Cognition and self-control: Cognitive control of painful sensory input

Eighty Ss were first tested for base-level response to a pain-producing stimulus and then were re-tested on the same pain stimulus after receiving 1 of 8 experimental treatments. The 8 treatments were arranged in a 2×2×2 factorial design: presence or absence of hypnotic induction procedure; presence or absence of instructions for anesthesia; and presence or absence of demands for honest reports. Neither the hypnotic-induction procedure nor the demands for honesty affected the Ss’ reports of the degree of pain experienced. The anesthesia instructions—“think of the hand as numb and insensitive as if it were a piece of rubber...”— produced an equal degree of pain reduction in hypnotic and non-hypnotic Ss and in Ss who were and those who were not exposed to demands for honesty. The results indicate that (a) Ss’ reports of pain are less affected by demands for honesty and are more closely related to their actual experiences than has been previously assumed and (b) instructions which direct Ss to exercise cognitive control over painful sensory input are effective (with or without ‘hypnosis’) in reducing the experience of pain.     

Action-based and vision-based selection of input: Two sources of control

In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models.     

The effects of visual input on postural control of the lumbar spine in unstable sitting

Postural control of the lumbar spine in unstable sitting was quantified through the analysis of the center of pressure (CoP) movement recorded by a force plate situated underneath a seat that incorporated a hemisphere. Thirteen healthy subjects were tested under conditions of increasing seat instability and elimination of visual input. The purpose of this study was to determine the relative effects of visual input and support surface instability on open and closed loop postural control mechanisms in sitting and to determine the association between traditional summary statistics and random walk analysis of CoP movement. The effects of the seat instability level and visual input on the CoP movement parameters were tested with a two-factor, repeated measures ANOVA (p<0.01). In all summary statistics CoP movement parameters increased significantly due to the seat instability level and lack of visual input. The random walk analysis identified two regions, short- and long-term, which has been postulated to represent open and closed loop control mechanism, respectively. While short-term scaling exponents were independent from visual input, CoP displacement in the short-term region was significantly increased in the eyes closed condition. Summary statistic of CoP total path length per second correlated highly with critical point coordinates and short-term diffusion coefficients. The CoP movement in the long-term region was consistent with a closed loop control mechanisms. The findings of visual influence on what is assumed as an open-loop control mechanism does not, at face value, support the hypothesis that two separate mechanisms are working to achieve postural control.     

Prism adaptation with simultaneous receipt of normal input

A 20-diopter vertically-displacing prism was worn on one eye in conjunction with plane glass on the other. Five groups ofSs differed in the density of a neutral filter worn over one eye. No aftereffect could be measured in either eye in any condition where the luminance of the “normal” field was equal to or greater than that of the prism field. As the luminance of the “normal” field is decreased below that of the prism field, the magnitude of aftereffect increases and is measurable in each eye.     

Reasoning about partial functions with the aid of a computer

Partial functions are ubiquitous in both mathematics and computer science. Therefore, it is imperative that the underlying logical formalism for a general-purpose mechanized mathematics system provide strong support for reasoning about partial functions. Unfortunately, the common logical formalisms — first-order logic, type theory, and set theory — are usually only adequate for reasoning about partial functionsin theory. However, the approach to partial functions traditionally employed by mathematicians is quite adequatein practice. This paper shows how the traditional approach to partial functions can be formalized in a range of formalisms that includes first-order logic, simple type theory, and Von-Neumann—Bernays—Gödel set theory. It argues that these new formalisms allow one to directly reason about partial functions; are based on natural, well-understood, familiar principles; and can be effectively implemented in mechanized mathematics systems.Supported by the MITRE-Sponsored Research program. This paper is a written version (with references) of an address given at the Partial Functions and Programming: Foundational Questions conference held 17 February 1995 at the University ol California at Irvine.     

Response input interface

A circuit for interfacing experimental response signals with logic apparatus that controls experimental events is described. The unit shapes and holds the signal until its presence has been detected by the controlling program.     

The input bias: The misuse of input information in judgments of outcomes

In this paper we identify an input bias, the systematic misuse of input information in judgments of outcome quality. In many settings irrelevant input measures, such as the amount of time an employee spends in the office, influence outcome assessments, such as performance reviews. Across four studies we find that input values subtly, but significantly distort judgments of outcome quality. Irrelevant input information predictably influences outcome assessments even when people recognize that input measures should not matter and believe that input information did not matter. We examine the mechanics of the input bias, and suggest that because input measures are often easy to manipulate or misrepresent, the input bias is likely to have broad implications for managerial judgment and decision making.     

