The stroop effect: Failure to focus attention or failure to maintain focusing?

Subjects matched the position (high or low) of a first stimulus with either the position or the meaning of a word (HI or LO) presented after an interstimulus interval (ISI). The form of the first stimulus (X or O) varied randomly within trial blocks and specified the relevant feature (meaning or position) of the second stimulus to the subject. When the relevant feature was meaning, Stroop interference from the second stimulus position was observed. This interference decreased as ISI increased. At the longest ISI, it was eliminated completely. A number of explanations for these effects are discussed and then tested in two further matching experiments. In a fourth experiment a similar decrease in interference was observed. These reductions in interference with increase in ISI appear to represent the development of attentional focusing on the relevant feature of the second stimulus. Stroop interference may occur in experiments where the relevant attribute is constant because of a difficulty associated with repeated focusing on the same attribute.     

I thought that I heard you laughing: Contextual facial expressions modulate the perception of authentic laughter and crying

It is well established that categorising the emotional content of facial expressions may differ depending on contextual information. Whether this malleability is observed in the auditory domain and in genuine emotion expressions is poorly explored. We examined the perception of authentic laughter and crying in the context of happy, neutral and sad facial expressions. Participants rated the vocalisations on separate unipolar scales of happiness and sadness and on arousal. Although they were instructed to focus exclusively on the vocalisations, consistent context effects were found: For both laughter and crying, emotion judgements were shifted towards the information expressed by the face. These modulations were independent of response latencies and were larger for more emotionally ambiguous vocalisations. No effects of context were found for arousal ratings. These findings suggest that the automatic encoding of contextual information during emotion perception generalises across modalities, to purely non-verbal vocalisations, and is not confined to acted expressions.     

Effects of morphine and naloxone upon the reactions of rats to a heat stressor

Five experiments used rats to examine the conditioned hypoalgesia induced by exposure to a heated floor. Experiments 1 and 2 demonstrated that this hypoalgesia is mediated by non-opioid mechanisms of pain control, as evidenced by insensitivity to the opioid antagonist naloxone and by the absence of cross-tolerance with the opioid agonist morphine. Although non-opioid in nature, the acquisition of conditioned hypoalgesia was facilitated by naloxone and impaired by morphine (Experiments 3 and 4). These effects did not appear to be due to an opioid regulation of pain. (1) Pairing morphine with the heated floor attenuated acquisition in drug-tolerant rats. (2) This attenuation by morphine was removed when naloxone was given after exposure to the heated floor. (3) Conditioning was facilitated when naloxone was given after exposure to the heated floor (Experiment 5). The results were discussed in terms of an opioid regulation of (a) surprise, (b) arousal of an aversive motivational system, and (c) the affective component of pain.     

Fatigue and Quality of Life Following Radiotherapy for Breast Cancer: A Comparative Study

Clinical reports suggest that fatigue is a common and disruptive long-term side effect of radiotherapy; however, there has been little systematic attention given to this phenomenon. The primary aim of this study was to assess fatigue its impact on quality of life in women who had completed radiotherapy for breast cancer. A key feature of this study was the inclusion of a comparison group of women of similar age with no history of cancer. The results indicated that the fatigue experienced by women after radiotherapy for breast cancer was not significantly different in intensity, duration, or disruptiveness from fatigue experienced by healthy women. In addition, radiotherapy recipients reported a quality of life similar to that of the healthy women. For both groups of women greater fatigue was related to a poorer quality of life. These findings suggest that following radiotherapy for breast cancer, women can expect to experience fatigue which is not worse than what they might normally experience. This information may be a useful part of psychoeducational interventions designed for women scheduled to begin radiotherapy for breast cancer.     

A Search for the Optimal Stimulus

How do stimulus size and item number relate to the magnitude and direction of error on center estimation and line cancellation tests? How might this relationship inform theories concerning spatial neglect? These questions were addressed by testing twenty patients with right hemisphere lesions, eleven with left hemisphere lesions and eleven normal control subjects on multiple versions of center estimation and line cancellation tests. Patients who made large errors on these tests also demonstrated an optimal or pivotal stimulus value, i.e., a particular size center estimation test or number of lines on cancellation that either minimized error magnitude relative to other size stimuli (optimal) or marked the boundary between normal and abnormal performance (pivotal). Patients with right hemisphere lesions made increasingly greater errors on the center estimation test as stimuli were both larger and smaller than the optimal value, whereas those with left hemisphere lesions made greater errors as stimuli were smaller than a pivotal value. In normal subjects, the direction of errors on center estimation stimuli shifted from the right of true center to the left as stimuli decreased in size (i.e., the crossover effect). Right hemisphere lesions exaggerated this effect, whereas left hemisphere lesions diminished and possibly reversed the direction of crossover. Error direction did not change as a function of stimulus value on cancellation tests. The demonstration of optimal and pivotal stimulus values indicates that performances on center estimation and cancellation tests in neglect are only relative to the stimuli used. In light of other studies, our findings indicate that patients with spatial neglect grossly overestimate the size of small stimuli and underestimate the size of large stimuli, that crossover represents an “apparent” shift in error direction that actually results from normally occurring errors in size perception, and that the left hemisphere is specialized for one aspect of size estimation, whereas the right performs dual roles.     

Switching attention between the ears to monitor tones Nigel Harvey

Alternating dichotic presentation of tones was compared with monaural presentation in two different perceptual tasks. When Ss were asked to detect higher frequency target tones in fists of six background tones, they missed less than 5%. However, when the presentation was fast (10/sec) and the tones alternated dichotically, Ss reported “hearing” only three or four tones. In two further experiments, Ss were asked to judge the number of tones or to report their spatial and temporal positions; these tasks were much less accurately performed, for the dichotic lists, than the target detection task. The differing effects of switching rate on these tasks are discussed in relation to the types of processing they require.     

The reliability of an extrapolated measure of an aversive threshold of pain from radiant stimulation

The relationship between the logarithm of pain threshold latency (sec) and the logarithm of the stimulus intensity (mcal/cm²/sec) has been shown to be linear, and the extrapolated x-intercept value of the linear equation could be a useful measure in pain research. In order to assess the reliability of the x-intercept, pain latency thresholds, were obtained from 23 Ss by utilizing the D’Amour-Smith modification of the dolorimetric technique and by testing under a variety of conditions at each of four stimulus intensities. The empirically determined log t (sec) values were shown to be slightly, but significantly, higher when stimulation was applied to either the dominant limb or to the legs rather than to the nondominant limb or to the arms. The computed slope and x-intercept values did not differ between limbs or between dominant and nondominant sides. None of the three measures changed significantly between the two sessions. The x-intercept value was interpreted as an index of a threshold of aversion and its meaning and applicability were discussed.