Attention and Heart Rate

The hundreds of theories developed by leading psychologists are often daunting and difficult to understand. This is a shame however as many of them carry useful and insightful observations that could be used in our every day lives. Lacey’s theory is one such example and describes the effect that attention has on our heart rates.

Lacey’s hypothesis on intake and rejection (1967) is described by Hahn (1973). Their study was based on empathic listening and visual attention. The theory concerns the deceleration of heart rate due diverting attention towards the environment or carrying out an external task. Alternatively when the environment needs to be rejected to focus attention on internal cues the heart rate accelerates. Jenings cites Lacey and Lacey (1980) as saying the decreased heart rate could serve to make the person more sensitive to new information. This article aims to describe and examine Lacey’s views on attention and culminates in a study that aims to test both aspects of Lacey’s theory to see whether the findings support it.

Attention is conceptualised as showing a certain intensity and duration, by Jennings (1986). Jennings assesses the biological aspects of attention. The autonomic nervous system allocates energy and effort in relation to the information that needs to be processed. This energy comes in the form of enhanced blood flow to events being attended to, and the energy is denied to other events. So in the internal condition, the heart rate is increasing to deny other events and increase blood flow to the brain area needed to complete the task. He discusses how the heart rate decelerates before an anticipated event or just after a significant unexpected event. This means that when psychologically active heart rate is slower, similar to when rejecting information from the environment as the brain needs to be active to do this. If the event is not significant to the person the deceleration will not happen, possibly as they never need actually focus on it. When being assessed with a task the information gains significance so heart rate will decrease.

An alternative view of why heart rate increases is mentioned by Coles (1983). Coles discusses it being regulated in the forebrain area of the cortex, and that it is directly linked with the rate of respiration. It is also stated that arousal and skin conductance is related to heart rate. Coles talks within the text about his 1972 study where he tested Lacey’s intake-rejection hypothesis. Visual search tasks were given to participants with a low and high difficulty rating. The findings were that the heart rates were lower during the low difficulty tasks. This supports Lacey’s findings as the lower difficulty task requires more effort to reject more information, leading to an increased heart rate.

In a real life situation, a person is not always either only listening and performing tasks or only conducting visual tasks. Some tasks require intake and rejection. Coles (1972) cite Lacey and Lacey (1967) where they state that if both conditions are combined there will be no change in heart rate. Coles tested whether searching speed and the amount of letters to search from had an effect on heart rate, if it did this could confound lacey’s findings. It was found that neither had an effect, therefore it is attention alone that affects the heart rate.

A Study…

This study needs to be tested on a modern group as many of these studies were carried out a long time ago. They also need to be carried out on more females dues to the most females in any of these studies being three in Coles’ experiment.

To test Lacey’s hypothesis participants will be connected to an electro-cardio-gram, with electrodes on their sternum and ankle. They will be asked to participate in mental arithmetic tasks to test whether heart rate accelerates for internal attention, and rejection of the environment. There will be both a hard and an easy test as the harder the test is, the environment will need to be rejected more according to lacey’s hypothesis meaning a larger increase in heart rate. To test the suggested deceleration of heart rate a visual search task will be conducted, meaning attention is diverting towards the environment. Again, there will be a hard and easy task as the harder the task, the less of the environment need to be rejected and heart rate should decelerate. The hypothesis for this study is that there will be a bigger increase in heart rate for the harder mental arithmetic task than the easy one, and the heart rate will decelerate more for the hard visual search task than the easy one. The amount of correct answers in the easy and hard conditions will then be compared to make sure that the hard condition is actually harder than the easy condition. The hypothesis is that there will be more correct answers in the easy conditions than the hard conditions due to it being easier.