Two-alternative learning situations with partial reinforcement

The comparative effects of reward and nonreward on learning are considered in connection with a two-alternative learning situation. Conditions are more general in nature than those discussed in an earlier article. In the statistical model proposed, the question of whether reward and nonreward are equivalent in their effects on learning reduces to testing a composite hypothesis on a multivariate probability distribution. An asymptotic test of this hypothesis is described, and its use is illustrated with data from psychological experiments.This paper was prepared with the partial support of the Office of Naval Research, and may be reproduced in whole or in part for any purpose of the United States government.I wish to express my gratitude to Professors J. Neyman and E. L. Scott of the University of California, Department of Statistics, for their constant assistance and encouragement throughout the research that led to this paper and during its preparation, and to Professor F. W. Irwin of the University of Pennsylvania Department of Psychology for his many helpful suggestions and comments.     

Time-dependent effects of kinesthetic input

Sensory input can be used by the nervous system to control the spatial parameters of motor responses (e.g., distance, velocity, and direction) by initializing these parameters before movement onset and then by adjusting these parameters during movement. Sensory input can also be used to trigger movements. In the experiments reported in this paper, we compared the effects of kinesthetic input on a triggered motor response when the kinesthetic input was generated at different times relative to the onset of the motor response. Human subjects responded to a visual stimulus by intentionally increasing elbow torque to a target level. Kinesthetic input was generated by unexpectedly rotating each subject's elbow 100 ms before the onset of the intentional torque response (early) or coincident with the onset of the intentional torque response (late). The effect of early kinesthetic input on the intentional torque response markedly differed from the effect of late kinesthetic input. The effect of early kinesthetic input was relatively independent of the direction of elbow rotation, had a different dependence on the amplitude of rotation, and required a shorter duration of rotation compared to the effect of late kinesthetic input. These differences in the effects of early and late kinesthetic input might be related to the initialization, triggering, and adjustment of motor responses.     

Detecting and correcting partial errors: Evidence for efficient control without conscious access

Appropriate reactions to erroneous actions are essential to keeping behavior adaptive. Erring, however, is not an all-or-none process: electromyographic (EMG) recordings of the responding muscles have revealed that covert incorrect response activations (termed “partial errors”) occur on a proportion of overtly correct trials. The occurrence of such “partial errors” shows that incorrect response activations could be corrected online, before turning into overt errors. In the present study, we showed that, unlike overt errors, such “partial errors” are poorly consciously detected by participants, who could report only one third of their partial errors. Two parameters of the partial errors were found to predict detection: the surface of the incorrect EMG burst (larger for detected) and the correction time (between the incorrect and correct EMG onsets; longer for detected). These two parameters provided independent information. The correct(ive) responses associated with detected partial errors were larger than the “pure-correct” ones, and this increase was likely a consequence, rather than a cause, of the detection. The respective impacts of the two parameters predicting detection (incorrect surface and correction time), along with the underlying physiological processes subtending partial-error detection, are discussed.     

Manipulation with no or partial vision.

The present research investigated the role of vision in closed- and open-loop processing during manipulation. In Experiment 1, participants performed common manipulatory tasks with 100% accuracy in less than 1 s without vision. In Experiment 2, the effects of extensive practice of a peg-in-hole task were examined within 4 functionally significant stages of manipulation. Performance was consistently faster with than without vision in the prereach, grasp, and transport + insert stages; reverse effects were observed during the reach stage. In Experiment 3, the effects of practice with partial vision were examined: Participants initially learned the peg-in-hole task with full vision and then transferred to learning the same task with vision available only during 1 functional stage. Overall, performance was fastest when vision was limited to the prereach and reach stages.     

On the relation between sensory input and action

The role of sensory return in movement has recently been considered in relation to models involving feedforward control and in the comparison of predicted and actual states. The author suggests that sensory feedback may also have other effects at the level of movement initiation. The experiences of 3 individuals with differing impairments are reported, 1 with acute withdrawal of movement and position sense, 1 with acute meningitis, and the 3rd after prolonged immobilization following a heel injury. All were surprised to find difficulty in turning an intention to move into action in the affected body areas. One suggested that he had "forgotten what to do," even though the original injury had healed. The path from intention to movement may be dependent on feedback from the peripheral sensory apparatus at levels below attention, at least until voluntary action is required.