Dr. Dana Murphy
Current & Future Research
We currently have a few projects underway. One is based on an experiment by one of our previous thesis students. The experiment is called "The influence of emotionality on change detection in younger and older adults: A replication and extension". This experiment involves pictures that have been changed either centrally or peripherally. The original picture, a blank screen, followed by the altered picture are flashed continuously until the participant locates the change between the pictures. Each of the pictures used have been rated in valence as either negative, neutral, or positive. Reaction time is measured in order to determine if each of the conditions are related to slower or faster reaction times. This experiment will also be evaluating changes in pulse and is being performed in conjunction with one of Nipissing University's Physical Education labs, the Human Performance Lab.
The second experiment is a thesis project that we have just finished running called "Effects of aging on temporal processing and central auditory integration". In this project, participants are presented sentences and are required to repeat the last word of the sentence. There are four conditions of sentences, one where we have presented only a low frequency of the sentence, one where we have presented only a high frequency, another where we present a low frequency to one ear and a high frequency to the other, and a final condition where we combine the low and high frequencies and then present the combination to one ear. Accuracy is measured and a percent correct is calculated for each different condition.
Many projects in the centre attempt to determine if younger and older adults differ in their ability to focus on relevant information and ignore irrelevant or extraneous information. Some theorists claim that older adults have more difficulty than younger adults ignoring irrelevant aspects of the environment. This greater susceptibility to distraction on the part of the older adult could be contributing to their greater difficulty hearing and understanding speech in noise. In particular, the possibility exists that the reason seniors have more difficulty hearing speech in noise is that the older person is more distracted by the noise than is the younger person. The experiments listed below both address this issue using auditory and visual information as attended and ignored information.
An assessment of inhibitory differences between younger and older adults using auditory and visual information
In this experiment, individuals complete an auditory or visual task while ignoring other information presented on the screen or over headphones. In the auditory task, individuals hear a series of tones and are to press a button whenever they hear a specified tone. In the visual task, individuals are to watch the computer screen and press a button whenever they see a square in the previously identified colour. While participants are completing the primary task, words will be presented either on the screen or over the headphones and participants are to ignore the information they are seeing or hearing. After this portion of the experiment, all participants will complete a word identification task in which they are to write the words they are hearing over their headphones.
A comparison of susceptibility to distraction in the auditory and visual modalities using parallel auditory and visual stroop tasks
In this study, participants are required to focus on the computer screen or respond to words that they are hearing or seeing on the screen in front of them. They are to respond only to the location of the words that they are seeing or hearing. For instance, in the visual portion of this experiment, words will be presented on the computer screen and individuals are to indicate if the word is to the right or to the left of the center of the screen. All respondents are to ignore the meaning of the words that they are seeing or hearing and simply identify the location of these words. In this experiment, individuals are to respond as quickly and as accurately as possible.
The findings of our research lab are ultimately written up as articles and submitted to various journals for review and publication. As well, many of the centre's research projects have been presented at conferences and conventions within both the United States and Canada. This year the APA 117th Annual Convention is being held in Toronto and our lab will be presenting two posters in the Cognition and Social Cognition session.
Mitchell, D. B., Brown, A. S., & Murphy, D. R. (1990).Dissociations between procedural and episodic memory: Effects of time and aging.Psychology and Aging,5(2), 264-276.
Murphy, D. R., Craik, F. I. M., Li, K. Z. H. & Schneider, B. A. (2000). Comparing the Effects of Aging and Background Noise on Short-term Memory Performance.Psychology and Aging, 15, 323-334.
Murphy, D. R., Daneman, M., & Schneider, B. A. (2006).Why do older adults have difficulty following conversations?Psychology and Aging,21(1), 49-61.
Murphy, D. R., McDowd, J. M., & Wilcox, K. A. (1999):Inhibition and aging: Similarities between younger and older adults as revealed by the processing of unattended auditory information.Psychology and Aging, 14, 44-59.
Murphy, D. R., Schneider, B. A., Speranza, F., & Moraglia, G. (2006).A comparison of higher order auditory processes in younger and older adults.Psychology and Aging, 21(4), 763-773.
Parker, S., Murphy, D. R., & Schneider, B. A. (2002).Top-down gain control in the auditory system: Evidence from identification and discrimination experiments. Perception and Psychophysics, 64, 598-615.
Schneider, B. A., Daneman, M., & Murphy, D. R. (2005).Speech comprehension difficulties in older adults: Cognitive slowing or age-related changes in hearing?Psychology and Aging,20(2), 261-271.
Schneider, B. A., Daneman, M., Murphy, D. R., & Kwong See, S. (2000). Listening to discourse in distracting settings: The effects of aging.Psychology and Aging, 15, 110-125.