Relations between source amnesia and frontal lobe functioning in older adults

A study is reported in which the relations among normal aging, source amnesia, and frontal lobe functioning were explored. Twenty-four older adults (aged 60-84 years) were tested on their ability to remember where they had acquired new factual information; they were also given the Wisconsin Card Sorting Test (WCST), a test of verbal fluency, and other psychometric tests. The degree of source amnesia in this normal sample correlated with age, verbal fluency, and some measures from the WCST. Source amnesia was not related to Performance IQ, however, or to a measure of fact recall. The implications for the relations among aging, memory, and frontal lobe functions are discussed.     

Differential effects of shared attention on perception of heading and 3-D object motion

When a person moves in a straight line through a stationary environment, the images of object surfaces move in a radial pattern away from a single point. This point, known as thefocus of expansion (FOE), corresponds to the person’s direction of motion. People judge their heading from image motion quite well in this situation. They perform most accurately when they can see the region around the FOE, which contains the most useful information for this task. Furthermore, a large moving object in the scene has no effect on observer heading judgments unless it obscures the FOE. Therefore, observers may obtain the most accurate heading judgments by focusing their attention on the region around the FOE. However, in many situations (e.g., driving), the observer must pay attention to other moving objects in the scene (e.g., cars and pedestrians) to avoid collisions. These objects may be located far from the FOE in the visual field. We tested whether people can accurately judge their heading and the three-dimensional (3-D) motion of objects while paying attention to one or the other task. The results show that differential allocation of attention affects people’s ability to judge 3-D object motion much more than it affects their ability to judge heading. This suggests that heading judgments are computed globally, whereas judgments about object motion may require more focused attention.     

Implementation Intentions,Information, and Voter Turnout: An Experimental Study

Are citizens more likely to vote when they are asked to make plans about how they will cast their ballots? Such planning—typically described as “implementation intentions”—has been shown to increase many types of desirable behaviors, including exercising and healthy eating, receiving vaccinations, physical rehabilitation, and recycling. Important earlier work in political science suggests voter turnout can also be influenced by implementation intention interventions, whereby electors are prompted to “make a plan” to vote (Nickerson & Rogers, 2010 ), though this finding has gone largely unreplicated. At the same time, elections management bodies (EMBs) in many contexts regularly conduct informational campaigns in the period leading up to elections, though little is known about the effects of such efforts upon turnout. Using data from an online experiment conducted at the time of the 2015 Canadian Federal Election, we demonstrate that implementation intention interventions can improve voter turnout but that this effect is conditional upon electors being exposed to informational materials about how to vote in the election. When survey respondents were provided with information on voting requirements and methods, and then prompted with questions forcing them to contemplate the act of casting their ballots, we observe a sizable increase in turnout rates.     

Integrating multiple cues to depth order at object boundaries

We examined the interaction between motion and stereo cues to depth order along object boundaries. Relative depth was conveyed by a change in the speed of image motion across a boundary (motion parallax), the disappearance of features on a surface moving behind an occluding object (motion occlusion), or a difference in the stereo disparity of adjacent surfaces. We compared the perceived depth orders for different combinations of cues, incorporating conditions with conflicting depth orders and conditions with varying reliability of the individual cues. We observed large differences in performance between subjects, ranging from those whose depth order judgments were driven largely by the stereo disparity cues to those whose judgments were dominated by motion occlusion. The relative strength of these cues influenced individual subjects' behavior in conditions of cue conflict and reduced reliability.     

Motivated to Forgive? Partisan Scandals and Party Supporters

In this study, we investigate how partisan motivations shape voters' reactions to a political scandal by drawing on a unique survey experiment fielded immediately after Justin Trudeau's brownface/blackface scandal broke during the 2019 Canadian election. We thus explore motivated reasoning in real time in a competitive and highly partisan election context. Are voters more willing to forgive politicians for past behavior when their own party leader's impropriety is cued? To what extent do personal interests, such as cross-pressures or electoral concerns, affect the motivation to forgive? Our findings show that partisan-motivated reasoning is overwhelmingly powerful, producing politically biased judgments of politicians implicated in scandals. Furthermore, voters' willingness to forgive scandals is also influenced by “strategic” considerations, in that preferences over which political party wins or loses in the election affect opinions about whether someone should be forgiven or whether the scandal is considered important at all. However, we find no evidence that personal involvement in the issue raised by the scandal conditions partisan motivations. We posit that the environment—in this case, a competitive election—is an important consideration for understanding the extent and limits of partisan-motivated reasoning.     

Differential effects of shared attention on perception of heading and 3-D object motion

When a person moves in a straight line through a stationary environment, the images of object surfaces move in a radial pattern away from a single point. This point, known as the focus of expansion (FOE), corresponds to the person's direction of motion. People judge their heading from image motion quite well in this situation. They perform most accurately when they can see the region around the FOE, which contains the most useful information for this task. Furthermore, a large moving object in the scene has no effect on observer heading judgments unless it obscures the FOE. Therefore, observers may obtain the most accurate heading judgments by focusing their attention on the region around the FOE. However, in many situations (e.g., driving), the observer must pay attention to other moving objects in the scene (e.g., cars and pedestrians) to avoid collisions. These objects may be located far from the FOE in the visual field. We tested whether people can accurately judge their heading and the three-dimensional (3-D) motion of objects while paying attention to one or the other task. The results show that differential allocation of attention affects people's ability to judge 3-D object motion much more than it affects their ability to judge heading. This suggests that heading judgments are computed globally, whereas judgments about object motion may require more focused attention.     

Visual search asymmetries in motion and optic flow fields

In visual search, items defined by a unique feature are found easily and efficiently. Search for a moving target among stationary distractors is one such efficient search. Search for a stationary target among moving distractors is markedly more difficult. In the experiments reported here, we confirm this finding and further show that searches for a stationary target within a structured flow field are more efficient than searches for stationary targets among distractors moving in random directions. The structured motion fields tested included uniform direction of motion, a radial flow field simulating observer forward motion, and a deformation flow field inconsistent with observer motion. The results using optic flow stimuli were not significantly different from the results obtained with other structured fields of distractors. The results suggest that the local properties of the flow fields rather than global optic flow properties are important for determining the efficiency of search for a stationary target.