What determines saccade timing in sequences of coordinated eye and hand movements?

In action sequences, the eyes are generally fixated ahead of the stimulus being responded to, overlapping the processing of adjacent stimuli. What determines when the saccade to the next item is initiated and what processing is overlapped remain controversial. Saccade initiation has been linked directly to the difficulty of the underlying processing on the fixated item or to a rhythmic timer whose period is adjusted to the difficulty of the context. We compared the effects of item and context difficulty when subjects made speeded choice responses to five visual stimuli arrayed linearly. Item difficulty was manipulated by varying stimulus-response compatibility, creating contexts (sequences) whose average item difficulty differed. Results showed that saccade initiation time reflected item difficulty, not context difficulty, with evidence that saccade initiation was delayed until central processing was completed. We discuss the implications of these results for the control of saccades and processing in action sequences.     

What determines visual cue reliability?

Visual environments contain many cues to properties of an observed scene. To integrate information provided by multiple cues in an efficient manner, observers must assess the degree to which each cue provides reliable versus unreliable information. Two hypotheses are reviewed regarding how observers estimate cue reliabilities, namely that the estimated reliability of a cue is related to the ambiguity of the cue, and that people use correlations among cues to estimate cue reliabilities. Cue reliabilities are shown to be important both for cue combination and for aspects of visual learning.     

What determines the impact of context on sequential action?

In the current study we build on earlier observations that memory-based sequential action is better in the original learning context than in other contexts. We examined whether changes in the perceptual context have differential impact across distinct processing phases (preparation versus execution of a motor chunk) within an ongoing movement sequence. Participants were trained on two discrete keying sequences, each of which was systematically presented in its own unique color during a practice session with either limited or extended practice. In a subsequent test session, sequences were performed with the same, with reversed, and with completely novel sequence-specific colors. The results confirm context-dependence in sequential action, the relevance of practice for its development, and its selective expression for the preparation but not the execution of highly practiced motor chunks. As such, the current study provides novel insights into the determinants of context-dependent sequential action. We finish by outlining the overall status of context-dependence in sequential motor behavior, and specify a general working model.     

What determines biological fitness? The problem of the reference environment

Organisms’ environments are thought to play a fundamental role in determining their fitness and hence in natural selection. Existing intuitive conceptions of environment are sufficient for biological practice. I argue, however, that attempts to produce a general characterization of fitness and natural selection are incomplete without the help of general conceptions of what conditions are included in the environment. Thus there is a “problem of the reference environment”—more particularly, problems of specifying principles which pick out those environmental conditions which determine fitness. I distinguish various reference environment problems and propose solutions to some of them. While there has been a limited amount of work on problems concerning what I call “subenvironments”, there appears to be no earlier work on problems of what I call the “whole environment”. The first solution I propose for a whole environment problem specifies the overall environment for natural selection on a set of biological types present in a population over a specified period of time. The second specifies an environment relevant to extinction of types in a population; this kind of environment is especially relevant to certain kinds of long-term evolution.     

What determines a feeling's position in affective space? A case for appraisal

The location of verbally reported feelings in a three-dimensional affective space is determined by the results of appraisal processes that elicit the respective states. One group of participants rated their evaluation of 59 pictures from the International Affective Picture System (IAPS) on a profile of nine appraisal criteria. Another group rated their affective reactions to the same pictures on the classic dimensions of affective meaning (valence, arousal, potency). The ratings on the affect dimensions correlate differentially with specific appraisal ratings. These results can be interpreted as showing that the reactions to the IAPS pictures are predictably produced through appraisal of picture content. The relevance of the findings for emotion induction paradigms and for emotion theory in general is discussed.     

