Perceptions of absolute versus relative differences between personal and comparison health risk.

OBJECTIVE: To explain inconsistent results in previous attempts to determine whether, when presented with health risk information, people focus primarily on information about their own risk status or on a comparison with others. DESIGN: A randomized between-groups experiment in which participants were presented with hypothetical cardiac risk information. We examined whether affective responses were primarily sensitive to the relative difference between personal and comparison risk, rather than the absolute difference. MAIN OUTCOME MEASURES: Participants' negative affective response to the risk information. RESULTS: When relative differences were held constant, participants' responses were independently influenced by both personal risk and comparative standing, effects that were greatly attenuated when absolute differences were held constant. When maintaining constant absolute differences, personal and comparison risk information appeared to interact. CONCLUSION: Previous studies tended to maintain constant absolute risk differences and so may have underestimated the impact of personal risk information. Participants' responses were sensitive to the way the risk difference was constructed. Basing experimental design decisions on assumptions about the information participants will respond to can lead to misinterpretations of the basis of risk judgments.     

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.