BIO - Hormones & Pheromones

Hormones

Chemicals released by specific glands in the body to regulate medium- and long-term changes in the body

They are released directly into the bloodstream, yet hormones may act as neurotransmitters and attach to post-synaptic receptor sites when they act on the brain

Our chosen hormone

Cortisol

Doesn’t affect heart rate. Helps control blood sugar, regulate metabolism, reduce inflammation, and assist with memory formation.

!Moderate levels of cortisol help in the consolidation and retrieval of memories!  However, high levels of cortisol - or sustained levels of cortisol - impair memory retrieval.

Cortisol in threatening scenario

Hypothalamic-pituitary-adrenal axis – or HPA axis.

Stimulus threat → hypothalamus responds by activating pituitary gland → releases a hormone that activates the adrenal glands→ cortisol is released into the bloodstream. 

Cortisol dumps glucose into your bloodstream to provide energy — important part in the ‘fight or flight’ response. (Help humans survive in the face of danger so that they can quickly escape an immediate threat)

Hormones - Study

Newcomer et al (1999)

Newcomer et al (1999) AIM

To investigate whether high levels of the stress hormone cortisol interfere with verbal declarative memory.

Newcomer et al (1999) PROCEDURE

Sample: 51 Employees or students at Washington University Medical Centre

4 days - double-bling laboratory experiment. Participants were matched with age and gender to the conditions

1. High level of cortisol (daily pill of 160mg) – major stressor

2. Low level of cortisol (40mg of cortisol) – minor stressor

3. Control condition with identical placebo pill

Participants were asked to listen and recall a paragraph of prose. Each day: 3x with a new equally difficult paragraph of prose.

Participants were tested: BEFORE cortisol, 1 day later, 4 days later, and again 6 days later (no longer taking cortisol)

Newcomer et al (1999) RESULTS

Highest level of cortisol = worst performance in memory task.

However, after stopping the hormone, participants in the high cortisol condition returned to normal. 

No statistical difference between the low dose and placebo groups on any day of testing. Researchers claimed that performance increased over time for these two group due to practice effect or procedural learning

Newcomer et al (1999) FINDINGS 

High cortisol levels impaired memory task performance; however, this change was not permanent. According to Newcomer et al, the results demonstrate a clear link between levels of cortisol and memory performance.

Pheromone

A secreted or excreted chemical factor that triggers a social response in members of the (usually) the same species. In humans, they are called PUTATIVE CHEMICAL CUES, as scientists have yet to identify any human pheromones or a way to process them

Our chosen pheromone

(Androstadienone) AND - male semen and sweat

(Estratetraenol) EST - female urine

→ Effect on attraction however not overtly. Heightens sympathetic arousal, alters levels of cortisol, and promotes a positive mood state in females. AND is found to activate the hypothalamus in heterosexual females and homosexual males, but not in heterosexual males or homosexual females. EST is the female equivalent of this steroid. 

However humans is our lack of a functional vomeronasal organ [VNO] and an accessory olfactory bulb. Without the anatomical ability to detect the scent of a pheromone, it is unclear how a pheromone would affect human behavior.  

Pheromones - Study

Zhou et al. (2014)

Zhou et al. (2014) AIM

To investigate the effect of AND and EST on heterosexual and homosexual men and women

Zhou et al. (2014) PROCEDURE

Sample: 4 groups of 24 of homo or heterosexual men or women

Ps watched stick figures walking on a screen and determined their gender - called teh point light walker tas (PLW). Simultaneously exposed to the smell of cloves. there wer ethree conditions

1) And

2) Est

3) Control

Counterbalancing was donen to control for order effects

Zhou et al. (2014) RESULTS

When hetero FEM and homo MALE were exposed to AND = higher rate of identifying the stick figure as “masculine” than the control group. 

AND had no significant effect on heterosexual men or lesbian women.

When hetero MALE were exposed to EST = they systematically biased toward perceiving the walkers as more feminine. The effect was NOT statistically significant in homo FEM.

Zhou et al (2014) FINDINGS

AND and EST may have some effect on human sexual behavior.

The researchers concluded that pheromones influence the communication of gender information in a sex-specific manner.