What determines auditory similarity? The effect of stimulus group and methodology

Two experiments on the internal representation of auditory stimuli compared the pairwise and grouping methodologies as means of deriving similarity judgements. A total of 45 undergraduate students participated in each experiment, judging the similarity of short auditory stimuli, using one of the methodologies. The experiments support and extend Bonebright's (1996) findings, using a further 60 stimuli. Results from both methodologies highlight the importance of category information and acoustic features, such as root mean square (RMS) power and pitch, in similarity judgements. Results showed that the grouping task is a viable alternative to the pairwise task with N > 20 sounds whilst highlighting subtle differences, such as cluster tightness, between the different task results. The grouping task is more likely to yield category information as underlying similarity judgements.     

What determines auditory similarity? The effect of stimulus group and methodology

Two experiments on the internal representation of auditory stimuli compared the pairwise and grouping methodologies as means of deriving similarity judgements. A total of 45 undergraduate students participated in each experiment, judging the similarity of short auditory stimuli, using one of the methodologies. The experiments support and extend Bonebright's (1996) findings, using a further 60 stimuli. Results from both methodologies highlight the importance of category information and acoustic features, such as root mean square (RMS) power and pitch, in similarity judgements. Results showed that the grouping task is a viable alternative to the pairwise task with N > 20 sounds whilst highlighting subtle differences, such as cluster tightness, between the different task results. The grouping task is more likely to yield category information as underlying similarity judgements.     

What determines the eyes' landing position in words?

The place at which the eyes first fixate in a word during continuous reading, called the preferred landing position (PLP), is usually located halfway between the beginning and the middle of the word. To propose a mechanism that might account for the off-center location of the PLP, six eye movement experiments were conducted using a lexical decision task (Experiment 1) and a stimulus bisection task (Experiments 2-6). The type of stimulus--linguistic (words and nonwords) versus nonlinguistic (strings of hashes, dotted lines, and solid lines)--and the stimulus presentation side (left vs. right) were manipulated. The results showed that (1) stimulus discreteness versus continuousness is an important factor in saccade computation and (2) PLP asymmetry can be explained in terms of attentional and/or oculomotor processes.     

What Punishment for the Murder of 10,000?

Those who commit crime on a grand scale, numbering their victims in the thousands, seem to pose a special problem both for consequentialist and for non-consequentialist theories of punishment, a problem the International Criminal Court makes practical. This paper argues that at least one non-consequentialist theory of punishment, the fairness theory, can provide a justification of punishment for great crimes. It does so by dividing the question into two parts, the one of proportion which it answers directly, and the other of ‘anchoring points’ which it assigns to a broader theory of enforcement (which may have a non-consequentialist or consequentialist version).     

What do eye movements reveal about the role of memory in visual search?

Horowitz and Wolfe (1998, 2003) have challenged the view that serial visual search involves memory processes that keep track of already inspected locations. The present study used a search paradigm similar to Horowitz and Wolfe's (1998), comparing a standard static search condition with a dynamic condition in which display elements changed locations randomly every 111 ms. In addition to measuring search reaction times, observers' eye movements were recorded. For target-present trials, the search rates were near-identical in the two search conditions, replicating Horowitz and Wolfe's findings. However, the number of fixations and saccade amplitude were larger in the static than in the dynamic condition, whereas fixation duration and the latency of the first saccade were longer in the dynamic condition. These results indicate that an active, memory-guided search strategy was adopted in the static condition, and a passive “sit-and-wait” strategy in the dynamic condition.     

What do eye movements reveal about the role of memory in visual search?

Horowitz and Wolfe (1998, 2003) have challenged the view that serial visual search involves memory processes that keep track of already inspected locations. The present study used a search paradigm similar to Horowitz and Wolfe's (1998), comparing a standard static search condition with a dynamic condition in which display elements changed locations randomly every 111 ms. In addition to measuring search reaction times, observers' eye movements were recorded. For target-present trials, the search rates were near-identical in the two search conditions, replicating Horowitz and Wolfe's findings. However, the number of fixations and saccade amplitude were larger in the static than in the dynamic condition, whereas fixation duration and the latency of the first saccade were longer in the dynamic condition. These results indicate that an active, memory-guided search strategy was adopted in the static condition, and a passive “sit-and-wait” strategy in the dynamic condition.     

