evaluation

• research support from Sifre (1975) where he found the absence of external cues significantly altered his circadian rhythm, when he returned from an underground stay with no clocks or light, he believed the date to be a month earlier than it actually was, therefore suggesting that his 24 hour sleep wake cycle was increased by the lack of external cues, making him believe one day was longer than it was, and leading to his thinking that fewer days had passed.
• individual differences- Duffy et al (2001) found that 'morning people' prefer to rise and go to bed early (around 6am and 10pm) whereas 'evening people' prefer to wake up and go to bed later (around 10am and 1am), this demonstrates how there may be innate individual differences in circadian rhythms, which suggests that these researchers should focus on these differences during investigations
• Buhr et al (2010)- found that fluctuations in temperature set the timing of cells in the body and caused tissues and organs to become active or inactive, Buhr claimed that information about light levels is transformed into neural messages that set the body's temperature, body temp fluctuates on a 24 hour circadian rhythm and even small changes in it can send a powerful signal to our body clocks. this shows that circadian rhythms are controlled and affected by several different factors, and suggests a more holistic approach to research may be preferable.