Experimental design: smell of fear


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This slide-show originated at a one-day teaching workshop in January 2011. The event, organised by the Physiological Society was held at the University of Leeds.

The slides describe an activity used with undergraduate students at the University of Leicester, in which a short video "the smell of fear" from the popular (and populist) science programme Brainiac is used to introduce the notion of experimental design. This is used hand-in-hand with discussion of a formal scientific paper on the same topic.

This set of slides is to talk about the activity. There is a second set with a similar title http://www.slideshare.net/cjrw2/experimental-design-the-smell-of-fear which are intended for use by anyone actually using the activity to teach experimental design.

The colour of the background to the slides in the current presentation is significant - the purple slides are ABOUT the activity, the black slides are examples of pages from within the activity.

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Experimental design: smell of fear

  1. 1. Dr Chris Willmott Dept of Biochemistry, University of Leicester [email_address] Experimental design: Can you smell fear? Physiological Society Workshop, January 2011 University of Leicester
  2. 2. Introduction to talk <ul><li>Importance of experimental design </li></ul><ul><li>QAA Benchmark, 2007: “ students should develop competence in comparing the merits of alternative hypotheses and receive guidance in terms of how to construct experiments or to make observations to challenge them ” </li></ul><ul><li>50 minute activity </li></ul><ul><li>Year 1 module (n = 80) </li></ul><ul><li>Combination of video from popular science programme and an open access paper </li></ul>
  3. 3. Introduction to session <ul><li>value of scientific data relies on research being conducted in an appropriate way </li></ul><ul><li>quantity of data is no substitute for quality </li></ul><ul><li>in addition to ‘wrong’ findings there may be cost in terms of time , money and harm if experiment badly designed </li></ul><ul><li>purpose of session = to begin to consider aspects of good (and poor) experimental design </li></ul>Ruxton and Colegrave (2006) 5 mins
  4. 4. The smell of fear <ul><li>watch this short clip describing an experiment to investigate whether you can smell if someone is afraid </li></ul><ul><li>having watched the clip, consider: - what was good about the design of the expt? - what was wrong with the experiment? </li></ul>
  5. 5. The smell of fear Brainiac Science Abuse, Sky1 (28 th January 2009) 2.5 mins
  6. 6. Good aspects of Brainiac expt? <ul><li>included a negative control (no fear, no sport) </li></ul><ul><li>all subjects carried out their activity for same time </li></ul><ul><li>all subjects were “sniffed” by same person </li></ul><ul><li>all subjects were same gender </li></ul><ul><li> … but little else is good </li></ul>3 mins talking to neighbour, 5 mins pooling responses
  7. 7. What was wrong with this expt? <ul><li>only one “sniff-er” </li></ul><ul><li>only three “sweat-ers” </li></ul><ul><li>wasn’t same person on crane/running/relaxing </li></ul><ul><li>distance nose-to-armpit not same in all cases </li></ul><ul><li>may have been other explanations for the observed differences, e.g. </li></ul><ul><ul><li>natural body odour differences between the three </li></ul></ul><ul><ul><li>use of deodorant </li></ul></ul><ul><ul><li>eating of smelly foods </li></ul></ul><ul><li>olfactory fatigue/adaptation may have occurred </li></ul>3 mins confirming their ideas and adding things missed
  8. 8. Design a better version <ul><li>work with those sitting near you to design a better experiment looking into whether it is possible to smell fear </li></ul>8 mins talking to neighbours, 8 mins collecting suggestions
  9. 9. A more scientific approach Prehn-Kristensen et al (2009), PLoS ONE 4(6): e5987 http://tinyurl.com/anxietypaper 15 mins
  10. 10. A more scientific approach <ul><li>Discuss: </li></ul><ul><ul><li>Recruitment of sweat donors (n= 49, controlled for many factors) </li></ul></ul><ul><ul><li>Recruitment of smellers (n=24, controlled for many factors) </li></ul></ul><ul><ul><li>Sweat collection (same people both conditions, same time of day, pooled into 4 groups) </li></ul></ul><ul><ul><li>Odour delivery (modified oxygen mask) </li></ul></ul><ul><ul><li>Data collected (qualitative response and fMRI) </li></ul></ul>
  11. 11. Conclusions <ul><li>Questions about perception : conscious mind did not detect difference anxiety v sport </li></ul><ul><li>fMRI scans : but subconscious mind did demonstrate differences </li></ul><ul><li>Authors consciously recognise limits : findings about anxiety do not necessarily translate to other chemosensory signals </li></ul>
  12. 12. All of the resources available now The Brainiac video (nb long than one used here) http://tinyurl.com/brainiacfear The PLoS ONE paper http://tinyurl.com/anxietypaper The slides for session http://tinyurl.com/fearexperiment Paper describing this activity Introduction to experimental design: can you smell fear? Journal of Biological Education (2011, in press)
  13. 13. Thank you E-mail : [email_address] Twitter : cjrw Slideshare : cjrw2 Delicious : chriswillmott Blogs : www.bioethicsbytes.wordpress.com www.biosciencecareers.wordpress.com www.lefthandedbiochemist.wordpress.com University of Leicester
  14. 14. Evaluation (voluntary online survey) Likert scale from 1= strongly disagree to 5 = strongly agree “ I enjoyed the session on experimental design” Mean = 4.44 “ I found the session on experimental design useful” Mean = 4.25 Lowest score in each case being given by one student who indicated that they “neither agreed not disagreed” in relation to both statements (n=16 students, 20% of cohort)
  15. 15. Evaluation: Open text (1) • The experiment presented was really entertaining. The task of coming up with a more effective experiment was stimulating. • The set up - looking at a particular experiment, discussing among ourselves faults and then discussing as a group the experiment design was good • It encourages me to really think about all the detail that has to go into experimental design and the variety of areas that can be explored in connection with an experiments (sic) design • It raised an interesting discussion about something I had very little ideas about
  16. 16. Evaluation: Open text (2) • It described an experiment that was carried out (not the Hammond experiment but the sweat-collecting experiment) which was complex and professional. This will help to think about future experiments that us as students may like to carry out. • It worked very well, and engaged everyone instead of just talking about how to set up a good study • Engaging, humorous and up-to-date • The Brainiac video was quite amusing and made the lecture interesting • The video broke up the typical structure of a lecture so was fun