; (c) when key pecking was required in both multiple components; and (d) when key pecking was required on one schedule and lever pressing was required on the concurrently-available schedule. Only the absolute level of responding was changed by different response requirements. Analyzed by the generalized matching law, performance under different response requirements resulted in a bias toward key pecking, and the measured response bias was the same in multiple and concurrent schedule arrangements. The bias in time measures obtained from concurrent schedule performance was reliably smaller than the obtained response biases. The sensitivity to reinforcement-rate changes was ordered: concurrent key-lever; multiple key-key; multiple lever-key; and, the least sensitive, multiple lever-lever. The results confirm that requirements of different topographical responses can be handled by the generalized matching law mainly in the bias parameter, but problems for this type of analysis may be caused by the changing sensitivity to reinforcement in multiple schedule performance as response requirements are changed.     

Imitation of Gestures in Children is Goal-directed

The view that the motor program activated during imitation is organized by goals was investigated by asking pre-school children to imitate a set of hand gestures of varying complexity that were made by an experimenter sitting in front of them. In Experiments 1 and 3, children reached for the correct object (one of their own ears or one of two dots on a table) but preferred to use the ipsilateral hand. This ipsilateral preference was not observed when hand movements were made to only one ear (Experiment 2), or when movements were diercted at space rather than physical objects (Experiment 3). The results are consistent with the notion that imitation is guided by goals and provide insights about how these goals are organized.