Individual differences

Question 1

what are the causes of individual differences?

Answer 1

• Neural basis
  - Vision
• Cultural basis
  - Vision
  - Speech Perception
• Emotional factors

Question 2

what are the distributions of S, M and L cones?

Answer 2

• There is quite a lot of variability in the distribution of S, M and L cones between individuals, yet we all seem to be able to process the same range of colours.

Question 3

what is colour deficiency/anomaly?

Answer 3

• Colour deficiency occurs when the cones are not sensitive to the typical range of wavelengths.
• There are three types of colour anomaly: protanopia, deuteranopia, tritanopia.

Question 4

what is colour anomaly?

Answer 4

• When there is a shift in your S, M or L cones’ sensitivities, the colours perceived by a person becomes distorted and some colours cannot be discriminated with others.
• Protanope: shifted L cones’ sensitivity
• Deuteranope: shifted M cones’ sensitivity
• Tritanope: shifted S cones’ sensitivity.

Question 5

what is achromatopsia?

Answer 5

• This is when you do not have colour vision and only see objects in shades of gray.

Question 6

what is prosopagnosia?

Answer 6

• The difficulty with recognising faces.

Question 7

what did Tranel and Damasio 1985 study?

Answer 7

• When the occipito-temporal lobe was lesioned, the patients had difficulty recognising faces, but familiar faces produced different physiological (skin conductance) responses compared to unfamiliar faces.
• Alternatively, when ventro-medial lobe was lesioned, the patients could recognise the faces, but their skin conductance did not differ between familiar and unfamiliar faces.

Question 8

what is Prosopagnosia and Capgras syndrome?

Answer 8

• This is a rare psychiatric disorder where patients believe that someone (spouse or child) has been replaced by an imposter or a double.
• Ellis and Lewis (2001) suggest that this is a “mirror image’ of prosopagnosia in that the patients recognise the face but do not get the feeling of familiarity.

Question 9

what is colour preference?

Answer 9

• Eysenck (1941) suggested a universal preference of colours:
  - Blue > Red > Green > Violet > Orange > Yellow
• Interestingly, most people’s favourite colour is blue, with red and green coming in second. This preference for blue and red extends to three-month old infants (Adams, 1987).
• Primates also a strong preference for blue over red and green (Well et al., 2008).

Question 10

what is the correlation of colour preference across cultures?

Answer 10

• Palmer and Schloss (2010) proposed an Ecological Valence Theory (EVT) that proposes colour preferences are caused by individuals’ emotional experiences with colour-associated objects (Palmer & Schloss, 2010).

Question 11

what did Yokosawa et al. 2016 study?

Answer 11

• Yokosawa et al., (2016) also measured how much participants like objects associated with each colour (WAVEs) and found that EVT played less of a role in Japan compared to the US.
• The authors suggest that perhaps this is because colour preference in Japanese culture is led by symbolism rather than ecology.

Question 12

what did Oishi et al. 2014 study?

Answer 12

• Oishi et al. (2014) conducted 3 studies to explore cultural differences in global versus local processing and their developmental trajectories.
• In their Study 1 (N =363), they found that Japanese college students were less globally oriented in their processing than American or Argentine participants.
• They replicated this effect in Study 2 (N =1,843) using a nationally representative sample of Japanese and American adults aged between 20 and 69.
• They also found that adults in both cultures become more globally oriented with age.
• In Study 3 (N=133), they investigated Japanese and American children, and found cultural differences evident from 4 years of age.
• Cultural variations in global versus local processing emerge in early childhood, and remain throughout adulthood.

Question 13

what are the cultural differences in categorisation?

Answer 13

• Norenzayan et al. (2002) presented European American, Asian American and East Asian participants with a target object and and asked them to judge which of two groups of four objects the target object was most similar to.
• Members shared a large number of features with the target, although not one of these was shared by all the members
• Members shared the same stem as the target object
• FAMILY RESEMBLANCE: Group 1 was holistically more similar to the target.
• RULE:
  Group 2 shared a unidimensional rule with the target
• European Americans perceived similarities based on the unidimensional rule much more often, whereas East Asians more frequently perceived similarities based on holistic judgments of family resemblance. Asian Americans were intermediate.
• There are cultural differences in the way stimuli are compared in the process of categorization.

