PSYC201 Week 5

Invariance problem:

Object perception seems rapid and effortless but it is actually an extremely difficult task. Images of an object can vary widely as the exemplar, viewpoint, and other viewing conditions change.

Structural description model

This model suggests that object perception works by decomposing objects into a set of primitive parts or components with a fixed spatial relationship between them.

Apperceptive visual agnosia

Impaired visual perception of objects despite intact visual acuity and normal perception of basic attributes such as lightness, colour, and motion.

Associative visual agnosia

Impaired visual recognition of objects despite apparently good visual perception of the form or shape of those objects.

Category-selectivity in ventral pathway

The ventral pathway contains a set of visual areas each selective for a particular meaningful category like faces, bodies, scenes, words, and everyday objects.

Prosopagnosia

The inability to recognise faces despite otherwise normal vision and cognition. Prosopagnosia can occur because of brain damage (acquired prosopagnosia) or maldevelopment of the face processing system (developmental prosopagnosia).

Functional implication of prosopagnosia

Prosopagnosia can be accounted by two kinds of functional organisation in the visual system: (1) face processes that are separate but still rely on object-generic processes, or (2) face and object processes that are independent.

Some features of human language:

Discreteness, Arbitrariness, Displacement, Productivity

Discreteness in language…

units of language are set in a fix categories, every speech sound in English is perceived as belonging to one of 40+ phonemes, the way we perceive sound is by classifying the sound into a category. 

Arbitrariness in language…

there is no necessary relationship between actual objects or events in the world and the words that stand for those objects or events. The relationship between should/shape of a word and its meaning is arbitrary. 

Displacement in language…

Language can describe events happening elsewhere (spatial displacement) and events that happened before the moment when the person speaks and events that have no yet happen as the person is speaking (temporal displacement). 

Productivity in language…

Also known as open-endedness or creativity. Human language is continually used to create new expressions and say new things. The potential number of novel utterances in any human language is infinite. 

Behaviourist view of language development:

Language acquisition is driven by domain-general principles of learning and association that explains non linguistic behaviour.

Nativist view of language development: 

Humans are born with language acquisition device (LAD) a specialised cognitive system for leaning language. Some arguments for LAD are that there are consistent developmental milestones and the generalisations/over generalisation of rules. 

Recursion is…

the embedding of a structure within another structure of the same type. Recursion is argued to be a universal feature of human language that is not found in other animal communication systems. 

What are speech sounds?

Rapid fluctuation in air pressure created by the vocal organs. The acoustics of speech can be visualised with a waveform or. A spectrogram the goal of speech perception is to identify words from the acoustic input. 

Three problems in speech perception: 

Segmentation 

Co-articulation 

Talker Variability 

Segmentation in speech perception is…

The lack of consistent mapping between the breaks and the gaps in the acoustic signals with the breaks and the gaps we hear psychologically.  

Co-articulation in speech perception is…  

Seek/Soon both start with /s/ but the acoustics of the s/s is not identical. Seek has a lip position where the lips a e retracted. Soon has a lop position where the lips are protruded. 

Talker variability in speech perception is…

Different people have different vocal tract size and shapes resulting in different acoustics of the same phoneme.  

Categorial perception of langauge…

Adult listeners of a particular language tend to classify the sounds of their languages as one phoneme or another, showing no sensitivity to intermediate sounds. This effect can be shown using identification and discrimination tasks. 

Identification task: 

There are two sounds (ra) (la) which can be morphed and one another, the change from one another is gradual. Listeners identify each sound from a series of stimuli that vary in small, physically equal acoustic steps from one phoneme to another.

Discrimination task: 

Presents two sounds , you must say whether the sounds are the same or different. Pairs of sound stimuli with equal acoustic distances are presented to listeners, and they are asked to discriminate the sound pairs as ‘same’ or ‘different’.

Phonemic restoration effect is…

When there are missing sounds in a sentence your brain can fill in the missing information 

Ganong effect is…

Ambigous phoneme (50-50 sound between /g/ or /k/) can be perceived differently depending on words the sound is used in

Multisensory cues in speech perception…

cues from the auditory system and the visual system are used in speech perception. A classic example is the McGurk effect, in which the same sound is heard differently depending on the movement of the lips.

Semantics and syntax: 

Two key components of language are semantics (the meaning of words and sentences) and syntax (the rules used for constructing sentences). Semantics processing and syntax processing dissociate in aphasia patients 

Wernicke's aphasia: 

Also known as fluent aphasia. Marked by speech that is fluent and grammatically correct but tends to be incoherent. Wernicke’s aphasia is linked to impaired processing of semantics. 

Broca’s aphasia: 

Also known as non-fluent aphasia. Marked by slow/labored speech and jumbled sentences. Patients may also have trouble with sentences that use connecting words. Broca’s aphasia is linked to impaired processing of syntax. 

Lexical ambiguity: 

Some words have multiple meanings some words have meanings that are more dominant and more frequently used. Other words have meaning that are more balanced processing time is longer for words with more balanced meanings. 

Garden path sentences

Sentences that are deisgned to be confusing for the reader 

Approaches to solve the garden path problem: 

Syntax fist approach

Interactionist approach

Syntax first approach is…

 

 Sentence parsing depends primarily on syntax not semantics. One syntax first rule is “late closure” (keep adding words to the current phrase for as long as possible; reconsider only if the sentence no longer makes sense). 

 

Interactionist approach is…

Sentence parsing depends on both syntax and semantics. The meaning of words can influence parsing right from the start. Two sentences with identical structure can be ambiguous or not depending on the meaning of words. 

semantics is…

The meaning of words and sentences

Syntax is…

The rules used for constructing sentences

anaphoric inference about a sentence

occurs when a word refers to something mentioned earlier 

Cataphoric inference about a sentence

occurs when a word refers to something mentioned later 

Situation model for understanding of sentences and stories

When you try to make sense of a story, you come up with a model in your head. You construct a representation in your mind of what is happening in the story.