The Ethics of Geoengineering: Moral Considerability and the Convergence Hypothesis

Although it could avoid some harmful effects of climate change, sulphate aerosol geoengineering (SAG), or injecting sulphate aerosols into the stratosphere in order to reflect incoming solar radiation, threatens substantial harm to humans and non‐humans. I argue that SAG is prima facie ethically problematic from anthropocentric, animal liberationist, and biocentric perspectives. This might be taken to suggest that ethical evaluations of SAG can rely on Bryan Norton's convergence hypothesis, which predicts that anthropocentrists and non‐anthropocentrists will agree to implement the same or similar environmental policies. However, there are potential scenarios in which anthropocentrists and non‐anthropocentrists would seem to diverge on whether a particular SAG policy ought to be implemented. This suggests that the convergence hypothesis should not be relied on in ethical evaluation of SAG. Instead, ethicists should consider the merits and deficiencies of both non‐anthropocentric perspectives and the ethical evaluations of SAG such perspectives afford.     

An apparent-motion confound causes the negative exogenous cuing effect at SOAs with larger numbers of target locations

Salient but irrelevant stimuli seem to cause an automatic orienting of covert attention, facilitating the detection of targets at the cued location for a brief period of time. However, this finding is highly dependent on the number of possible target locations, at least when the simple detection of targets is all that the task requires. Whereas small numbers of possible target locations (e.g., 2 or 3) produce the well-known advantage in response time for valid cue trials (i.e., a positive cuing effect), larger numbers of possible target locations (e.g., 6 or 8) produce a negative cuing effect. If not explained in terms of a nonattentional mechanism, this latter finding raises serious questions about the standard interpretation of positive cuing effects. The present experiment tested a particular nonattentional mechanism: that a confound between target presence and apparent motion, which occurs only on invalid cue trials, is responsible for negative cuing effect. We reduced or eliminated this confound by the use of a new type of catch trial and eliminated the negative cuing effect with large numbers of target locations.     

Dissociating positive and negative influences of verbal processing on the recognition of pictures of faces and objects

Four experiments investigated the role of verbal processing in the recognition of pictures of faces and objects. We used (a) a stimulus-encoding task where participants learned sequentially presented pictures in control, articulatory suppression, and describe conditions and then engaged in an old-new picture recognition test and (b) a poststimulus-encoding task where participants learned the stimuli without any secondary task and then either described or not a single item from memory before the recognition test. The main findings were as follows: First, verbalization influenced picture recognition. Second, there were contrasting influences of verbalization on the recognition of faces, compared with objects, that were driven by (a) the stage of processing during which verbalization took place (as assessed by the stimulus-encoding and poststimulus-encoding tasks), (b) whether verbalization was subvocal (whereby one goes through the motions of speaking but without making any sound) or overt, and (c) stimulus familiarity. During stimulus encoding there was a double dissociation whereby subvocal verbalization interfered with the recognition of faces but not objects, while overt verbalization benefited the recognition of objects but not faces. In addition, stimulus familiarity provided an independent and beneficial influence on performance. Post stimulus encoding, overt verbalization interfered with the recognition of both faces and objects, and this interference was apparent for unfamiliar but not familiar stimuli. Together these findings extend work on verbalization to picture recognition and place important parameters on stimulus and task constraints that contribute to contrasting beneficial and detrimental effects of verbalization on recognition memory.     

Observation: Three reasons to avoid having half of the trials be congruent in a four-alternative forced-choice experiment on sequential modulation

Sequential modulation is the finding that the sizes of several selective-attention phenomena--namely, the Simon, flanker, and Stroop effects--are larger following congruent trials than following incongruent trials. In order to rule out relatively uninteresting explanations of sequential modulation that are based on a variety of stimulus- and response-repetition confounds, a four-alternative forced choice task must be used, such that all trials with any kind of repetition can be omitted from the analysis. When a four-alternative task is used, the question arises as to whether to have the proportions of congruent and incongruent trials be set by chance (and, therefore, be 25% congruent and 75% incongruent) or to raise the proportion of congruent trials to 50%, so that it matches the proportion of incongruent trials. In this observation, it is argued that raising the proportion of congruent trials to 50% should not be done. For theoretical, practical, and empirical reasons, having half of the trials be congruent in a four-alternative task aimed at providing unambiguous evidence of sequential modulation should be avoided.     

Bicultural Effects on the Creative Potential of Chinese and French Children

This study examined possible bicultural effects on creative potential of children in four groups of Chinese and French children in Hong Kong and Paris. An international battery of widely used divergent measures (Wallach-Kogan Creativity Tests; WKCT) and newly constructed divergent-plus-integrative measures (Evaluation of Potential Creativity; EPoC) was established for assessment. Study 1 showed that most measures of WKCT and EPoC were reasonably high in reliability and they had expected correlations with the fluency scores of some subtests of Torrance Tests of Creative Thinking. Study 2 found some interestingly mixed bicultural effects favoring verbal divergent responses for French children and graphic integrative responses for Chinese children. Compared with Paris-French children, the bicultural Hong Kong-French children had significantly higher scores in figural fluency, figural flexibility, and figural uniqueness of WKCT (requiring only verbal divergent responses) but significantly lower scores in the graphic divergent-exploratory measure of EPoC. Compared with Hong Kong-Chinese children, the bicultural Paris-Chinese children had significantly higher scores in the graphic convergent-integrative measure of EPoC, but significantly lower scores in verbal fluency, verbal flexibility, figural fluency, figural flexibility, figural uniqueness, and figural unusualness of WKCT. Implications of the mixed bicultural effects in relation to the diverse creativity measures and children groups are discussed.     

Contingent Capture at a very short SOA: Evidence against Rapid Disengagement

Salient cues that do not contain the target's defining attribute do not cause a spatial cueing effect in response time when presented 150 ms before the target. This can be explained by Contingent Capture (under which incongruent cues do not capture attention) and also by Rapid Disengagement (under which salient but incongruent cues cause only brief capture). To discriminate between these models, a very short SOA of 35ms was employed in the standard paradigm. As is true for longer SOAs, there was no evidence of attentional capture by salient but incongruent cues. Thus, the evidence to date favours Contingent Capture over Rapid Disengagement.     

Truth, Dependence and Supervaluation: Living with the Ghost

In J Philos Logic 34:155–192, 2005, Leitgeb provides a theory of truth which is based on a theory of semantic dependence. We argue here that the conceptual thrust of this approach provides us with the best way of dealing with semantic paradoxes in a manner that is acceptable to a classical logician. However, in investigating a problem that was raised at the end of J Philos Logic 34:155–192, 2005, we discover that something is missing from Leitgeb’s original definition. Moreover, we show that once the appropriate repairs have been made, the resultant definition is equivalent to a version of the supervaluation definition suggested in J Philos 72:690–716, 1975 and discussed in detail in J Symb Log 51(3):663–681, 1986. The upshot of this is a philosophical justification for the simple supervaluation approach and fresh insight into its workings.