On the Relation Between Time Perception and the Timing of Motor Action: Evidence for a Temporal Oscillator Controlling the Timing of Movement

Studies of time estimation have provided evidence that human time perception is determined by an internal clock containing a temporal oscillator and have also provided estimates of the frequency of this oscillator (Treisman, Faulkner, Naish, & Brogan, 1992; Treisman & Brogan, 1992). These estimates were based on the observation that when the intervals to be estimated are accompanied by auditory clicks that recur at certain critical rates, perturbations in time estimation occur. To test the hypothesis that the mechanisms that underlie the perception of time and those that control the timing of motor performance are similar, analogous experiments were performed on motor timing, with the object of seeing whether evidence for a clock would be obtained and if so whether its properties resemble those of the time perception clock. The prediction was made that perturbations in motor timing would be seen at the same or similar critical auditory click rates. The experiments examined choice reaction time and typing. The results support the hypothesis that a temporal oscillator paces motor performance and that this oscillator is similar to the oscillator underlying time perception. They also provide an estimate of the characteristic frequency of the oscillator.     

Developmental psychology in the real world: A paradigm of parent education

Twenty years ago, William Kessen, Greta Fein and I developed and tested a model of parent education, a model which involved variation in curricular content, didactic approaches, and child outcomes–experimentally contrasted. Our experience yielded some valuable lessons about the extent to which researchers can influence parents' behaviour, and parents their children's development. In the present article I suggest that these lessons might be useful for researchers now as they were for us then. I present some observations about the research that developmental psychologists have done in the intervening two decades and suggest that we could learn much by using such a model of parent education to answer questions about the effets of parents' behaviour on children's development. Carefully done, parent education studies can yield valuable information about many of the questions raised in recent correlational research. Parent training research can suggest hypotheses that can be tested with data collected non-interventively and analysed in causal model analyses–and vice versa. What is more, because one reason for studying parent effects is so that we can offer guidance to parents about rearing their children, this design has a particular advantage; it is both the medium and the message.     

Age differences in source forgetting: effects on reality monitoring and on eyewitness testimony

Age differences in memory for the source of memories were investigated using two different experimental paradigms. Experiment 1 used a reality monitoring paradigm. A series of actions were either performed, imagined, or watched, and subjects were later tested for their ability to recognize the actions and identify their origins. Elderly subjects made more false positive responses than did young subjects, and they made more source confusion errors, attributing actions to the wrong sources. Both new and imagined actions were most often misclassified as watched. Experiment 2 used an eyewitness testimony paradigm. After watching a film, subjects read a written version of the story. A recognition test showed that elderly subjects were more often misled by false information in the story than were the younger subjects, and were more confident that their erroneous responses were correct. The findings suggest that a decline in memory for sources may diminish the accuracy of elderly witnesses.     

Cross-sex comparisons: A word of caution

A cross-sex difference on one variable is often hypothesized to be related to a gender difference on a second variable. However, caution should be exercised in making such comparative hypotheses. We gathered the expected and actual examination grades for 168 female and 163 male college students. As in prior research, males had higher expectancies than females (p<.05). But analysis of the intrasex regression equations indicated that the relationship of expectancies to performance was different for women than it was for men. Thus, a cross-sex difference in expectancies did not correspond to a parallel difference in grades. This finding highlights the potential hazards of making certain cross-sex comparisons, and we argue for more caution in their application.     

The Effectiveness of Encounter Groups: Implications of Research for Counselling Practice

In the past decade, encounter groups have become a widely recognised technique of intervention for counsellors. Empirical research on encounter groups is confusing. Trends in research are obscured by a diversity of definitions, methodologies and subjects. This review considers the most significant research on the effectiveness of encounter groups, focusing on positive and negative effects, leader behaviour, group characteristics, participant characteristics, and the maintenance of change. Conclusions are drawn relating the research to practice, with some suggested guidelines for use of encounter groups in counselling interventions.     

A preliminary study of Hare's “Research Scale for the Assessment of Psychopathy” in mentally-abnormal offenders

The abbreviated (15-item) version of Hare's Research Scale for the Assessment of Psychopathy (RSAP) was investigated in a sample of male admissions to Broadmoor Special Hospital (N = 50), along with five MMPI measures relevant to psychopathy (Impulsivity, Sociability, Psychopathic Deviate, Anxiety and Sociopathy). Patients were assigned to one of four clinical diagnostic groups: Personality Disorder, Mixed (personality disorder with schizophrenia), Schizophrenia and Affective Disorder. Results indicated that while both psychopathic groups (Mixed and Personality Disorder) showed high scores on almost all RSAP items, the Affective Disorder group showed low scores on almost all items. Results of a discriminant function analysis indicated that Hare's RSAP was superior to the MMPI measures at discriminating between psychopaths and non-psychopaths. Use of the discriminant function to re-allocate patients to criterion groups showed a high hit rate (94%) for psychopathic patients but a hit rate of only 61% for non-psychopathic patients. Half of the schizophrenic patients were mis-allocated to the psychopathic group. The results support the idea of an affective deficit common to psychopaths and schizophrenics, but suggest that psychopaths additionally show a deficit which may be characterized by a lack of goal-directed behaviour.     

Anxiety and the spelling and use in sentences of threat/neutral homophones

The disambiguation of threat/neutral homophones was investigated in high- and low-trait anxiety subjects who had been exposed to either a positive or a negative mood manipulation procedure. Subjects were required first to spell each auditorily presented word and second, to generate and speak a sentence using the word. Difference indices were calculated for the spelling and the sentence usage data, i.e. the number of threat minus neutral interpretations. Examination of these indices revealed that subjects exposed to the negative mood manipulation procedure produced relatively more threat than neutral interpretations (for both spelling and sentence usage) than did subjects exposed to the positive mood manipulation procedure. Multiple regression analyses revealed that both the trait anxiety and mood manipulation variables contributed significantly to the prediction of the difference index on the spelling task. In the analysis of the use of homophones in sentences, only the mood manipulation variable contributed significantly to the prediction of the difference index on the sentence usage task.     

The internal clock: evidence for a temporal oscillator underlying time perception with some estimates of its characteristic frequency

Evidence for the proposition that human time perception is determined by an internal clock is largely indirect. It would strengthen the case for this hypothesis if a model for the internal clock were available from which predictions could be derived and tested, and if the basic parameter of such a model, the frequency at which the clock runs, could be estimated. A model for an internal temporal pacemaker is briefly described and its properties are explored by computer simulation. Results are obtained that provide a basis for predicting that, under appropriate conditions, interference between an imposed rhythm and the frequency of a temporal oscillator may cause perturbations in temporal judgment which are related to the characteristic frequency of that oscillator. Experimental data are reported which appear to demonstrate such an interference pattern. These results allow some estimates of the characteristic frequency of the temporal oscillator to be obtained.