The Mental Model Theory of Conditionals: A Reply to Guy Politzer

This paper replies to Politzer’s (2007) criticisms of the mental model theory of conditionals. It argues that the theory provides a correct account of negation of conditionals, that it does not provide a truth-functional account of their meaning, though it predicts that certain interpretations of conditionals yield acceptable versions of the ‘paradoxes’ of material implication, and that it postulates three main strategies for estimating the probabilities of conditionals.     

Spider monkey ranging patterns in Mexican subtropical forest: do travel routes reflect planning?

Although it is well known that frugivorous spider monkeys (Ateles geoffroyi yucatanensis) occupy large home ranges, travelling long distances to reach highly productive resources, little is known of how they move between feeding sites. A 11 month study of spider monkey ranging patterns was carried out at the Otochma’ax Yetel Kooh reserve, Yucatán, Mexico. We followed single individuals for as long as possible each day and recorded the routes travelled with the help of a GPS (Global Positioning System) device; the 11 independently moving individuals of a group were targeted as focal subjects. Travel paths were composed of highly linear segments, each typically ending at a place where some resource was exploited. Linearity of segments did not differ between individuals, and most of the highly linear paths that led to food resources were much longer than the estimate visibility in the woodland canopy. Monkeys do not generally continue in the same ranging direction after exploiting a resource: travel paths are likely to deviate at the site of resource exploitation rather than between such sites. However, during the harshest months of the year consecutive route segments were more likely to retain the same direction of overall movement. Together, these findings suggest that while moving between feeding sites, spider monkeys use spatial memory to guide travel, and even plan more than one resource site in advance. This contribution is part of the special issue “A Socioecological Perspective on Primate Cognition” (Cunningham and Janson 2007).     

What wild primates know about resources: opening up the black box

We present the theoretical and practical difficulties of inferring the cognitive processes involved in spatial movement decisions of primates and other animals based on studies of their foraging behavior in the wild. Because the possible cognitive processes involved in foraging are not known a priori for a given species, some observed spatial movements could be consistent with a large number of processes ranging from simple undirected search processes to strategic goal-oriented travel. Two basic approaches can help to reveal the cognitive processes: (1) experiments designed to test specific mechanisms; (2) comparison of observed movements with predicted ones based on models of hypothesized foraging modes (ideally, quantitative ones). We describe how these two approaches have been applied to evidence for spatial knowledge of resources in primates, and for various hypothesized goals of spatial decisions in primates, reviewing what is now established. We conclude with a synthesis emphasizing what kinds of spatial movement data on unmanipulated primate populations in the wild are most useful in deciphering goal-oriented processes from random processes. Basic to all of these is an estimate of the animal’s ability to detect resources during search. Given knowledge of the animal’s detection ability, there are several observable patterns of resource use incompatible with a pure search process. These patterns include increasing movement speed when approaching versus leaving a resource, increasingly directed movement toward more valuable resources, and directed travel to distant resources from many starting locations. Thus, it should be possible to assess and compare spatial cognition across a variety of primate species and thus trace its ecological and evolutionary correlates. This contribution is part of the special issue “A Socioecological Perspective on Primate Cognition” (Cunningham and Janson 2007b)     

Précis of The rational imagination: how people create alternatives to reality

The human imagination remains one of the last uncharted terrains of the mind. People often imagine how events might have turned out "if only" something had been different. The "fault lines" of reality, those aspects more readily changed, indicate that counterfactual thoughts are guided by the same principles as rational thoughts. In the past, rationality and imagination have been viewed as opposites. But research has shown that rational thought is more imaginative than cognitive scientists had supposed. In The Rational Imagination, I argue that imaginative thought is more rational than scientists have imagined. People exhibit remarkable similarities in the sorts of things they change in their mental representation of reality when they imagine how the facts could have turned out differently. For example, they tend to imagine alternatives to actions rather than inactions, events within their control rather than those beyond their control, and socially unacceptable events rather than acceptable ones. Their thoughts about how an event might have turned out differently lead them to judge that a strong causal relation exists between an antecedent event and the outcome, and their thoughts about how an event might have turned out the same lead them to judge that a weaker causal relation exists. In a simple temporal sequence, people tend to imagine alternatives to the most recent event. The central claim in the book is that counterfactual thoughts are organised along the same principles as rational thought. The idea that the counterfactual imagination is rational depends on three steps: (1) humans are capable of rational thought; (2) they make inferences by thinking about possibilities; and (3) their counterfactual thoughts rely on thinking about possibilities, just as rational thoughts do. The sorts of possibilities that people envisage explain the mutability of certain aspects of mental representations and the immutability of other aspects.     

