Investigating the structure of autobiographical memory using reaction times

The study investigated the structure of autobiographical memory using reaction time measures. A total of 18 participants took photographs over their summer holidays and then reacted to pairs of these photographs displayed via a computer. They also subsequently sorted their photographs according to the autobiographical themes and events with which they were associated. When photographic sequence and the physical similarities in the photographs were controlled for by considering the results of “stranger” participants who were unfamiliar with the photographs, reaction times were significantly faster to pairs of photographs from the same theme or event. The results are consistent with currently held assumptions about the structure of autobiographical memory. Furthermore, the results suggest that reaction time measures may provide a valuable means by which aspects of autobiographical memory can be explored.     

Semantic Externalism and Presentism

Abstract

In this paper I discuss an unconventional form of presentism which, I claim, captures better than all other versions of the doctrine the fundamental notion underpinning it, namely, the notion that ‘only what is present is real’. My proposal is to take this maxim as stating, not the rather uncontroversial view that past things are not real now, but the more radical idea that they never were. This rendition of presentism is, I argue, the only one that is neither trivial nor absurd. I examine this proposal by considering it against a sceptical hypothesis that bears similarities to it, viz., the hypothesis that the world was created five minutes ago. On this hypothesis, the past, all but five minutes of it, is unreal, in precisely the sense in which the presentism I discuss claims it is. I show that, assuming semantic externalism, this sceptical hypothesis cannot be sustained, but that a somewhat weaker hypothesis, the Creationist hypothesis that the world is 5,768 years old, cannot be refuted. Together, these conclusions enable a demarcation of those presentist intuitions that language and thought tolerate and those they do not.     

Notes on Time and Aspect

Abstract

What is time? Neither the numbering of the motion of things nor their schema, but their way of being. In language, time shows itself as tense. But every verb has both tense and aspect. So what is aspect? Irreducible to tense, it is the way in which anything is at any time whatsoever. Thus the way things are, their being, is not merely temporal – for it is just as aspectual.     

Larger reward values alone are not enough to entice more cooperation

Two experiments using an iterated prisoner's dilemma game examined under which conditions participants' cooperation rates would either change due to monetary value changes (e.g., 3 cents to 3 dollars) or not change due to numeric value changes (e.g., 3 dollars to 300 cents). A total of 102 university students played the game against a computer that employed one of four strategies across blocks. Results showed high rates of cooperation when participants played against a tit-for-tat strategy and low rates of cooperation against a random strategy. There was no change in cooperation rates due to changes in numeric value alone and a decrease in cooperation rates when large monetary values were at stake. Cooperation rates were higher and cooperation responses slower at earlier stages of the game. I argue that people's ability to strategize plays a key role in the changing rates and speed of cooperative behaviour in the prisoner's dilemma.     

The insistence of vision: Why do people look at a salient stimulus when it signals target absence?

Researchers and practitioners across many fields would benefit from the ability to predict human search time in complex visual displays. However, a missing element in our ability to predict search time is our ability to quantify the exogenous attraction of visual objects in terms of their impact on search time. The current work represents an initial step in this direction. We present two experiments using a quadrant search task to investigate how exogenous and endogenous factors influence human visual search. In Experiment 1, we measure the oculomotor capture—or the tendency of a stimulus to elicit a saccade—of a salient quadrant under conditions in which the salient quadrant does not predict target location. Despite the irrelevance of quadrant salience, we find that subjects persist in making saccades towards the salient quadrant at above-chance levels. We then present a Bayesian-based ideal performer model that predicts search time and oculomotor capture when the salient quadrant never contains the search target. Experiment 2 tested the predictions of the ideal performer model and revealed human performance to be in close correspondence with the model. We conclude that, in our speeded search task, the influence of an exogenous attractor on saccades can be quantified in terms of search time costs and, when these costs are considered, both search time and search behaviour reflect a boundedly optimal adaptation to the cost structure of the environment.     

The Relationship between Everyday Problem Solving and Inconsistency in Reaction Time in Older Adults

ABSTRACT

The purpose of the present study was to investigate whether inconsistency in reaction time (RT) is predictive of older adults' ability to solve everyday problems. A sample of 304 community dwelling non-demented older adults, ranging in age from 62 to 92, completed a measure of everyday problem solving, the Everyday Problems Test (EPT). Inconsistency in latencies across trials was assessed on four RT tasks. Performance on the EPT was found to vary according to age and cognitive status. Both mean latencies and inconsistency were significantly associated with EPT performance, such that slower and more inconsistent RTs were associated with poorer everyday problem solving abilities. Even after accounting for age, education, and mean level of performance, inconsistency in reaction time continued to account for a significant proportion of the variance in EPT scores. These findings suggest that indicators of inconsistency in RT may be of functional relevance.     

Motor Programming as a Function of Constraints on Movement Initiation

Three experiments are reported that test the hypothesis that under certain conditions programming time is a function of the directional accuracy demand of a response, directional accuracy being quantified by the minimal angle subtended at the point of movement initiation by the circular targets within the response. Subjects in three simple reaction time experiments were required to tap a single target or a series of circular targets as rapidly as possible with a hand-held stylus. Experiments 1 and 3 showed that the subtended angle (SA) of a response can have a more powerful effect on programming time, as indexed by reaction time and premotor time, than the number of movement parts in the response. The results of Experiment 2 revealed that the locus of the directional accuracy effect was SA and not target size or movement distance. In all three experiments, response SA was a better predictor of programming time than was number of movement parts, target size, movement distance, movement time, and average movement velocity. The findings support the notion that constraints placed upon movement initiation by the directional accuracy demand of the task can play an important role in determining the length of the programming process.     

Color Vision in Relation to Artistic Ability

The present experiment tests Hobbes' superiority theory of humor in relation to identification classes (a replacement for the construct of reference group)—i.e., a vicarious superiority theory of humor is examined. Joke content concerns Canadian-American relations. Ss were selected so as to be either pro-Canadian Canadians or pro-American Americans. Consistent with prediction (p < .01) each of the two groups tended to find that permutation of jokes funnier in which its positive identification class was victorious and its negative the butt than was the opposite permutation in which the negative identification class was victorious and the positive the butt.