The Procedure

The experiment was carried out on small groups of about six participants at a time in a laboratory setting. In a room alone was the participant, a timer and the instructor. The rest of the group were in a different room where the ECG was kept, they could see the active members of the group through a blacked out window. The roles were rotated. The participant was asked to wash their sternum and an ankle with cleaning materials provided. Then they attached an electrode to each of the areas they had just washed. The participant was instructed to try to relax and not to move too much, talk or laugh as this may confound the results. The participant was then instructed what each of the four tasks would require them to do and informed that each condition would last for ninety seconds. The timer said ‘go,’ pressed the event recorder button and started the stopwatch. The other instructor then either read out the questions for the mental arithmetic questions so the participant could write the answer down, or gave them the visual search task to circle the letters they were looking for. After the ninety seconds the timer said ‘stop,’ pressed the event recorder button to signal the end of the task on the tachometer, and stopped the stopwatch. The instructor then collected in the answer sheet for the mental arithmetic task or the visual search task. This process was the same for all four tasks, a brief break was had in between tasks. Then the results from the tachometer were analysed for the mean heart rate for each task and the overall number of correct answers was calculated.

Conclusion…

Firstly, it was confirmed that the tasks were at the difficulty level stated to validate the study. The main findings were that when the difficulty of the mental arithmetic tasks increased, the heart rate also did, and when the visual search task’s difficulty increased the heart rate decreased. This supports Lacey’s intake-rejection hypothesis and means that the hypothesis for this study was accepted.

The findings supported Lacey (1967). The theory was tested using different tasks in this study and found the same results, this makes the theory proposed by Lacey more credible. It shows that the findings of the previous study were not just found due to the method used to gather them. Visual search and mental arithmetic clearly test internal and external attention and show the same findings as Lacey found with his method. There was a doubt mentioned by Hahn (1973) that Lacey failed to define the term attention well enough. Meaning that as attention was not defined, the heart rate change could have been caused by a number of factors but Lacey just put it under the general label of attention. Jennings’ (1986) definition of attention was used as a template for this study, and the process was clearly analysed and linked in. This means that how attention was being defined and measured was clearly stated from the start, and allows this study to fairly attribute the change in heart rate to whether internal or external attention is being applied. The findings support Coles (1983), this solely concentrates on the deceleration part of the theory. Both studies used visual search tasks and both found when the task was harder the heart rate was lower due to less of the environment needing to be rejected.

The study lacks ecological validity as being attached to a machine by electrodes is an unusual situation for the participants to find themselves in. It is also unlikely that in a normal situation a person will be only rejecting or only taking in an environment. In Coles (1972), Lacey is cited as saying when a person is simultaneously intaking or rejecting the environment their heart rate remains the same. People are rarely in a situation where this is not the case. Due to being in a strange situation the heart rates may have been higher than usual. If possible a future improvement could be to get participants to do normal tasks throughout the day in their own environment and see how this impacts on heart rate, then link it back to whether the tasks require intake or rejection.

The environment that the experiment was conducted in left it vulnerable to confounding variables. The room was not sound proof meaning that noises could have affected the heart rate of the participants and acted as a distraction. During the study it was possible to hear talking and a car horn was heard from outside. These noises made it difficult to entirely reject the environment and according to Lacey’s hypothesis would affect the heart rate. Due to the study being carried out on participants that knew each other there was distractions where people were making each other laugh, this is not a professional environment and can affect heart rate. There was a lack of consistency in the experiment due to the timer and the instructor changing for every person who partook in the experiment. Varying techniques could affect the results, especially clarity of the mental arithmetic questions being read out. These issues could be rectified in future experiments by having a soundproof room with no windows meaning that no other stimuli can affect the results of the tasks. The participants should do the experiment alone to avoid being influenced by other people, and the instructor and timer should remain the same so that the experiment is the same for everyone.

To avoid generalising these findings to a non student population, further studies should be carried out on different demographics to see if the same results are found. There should be several studies done where people are strictly placed into different groups by age, gender, weight and fitness. The overall results of each group can be compared to see if they support Lacey’s theory. If people have different fitness levels, there could be a confound in the results. A less fit person may have a higher heart rate. When the tasks are completed and the means are taken they will cause the mean to be higher than it possibly should be. This means that the increase in heart rate could be attributed to the person’s fitness more than the task. Splitting people into similar groups will give better, more accurate trends as they will all naturally be performing to a similar standard.

The main findings however remain that when the mental arithmetic task was made more difficult the heart rates increased, and when the visual search task was made harder the heart decreased. This means that rejecting the environment to focus on internal attention causes the heart rate to increase, and focusing on external stimuli causes it to decrease. This supports Lacey’s intake rejection hypothesis.

Mack LeMouse

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