Question 14

what is the Framed line test?

Answer 14

• Kitayama et al. presented participants were shown a square frame with a vertical line (top centre). They were then shown a new square frame of a different size and were asked to draw a line that was identical to the first line:
  
  • in absolute length (absolute task; bottom left) or
  • in proportion to the surrounding frame (relative task; bottom right)
• The error scores show that American participants were more accurate in the absolute task, whereas Japanese were more accurate in the relative task, suggesting that Japanese were paying more attention to the frame than Americans were.
• East Asian perception seems to be holistic not merely with respect to perception of a single stimulus but with respect to perception of the visual field as a whole.

Question 15

what is the critical period in speech perception?

Answer 15

• For normal language development, children have to be exposed to a rich source of language during this period of flexibility, before the brain has matured. After this period, there is a systematic decline in sensitivity to non-native language stimuli.
• Werker (1989) reported that infants show a decline universal phonetic sensitivity in the during the second half of their first year.

Question 16

what did Miyawaki et al. 1975 study?

Answer 16

• In the Japanese language, [r] snd [l] sounds are not distinguished. So Japanese native speakers would not have learned to discriminate these two sounds.
• Miyawaki et al. (1975) tested 21 Japanese and 39 American adults on their ability discriminate [ra] and [Ia] sounds using a set of synthetic speech-like stimuli.
• Participants were presented with 13 sounds that went from a very clear [ra] at one end to a very [la] at the other.
• The graph below shows how American participants categorised the 13 different sounds. There is a clear shift from hearing [ra] to [la] between sounds 6 and 8: 6 is a clear [ra], 8 is a clear [la], and 7 is more ambiguous.
• The sounds were presented in pairs: 1-4, 2-5, 3-6, etc etc. Participants were asked whether the sounds from each pairs were the same of different. (Same if they could not differentiate , different if they could.)
• There were two conditions:
  - Speech sounds: Participants were told they were presented with speech sounds
  - Non-Speech sounds: Participants were told the sounds were related to speech sounds but they would not sound like speech.

Question 17

what are the phonemic discrimination results?

Answer 17

• For Americans, the discrimination of the speech stimuli was nearly categorical, i.e., comparison pairs which were identified as different phonemes were discriminated with high accuracy, while pairs which were identified as the same phoneme were discriminated relatively poorly.
• In comparison, discrimination of speech stimuli by Japanese subjects was only slightly better than chance for all comparison pairs.

Question 18

what are the non-phonemic discrimination results?

Answer 18

• Performance on nonspeech stimuli, however, was virtually identical for Japanese and American subjects: Both groups showed highly accurate discrimination of all comparison pairs.
• These results suggest that the effect of linguistic experience is specific to perception in the “speech mode.”

Question 19

what is the correlation between social phobias and face perception?

Answer 19

• There are theories that suggest social phobias are associated with hypervigilance to threat and negative emotions, which in turn can worsen social anxiety.
• Horley et al. (2004) examined how participants with and without social phobias scan faces expressing different emotions.
• Results show that participants with social phobias engage in hyperscanning (hypervigilance) and eye avoidance for overt expressions of threat, particularly for angry faces.
• These findings were consistent with theories emphasising the role of information processing biases in social phobia.

Question 20

what is the correlation between optimism and face perception?

Answer 20

• Peters et al. (2015) examined whether optimism is associated with an attentional bias for positive stimuli.
• Participants performed an eye-tracking task twice, while their gazing time at faces displaying joy, anger, pain, or a neutral expression was measured.
• Participants scoring high on optimism (responders) tended to gaze longer at joy faces compared to participants scoring lower on optimism (non-responders).