lecture 7 Flashcards
how is sexual dimorohism determined by hormones
Standard paths to genetic diversity: mutation and sex
Sexual dimorphism: determined the instant the egg is fertilised by the sperm cell.
Sex chromosomes: X from egg and XY from sperm, althought genetic mechaisms controlling sex are more complex
Hormones have an organisaiton role in development of sex organs and CNS
Ovaries-Estrogens (estradiol) and progestogens (progesterone)
Testes-androgens (testosterone)
Gonadal development at 6 weeks determined by growth of mullerian (female) and wolffian (male) systems.
Secondary sexual characteristics determined by gonadotropin releasing hormones secreted by cells in hypothalamus
Triggering release of follicle stimulating hormone (FSH) and luteinizing hormone (LH)
Genes determining physical structure and behaviour
which two factors induce arousability
Steroidal hormone action in the brain
Expectations based on experience of sexual activity, desire, arousal and behaviour
what is the role of conditionin in stimulus elicited arousal
Stimulus elicited arousal as an orienting response
Learning allows outbreeding (Verzijden et al., 2012)
Pavlovian associations allowing prediction of sexula outcomes (Pfaus, 2012)
Instrumental responses for sexual rewards
How does imprinting and early experince influence mate preferences?
Theorised that evolution should mean that animals are most attracted to mates that are the opposite to their own genetic makeup, given genetic diversity is optimal.
However this does not seem to be the case, instead early experience determines what male of species is aroused by.
Moreover, in animals males do not invariably respond with greater sexual interest provided by a female
Nyby et al., (1983) male mice
Allen (1934) male grouse
Noble & Vogt (1935) blackbirds
Domjan & Ravert (1991) Japanese Quail (one of the most studied species for sexual learning and discrimination
what is sexual imprinting
Preferences can be elicited by initial context/ fixed action patterns.
Lorenz’s duck - by being present at birth, ducks imprinted on him.
Panda bear - constant interaction with humans produces such flexibility in sexual stimuli that there is confusion about who their species is and who they should mate with
what do banerjee & Regan’s 2014 imprinting study with zebra finches find
Investigated the effect of uniparental rearing by males alone by removing females.
No differences in weight but differences in directed song, nesting and pairing.
Zebra finches raised by male birds tend to mate and nest with other male birds
Those who are ‘female deprived’ have non-specific song behaviour
what does kendrick et al.’s 1998 mating choices study with sheep and goats reveal
Mating choices in sheep and goats are influenced by maternal experience.
Male or female goats or sheep raised with an opposite maternal species and with either other maternal or genetic members.
Both male and females of both species then selected mates that were of the maternal species (females less prone to do this)
Sexual preferences can be based on imprinting - a form of early experience
what does nash and domjan’s japanese quail mating study show
Exposure trains mate choice in Japanese Quail
Males exposed to female japanese quail
Novel female exposure generates long lasting preference
First exposure seems to matter most
Males exposed to males or females - preference for first exposure although still preference for females
what does Graham & Desjardins 1980 study reveal about pavlovian hormone release
Pavlovian learning produces conditioning of hormone response in anticipation of sexual activity
Have to put animal in sexually receptive state through using hormones
Tested 14 male rats in one of 5 treatments: CS-US; CS only; CS/US delay; US only; homecage control.
CS: 14 pairings of methyl salicylate
US: sexualy receptive female rat
Measured physiological responses for luteinizing hormone and testosterone
Strongest, identical response for CS-US and US indicating learning
what does pfaus’s 2012 study of the pavlovian release of dopamine show
CS-US dopamine release in nucleus accumbens in response to three odours paired with sexual reward (Pfaus, 2012)
Different stimuli have different saliences
Dopamine is reward signal for sexual behavior as it is with food and water
what does koksai et al;’s pavlovian conditioning and extinciton study tell us about sign and goal tracking
Showed sexual conditioning to either a light (L) or soft terry cloth (T) in a Japanese quail group where the US is access to a receptive female.
Extinction measures discriminate between approaching behaviour and touching.
T-Contact shows the strongest approach behaviour to the CS.
tactile (salience of cues determine strength of conditioned response)
T-NoContact shows little approach behaviour/touching suggesting this group may be goal trackers.
UP received unpaired T and US.
Sign and goal tracking (focus on stimulus predicting US vs US)
T-Contact don’t show extinction.
Goal trackers maintain behaviour longer than sign trackers.
what does zamble et al.’s 1985 higher order learning study show
Second order creates distance between stimulus we learn about and the goal we receive
Chains of CSs
Experiment 1
injection of estradiol to make females rats sexually receptive
Then males were exposed to pairing of (10min plastic object) with sights, sounds, smells
limited contact but no intromission (10CS—>US)
or unrelated exposure in control group (10CS/US)
Experiment 2:
CS1 was light or plastic object trained as in Experiment 1,
Then CS1 paired with CS2 (no US)
Then test of CS2
CS prepare animals for sexual activity
results show increase in mean ejaculation latency
how can conditioning research be applied (Pfaus et al., 2001)
Sexual counterconditioning: Replacement of natural aversive response using CS-US conditioning
Excitatory conditioning of a naturally aversive odor (CS: cadaver) with US (access to sexually receptive female in oestrus ) results in strong replacement of the aversive response with approach and appetitive behaviours
This result has implications paraphilias suggesting that aversive stimuli can be transformed into appetitive stimuli
what is the role of imprinting on learning in human sexual behaviour
Unclear how experience plays out
Experimental evidence for early experience is sparse but correlative data exist.
Homogamy—matches for physical and personality characteristics between opposite sex parent and current partner (Gyuris et al. 2010) and adoptive parents (Bereczkei et al., 2004).
Early experience with Body features (Rantala et al., 2010), Age (Perret et al, 2002)- for instance age of parents seem correlated with adult preference.
Correlative studies - arousal as an adult taking into account self-report experience and similarity with parents and partners
Seem to be features that carry - body and age etc
what is Hoffman et al.’s 2012 conditioning field study
Lab data may be less effective than real experiences
Introduce CS to couples normal sexual activity - field study
Secretly instructs woman to introduce novel odour on clothing before sex
Following training trials men are presented with CS and novel stimulus
Evidence for conditioned response and this being easy to generate