Do Colours Look Like Dispositions? Reply to Langsam and Others

Dispositional theories of colour have been attacked by McGinn and others on the ground that 'Colours do not look like dispositions'. Langsam has argued that on the contrary they do, in 'Why Colours Do Look Like Dispositions', The Philosophical Quarterly , 50 (2000), pp. 68–75. I make three claims. First, neither side has made its case. Secondly, it is true, at least on one interpretation, that colours do not look like dispositions. Thirdly, this does not show that dispositionalism about colours is false.     

Manual dexterity in the gorilla: bimanual and digit role differentiation in a natural task

The manipulative actions of mountain gorillas Gorilla g. beringei were examined in the context of foraging on hard-to-process plant foods in the field, in particular those used in tackling thistle Carduus nyassanus. A repertoire of 72 functionally distinct manipulative actions was recorded. Many of these actions were used in several variants of grip, finger(s) and movement path, both by different individuals and by the same individual at different times. The repertoire appears somewhat greater than that observed in comparable studies of monkeys, but a far more striking difference is found in the use of differentiated actions in concert. Mountain gorillas routinely and frequently deal with problems that involve: (1) bimanual role differentiation, with the two hands taking different roles but synchronized in time and space, and (2) digit role differentiation, with independent control of parts of the same hand used for separate purposes at the same time. The independent control that allows these abilities, so crucial to human manual constructional ability, is apparently general in African great apes. Role differentiation, between and within the hand, is evidently a primitive characteristic in the human arsenal of skills. Accepted after revision: 6 April 2001 Electronic Publication     

An account of human “impulsivity” on self-control tasks

Three experiments examined the effects of economic constraint (time restriction—trials restriction) on adult humans' performance on concurrent chained schedules of reinforcement in which terminal links differed both in reward size and pre-reward delay levels. In the first, terminal links offered a long delay (20, 30, 40, 50 sec) followed by 2 points, or a short delay (10 sec) followed by 1 point. Initial links consisted of the same variable interval schedules for each alternative. Subjects showed a conditional sensitivity to increases in delay. Under a time constraint, there was an increasing preference for the smaller reward as the delay to the larger reward was increased, whereas under a trials constraint subjects were totally insensitive to such changes. In the second experiment, this finding was replicated using long and short periods of video game playing as large and small rewards. In the third experiment terminal link parameters remained constant (2 points after 15 sec, or 1 point immediately), but initial link parameters were manipulated (either VI 1-sec, 8-sec, or 20-sec) so that the higher relative rate of reward shifted from being associated with the small reward to being associated with the large reward. Again subjects chose differently under the two constraints. Subjects under the time constraint exhibited a preference for the small reward at all levels of initial link, but under the trials constraint subjects preferred the large reward. Subjects in the time constraint condition thus exhibited a maladaptive insensitivity to changes in the initial link duration. These findings are interpreted as supporting a miscalculation rather than a discounting interpretation of human performance on “self-control” tasks.     

The Waffle Phenomenon: Negative Evaluations of Those Who Shift Attitudinally1

The past two presidential campaigns have been filed with charges that the Democratic nominee “changed his mind” on various issues. The present research explored the possibility that negative evaluations may be produced by attitude change per se. In the first experiment, subjects responded to a stranger whose attitudes remained stable or who changed his attitudes over a period of two months vs. one year. Individuals who changed their attitudes were generally evaluated more negatively than those whose attitudes remained stable; the amount of time over which the change occurred produced no effect. A second expcriment sought to determine if the direction of change (toward increased or decreased similarity with subjects) influenced evaluations of a stranger. Attitude change which resulted in decreased similarity was rated most negatively. Even when a stranger changed his attitudes in the direction of greater similarity with subjects, however, he was still regarded as less decisive, less reliable, and a worse leader than was an individual with stable attitudes. This negative evaluation of attitude change was labeled the “waffle phenomenon”, and the implications for political candidates were discussed.     

An empirical test of the problem solving model of depression and its application to the prediction of anxiety and anger

Building on research which has found positive but small correlations between stressful life events and negative psychological outcomes as well as studies which have demonstrated support for the problem solving model of depression, this study replicated the Problem Solving Model of Depression using instruments not previously used in this area. Additionally, this study tested the application and extension of the problem solving model to other emotions by assessing the efficacy of three variables, Negative Life Events, Current Problem, and Problem Solving as predictors of Depression, Anxiety, and Anger. To test this model, five assessment instruments were administered to 110 male and 178 female graduate students. Support was found for the application of this model to the prediction of Depression. While Current Problem and Problem Solving were related to Anxiety, Negative Life Events were not. In predicting Anger, some limited support was found for this model with females but no support was found with males.