The Howard Sheth Model of Buying Behaviour serves two purposes:

1. It indicates how complex the whole question of consumer behaviour is.
2. It provides the framework for including various concepts like learning, perception, attitudes, etc., which play a role in influencing consumer behaviour.

Inputs: In the Howard Sheth theory, the most significant stimulus affecting the buying behaviour are the information cues about the characteristics of the product. These cues may be significant if it comes to the buyer from the product itself when he is involved in a shopping activity. A similar set of cues, which are symbolic in nature, may also act as information sources. Both these significative and symbolic information cues represent the firms marketing efforts. The broad or product characteristics acting as information cues are quality, price, distinctiveness, service and availability.
There are impersonal sources like mass media communications and advertising, over which the firm has no control. However, the information sources also include sales and service personnel who can add and help the marketing efforts of the firm. The third source is social information cues which could affect buying behaviour towards the product or brand and these include family, friends or other members of the group with whom buyer comes into contact or to which he aspires to be in. The social source is personal and the company marketer has no control over this source.

Perceptual Constructs: This refers to all the complex states or psychological processes (perception) and how the individual deals with the information cues received from various sources. It can be seen that all information available is not attended to (attention) and may not always be crystal clear in its meanings
(ambiguity). Although the individual may be engaged in an overt search for information, sometimes he/she may be bombarded with unwanted information. Moreover, any information cues to which the individual may attend may be distorted (perceptual bias) as result of his own frame of reference.

Learning Constructs: The second set of hypothetical constructs in the Howard Sheth model of buying behaviour are more complex and numerous. ‘Motives’ refers to the goals the individual attempts to achieve
through his/her buying behaviour. These goals are derived from the various drives (needs), which may be acting as a cue for his/her motive.

More closely related to the buyers intention in his attitude towards the product/brand. Whether he/she formed a positive attitude towards the product/brand. Other learning constructs include ‘brand comprehension’ i.e.,
knowledge/awareness about the brand characteristic features that forms the basis for the buyers evoked set of alternatives; choice criteria, and the confidence the individual has about his/ her brand comprehension, attitudes, or intentions. Finally, the Howard Sheth model includes a construct, ‘satisfaction’. This refers to ‘feedback’ mechanism, i.e., the post purchase and post use evaluation of the output of the process.

Output: The purchase decision is the output. If after using the product, the consumer is satisfied with it, this will reinforce his positive attitude and purchase intent about the product and brand. Also, the positive attitude makes the consumer more attentive to the product/brand’s stimuli and further increases his brand comprehension.

If the consumer is dissatisfied with experience of using the product/brand, it will trigger off a reaction of negative attitude, low attention to the product stimuli. Poor brand comprehension and negative intention to purchase.

Exogenous or external Variables: Howard Sheth model theory also includes a number of variables, which are not explained but have a bearing on some or all of the constructs discussed above and indirectly
influences the output or consumer response.

1. Social and organizational setting: Man is basically a social animal. Because of his interactions with various groups and society, they look to each other for guidance regarding what to buy, how to buy/dress, etc.

2. Social class: In order to conform to the norms of the social class to which he/she belongs, the individual will be engaged in a behaviour, which will be acceptable to the social class to which it belongs.

3. Culture: refers to the shared, somewhat consistent pattern of behaviour of a group of people. Each culture has a set of beliefs, values, etc. So the pattern of buyer behaviour will be based on a pattern of behaviour shared in a specific subset of a larger culture-a subculture trait.

4. Purchasing power/ Financial status: The money/income available for purchasing goods and services during some specific time period also plays a role in influencing the consumption pattern and thereby his buying behaviour.