What is chosen first,the hand used for reaching or the target that is reached?

Models of information processing generally assume that stimuli are processed before actions are selected, at least in typical laboratory experiments where stimuli are presented and responses follow. In everyday life, however, there are generally fewer constraints on the ordering of decisions pertaining to stimuli and actions. This raises the question of which sorts of decisions normally precede which others. To address this question, we asked participants to aim for either of two targets with either hand on the basis of whichever combination seemed easiest. We analyzed the choices made in this free condition with choices made when the hand was specified or when the target was specified. We found that a model assuming similar selection processes in the hand-specified condition and the free condition provided the best account for the data. The data accord with the hypothesis that hand was generally chosen first in the free-choice condition.     

What determines the eyes’ landing position in words?

The place at which the eyes first fixate in a word during continuous reading, called thepreferred landing position(PLP), is usually located halfway between the beginning and the middle of the word. To propose a mechanism that might account for the off-center location of the PLP, six eye movement experiments were conducted using a lexical decision task (Experiment 1) and a stimulus bisection task (Experiments 2–6). The type of stimulus—linguistic (words and nonwords) versus nonlinguistic (strings of hashes, dotted lines, and solid lines)—and the stimulus presentation side (left vs. right) were manipulated. The results showed that (1) stimulus discreteness versus continuousness is an important factor in saccade computation and (2) PLP asymmetry can be explained in terms of attentional and/or oculomotor processes.     

What kinds of alternative possibilities are required of the folk concept(s) of choice?

Our concept of choice is integral to the way we understand others and ourselves, especially when considering ourselves as free and responsible agents. Despite the importance of this concept, there has been little empirical work on it. In this paper we report four experiments that provide evidence for two concepts of choice—namely, a concept of choice that is operative in the phrase having a choice and another that is operative in the phrase making a choice. The experiments indicate that the two concepts of choice can be differentiated from each other on the basis of the kind of alternatives to which each is sensitive. The results indicate that the folk concept of choice is more nuanced than has been assumed. This new, empirically informed understanding of the folk concept of choice has important implications for debates concerning free will, responsibility, and other debates spanning psychology and philosophy.     

What should we expect from a dual-process theory of preference construction in choice?

Dhar and Gorlin (2013) proposed a dual-process framework for understanding the effects of preference construction in choice. Drawing on the distinction operating principles and operating conditions, it is argued that their emphasis on cognitive elaboration fails to specify the mental operations involved in preference construction. This limitation makes their dual-process framework circular and susceptible to the criticism of single-process alternatives. The distinction between associative and propositional processes has the potential to fill this conceptual gap, thereby providing a more thorough understanding of preference construction effects in choice.     

What Ethics for Bioart?

Living artworks created with biotechnology raise a range of ethical questions, some of which are unprecedented, others well known from other contexts. These questions are often discussed within the framework of bioethics, the ethics of the life sciences. The basic concern of institutionalised bioethics is to develop and implement ethical guidelines for ethically responsible handling of living material in technological and scientific contexts. Notably, discussions of ethical issues in bioart do not refer to existing discourses on art and morality from the field of aesthetics. The latter framework is primarily concerned with how the moral value of an artwork affects its artistic value. The author argues that a successful integration of these two frameworks will make possible an ethics of bioart that is adequate to its subject matter and relevant for practice. Such an integrated approach can give increased depth to understandings of ethical issues in bioart, inspire new ways of thinking about ethics in relation to art in general and give novel impulses to bioethics and technology assessment. Artworks by the Tissue Culture and Art Project and their reception serve as the empirical starting point for connecting perspectives in art with those of bioethics, developing an ethics for bioart. The author suggests that consideration of the effect of these artworks is vital in validating ethically problematical applications of biotechnology for art. It is argued that the affective, visceral qualities of living artworks may spur the audience to adjust, revise or develop their personal ethical framework.